michael@0: michael@0: /* png.c - location for general purpose libpng functions michael@0: * michael@0: * Last changed in libpng 1.6.9 [February 6, 2014] michael@0: * Copyright (c) 1998-2014 Glenn Randers-Pehrson michael@0: * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) michael@0: * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) michael@0: * michael@0: * This code is released under the libpng license. michael@0: * For conditions of distribution and use, see the disclaimer michael@0: * and license in png.h michael@0: */ michael@0: michael@0: #include "pngpriv.h" michael@0: michael@0: /* Generate a compiler error if there is an old png.h in the search path. */ michael@0: typedef png_libpng_version_1_6_10 Your_png_h_is_not_version_1_6_10; michael@0: michael@0: /* Tells libpng that we have already handled the first "num_bytes" bytes michael@0: * of the PNG file signature. If the PNG data is embedded into another michael@0: * stream we can set num_bytes = 8 so that libpng will not attempt to read michael@0: * or write any of the magic bytes before it starts on the IHDR. michael@0: */ michael@0: michael@0: #ifdef PNG_READ_SUPPORTED michael@0: void PNGAPI michael@0: png_set_sig_bytes(png_structrp png_ptr, int num_bytes) michael@0: { michael@0: png_debug(1, "in png_set_sig_bytes"); michael@0: michael@0: if (png_ptr == NULL) michael@0: return; michael@0: michael@0: if (num_bytes > 8) michael@0: png_error(png_ptr, "Too many bytes for PNG signature"); michael@0: michael@0: png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes); michael@0: } michael@0: michael@0: /* Checks whether the supplied bytes match the PNG signature. We allow michael@0: * checking less than the full 8-byte signature so that those apps that michael@0: * already read the first few bytes of a file to determine the file type michael@0: * can simply check the remaining bytes for extra assurance. Returns michael@0: * an integer less than, equal to, or greater than zero if sig is found, michael@0: * respectively, to be less than, to match, or be greater than the correct michael@0: * PNG signature (this is the same behavior as strcmp, memcmp, etc). michael@0: */ michael@0: int PNGAPI michael@0: png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check) michael@0: { michael@0: png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; michael@0: michael@0: if (num_to_check > 8) michael@0: num_to_check = 8; michael@0: michael@0: else if (num_to_check < 1) michael@0: return (-1); michael@0: michael@0: if (start > 7) michael@0: return (-1); michael@0: michael@0: if (start + num_to_check > 8) michael@0: num_to_check = 8 - start; michael@0: michael@0: return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check))); michael@0: } michael@0: michael@0: #endif /* PNG_READ_SUPPORTED */ michael@0: michael@0: #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) michael@0: /* Function to allocate memory for zlib */ michael@0: PNG_FUNCTION(voidpf /* PRIVATE */, michael@0: png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED) michael@0: { michael@0: png_alloc_size_t num_bytes = size; michael@0: michael@0: if (png_ptr == NULL) michael@0: return NULL; michael@0: michael@0: if (items >= (~(png_alloc_size_t)0)/size) michael@0: { michael@0: png_warning (png_voidcast(png_structrp, png_ptr), michael@0: "Potential overflow in png_zalloc()"); michael@0: return NULL; michael@0: } michael@0: michael@0: num_bytes *= items; michael@0: return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes); michael@0: } michael@0: michael@0: /* Function to free memory for zlib */ michael@0: void /* PRIVATE */ michael@0: png_zfree(voidpf png_ptr, voidpf ptr) michael@0: { michael@0: png_free(png_voidcast(png_const_structrp,png_ptr), ptr); michael@0: } michael@0: michael@0: /* Reset the CRC variable to 32 bits of 1's. Care must be taken michael@0: * in case CRC is > 32 bits to leave the top bits 0. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_reset_crc(png_structrp png_ptr) michael@0: { michael@0: /* The cast is safe because the crc is a 32 bit value. */ michael@0: png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0); michael@0: } michael@0: michael@0: /* Calculate the CRC over a section of data. We can only pass as michael@0: * much data to this routine as the largest single buffer size. We michael@0: * also check that this data will actually be used before going to the michael@0: * trouble of calculating it. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length) michael@0: { michael@0: int need_crc = 1; michael@0: michael@0: if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)) michael@0: { michael@0: if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == michael@0: (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) michael@0: need_crc = 0; michael@0: } michael@0: michael@0: else /* critical */ michael@0: { michael@0: if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) michael@0: need_crc = 0; michael@0: } michael@0: michael@0: /* 'uLong' is defined in zlib.h as unsigned long; this means that on some michael@0: * systems it is a 64 bit value. crc32, however, returns 32 bits so the michael@0: * following cast is safe. 'uInt' may be no more than 16 bits, so it is michael@0: * necessary to perform a loop here. michael@0: */ michael@0: if (need_crc && length > 0) michael@0: { michael@0: uLong crc = png_ptr->crc; /* Should never issue a warning */ michael@0: michael@0: do michael@0: { michael@0: uInt safe_length = (uInt)length; michael@0: if (safe_length == 0) michael@0: safe_length = (uInt)-1; /* evil, but safe */ michael@0: michael@0: crc = crc32(crc, ptr, safe_length); michael@0: michael@0: /* The following should never issue compiler warnings; if they do the michael@0: * target system has characteristics that will probably violate other michael@0: * assumptions within the libpng code. michael@0: */ michael@0: ptr += safe_length; michael@0: length -= safe_length; michael@0: } michael@0: while (length > 0); michael@0: michael@0: /* And the following is always safe because the crc is only 32 bits. */ michael@0: png_ptr->crc = (png_uint_32)crc; michael@0: } michael@0: } michael@0: michael@0: /* Check a user supplied version number, called from both read and write michael@0: * functions that create a png_struct. michael@0: */ michael@0: int michael@0: png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver) michael@0: { michael@0: if (user_png_ver) michael@0: { michael@0: int i = 0; michael@0: michael@0: do michael@0: { michael@0: if (user_png_ver[i] != png_libpng_ver[i]) michael@0: png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; michael@0: } while (png_libpng_ver[i++]); michael@0: } michael@0: michael@0: else michael@0: png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; michael@0: michael@0: if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) michael@0: { michael@0: /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so michael@0: * we must recompile any applications that use any older library version. michael@0: * For versions after libpng 1.0, we will be compatible, so we need michael@0: * only check the first and third digits (note that when we reach version michael@0: * 1.10 we will need to check the fourth symbol, namely user_png_ver[3]). michael@0: */ michael@0: if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] || michael@0: (user_png_ver[0] == '1' && (user_png_ver[2] != png_libpng_ver[2] || michael@0: user_png_ver[3] != png_libpng_ver[3])) || michael@0: (user_png_ver[0] == '0' && user_png_ver[2] < '9')) michael@0: { michael@0: #ifdef PNG_WARNINGS_SUPPORTED michael@0: size_t pos = 0; michael@0: char m[128]; michael@0: michael@0: pos = png_safecat(m, (sizeof m), pos, michael@0: "Application built with libpng-"); michael@0: pos = png_safecat(m, (sizeof m), pos, user_png_ver); michael@0: pos = png_safecat(m, (sizeof m), pos, " but running with "); michael@0: pos = png_safecat(m, (sizeof m), pos, png_libpng_ver); michael@0: PNG_UNUSED(pos) michael@0: michael@0: png_warning(png_ptr, m); michael@0: #endif michael@0: michael@0: #ifdef PNG_ERROR_NUMBERS_SUPPORTED michael@0: png_ptr->flags = 0; michael@0: #endif michael@0: michael@0: return 0; michael@0: } michael@0: } michael@0: michael@0: /* Success return. */ michael@0: return 1; michael@0: } michael@0: michael@0: /* Generic function to create a png_struct for either read or write - this michael@0: * contains the common initialization. michael@0: */ michael@0: PNG_FUNCTION(png_structp /* PRIVATE */, michael@0: png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr, michael@0: png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, michael@0: png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) michael@0: { michael@0: png_struct create_struct; michael@0: # ifdef PNG_SETJMP_SUPPORTED michael@0: jmp_buf create_jmp_buf; michael@0: # endif michael@0: michael@0: /* This temporary stack-allocated structure is used to provide a place to michael@0: * build enough context to allow the user provided memory allocator (if any) michael@0: * to be called. michael@0: */ michael@0: memset(&create_struct, 0, (sizeof create_struct)); michael@0: michael@0: /* Added at libpng-1.2.6 */ michael@0: # ifdef PNG_USER_LIMITS_SUPPORTED michael@0: create_struct.user_width_max = PNG_USER_WIDTH_MAX; michael@0: create_struct.user_height_max = PNG_USER_HEIGHT_MAX; michael@0: michael@0: # ifdef PNG_USER_CHUNK_CACHE_MAX michael@0: /* Added at libpng-1.2.43 and 1.4.0 */ michael@0: create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX; michael@0: # endif michael@0: michael@0: # ifdef PNG_USER_CHUNK_MALLOC_MAX michael@0: /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists michael@0: * in png_struct regardless. michael@0: */ michael@0: create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX; michael@0: # endif michael@0: # endif michael@0: michael@0: /* The following two API calls simply set fields in png_struct, so it is safe michael@0: * to do them now even though error handling is not yet set up. michael@0: */ michael@0: # ifdef PNG_USER_MEM_SUPPORTED michael@0: png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn); michael@0: # else michael@0: PNG_UNUSED(mem_ptr) michael@0: PNG_UNUSED(malloc_fn) michael@0: PNG_UNUSED(free_fn) michael@0: # endif michael@0: michael@0: /* (*error_fn) can return control to the caller after the error_ptr is set, michael@0: * this will result in a memory leak unless the error_fn does something michael@0: * extremely sophisticated. The design lacks merit but is implicit in the michael@0: * API. michael@0: */ michael@0: png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn); michael@0: michael@0: # ifdef PNG_SETJMP_SUPPORTED michael@0: if (!setjmp(create_jmp_buf)) michael@0: { michael@0: /* Temporarily fake out the longjmp information until we have michael@0: * successfully completed this function. This only works if we have michael@0: * setjmp() support compiled in, but it is safe - this stuff should michael@0: * never happen. michael@0: */ michael@0: create_struct.jmp_buf_ptr = &create_jmp_buf; michael@0: create_struct.jmp_buf_size = 0; /*stack allocation*/ michael@0: create_struct.longjmp_fn = longjmp; michael@0: # else michael@0: { michael@0: # endif michael@0: /* Call the general version checker (shared with read and write code): michael@0: */ michael@0: if (png_user_version_check(&create_struct, user_png_ver)) michael@0: { michael@0: png_structrp png_ptr = png_voidcast(png_structrp, michael@0: png_malloc_warn(&create_struct, (sizeof *png_ptr))); michael@0: michael@0: if (png_ptr != NULL) michael@0: { michael@0: /* png_ptr->zstream holds a back-pointer to the png_struct, so michael@0: * this can only be done now: michael@0: */ michael@0: create_struct.zstream.zalloc = png_zalloc; michael@0: create_struct.zstream.zfree = png_zfree; michael@0: create_struct.zstream.opaque = png_ptr; michael@0: michael@0: # ifdef PNG_SETJMP_SUPPORTED michael@0: /* Eliminate the local error handling: */ michael@0: create_struct.jmp_buf_ptr = NULL; michael@0: create_struct.jmp_buf_size = 0; michael@0: create_struct.longjmp_fn = 0; michael@0: # endif michael@0: michael@0: *png_ptr = create_struct; michael@0: michael@0: /* This is the successful return point */ michael@0: return png_ptr; michael@0: } michael@0: } michael@0: } michael@0: michael@0: /* A longjmp because of a bug in the application storage allocator or a michael@0: * simple failure to allocate the png_struct. michael@0: */ michael@0: return NULL; michael@0: } michael@0: michael@0: /* Allocate the memory for an info_struct for the application. */ michael@0: PNG_FUNCTION(png_infop,PNGAPI michael@0: png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED) michael@0: { michael@0: png_inforp info_ptr; michael@0: michael@0: png_debug(1, "in png_create_info_struct"); michael@0: michael@0: if (png_ptr == NULL) michael@0: return NULL; michael@0: michael@0: /* Use the internal API that does not (or at least should not) error out, so michael@0: * that this call always returns ok. The application typically sets up the michael@0: * error handling *after* creating the info_struct because this is the way it michael@0: * has always been done in 'example.c'. michael@0: */ michael@0: info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr, michael@0: (sizeof *info_ptr))); michael@0: michael@0: if (info_ptr != NULL) michael@0: memset(info_ptr, 0, (sizeof *info_ptr)); michael@0: michael@0: return info_ptr; michael@0: } michael@0: michael@0: /* This function frees the memory associated with a single info struct. michael@0: * Normally, one would use either png_destroy_read_struct() or michael@0: * png_destroy_write_struct() to free an info struct, but this may be michael@0: * useful for some applications. From libpng 1.6.0 this function is also used michael@0: * internally to implement the png_info release part of the 'struct' destroy michael@0: * APIs. This ensures that all possible approaches free the same data (all of michael@0: * it). michael@0: */ michael@0: void PNGAPI michael@0: png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr) michael@0: { michael@0: png_inforp info_ptr = NULL; michael@0: michael@0: png_debug(1, "in png_destroy_info_struct"); michael@0: michael@0: if (png_ptr == NULL) michael@0: return; michael@0: michael@0: if (info_ptr_ptr != NULL) michael@0: info_ptr = *info_ptr_ptr; michael@0: michael@0: if (info_ptr != NULL) michael@0: { michael@0: /* Do this first in case of an error below; if the app implements its own michael@0: * memory management this can lead to png_free calling png_error, which michael@0: * will abort this routine and return control to the app error handler. michael@0: * An infinite loop may result if it then tries to free the same info michael@0: * ptr. michael@0: */ michael@0: *info_ptr_ptr = NULL; michael@0: michael@0: png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); michael@0: memset(info_ptr, 0, (sizeof *info_ptr)); michael@0: png_free(png_ptr, info_ptr); michael@0: } michael@0: } michael@0: michael@0: /* Initialize the info structure. This is now an internal function (0.89) michael@0: * and applications using it are urged to use png_create_info_struct() michael@0: * instead. Use deprecated in 1.6.0, internal use removed (used internally it michael@0: * is just a memset). michael@0: * michael@0: * NOTE: it is almost inconceivable that this API is used because it bypasses michael@0: * the user-memory mechanism and the user error handling/warning mechanisms in michael@0: * those cases where it does anything other than a memset. michael@0: */ michael@0: PNG_FUNCTION(void,PNGAPI michael@0: png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size), michael@0: PNG_DEPRECATED) michael@0: { michael@0: png_inforp info_ptr = *ptr_ptr; michael@0: michael@0: png_debug(1, "in png_info_init_3"); michael@0: michael@0: if (info_ptr == NULL) michael@0: return; michael@0: michael@0: if ((sizeof (png_info)) > png_info_struct_size) michael@0: { michael@0: *ptr_ptr = NULL; michael@0: /* The following line is why this API should not be used: */ michael@0: free(info_ptr); michael@0: info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL, michael@0: (sizeof *info_ptr))); michael@0: *ptr_ptr = info_ptr; michael@0: } michael@0: michael@0: /* Set everything to 0 */ michael@0: memset(info_ptr, 0, (sizeof *info_ptr)); michael@0: } michael@0: michael@0: /* The following API is not called internally */ michael@0: void PNGAPI michael@0: png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr, michael@0: int freer, png_uint_32 mask) michael@0: { michael@0: png_debug(1, "in png_data_freer"); michael@0: michael@0: if (png_ptr == NULL || info_ptr == NULL) michael@0: return; michael@0: michael@0: if (freer == PNG_DESTROY_WILL_FREE_DATA) michael@0: info_ptr->free_me |= mask; michael@0: michael@0: else if (freer == PNG_USER_WILL_FREE_DATA) michael@0: info_ptr->free_me &= ~mask; michael@0: michael@0: else michael@0: png_error(png_ptr, "Unknown freer parameter in png_data_freer"); michael@0: } michael@0: michael@0: void PNGAPI michael@0: png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask, michael@0: int num) michael@0: { michael@0: png_debug(1, "in png_free_data"); michael@0: michael@0: if (png_ptr == NULL || info_ptr == NULL) michael@0: return; michael@0: michael@0: #ifdef PNG_TEXT_SUPPORTED michael@0: /* Free text item num or (if num == -1) all text items */ michael@0: if ((mask & PNG_FREE_TEXT) & info_ptr->free_me) michael@0: { michael@0: if (num != -1) michael@0: { michael@0: if (info_ptr->text && info_ptr->text[num].key) michael@0: { michael@0: png_free(png_ptr, info_ptr->text[num].key); michael@0: info_ptr->text[num].key = NULL; michael@0: } michael@0: } michael@0: michael@0: else michael@0: { michael@0: int i; michael@0: for (i = 0; i < info_ptr->num_text; i++) michael@0: png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i); michael@0: png_free(png_ptr, info_ptr->text); michael@0: info_ptr->text = NULL; michael@0: info_ptr->num_text=0; michael@0: } michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_tRNS_SUPPORTED michael@0: /* Free any tRNS entry */ michael@0: if ((mask & PNG_FREE_TRNS) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->trans_alpha); michael@0: info_ptr->trans_alpha = NULL; michael@0: info_ptr->valid &= ~PNG_INFO_tRNS; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_sCAL_SUPPORTED michael@0: /* Free any sCAL entry */ michael@0: if ((mask & PNG_FREE_SCAL) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->scal_s_width); michael@0: png_free(png_ptr, info_ptr->scal_s_height); michael@0: info_ptr->scal_s_width = NULL; michael@0: info_ptr->scal_s_height = NULL; michael@0: info_ptr->valid &= ~PNG_INFO_sCAL; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_pCAL_SUPPORTED michael@0: /* Free any pCAL entry */ michael@0: if ((mask & PNG_FREE_PCAL) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->pcal_purpose); michael@0: png_free(png_ptr, info_ptr->pcal_units); michael@0: info_ptr->pcal_purpose = NULL; michael@0: info_ptr->pcal_units = NULL; michael@0: if (info_ptr->pcal_params != NULL) michael@0: { michael@0: unsigned int i; michael@0: for (i = 0; i < info_ptr->pcal_nparams; i++) michael@0: { michael@0: png_free(png_ptr, info_ptr->pcal_params[i]); michael@0: info_ptr->pcal_params[i] = NULL; michael@0: } michael@0: png_free(png_ptr, info_ptr->pcal_params); michael@0: info_ptr->pcal_params = NULL; michael@0: } michael@0: info_ptr->valid &= ~PNG_INFO_pCAL; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_iCCP_SUPPORTED michael@0: /* Free any profile entry */ michael@0: if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->iccp_name); michael@0: png_free(png_ptr, info_ptr->iccp_profile); michael@0: info_ptr->iccp_name = NULL; michael@0: info_ptr->iccp_profile = NULL; michael@0: info_ptr->valid &= ~PNG_INFO_iCCP; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_sPLT_SUPPORTED michael@0: /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ michael@0: if ((mask & PNG_FREE_SPLT) & info_ptr->free_me) michael@0: { michael@0: if (num != -1) michael@0: { michael@0: if (info_ptr->splt_palettes) michael@0: { michael@0: png_free(png_ptr, info_ptr->splt_palettes[num].name); michael@0: png_free(png_ptr, info_ptr->splt_palettes[num].entries); michael@0: info_ptr->splt_palettes[num].name = NULL; michael@0: info_ptr->splt_palettes[num].entries = NULL; michael@0: } michael@0: } michael@0: michael@0: else michael@0: { michael@0: if (info_ptr->splt_palettes_num) michael@0: { michael@0: int i; michael@0: for (i = 0; i < info_ptr->splt_palettes_num; i++) michael@0: png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, (int)i); michael@0: michael@0: png_free(png_ptr, info_ptr->splt_palettes); michael@0: info_ptr->splt_palettes = NULL; michael@0: info_ptr->splt_palettes_num = 0; michael@0: } michael@0: info_ptr->valid &= ~PNG_INFO_sPLT; michael@0: } michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED michael@0: if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) michael@0: { michael@0: if (num != -1) michael@0: { michael@0: if (info_ptr->unknown_chunks) michael@0: { michael@0: png_free(png_ptr, info_ptr->unknown_chunks[num].data); michael@0: info_ptr->unknown_chunks[num].data = NULL; michael@0: } michael@0: } michael@0: michael@0: else michael@0: { michael@0: int i; michael@0: michael@0: if (info_ptr->unknown_chunks_num) michael@0: { michael@0: for (i = 0; i < info_ptr->unknown_chunks_num; i++) michael@0: png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, (int)i); michael@0: michael@0: png_free(png_ptr, info_ptr->unknown_chunks); michael@0: info_ptr->unknown_chunks = NULL; michael@0: info_ptr->unknown_chunks_num = 0; michael@0: } michael@0: } michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_hIST_SUPPORTED michael@0: /* Free any hIST entry */ michael@0: if ((mask & PNG_FREE_HIST) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->hist); michael@0: info_ptr->hist = NULL; michael@0: info_ptr->valid &= ~PNG_INFO_hIST; michael@0: } michael@0: #endif michael@0: michael@0: /* Free any PLTE entry that was internally allocated */ michael@0: if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) michael@0: { michael@0: png_free(png_ptr, info_ptr->palette); michael@0: info_ptr->palette = NULL; michael@0: info_ptr->valid &= ~PNG_INFO_PLTE; michael@0: info_ptr->num_palette = 0; michael@0: } michael@0: michael@0: #ifdef PNG_INFO_IMAGE_SUPPORTED michael@0: /* Free any image bits attached to the info structure */ michael@0: if ((mask & PNG_FREE_ROWS) & info_ptr->free_me) michael@0: { michael@0: if (info_ptr->row_pointers) michael@0: { michael@0: png_uint_32 row; michael@0: for (row = 0; row < info_ptr->height; row++) michael@0: { michael@0: png_free(png_ptr, info_ptr->row_pointers[row]); michael@0: info_ptr->row_pointers[row] = NULL; michael@0: } michael@0: png_free(png_ptr, info_ptr->row_pointers); michael@0: info_ptr->row_pointers = NULL; michael@0: } michael@0: info_ptr->valid &= ~PNG_INFO_IDAT; michael@0: } michael@0: #endif michael@0: michael@0: if (num != -1) michael@0: mask &= ~PNG_FREE_MUL; michael@0: michael@0: info_ptr->free_me &= ~mask; michael@0: } michael@0: #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ michael@0: michael@0: /* This function returns a pointer to the io_ptr associated with the user michael@0: * functions. The application should free any memory associated with this michael@0: * pointer before png_write_destroy() or png_read_destroy() are called. michael@0: */ michael@0: png_voidp PNGAPI michael@0: png_get_io_ptr(png_const_structrp png_ptr) michael@0: { michael@0: if (png_ptr == NULL) michael@0: return (NULL); michael@0: michael@0: return (png_ptr->io_ptr); michael@0: } michael@0: michael@0: #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) michael@0: # ifdef PNG_STDIO_SUPPORTED michael@0: /* Initialize the default input/output functions for the PNG file. If you michael@0: * use your own read or write routines, you can call either png_set_read_fn() michael@0: * or png_set_write_fn() instead of png_init_io(). If you have defined michael@0: * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a michael@0: * function of your own because "FILE *" isn't necessarily available. michael@0: */ michael@0: void PNGAPI michael@0: png_init_io(png_structrp png_ptr, png_FILE_p fp) michael@0: { michael@0: png_debug(1, "in png_init_io"); michael@0: michael@0: if (png_ptr == NULL) michael@0: return; michael@0: michael@0: png_ptr->io_ptr = (png_voidp)fp; michael@0: } michael@0: # endif michael@0: michael@0: #ifdef PNG_SAVE_INT_32_SUPPORTED michael@0: /* The png_save_int_32 function assumes integers are stored in two's michael@0: * complement format. If this isn't the case, then this routine needs to michael@0: * be modified to write data in two's complement format. Note that, michael@0: * the following works correctly even if png_int_32 has more than 32 bits michael@0: * (compare the more complex code required on read for sign extension.) michael@0: */ michael@0: void PNGAPI michael@0: png_save_int_32(png_bytep buf, png_int_32 i) michael@0: { michael@0: buf[0] = (png_byte)((i >> 24) & 0xff); michael@0: buf[1] = (png_byte)((i >> 16) & 0xff); michael@0: buf[2] = (png_byte)((i >> 8) & 0xff); michael@0: buf[3] = (png_byte)(i & 0xff); michael@0: } michael@0: #endif michael@0: michael@0: # ifdef PNG_TIME_RFC1123_SUPPORTED michael@0: /* Convert the supplied time into an RFC 1123 string suitable for use in michael@0: * a "Creation Time" or other text-based time string. michael@0: */ michael@0: int PNGAPI michael@0: png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime) michael@0: { michael@0: static PNG_CONST char short_months[12][4] = michael@0: {"Jan", "Feb", "Mar", "Apr", "May", "Jun", michael@0: "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; michael@0: michael@0: if (out == NULL) michael@0: return 0; michael@0: michael@0: if (ptime->year > 9999 /* RFC1123 limitation */ || michael@0: ptime->month == 0 || ptime->month > 12 || michael@0: ptime->day == 0 || ptime->day > 31 || michael@0: ptime->hour > 23 || ptime->minute > 59 || michael@0: ptime->second > 60) michael@0: return 0; michael@0: michael@0: { michael@0: size_t pos = 0; michael@0: char number_buf[5]; /* enough for a four-digit year */ michael@0: michael@0: # define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string)) michael@0: # define APPEND_NUMBER(format, value)\ michael@0: APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value))) michael@0: # define APPEND(ch) if (pos < 28) out[pos++] = (ch) michael@0: michael@0: APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day); michael@0: APPEND(' '); michael@0: APPEND_STRING(short_months[(ptime->month - 1)]); michael@0: APPEND(' '); michael@0: APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year); michael@0: APPEND(' '); michael@0: APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour); michael@0: APPEND(':'); michael@0: APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute); michael@0: APPEND(':'); michael@0: APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second); michael@0: APPEND_STRING(" +0000"); /* This reliably terminates the buffer */ michael@0: michael@0: # undef APPEND michael@0: # undef APPEND_NUMBER michael@0: # undef APPEND_STRING michael@0: } michael@0: michael@0: return 1; michael@0: } michael@0: michael@0: # if PNG_LIBPNG_VER < 10700 michael@0: /* To do: remove the following from libpng-1.7 */ michael@0: /* Original API that uses a private buffer in png_struct. michael@0: * Deprecated because it causes png_struct to carry a spurious temporary michael@0: * buffer (png_struct::time_buffer), better to have the caller pass this in. michael@0: */ michael@0: png_const_charp PNGAPI michael@0: png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime) michael@0: { michael@0: if (png_ptr != NULL) michael@0: { michael@0: /* The only failure above if png_ptr != NULL is from an invalid ptime */ michael@0: if (!png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime)) michael@0: png_warning(png_ptr, "Ignoring invalid time value"); michael@0: michael@0: else michael@0: return png_ptr->time_buffer; michael@0: } michael@0: michael@0: return NULL; michael@0: } michael@0: # endif michael@0: # endif /* PNG_TIME_RFC1123_SUPPORTED */ michael@0: michael@0: #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ michael@0: michael@0: png_const_charp PNGAPI michael@0: png_get_copyright(png_const_structrp png_ptr) michael@0: { michael@0: PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ michael@0: #ifdef PNG_STRING_COPYRIGHT michael@0: return PNG_STRING_COPYRIGHT michael@0: #else michael@0: # ifdef __STDC__ michael@0: return PNG_STRING_NEWLINE \ michael@0: "libpng version 1.6.10 - March 6, 2014" PNG_STRING_NEWLINE \ michael@0: "Copyright (c) 1998-2014 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ michael@0: "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ michael@0: "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ michael@0: PNG_STRING_NEWLINE; michael@0: # else michael@0: return "libpng version 1.6.10 - March 6, 2014\ michael@0: Copyright (c) 1998-2014 Glenn Randers-Pehrson\ michael@0: Copyright (c) 1996-1997 Andreas Dilger\ michael@0: Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; michael@0: # endif michael@0: #endif michael@0: } michael@0: michael@0: /* The following return the library version as a short string in the michael@0: * format 1.0.0 through 99.99.99zz. To get the version of *.h files michael@0: * used with your application, print out PNG_LIBPNG_VER_STRING, which michael@0: * is defined in png.h. michael@0: * Note: now there is no difference between png_get_libpng_ver() and michael@0: * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, michael@0: * it is guaranteed that png.c uses the correct version of png.h. michael@0: */ michael@0: png_const_charp PNGAPI michael@0: png_get_libpng_ver(png_const_structrp png_ptr) michael@0: { michael@0: /* Version of *.c files used when building libpng */ michael@0: return png_get_header_ver(png_ptr); michael@0: } michael@0: michael@0: png_const_charp PNGAPI michael@0: png_get_header_ver(png_const_structrp png_ptr) michael@0: { michael@0: /* Version of *.h files used when building libpng */ michael@0: PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ michael@0: return PNG_LIBPNG_VER_STRING; michael@0: } michael@0: michael@0: png_const_charp PNGAPI michael@0: png_get_header_version(png_const_structrp png_ptr) michael@0: { michael@0: /* Returns longer string containing both version and date */ michael@0: PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ michael@0: #ifdef __STDC__ michael@0: return PNG_HEADER_VERSION_STRING michael@0: # ifndef PNG_READ_SUPPORTED michael@0: " (NO READ SUPPORT)" michael@0: # endif michael@0: PNG_STRING_NEWLINE; michael@0: #else michael@0: return PNG_HEADER_VERSION_STRING; michael@0: #endif michael@0: } michael@0: michael@0: #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED michael@0: /* NOTE: this routine is not used internally! */ michael@0: /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth michael@0: * large of png_color. This lets grayscale images be treated as michael@0: * paletted. Most useful for gamma correction and simplification michael@0: * of code. This API is not used internally. michael@0: */ michael@0: void PNGAPI michael@0: png_build_grayscale_palette(int bit_depth, png_colorp palette) michael@0: { michael@0: int num_palette; michael@0: int color_inc; michael@0: int i; michael@0: int v; michael@0: michael@0: png_debug(1, "in png_do_build_grayscale_palette"); michael@0: michael@0: if (palette == NULL) michael@0: return; michael@0: michael@0: switch (bit_depth) michael@0: { michael@0: case 1: michael@0: num_palette = 2; michael@0: color_inc = 0xff; michael@0: break; michael@0: michael@0: case 2: michael@0: num_palette = 4; michael@0: color_inc = 0x55; michael@0: break; michael@0: michael@0: case 4: michael@0: num_palette = 16; michael@0: color_inc = 0x11; michael@0: break; michael@0: michael@0: case 8: michael@0: num_palette = 256; michael@0: color_inc = 1; michael@0: break; michael@0: michael@0: default: michael@0: num_palette = 0; michael@0: color_inc = 0; michael@0: break; michael@0: } michael@0: michael@0: for (i = 0, v = 0; i < num_palette; i++, v += color_inc) michael@0: { michael@0: palette[i].red = (png_byte)v; michael@0: palette[i].green = (png_byte)v; michael@0: palette[i].blue = (png_byte)v; michael@0: } michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED michael@0: int PNGAPI michael@0: png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name) michael@0: { michael@0: /* Check chunk_name and return "keep" value if it's on the list, else 0 */ michael@0: png_const_bytep p, p_end; michael@0: michael@0: if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0) michael@0: return PNG_HANDLE_CHUNK_AS_DEFAULT; michael@0: michael@0: p_end = png_ptr->chunk_list; michael@0: p = p_end + png_ptr->num_chunk_list*5; /* beyond end */ michael@0: michael@0: /* The code is the fifth byte after each four byte string. Historically this michael@0: * code was always searched from the end of the list, this is no longer michael@0: * necessary because the 'set' routine handles duplicate entries correcty. michael@0: */ michael@0: do /* num_chunk_list > 0, so at least one */ michael@0: { michael@0: p -= 5; michael@0: michael@0: if (!memcmp(chunk_name, p, 4)) michael@0: return p[4]; michael@0: } michael@0: while (p > p_end); michael@0: michael@0: /* This means that known chunks should be processed and unknown chunks should michael@0: * be handled according to the value of png_ptr->unknown_default; this can be michael@0: * confusing because, as a result, there are two levels of defaulting for michael@0: * unknown chunks. michael@0: */ michael@0: return PNG_HANDLE_CHUNK_AS_DEFAULT; michael@0: } michael@0: michael@0: #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\ michael@0: defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED) michael@0: int /* PRIVATE */ michael@0: png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name) michael@0: { michael@0: png_byte chunk_string[5]; michael@0: michael@0: PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name); michael@0: return png_handle_as_unknown(png_ptr, chunk_string); michael@0: } michael@0: #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */ michael@0: #endif /* SET_UNKNOWN_CHUNKS */ michael@0: michael@0: #ifdef PNG_READ_SUPPORTED michael@0: /* This function, added to libpng-1.0.6g, is untested. */ michael@0: int PNGAPI michael@0: png_reset_zstream(png_structrp png_ptr) michael@0: { michael@0: if (png_ptr == NULL) michael@0: return Z_STREAM_ERROR; michael@0: michael@0: /* WARNING: this resets the window bits to the maximum! */ michael@0: return (inflateReset(&png_ptr->zstream)); michael@0: } michael@0: #endif /* PNG_READ_SUPPORTED */ michael@0: michael@0: /* This function was added to libpng-1.0.7 */ michael@0: png_uint_32 PNGAPI michael@0: png_access_version_number(void) michael@0: { michael@0: /* Version of *.c files used when building libpng */ michael@0: return((png_uint_32)PNG_LIBPNG_VER); michael@0: } michael@0: michael@0: michael@0: michael@0: #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) michael@0: /* Ensure that png_ptr->zstream.msg holds some appropriate error message string. michael@0: * If it doesn't 'ret' is used to set it to something appropriate, even in cases michael@0: * like Z_OK or Z_STREAM_END where the error code is apparently a success code. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_zstream_error(png_structrp png_ptr, int ret) michael@0: { michael@0: /* Translate 'ret' into an appropriate error string, priority is given to the michael@0: * one in zstream if set. This always returns a string, even in cases like michael@0: * Z_OK or Z_STREAM_END where the error code is a success code. michael@0: */ michael@0: if (png_ptr->zstream.msg == NULL) switch (ret) michael@0: { michael@0: default: michael@0: case Z_OK: michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code"); michael@0: break; michael@0: michael@0: case Z_STREAM_END: michael@0: /* Normal exit */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream"); michael@0: break; michael@0: michael@0: case Z_NEED_DICT: michael@0: /* This means the deflate stream did not have a dictionary; this michael@0: * indicates a bogus PNG. michael@0: */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary"); michael@0: break; michael@0: michael@0: case Z_ERRNO: michael@0: /* gz APIs only: should not happen */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error"); michael@0: break; michael@0: michael@0: case Z_STREAM_ERROR: michael@0: /* internal libpng error */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib"); michael@0: break; michael@0: michael@0: case Z_DATA_ERROR: michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream"); michael@0: break; michael@0: michael@0: case Z_MEM_ERROR: michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory"); michael@0: break; michael@0: michael@0: case Z_BUF_ERROR: michael@0: /* End of input or output; not a problem if the caller is doing michael@0: * incremental read or write. michael@0: */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated"); michael@0: break; michael@0: michael@0: case Z_VERSION_ERROR: michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version"); michael@0: break; michael@0: michael@0: case PNG_UNEXPECTED_ZLIB_RETURN: michael@0: /* Compile errors here mean that zlib now uses the value co-opted in michael@0: * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above michael@0: * and change pngpriv.h. Note that this message is "... return", michael@0: * whereas the default/Z_OK one is "... return code". michael@0: */ michael@0: png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return"); michael@0: break; michael@0: } michael@0: } michael@0: michael@0: /* png_convert_size: a PNGAPI but no longer in png.h, so deleted michael@0: * at libpng 1.5.5! michael@0: */ michael@0: michael@0: /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ michael@0: #ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */ michael@0: static int michael@0: png_colorspace_check_gamma(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, png_fixed_point gAMA, int from) michael@0: /* This is called to check a new gamma value against an existing one. The michael@0: * routine returns false if the new gamma value should not be written. michael@0: * michael@0: * 'from' says where the new gamma value comes from: michael@0: * michael@0: * 0: the new gamma value is the libpng estimate for an ICC profile michael@0: * 1: the new gamma value comes from a gAMA chunk michael@0: * 2: the new gamma value comes from an sRGB chunk michael@0: */ michael@0: { michael@0: png_fixed_point gtest; michael@0: michael@0: if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 && michael@0: (!png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) || michael@0: png_gamma_significant(gtest))) michael@0: { michael@0: /* Either this is an sRGB image, in which case the calculated gamma michael@0: * approximation should match, or this is an image with a profile and the michael@0: * value libpng calculates for the gamma of the profile does not match the michael@0: * value recorded in the file. The former, sRGB, case is an error, the michael@0: * latter is just a warning. michael@0: */ michael@0: if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2) michael@0: { michael@0: png_chunk_report(png_ptr, "gamma value does not match sRGB", michael@0: PNG_CHUNK_ERROR); michael@0: /* Do not overwrite an sRGB value */ michael@0: return from == 2; michael@0: } michael@0: michael@0: else /* sRGB tag not involved */ michael@0: { michael@0: png_chunk_report(png_ptr, "gamma value does not match libpng estimate", michael@0: PNG_CHUNK_WARNING); michael@0: return from == 1; michael@0: } michael@0: } michael@0: michael@0: return 1; michael@0: } michael@0: michael@0: void /* PRIVATE */ michael@0: png_colorspace_set_gamma(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, png_fixed_point gAMA) michael@0: { michael@0: /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't michael@0: * occur. Since the fixed point representation is assymetrical it is michael@0: * possible for 1/gamma to overflow the limit of 21474 and this means the michael@0: * gamma value must be at least 5/100000 and hence at most 20000.0. For michael@0: * safety the limits here are a little narrower. The values are 0.00016 to michael@0: * 6250.0, which are truly ridiculous gamma values (and will produce michael@0: * displays that are all black or all white.) michael@0: * michael@0: * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk michael@0: * handling code, which only required the value to be >0. michael@0: */ michael@0: png_const_charp errmsg; michael@0: michael@0: if (gAMA < 16 || gAMA > 625000000) michael@0: errmsg = "gamma value out of range"; michael@0: michael@0: # ifdef PNG_READ_gAMA_SUPPORTED michael@0: /* Allow the application to set the gamma value more than once */ michael@0: else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && michael@0: (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0) michael@0: errmsg = "duplicate"; michael@0: # endif michael@0: michael@0: /* Do nothing if the colorspace is already invalid */ michael@0: else if (colorspace->flags & PNG_COLORSPACE_INVALID) michael@0: return; michael@0: michael@0: else michael@0: { michael@0: if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, 1/*from gAMA*/)) michael@0: { michael@0: /* Store this gamma value. */ michael@0: colorspace->gamma = gAMA; michael@0: colorspace->flags |= michael@0: (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA); michael@0: } michael@0: michael@0: /* At present if the check_gamma test fails the gamma of the colorspace is michael@0: * not updated however the colorspace is not invalidated. This michael@0: * corresponds to the case where the existing gamma comes from an sRGB michael@0: * chunk or profile. An error message has already been output. michael@0: */ michael@0: return; michael@0: } michael@0: michael@0: /* Error exit - errmsg has been set. */ michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR); michael@0: } michael@0: michael@0: void /* PRIVATE */ michael@0: png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr) michael@0: { michael@0: if (info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) michael@0: { michael@0: /* Everything is invalid */ michael@0: info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB| michael@0: PNG_INFO_iCCP); michael@0: michael@0: # ifdef PNG_COLORSPACE_SUPPORTED michael@0: /* Clean up the iCCP profile now if it won't be used. */ michael@0: png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/); michael@0: # else michael@0: PNG_UNUSED(png_ptr) michael@0: # endif michael@0: } michael@0: michael@0: else michael@0: { michael@0: # ifdef PNG_COLORSPACE_SUPPORTED michael@0: /* Leave the INFO_iCCP flag set if the pngset.c code has already set michael@0: * it; this allows a PNG to contain a profile which matches sRGB and michael@0: * yet still have that profile retrievable by the application. michael@0: */ michael@0: if (info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) michael@0: info_ptr->valid |= PNG_INFO_sRGB; michael@0: michael@0: else michael@0: info_ptr->valid &= ~PNG_INFO_sRGB; michael@0: michael@0: if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) michael@0: info_ptr->valid |= PNG_INFO_cHRM; michael@0: michael@0: else michael@0: info_ptr->valid &= ~PNG_INFO_cHRM; michael@0: # endif michael@0: michael@0: if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) michael@0: info_ptr->valid |= PNG_INFO_gAMA; michael@0: michael@0: else michael@0: info_ptr->valid &= ~PNG_INFO_gAMA; michael@0: } michael@0: } michael@0: michael@0: #ifdef PNG_READ_SUPPORTED michael@0: void /* PRIVATE */ michael@0: png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr) michael@0: { michael@0: if (info_ptr == NULL) /* reduce code size; check here not in the caller */ michael@0: return; michael@0: michael@0: info_ptr->colorspace = png_ptr->colorspace; michael@0: png_colorspace_sync_info(png_ptr, info_ptr); michael@0: } michael@0: #endif michael@0: #endif michael@0: michael@0: #ifdef PNG_COLORSPACE_SUPPORTED michael@0: /* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for michael@0: * cHRM, as opposed to using chromaticities. These internal APIs return michael@0: * non-zero on a parameter error. The X, Y and Z values are required to be michael@0: * positive and less than 1.0. michael@0: */ michael@0: static int michael@0: png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ) michael@0: { michael@0: png_int_32 d, dwhite, whiteX, whiteY; michael@0: michael@0: d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z; michael@0: if (!png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d)) return 1; michael@0: if (!png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d)) return 1; michael@0: dwhite = d; michael@0: whiteX = XYZ->red_X; michael@0: whiteY = XYZ->red_Y; michael@0: michael@0: d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z; michael@0: if (!png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d)) return 1; michael@0: if (!png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d)) return 1; michael@0: dwhite += d; michael@0: whiteX += XYZ->green_X; michael@0: whiteY += XYZ->green_Y; michael@0: michael@0: d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z; michael@0: if (!png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d)) return 1; michael@0: if (!png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d)) return 1; michael@0: dwhite += d; michael@0: whiteX += XYZ->blue_X; michael@0: whiteY += XYZ->blue_Y; michael@0: michael@0: /* The reference white is simply the sum of the end-point (X,Y,Z) vectors, michael@0: * thus: michael@0: */ michael@0: if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1; michael@0: if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1; michael@0: michael@0: return 0; michael@0: } michael@0: michael@0: static int michael@0: png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy) michael@0: { michael@0: png_fixed_point red_inverse, green_inverse, blue_scale; michael@0: png_fixed_point left, right, denominator; michael@0: michael@0: /* Check xy and, implicitly, z. Note that wide gamut color spaces typically michael@0: * have end points with 0 tristimulus values (these are impossible end michael@0: * points, but they are used to cover the possible colors.) michael@0: */ michael@0: if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1; michael@0: if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1; michael@0: if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1; michael@0: if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1; michael@0: if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1; michael@0: if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1; michael@0: if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1; michael@0: if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1; michael@0: michael@0: /* The reverse calculation is more difficult because the original tristimulus michael@0: * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8 michael@0: * derived values were recorded in the cHRM chunk; michael@0: * (red,green,blue,white)x(x,y). This loses one degree of freedom and michael@0: * therefore an arbitrary ninth value has to be introduced to undo the michael@0: * original transformations. michael@0: * michael@0: * Think of the original end-points as points in (X,Y,Z) space. The michael@0: * chromaticity values (c) have the property: michael@0: * michael@0: * C michael@0: * c = --------- michael@0: * X + Y + Z michael@0: * michael@0: * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the michael@0: * three chromaticity values (x,y,z) for each end-point obey the michael@0: * relationship: michael@0: * michael@0: * x + y + z = 1 michael@0: * michael@0: * This describes the plane in (X,Y,Z) space that intersects each axis at the michael@0: * value 1.0; call this the chromaticity plane. Thus the chromaticity michael@0: * calculation has scaled each end-point so that it is on the x+y+z=1 plane michael@0: * and chromaticity is the intersection of the vector from the origin to the michael@0: * (X,Y,Z) value with the chromaticity plane. michael@0: * michael@0: * To fully invert the chromaticity calculation we would need the three michael@0: * end-point scale factors, (red-scale, green-scale, blue-scale), but these michael@0: * were not recorded. Instead we calculated the reference white (X,Y,Z) and michael@0: * recorded the chromaticity of this. The reference white (X,Y,Z) would have michael@0: * given all three of the scale factors since: michael@0: * michael@0: * color-C = color-c * color-scale michael@0: * white-C = red-C + green-C + blue-C michael@0: * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale michael@0: * michael@0: * But cHRM records only white-x and white-y, so we have lost the white scale michael@0: * factor: michael@0: * michael@0: * white-C = white-c*white-scale michael@0: * michael@0: * To handle this the inverse transformation makes an arbitrary assumption michael@0: * about white-scale: michael@0: * michael@0: * Assume: white-Y = 1.0 michael@0: * Hence: white-scale = 1/white-y michael@0: * Or: red-Y + green-Y + blue-Y = 1.0 michael@0: * michael@0: * Notice the last statement of the assumption gives an equation in three of michael@0: * the nine values we want to calculate. 8 more equations come from the michael@0: * above routine as summarised at the top above (the chromaticity michael@0: * calculation): michael@0: * michael@0: * Given: color-x = color-X / (color-X + color-Y + color-Z) michael@0: * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0 michael@0: * michael@0: * This is 9 simultaneous equations in the 9 variables "color-C" and can be michael@0: * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix michael@0: * determinants, however this is not as bad as it seems because only 28 of michael@0: * the total of 90 terms in the various matrices are non-zero. Nevertheless michael@0: * Cramer's rule is notoriously numerically unstable because the determinant michael@0: * calculation involves the difference of large, but similar, numbers. It is michael@0: * difficult to be sure that the calculation is stable for real world values michael@0: * and it is certain that it becomes unstable where the end points are close michael@0: * together. michael@0: * michael@0: * So this code uses the perhaps slightly less optimal but more michael@0: * understandable and totally obvious approach of calculating color-scale. michael@0: * michael@0: * This algorithm depends on the precision in white-scale and that is michael@0: * (1/white-y), so we can immediately see that as white-y approaches 0 the michael@0: * accuracy inherent in the cHRM chunk drops off substantially. michael@0: * michael@0: * libpng arithmetic: a simple invertion of the above equations michael@0: * ------------------------------------------------------------ michael@0: * michael@0: * white_scale = 1/white-y michael@0: * white-X = white-x * white-scale michael@0: * white-Y = 1.0 michael@0: * white-Z = (1 - white-x - white-y) * white_scale michael@0: * michael@0: * white-C = red-C + green-C + blue-C michael@0: * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale michael@0: * michael@0: * This gives us three equations in (red-scale,green-scale,blue-scale) where michael@0: * all the coefficients are now known: michael@0: * michael@0: * red-x*red-scale + green-x*green-scale + blue-x*blue-scale michael@0: * = white-x/white-y michael@0: * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1 michael@0: * red-z*red-scale + green-z*green-scale + blue-z*blue-scale michael@0: * = (1 - white-x - white-y)/white-y michael@0: * michael@0: * In the last equation color-z is (1 - color-x - color-y) so we can add all michael@0: * three equations together to get an alternative third: michael@0: * michael@0: * red-scale + green-scale + blue-scale = 1/white-y = white-scale michael@0: * michael@0: * So now we have a Cramer's rule solution where the determinants are just michael@0: * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve michael@0: * multiplication of three coefficients so we can't guarantee to avoid michael@0: * overflow in the libpng fixed point representation. Using Cramer's rule in michael@0: * floating point is probably a good choice here, but it's not an option for michael@0: * fixed point. Instead proceed to simplify the first two equations by michael@0: * eliminating what is likely to be the largest value, blue-scale: michael@0: * michael@0: * blue-scale = white-scale - red-scale - green-scale michael@0: * michael@0: * Hence: michael@0: * michael@0: * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale = michael@0: * (white-x - blue-x)*white-scale michael@0: * michael@0: * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale = michael@0: * 1 - blue-y*white-scale michael@0: * michael@0: * And now we can trivially solve for (red-scale,green-scale): michael@0: * michael@0: * green-scale = michael@0: * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale michael@0: * ----------------------------------------------------------- michael@0: * green-x - blue-x michael@0: * michael@0: * red-scale = michael@0: * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale michael@0: * --------------------------------------------------------- michael@0: * red-y - blue-y michael@0: * michael@0: * Hence: michael@0: * michael@0: * red-scale = michael@0: * ( (green-x - blue-x) * (white-y - blue-y) - michael@0: * (green-y - blue-y) * (white-x - blue-x) ) / white-y michael@0: * ------------------------------------------------------------------------- michael@0: * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) michael@0: * michael@0: * green-scale = michael@0: * ( (red-y - blue-y) * (white-x - blue-x) - michael@0: * (red-x - blue-x) * (white-y - blue-y) ) / white-y michael@0: * ------------------------------------------------------------------------- michael@0: * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) michael@0: * michael@0: * Accuracy: michael@0: * The input values have 5 decimal digits of accuracy. The values are all in michael@0: * the range 0 < value < 1, so simple products are in the same range but may michael@0: * need up to 10 decimal digits to preserve the original precision and avoid michael@0: * underflow. Because we are using a 32-bit signed representation we cannot michael@0: * match this; the best is a little over 9 decimal digits, less than 10. michael@0: * michael@0: * The approach used here is to preserve the maximum precision within the michael@0: * signed representation. Because the red-scale calculation above uses the michael@0: * difference between two products of values that must be in the range -1..+1 michael@0: * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The michael@0: * factor is irrelevant in the calculation because it is applied to both michael@0: * numerator and denominator. michael@0: * michael@0: * Note that the values of the differences of the products of the michael@0: * chromaticities in the above equations tend to be small, for example for michael@0: * the sRGB chromaticities they are: michael@0: * michael@0: * red numerator: -0.04751 michael@0: * green numerator: -0.08788 michael@0: * denominator: -0.2241 (without white-y multiplication) michael@0: * michael@0: * The resultant Y coefficients from the chromaticities of some widely used michael@0: * color space definitions are (to 15 decimal places): michael@0: * michael@0: * sRGB michael@0: * 0.212639005871510 0.715168678767756 0.072192315360734 michael@0: * Kodak ProPhoto michael@0: * 0.288071128229293 0.711843217810102 0.000085653960605 michael@0: * Adobe RGB michael@0: * 0.297344975250536 0.627363566255466 0.075291458493998 michael@0: * Adobe Wide Gamut RGB michael@0: * 0.258728243040113 0.724682314948566 0.016589442011321 michael@0: */ michael@0: /* By the argument, above overflow should be impossible here. The return michael@0: * value of 2 indicates an internal error to the caller. michael@0: */ michael@0: if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7)) michael@0: return 2; michael@0: if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7)) michael@0: return 2; michael@0: denominator = left - right; michael@0: michael@0: /* Now find the red numerator. */ michael@0: if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7)) michael@0: return 2; michael@0: if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7)) michael@0: return 2; michael@0: michael@0: /* Overflow is possible here and it indicates an extreme set of PNG cHRM michael@0: * chunk values. This calculation actually returns the reciprocal of the michael@0: * scale value because this allows us to delay the multiplication of white-y michael@0: * into the denominator, which tends to produce a small number. michael@0: */ michael@0: if (!png_muldiv(&red_inverse, xy->whitey, denominator, left-right) || michael@0: red_inverse <= xy->whitey /* r+g+b scales = white scale */) michael@0: return 1; michael@0: michael@0: /* Similarly for green_inverse: */ michael@0: if (!png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7)) michael@0: return 2; michael@0: if (!png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7)) michael@0: return 2; michael@0: if (!png_muldiv(&green_inverse, xy->whitey, denominator, left-right) || michael@0: green_inverse <= xy->whitey) michael@0: return 1; michael@0: michael@0: /* And the blue scale, the checks above guarantee this can't overflow but it michael@0: * can still produce 0 for extreme cHRM values. michael@0: */ michael@0: blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) - michael@0: png_reciprocal(green_inverse); michael@0: if (blue_scale <= 0) return 1; michael@0: michael@0: michael@0: /* And fill in the png_XYZ: */ michael@0: if (!png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse)) return 1; michael@0: if (!png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse)) return 1; michael@0: if (!png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1, michael@0: red_inverse)) michael@0: return 1; michael@0: michael@0: if (!png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse)) michael@0: return 1; michael@0: if (!png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse)) michael@0: return 1; michael@0: if (!png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1, michael@0: green_inverse)) michael@0: return 1; michael@0: michael@0: if (!png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1)) return 1; michael@0: if (!png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1)) return 1; michael@0: if (!png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale, michael@0: PNG_FP_1)) michael@0: return 1; michael@0: michael@0: return 0; /*success*/ michael@0: } michael@0: michael@0: static int michael@0: png_XYZ_normalize(png_XYZ *XYZ) michael@0: { michael@0: png_int_32 Y; michael@0: michael@0: if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 || michael@0: XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 || michael@0: XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0) michael@0: return 1; michael@0: michael@0: /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1. michael@0: * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore michael@0: * relying on addition of two positive values producing a negative one is not michael@0: * safe. michael@0: */ michael@0: Y = XYZ->red_Y; michael@0: if (0x7fffffff - Y < XYZ->green_X) return 1; michael@0: Y += XYZ->green_Y; michael@0: if (0x7fffffff - Y < XYZ->blue_X) return 1; michael@0: Y += XYZ->blue_Y; michael@0: michael@0: if (Y != PNG_FP_1) michael@0: { michael@0: if (!png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y)) return 1; michael@0: michael@0: if (!png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y)) return 1; michael@0: michael@0: if (!png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y)) return 1; michael@0: if (!png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y)) return 1; michael@0: } michael@0: michael@0: return 0; michael@0: } michael@0: michael@0: static int michael@0: png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta) michael@0: { michael@0: /* Allow an error of +/-0.01 (absolute value) on each chromaticity */ michael@0: return !(PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) || michael@0: PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) || michael@0: PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) || michael@0: PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) || michael@0: PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) || michael@0: PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) || michael@0: PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) || michael@0: PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta)); michael@0: } michael@0: michael@0: /* Added in libpng-1.6.0, a different check for the validity of a set of cHRM michael@0: * chunk chromaticities. Earlier checks used to simply look for the overflow michael@0: * condition (where the determinant of the matrix to solve for XYZ ends up zero michael@0: * because the chromaticity values are not all distinct.) Despite this it is michael@0: * theoretically possible to produce chromaticities that are apparently valid michael@0: * but that rapidly degrade to invalid, potentially crashing, sets because of michael@0: * arithmetic inaccuracies when calculations are performed on them. The new michael@0: * check is to round-trip xy -> XYZ -> xy and then check that the result is michael@0: * within a small percentage of the original. michael@0: */ michael@0: static int michael@0: png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy) michael@0: { michael@0: int result; michael@0: png_xy xy_test; michael@0: michael@0: /* As a side-effect this routine also returns the XYZ endpoints. */ michael@0: result = png_XYZ_from_xy(XYZ, xy); michael@0: if (result) return result; michael@0: michael@0: result = png_xy_from_XYZ(&xy_test, XYZ); michael@0: if (result) return result; michael@0: michael@0: if (png_colorspace_endpoints_match(xy, &xy_test, michael@0: 5/*actually, the math is pretty accurate*/)) michael@0: return 0; michael@0: michael@0: /* Too much slip */ michael@0: return 1; michael@0: } michael@0: michael@0: /* This is the check going the other way. The XYZ is modified to normalize it michael@0: * (another side-effect) and the xy chromaticities are returned. michael@0: */ michael@0: static int michael@0: png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ) michael@0: { michael@0: int result; michael@0: png_XYZ XYZtemp; michael@0: michael@0: result = png_XYZ_normalize(XYZ); michael@0: if (result) return result; michael@0: michael@0: result = png_xy_from_XYZ(xy, XYZ); michael@0: if (result) return result; michael@0: michael@0: XYZtemp = *XYZ; michael@0: return png_colorspace_check_xy(&XYZtemp, xy); michael@0: } michael@0: michael@0: /* Used to check for an endpoint match against sRGB */ michael@0: static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */ michael@0: { michael@0: /* color x y */ michael@0: /* red */ 64000, 33000, michael@0: /* green */ 30000, 60000, michael@0: /* blue */ 15000, 6000, michael@0: /* white */ 31270, 32900 michael@0: }; michael@0: michael@0: static int michael@0: png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ, michael@0: int preferred) michael@0: { michael@0: if (colorspace->flags & PNG_COLORSPACE_INVALID) michael@0: return 0; michael@0: michael@0: /* The consistency check is performed on the chromaticities; this factors out michael@0: * variations because of the normalization (or not) of the end point Y michael@0: * values. michael@0: */ michael@0: if (preferred < 2 && (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) michael@0: { michael@0: /* The end points must be reasonably close to any we already have. The michael@0: * following allows an error of up to +/-.001 michael@0: */ michael@0: if (!png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, 100)) michael@0: { michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_benign_error(png_ptr, "inconsistent chromaticities"); michael@0: return 0; /* failed */ michael@0: } michael@0: michael@0: /* Only overwrite with preferred values */ michael@0: if (!preferred) michael@0: return 1; /* ok, but no change */ michael@0: } michael@0: michael@0: colorspace->end_points_xy = *xy; michael@0: colorspace->end_points_XYZ = *XYZ; michael@0: colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS; michael@0: michael@0: /* The end points are normally quoted to two decimal digits, so allow +/-0.01 michael@0: * on this test. michael@0: */ michael@0: if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000)) michael@0: colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB; michael@0: michael@0: else michael@0: colorspace->flags &= PNG_COLORSPACE_CANCEL( michael@0: PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); michael@0: michael@0: return 2; /* ok and changed */ michael@0: } michael@0: michael@0: int /* PRIVATE */ michael@0: png_colorspace_set_chromaticities(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, const png_xy *xy, int preferred) michael@0: { michael@0: /* We must check the end points to ensure they are reasonable - in the past michael@0: * color management systems have crashed as a result of getting bogus michael@0: * colorant values, while this isn't the fault of libpng it is the michael@0: * responsibility of libpng because PNG carries the bomb and libpng is in a michael@0: * position to protect against it. michael@0: */ michael@0: png_XYZ XYZ; michael@0: michael@0: switch (png_colorspace_check_xy(&XYZ, xy)) michael@0: { michael@0: case 0: /* success */ michael@0: return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ, michael@0: preferred); michael@0: michael@0: case 1: michael@0: /* We can't invert the chromaticities so we can't produce value XYZ michael@0: * values. Likely as not a color management system will fail too. michael@0: */ michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_benign_error(png_ptr, "invalid chromaticities"); michael@0: break; michael@0: michael@0: default: michael@0: /* libpng is broken; this should be a warning but if it happens we michael@0: * want error reports so for the moment it is an error. michael@0: */ michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_error(png_ptr, "internal error checking chromaticities"); michael@0: break; michael@0: } michael@0: michael@0: return 0; /* failed */ michael@0: } michael@0: michael@0: int /* PRIVATE */ michael@0: png_colorspace_set_endpoints(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred) michael@0: { michael@0: png_XYZ XYZ = *XYZ_in; michael@0: png_xy xy; michael@0: michael@0: switch (png_colorspace_check_XYZ(&xy, &XYZ)) michael@0: { michael@0: case 0: michael@0: return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ, michael@0: preferred); michael@0: michael@0: case 1: michael@0: /* End points are invalid. */ michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_benign_error(png_ptr, "invalid end points"); michael@0: break; michael@0: michael@0: default: michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: png_error(png_ptr, "internal error checking chromaticities"); michael@0: break; michael@0: } michael@0: michael@0: return 0; /* failed */ michael@0: } michael@0: michael@0: #if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED) michael@0: /* Error message generation */ michael@0: static char michael@0: png_icc_tag_char(png_uint_32 byte) michael@0: { michael@0: byte &= 0xff; michael@0: if (byte >= 32 && byte <= 126) michael@0: return (char)byte; michael@0: else michael@0: return '?'; michael@0: } michael@0: michael@0: static void michael@0: png_icc_tag_name(char *name, png_uint_32 tag) michael@0: { michael@0: name[0] = '\''; michael@0: name[1] = png_icc_tag_char(tag >> 24); michael@0: name[2] = png_icc_tag_char(tag >> 16); michael@0: name[3] = png_icc_tag_char(tag >> 8); michael@0: name[4] = png_icc_tag_char(tag ); michael@0: name[5] = '\''; michael@0: } michael@0: michael@0: static int michael@0: is_ICC_signature_char(png_alloc_size_t it) michael@0: { michael@0: return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) || michael@0: (it >= 97 && it <= 122); michael@0: } michael@0: michael@0: static int michael@0: is_ICC_signature(png_alloc_size_t it) michael@0: { michael@0: return is_ICC_signature_char(it >> 24) /* checks all the top bits */ && michael@0: is_ICC_signature_char((it >> 16) & 0xff) && michael@0: is_ICC_signature_char((it >> 8) & 0xff) && michael@0: is_ICC_signature_char(it & 0xff); michael@0: } michael@0: michael@0: static int michael@0: png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: png_const_charp name, png_alloc_size_t value, png_const_charp reason) michael@0: { michael@0: size_t pos; michael@0: char message[196]; /* see below for calculation */ michael@0: michael@0: if (colorspace != NULL) michael@0: colorspace->flags |= PNG_COLORSPACE_INVALID; michael@0: michael@0: pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */ michael@0: pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */ michael@0: pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */ michael@0: if (is_ICC_signature(value)) michael@0: { michael@0: /* So 'value' is at most 4 bytes and the following cast is safe */ michael@0: png_icc_tag_name(message+pos, (png_uint_32)value); michael@0: pos += 6; /* total +8; less than the else clause */ michael@0: message[pos++] = ':'; michael@0: message[pos++] = ' '; michael@0: } michael@0: # ifdef PNG_WARNINGS_SUPPORTED michael@0: else michael@0: { michael@0: char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/ michael@0: michael@0: pos = png_safecat(message, (sizeof message), pos, michael@0: png_format_number(number, number+(sizeof number), michael@0: PNG_NUMBER_FORMAT_x, value)); michael@0: pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/ michael@0: } michael@0: # endif michael@0: /* The 'reason' is an arbitrary message, allow +79 maximum 195 */ michael@0: pos = png_safecat(message, (sizeof message), pos, reason); michael@0: PNG_UNUSED(pos) michael@0: michael@0: /* This is recoverable, but make it unconditionally an app_error on write to michael@0: * avoid writing invalid ICC profiles into PNG files. (I.e. we handle them michael@0: * on read, with a warning, but on write unless the app turns off michael@0: * application errors the PNG won't be written.) michael@0: */ michael@0: png_chunk_report(png_ptr, message, michael@0: (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR); michael@0: michael@0: return 0; michael@0: } michael@0: #endif /* sRGB || iCCP */ michael@0: michael@0: #ifdef PNG_sRGB_SUPPORTED michael@0: int /* PRIVATE */ michael@0: png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: int intent) michael@0: { michael@0: /* sRGB sets known gamma, end points and (from the chunk) intent. */ michael@0: /* IMPORTANT: these are not necessarily the values found in an ICC profile michael@0: * because ICC profiles store values adapted to a D50 environment; it is michael@0: * expected that the ICC profile mediaWhitePointTag will be D50, see the michael@0: * checks and code elsewhere to understand this better. michael@0: * michael@0: * These XYZ values, which are accurate to 5dp, produce rgb to gray michael@0: * coefficients of (6968,23435,2366), which are reduced (because they add up michael@0: * to 32769 not 32768) to (6968,23434,2366). These are the values that michael@0: * libpng has traditionally used (and are the best values given the 15bit michael@0: * algorithm used by the rgb to gray code.) michael@0: */ michael@0: static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */ michael@0: { michael@0: /* color X Y Z */ michael@0: /* red */ 41239, 21264, 1933, michael@0: /* green */ 35758, 71517, 11919, michael@0: /* blue */ 18048, 7219, 95053 michael@0: }; michael@0: michael@0: /* Do nothing if the colorspace is already invalidated. */ michael@0: if (colorspace->flags & PNG_COLORSPACE_INVALID) michael@0: return 0; michael@0: michael@0: /* Check the intent, then check for existing settings. It is valid for the michael@0: * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must michael@0: * be consistent with the correct values. If, however, this function is michael@0: * called below because an iCCP chunk matches sRGB then it is quite michael@0: * conceivable that an older app recorded incorrect gAMA and cHRM because of michael@0: * an incorrect calculation based on the values in the profile - this does michael@0: * *not* invalidate the profile (though it still produces an error, which can michael@0: * be ignored.) michael@0: */ michael@0: if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST) michael@0: return png_icc_profile_error(png_ptr, colorspace, "sRGB", michael@0: (unsigned)intent, "invalid sRGB rendering intent"); michael@0: michael@0: if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 && michael@0: colorspace->rendering_intent != intent) michael@0: return png_icc_profile_error(png_ptr, colorspace, "sRGB", michael@0: (unsigned)intent, "inconsistent rendering intents"); michael@0: michael@0: if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0) michael@0: { michael@0: png_benign_error(png_ptr, "duplicate sRGB information ignored"); michael@0: return 0; michael@0: } michael@0: michael@0: /* If the standard sRGB cHRM chunk does not match the one from the PNG file michael@0: * warn but overwrite the value with the correct one. michael@0: */ michael@0: if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 && michael@0: !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy, michael@0: 100)) michael@0: png_chunk_report(png_ptr, "cHRM chunk does not match sRGB", michael@0: PNG_CHUNK_ERROR); michael@0: michael@0: /* This check is just done for the error reporting - the routine always michael@0: * returns true when the 'from' argument corresponds to sRGB (2). michael@0: */ michael@0: (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE, michael@0: 2/*from sRGB*/); michael@0: michael@0: /* intent: bugs in GCC force 'int' to be used as the parameter type. */ michael@0: colorspace->rendering_intent = (png_uint_16)intent; michael@0: colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT; michael@0: michael@0: /* endpoints */ michael@0: colorspace->end_points_xy = sRGB_xy; michael@0: colorspace->end_points_XYZ = sRGB_XYZ; michael@0: colorspace->flags |= michael@0: (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); michael@0: michael@0: /* gamma */ michael@0: colorspace->gamma = PNG_GAMMA_sRGB_INVERSE; michael@0: colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA; michael@0: michael@0: /* Finally record that we have an sRGB profile */ michael@0: colorspace->flags |= michael@0: (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB); michael@0: michael@0: return 1; /* set */ michael@0: } michael@0: #endif /* sRGB */ michael@0: michael@0: #ifdef PNG_iCCP_SUPPORTED michael@0: /* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value michael@0: * is XYZ(0.9642,1.0,0.8249), which scales to: michael@0: * michael@0: * (63189.8112, 65536, 54060.6464) michael@0: */ michael@0: static const png_byte D50_nCIEXYZ[12] = michael@0: { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d }; michael@0: michael@0: int /* PRIVATE */ michael@0: png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: png_const_charp name, png_uint_32 profile_length) michael@0: { michael@0: if (profile_length < 132) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, profile_length, michael@0: "too short"); michael@0: michael@0: if (profile_length & 3) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, profile_length, michael@0: "invalid length"); michael@0: michael@0: return 1; michael@0: } michael@0: michael@0: int /* PRIVATE */ michael@0: png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: png_const_charp name, png_uint_32 profile_length, michael@0: png_const_bytep profile/* first 132 bytes only */, int color_type) michael@0: { michael@0: png_uint_32 temp; michael@0: michael@0: /* Length check; this cannot be ignored in this code because profile_length michael@0: * is used later to check the tag table, so even if the profile seems over michael@0: * long profile_length from the caller must be correct. The caller can fix michael@0: * this up on read or write by just passing in the profile header length. michael@0: */ michael@0: temp = png_get_uint_32(profile); michael@0: if (temp != profile_length) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "length does not match profile"); michael@0: michael@0: temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */ michael@0: if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */ michael@0: profile_length < 132+12*temp) /* truncated tag table */ michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "tag count too large"); michael@0: michael@0: /* The 'intent' must be valid or we can't store it, ICC limits the intent to michael@0: * 16 bits. michael@0: */ michael@0: temp = png_get_uint_32(profile+64); michael@0: if (temp >= 0xffff) /* The ICC limit */ michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "invalid rendering intent"); michael@0: michael@0: /* This is just a warning because the profile may be valid in future michael@0: * versions. michael@0: */ michael@0: if (temp >= PNG_sRGB_INTENT_LAST) michael@0: (void)png_icc_profile_error(png_ptr, NULL, name, temp, michael@0: "intent outside defined range"); michael@0: michael@0: /* At this point the tag table can't be checked because it hasn't necessarily michael@0: * been loaded; however, various header fields can be checked. These checks michael@0: * are for values permitted by the PNG spec in an ICC profile; the PNG spec michael@0: * restricts the profiles that can be passed in an iCCP chunk (they must be michael@0: * appropriate to processing PNG data!) michael@0: */ michael@0: michael@0: /* Data checks (could be skipped). These checks must be independent of the michael@0: * version number; however, the version number doesn't accomodate changes in michael@0: * the header fields (just the known tags and the interpretation of the michael@0: * data.) michael@0: */ michael@0: temp = png_get_uint_32(profile+36); /* signature 'ascp' */ michael@0: if (temp != 0x61637370) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "invalid signature"); michael@0: michael@0: /* Currently the PCS illuminant/adopted white point (the computational michael@0: * white point) are required to be D50, michael@0: * however the profile contains a record of the illuminant so perhaps ICC michael@0: * expects to be able to change this in the future (despite the rationale in michael@0: * the introduction for using a fixed PCS adopted white.) Consequently the michael@0: * following is just a warning. michael@0: */ michael@0: if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0) michael@0: (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/, michael@0: "PCS illuminant is not D50"); michael@0: michael@0: /* The PNG spec requires this: michael@0: * "If the iCCP chunk is present, the image samples conform to the colour michael@0: * space represented by the embedded ICC profile as defined by the michael@0: * International Color Consortium [ICC]. The colour space of the ICC profile michael@0: * shall be an RGB colour space for colour images (PNG colour types 2, 3, and michael@0: * 6), or a greyscale colour space for greyscale images (PNG colour types 0 michael@0: * and 4)." michael@0: * michael@0: * This checking code ensures the embedded profile (on either read or write) michael@0: * conforms to the specification requirements. Notice that an ICC 'gray' michael@0: * color-space profile contains the information to transform the monochrome michael@0: * data to XYZ or L*a*b (according to which PCS the profile uses) and this michael@0: * should be used in preference to the standard libpng K channel replication michael@0: * into R, G and B channels. michael@0: * michael@0: * Previously it was suggested that an RGB profile on grayscale data could be michael@0: * handled. However it it is clear that using an RGB profile in this context michael@0: * must be an error - there is no specification of what it means. Thus it is michael@0: * almost certainly more correct to ignore the profile. michael@0: */ michael@0: temp = png_get_uint_32(profile+16); /* data colour space field */ michael@0: switch (temp) michael@0: { michael@0: case 0x52474220: /* 'RGB ' */ michael@0: if (!(color_type & PNG_COLOR_MASK_COLOR)) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "RGB color space not permitted on grayscale PNG"); michael@0: break; michael@0: michael@0: case 0x47524159: /* 'GRAY' */ michael@0: if (color_type & PNG_COLOR_MASK_COLOR) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "Gray color space not permitted on RGB PNG"); michael@0: break; michael@0: michael@0: default: michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "invalid ICC profile color space"); michael@0: } michael@0: michael@0: /* It is up to the application to check that the profile class matches the michael@0: * application requirements; the spec provides no guidance, but it's pretty michael@0: * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer michael@0: * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these michael@0: * cases. Issue an error for device link or abstract profiles - these don't michael@0: * contain the records necessary to transform the color-space to anything michael@0: * other than the target device (and not even that for an abstract profile). michael@0: * Profiles of these classes may not be embedded in images. michael@0: */ michael@0: temp = png_get_uint_32(profile+12); /* profile/device class */ michael@0: switch (temp) michael@0: { michael@0: case 0x73636E72: /* 'scnr' */ michael@0: case 0x6D6E7472: /* 'mntr' */ michael@0: case 0x70727472: /* 'prtr' */ michael@0: case 0x73706163: /* 'spac' */ michael@0: /* All supported */ michael@0: break; michael@0: michael@0: case 0x61627374: /* 'abst' */ michael@0: /* May not be embedded in an image */ michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "invalid embedded Abstract ICC profile"); michael@0: michael@0: case 0x6C696E6B: /* 'link' */ michael@0: /* DeviceLink profiles cannnot be interpreted in a non-device specific michael@0: * fashion, if an app uses the AToB0Tag in the profile the results are michael@0: * undefined unless the result is sent to the intended device, michael@0: * therefore a DeviceLink profile should not be found embedded in a michael@0: * PNG. michael@0: */ michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "unexpected DeviceLink ICC profile class"); michael@0: michael@0: case 0x6E6D636C: /* 'nmcl' */ michael@0: /* A NamedColor profile is also device specific, however it doesn't michael@0: * contain an AToB0 tag that is open to misintrepretation. Almost michael@0: * certainly it will fail the tests below. michael@0: */ michael@0: (void)png_icc_profile_error(png_ptr, NULL, name, temp, michael@0: "unexpected NamedColor ICC profile class"); michael@0: break; michael@0: michael@0: default: michael@0: /* To allow for future enhancements to the profile accept unrecognized michael@0: * profile classes with a warning, these then hit the test below on the michael@0: * tag content to ensure they are backward compatible with one of the michael@0: * understood profiles. michael@0: */ michael@0: (void)png_icc_profile_error(png_ptr, NULL, name, temp, michael@0: "unrecognized ICC profile class"); michael@0: break; michael@0: } michael@0: michael@0: /* For any profile other than a device link one the PCS must be encoded michael@0: * either in XYZ or Lab. michael@0: */ michael@0: temp = png_get_uint_32(profile+20); michael@0: switch (temp) michael@0: { michael@0: case 0x58595A20: /* 'XYZ ' */ michael@0: case 0x4C616220: /* 'Lab ' */ michael@0: break; michael@0: michael@0: default: michael@0: return png_icc_profile_error(png_ptr, colorspace, name, temp, michael@0: "unexpected ICC PCS encoding"); michael@0: } michael@0: michael@0: return 1; michael@0: } michael@0: michael@0: int /* PRIVATE */ michael@0: png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: png_const_charp name, png_uint_32 profile_length, michael@0: png_const_bytep profile /* header plus whole tag table */) michael@0: { michael@0: png_uint_32 tag_count = png_get_uint_32(profile+128); michael@0: png_uint_32 itag; michael@0: png_const_bytep tag = profile+132; /* The first tag */ michael@0: michael@0: /* First scan all the tags in the table and add bits to the icc_info value michael@0: * (temporarily in 'tags'). michael@0: */ michael@0: for (itag=0; itag < tag_count; ++itag, tag += 12) michael@0: { michael@0: png_uint_32 tag_id = png_get_uint_32(tag+0); michael@0: png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */ michael@0: png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */ michael@0: michael@0: /* The ICC specification does not exclude zero length tags, therefore the michael@0: * start might actually be anywhere if there is no data, but this would be michael@0: * a clear abuse of the intent of the standard so the start is checked for michael@0: * being in range. All defined tag types have an 8 byte header - a 4 byte michael@0: * type signature then 0. michael@0: */ michael@0: if ((tag_start & 3) != 0) michael@0: { michael@0: /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is michael@0: * only a warning here because libpng does not care about the michael@0: * alignment. michael@0: */ michael@0: (void)png_icc_profile_error(png_ptr, NULL, name, tag_id, michael@0: "ICC profile tag start not a multiple of 4"); michael@0: } michael@0: michael@0: /* This is a hard error; potentially it can cause read outside the michael@0: * profile. michael@0: */ michael@0: if (tag_start > profile_length || tag_length > profile_length - tag_start) michael@0: return png_icc_profile_error(png_ptr, colorspace, name, tag_id, michael@0: "ICC profile tag outside profile"); michael@0: } michael@0: michael@0: return 1; /* success, maybe with warnings */ michael@0: } michael@0: michael@0: #ifdef PNG_sRGB_SUPPORTED michael@0: /* Information about the known ICC sRGB profiles */ michael@0: static const struct michael@0: { michael@0: png_uint_32 adler, crc, length; michael@0: png_uint_32 md5[4]; michael@0: png_byte have_md5; michael@0: png_byte is_broken; michael@0: png_uint_16 intent; michael@0: michael@0: # define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0) michael@0: # define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\ michael@0: { adler, crc, length, md5, broke, intent }, michael@0: michael@0: } png_sRGB_checks[] = michael@0: { michael@0: /* This data comes from contrib/tools/checksum-icc run on downloads of michael@0: * all four ICC sRGB profiles from www.color.org. michael@0: */ michael@0: /* adler32, crc32, MD5[4], intent, date, length, file-name */ michael@0: PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9, michael@0: PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0, michael@0: "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc") michael@0: michael@0: /* ICC sRGB v2 perceptual no black-compensation: */ michael@0: PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21, michael@0: PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0, michael@0: "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc") michael@0: michael@0: PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae, michael@0: PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0, michael@0: "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc") michael@0: michael@0: /* ICC sRGB v4 perceptual */ michael@0: PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812, michael@0: PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0, michael@0: "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc") michael@0: michael@0: /* The following profiles have no known MD5 checksum. If there is a match michael@0: * on the (empty) MD5 the other fields are used to attempt a match and michael@0: * a warning is produced. The first two of these profiles have a 'cprt' tag michael@0: * which suggests that they were also made by Hewlett Packard. michael@0: */ michael@0: PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce, michael@0: PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0, michael@0: "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc") michael@0: michael@0: /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not michael@0: * match the D50 PCS illuminant in the header (it is in fact the D65 values, michael@0: * so the white point is recorded as the un-adapted value.) The profiles michael@0: * below only differ in one byte - the intent - and are basically the same as michael@0: * the previous profile except for the mediaWhitePointTag error and a missing michael@0: * chromaticAdaptationTag. michael@0: */ michael@0: PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552, michael@0: PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/, michael@0: "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual") michael@0: michael@0: PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d, michael@0: PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/, michael@0: "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative") michael@0: }; michael@0: michael@0: static int michael@0: png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr, michael@0: png_const_bytep profile, uLong adler) michael@0: { michael@0: /* The quick check is to verify just the MD5 signature and trust the michael@0: * rest of the data. Because the profile has already been verified for michael@0: * correctness this is safe. png_colorspace_set_sRGB will check the 'intent' michael@0: * field too, so if the profile has been edited with an intent not defined michael@0: * by sRGB (but maybe defined by a later ICC specification) the read of michael@0: * the profile will fail at that point. michael@0: */ michael@0: png_uint_32 length = 0; michael@0: png_uint_32 intent = 0x10000; /* invalid */ michael@0: #if PNG_sRGB_PROFILE_CHECKS > 1 michael@0: uLong crc = 0; /* the value for 0 length data */ michael@0: #endif michael@0: unsigned int i; michael@0: michael@0: for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i) michael@0: { michael@0: if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] && michael@0: png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] && michael@0: png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] && michael@0: png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3]) michael@0: { michael@0: /* This may be one of the old HP profiles without an MD5, in that michael@0: * case we can only use the length and Adler32 (note that these michael@0: * are not used by default if there is an MD5!) michael@0: */ michael@0: # if PNG_sRGB_PROFILE_CHECKS == 0 michael@0: if (png_sRGB_checks[i].have_md5) michael@0: return 1+png_sRGB_checks[i].is_broken; michael@0: # endif michael@0: michael@0: /* Profile is unsigned or more checks have been configured in. */ michael@0: if (length == 0) michael@0: { michael@0: length = png_get_uint_32(profile); michael@0: intent = png_get_uint_32(profile+64); michael@0: } michael@0: michael@0: /* Length *and* intent must match */ michael@0: if (length == png_sRGB_checks[i].length && michael@0: intent == png_sRGB_checks[i].intent) michael@0: { michael@0: /* Now calculate the adler32 if not done already. */ michael@0: if (adler == 0) michael@0: { michael@0: adler = adler32(0, NULL, 0); michael@0: adler = adler32(adler, profile, length); michael@0: } michael@0: michael@0: if (adler == png_sRGB_checks[i].adler) michael@0: { michael@0: /* These basic checks suggest that the data has not been michael@0: * modified, but if the check level is more than 1 perform michael@0: * our own crc32 checksum on the data. michael@0: */ michael@0: # if PNG_sRGB_PROFILE_CHECKS > 1 michael@0: if (crc == 0) michael@0: { michael@0: crc = crc32(0, NULL, 0); michael@0: crc = crc32(crc, profile, length); michael@0: } michael@0: michael@0: /* So this check must pass for the 'return' below to happen. michael@0: */ michael@0: if (crc == png_sRGB_checks[i].crc) michael@0: # endif michael@0: { michael@0: if (png_sRGB_checks[i].is_broken) michael@0: { michael@0: /* These profiles are known to have bad data that may cause michael@0: * problems if they are used, therefore attempt to michael@0: * discourage their use, skip the 'have_md5' warning below, michael@0: * which is made irrelevant by this error. michael@0: */ michael@0: png_chunk_report(png_ptr, "known incorrect sRGB profile", michael@0: PNG_CHUNK_ERROR); michael@0: } michael@0: michael@0: /* Warn that this being done; this isn't even an error since michael@0: * the profile is perfectly valid, but it would be nice if michael@0: * people used the up-to-date ones. michael@0: */ michael@0: else if (!png_sRGB_checks[i].have_md5) michael@0: { michael@0: png_chunk_report(png_ptr, michael@0: "out-of-date sRGB profile with no signature", michael@0: PNG_CHUNK_WARNING); michael@0: } michael@0: michael@0: return 1+png_sRGB_checks[i].is_broken; michael@0: } michael@0: } michael@0: } michael@0: michael@0: # if PNG_sRGB_PROFILE_CHECKS > 0 michael@0: /* The signature matched, but the profile had been changed in some michael@0: * way. This probably indicates a data error or uninformed hacking. michael@0: * Fall through to "no match". michael@0: */ michael@0: png_chunk_report(png_ptr, michael@0: "Not recognizing known sRGB profile that has been edited", michael@0: PNG_CHUNK_WARNING); michael@0: break; michael@0: # endif michael@0: } michael@0: } michael@0: michael@0: return 0; /* no match */ michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_sRGB_SUPPORTED michael@0: void /* PRIVATE */ michael@0: png_icc_set_sRGB(png_const_structrp png_ptr, michael@0: png_colorspacerp colorspace, png_const_bytep profile, uLong adler) michael@0: { michael@0: /* Is this profile one of the known ICC sRGB profiles? If it is, just set michael@0: * the sRGB information. michael@0: */ michael@0: if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler)) michael@0: (void)png_colorspace_set_sRGB(png_ptr, colorspace, michael@0: (int)/*already checked*/png_get_uint_32(profile+64)); michael@0: } michael@0: #endif /* PNG_READ_sRGB_SUPPORTED */ michael@0: michael@0: int /* PRIVATE */ michael@0: png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace, michael@0: png_const_charp name, png_uint_32 profile_length, png_const_bytep profile, michael@0: int color_type) michael@0: { michael@0: if (colorspace->flags & PNG_COLORSPACE_INVALID) michael@0: return 0; michael@0: michael@0: if (png_icc_check_length(png_ptr, colorspace, name, profile_length) && michael@0: png_icc_check_header(png_ptr, colorspace, name, profile_length, profile, michael@0: color_type) && michael@0: png_icc_check_tag_table(png_ptr, colorspace, name, profile_length, michael@0: profile)) michael@0: { michael@0: # ifdef PNG_sRGB_SUPPORTED michael@0: /* If no sRGB support, don't try storing sRGB information */ michael@0: png_icc_set_sRGB(png_ptr, colorspace, profile, 0); michael@0: # endif michael@0: return 1; michael@0: } michael@0: michael@0: /* Failure case */ michael@0: return 0; michael@0: } michael@0: #endif /* iCCP */ michael@0: michael@0: #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED michael@0: void /* PRIVATE */ michael@0: png_colorspace_set_rgb_coefficients(png_structrp png_ptr) michael@0: { michael@0: /* Set the rgb_to_gray coefficients from the colorspace. */ michael@0: if (!png_ptr->rgb_to_gray_coefficients_set && michael@0: (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) michael@0: { michael@0: /* png_set_background has not been called, get the coefficients from the Y michael@0: * values of the colorspace colorants. michael@0: */ michael@0: png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y; michael@0: png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y; michael@0: png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y; michael@0: png_fixed_point total = r+g+b; michael@0: michael@0: if (total > 0 && michael@0: r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 && michael@0: g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 && michael@0: b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 && michael@0: r+g+b <= 32769) michael@0: { michael@0: /* We allow 0 coefficients here. r+g+b may be 32769 if two or michael@0: * all of the coefficients were rounded up. Handle this by michael@0: * reducing the *largest* coefficient by 1; this matches the michael@0: * approach used for the default coefficients in pngrtran.c michael@0: */ michael@0: int add = 0; michael@0: michael@0: if (r+g+b > 32768) michael@0: add = -1; michael@0: else if (r+g+b < 32768) michael@0: add = 1; michael@0: michael@0: if (add != 0) michael@0: { michael@0: if (g >= r && g >= b) michael@0: g += add; michael@0: else if (r >= g && r >= b) michael@0: r += add; michael@0: else michael@0: b += add; michael@0: } michael@0: michael@0: /* Check for an internal error. */ michael@0: if (r+g+b != 32768) michael@0: png_error(png_ptr, michael@0: "internal error handling cHRM coefficients"); michael@0: michael@0: else michael@0: { michael@0: png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r; michael@0: png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g; michael@0: } michael@0: } michael@0: michael@0: /* This is a png_error at present even though it could be ignored - michael@0: * it should never happen, but it is important that if it does, the michael@0: * bug is fixed. michael@0: */ michael@0: else michael@0: png_error(png_ptr, "internal error handling cHRM->XYZ"); michael@0: } michael@0: } michael@0: #endif michael@0: michael@0: #endif /* COLORSPACE */ michael@0: michael@0: void /* PRIVATE */ michael@0: png_check_IHDR(png_const_structrp png_ptr, michael@0: png_uint_32 width, png_uint_32 height, int bit_depth, michael@0: int color_type, int interlace_type, int compression_type, michael@0: int filter_type) michael@0: { michael@0: int error = 0; michael@0: michael@0: /* Check for width and height valid values */ michael@0: if (width == 0) michael@0: { michael@0: png_warning(png_ptr, "Image width is zero in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (height == 0) michael@0: { michael@0: png_warning(png_ptr, "Image height is zero in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: # ifdef PNG_SET_USER_LIMITS_SUPPORTED michael@0: if (width > png_ptr->user_width_max) michael@0: michael@0: # else michael@0: if (width > PNG_USER_WIDTH_MAX) michael@0: # endif michael@0: { michael@0: png_warning(png_ptr, "Image width exceeds user limit in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: # ifdef PNG_SET_USER_LIMITS_SUPPORTED michael@0: if (height > png_ptr->user_height_max) michael@0: # else michael@0: if (height > PNG_USER_HEIGHT_MAX) michael@0: # endif michael@0: { michael@0: png_warning(png_ptr, "Image height exceeds user limit in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (width > PNG_UINT_31_MAX) michael@0: { michael@0: png_warning(png_ptr, "Invalid image width in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (height > PNG_UINT_31_MAX) michael@0: { michael@0: png_warning(png_ptr, "Invalid image height in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: /* Check other values */ michael@0: if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && michael@0: bit_depth != 8 && bit_depth != 16) michael@0: { michael@0: png_warning(png_ptr, "Invalid bit depth in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (color_type < 0 || color_type == 1 || michael@0: color_type == 5 || color_type > 6) michael@0: { michael@0: png_warning(png_ptr, "Invalid color type in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || michael@0: ((color_type == PNG_COLOR_TYPE_RGB || michael@0: color_type == PNG_COLOR_TYPE_GRAY_ALPHA || michael@0: color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) michael@0: { michael@0: png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (interlace_type >= PNG_INTERLACE_LAST) michael@0: { michael@0: png_warning(png_ptr, "Unknown interlace method in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (compression_type != PNG_COMPRESSION_TYPE_BASE) michael@0: { michael@0: png_warning(png_ptr, "Unknown compression method in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: # ifdef PNG_MNG_FEATURES_SUPPORTED michael@0: /* Accept filter_method 64 (intrapixel differencing) only if michael@0: * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and michael@0: * 2. Libpng did not read a PNG signature (this filter_method is only michael@0: * used in PNG datastreams that are embedded in MNG datastreams) and michael@0: * 3. The application called png_permit_mng_features with a mask that michael@0: * included PNG_FLAG_MNG_FILTER_64 and michael@0: * 4. The filter_method is 64 and michael@0: * 5. The color_type is RGB or RGBA michael@0: */ michael@0: if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) && michael@0: png_ptr->mng_features_permitted) michael@0: png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); michael@0: michael@0: if (filter_type != PNG_FILTER_TYPE_BASE) michael@0: { michael@0: if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && michael@0: (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && michael@0: ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && michael@0: (color_type == PNG_COLOR_TYPE_RGB || michael@0: color_type == PNG_COLOR_TYPE_RGB_ALPHA))) michael@0: { michael@0: png_warning(png_ptr, "Unknown filter method in IHDR"); michael@0: error = 1; michael@0: } michael@0: michael@0: if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) michael@0: { michael@0: png_warning(png_ptr, "Invalid filter method in IHDR"); michael@0: error = 1; michael@0: } michael@0: } michael@0: michael@0: # else michael@0: if (filter_type != PNG_FILTER_TYPE_BASE) michael@0: { michael@0: png_warning(png_ptr, "Unknown filter method in IHDR"); michael@0: error = 1; michael@0: } michael@0: # endif michael@0: michael@0: if (error == 1) michael@0: png_error(png_ptr, "Invalid IHDR data"); michael@0: } michael@0: michael@0: #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) michael@0: /* ASCII to fp functions */ michael@0: /* Check an ASCII formated floating point value, see the more detailed michael@0: * comments in pngpriv.h michael@0: */ michael@0: /* The following is used internally to preserve the sticky flags */ michael@0: #define png_fp_add(state, flags) ((state) |= (flags)) michael@0: #define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY)) michael@0: michael@0: int /* PRIVATE */ michael@0: png_check_fp_number(png_const_charp string, png_size_t size, int *statep, michael@0: png_size_tp whereami) michael@0: { michael@0: int state = *statep; michael@0: png_size_t i = *whereami; michael@0: michael@0: while (i < size) michael@0: { michael@0: int type; michael@0: /* First find the type of the next character */ michael@0: switch (string[i]) michael@0: { michael@0: case 43: type = PNG_FP_SAW_SIGN; break; michael@0: case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break; michael@0: case 46: type = PNG_FP_SAW_DOT; break; michael@0: case 48: type = PNG_FP_SAW_DIGIT; break; michael@0: case 49: case 50: case 51: case 52: michael@0: case 53: case 54: case 55: case 56: michael@0: case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break; michael@0: case 69: michael@0: case 101: type = PNG_FP_SAW_E; break; michael@0: default: goto PNG_FP_End; michael@0: } michael@0: michael@0: /* Now deal with this type according to the current michael@0: * state, the type is arranged to not overlap the michael@0: * bits of the PNG_FP_STATE. michael@0: */ michael@0: switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY)) michael@0: { michael@0: case PNG_FP_INTEGER + PNG_FP_SAW_SIGN: michael@0: if (state & PNG_FP_SAW_ANY) michael@0: goto PNG_FP_End; /* not a part of the number */ michael@0: michael@0: png_fp_add(state, type); michael@0: break; michael@0: michael@0: case PNG_FP_INTEGER + PNG_FP_SAW_DOT: michael@0: /* Ok as trailer, ok as lead of fraction. */ michael@0: if (state & PNG_FP_SAW_DOT) /* two dots */ michael@0: goto PNG_FP_End; michael@0: michael@0: else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */ michael@0: png_fp_add(state, type); michael@0: michael@0: else michael@0: png_fp_set(state, PNG_FP_FRACTION | type); michael@0: michael@0: break; michael@0: michael@0: case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT: michael@0: if (state & PNG_FP_SAW_DOT) /* delayed fraction */ michael@0: png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT); michael@0: michael@0: png_fp_add(state, type | PNG_FP_WAS_VALID); michael@0: michael@0: break; michael@0: michael@0: case PNG_FP_INTEGER + PNG_FP_SAW_E: michael@0: if ((state & PNG_FP_SAW_DIGIT) == 0) michael@0: goto PNG_FP_End; michael@0: michael@0: png_fp_set(state, PNG_FP_EXPONENT); michael@0: michael@0: break; michael@0: michael@0: /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN: michael@0: goto PNG_FP_End; ** no sign in fraction */ michael@0: michael@0: /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT: michael@0: goto PNG_FP_End; ** Because SAW_DOT is always set */ michael@0: michael@0: case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT: michael@0: png_fp_add(state, type | PNG_FP_WAS_VALID); michael@0: break; michael@0: michael@0: case PNG_FP_FRACTION + PNG_FP_SAW_E: michael@0: /* This is correct because the trailing '.' on an michael@0: * integer is handled above - so we can only get here michael@0: * with the sequence ".E" (with no preceding digits). michael@0: */ michael@0: if ((state & PNG_FP_SAW_DIGIT) == 0) michael@0: goto PNG_FP_End; michael@0: michael@0: png_fp_set(state, PNG_FP_EXPONENT); michael@0: michael@0: break; michael@0: michael@0: case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN: michael@0: if (state & PNG_FP_SAW_ANY) michael@0: goto PNG_FP_End; /* not a part of the number */ michael@0: michael@0: png_fp_add(state, PNG_FP_SAW_SIGN); michael@0: michael@0: break; michael@0: michael@0: /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT: michael@0: goto PNG_FP_End; */ michael@0: michael@0: case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT: michael@0: png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID); michael@0: michael@0: break; michael@0: michael@0: /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E: michael@0: goto PNG_FP_End; */ michael@0: michael@0: default: goto PNG_FP_End; /* I.e. break 2 */ michael@0: } michael@0: michael@0: /* The character seems ok, continue. */ michael@0: ++i; michael@0: } michael@0: michael@0: PNG_FP_End: michael@0: /* Here at the end, update the state and return the correct michael@0: * return code. michael@0: */ michael@0: *statep = state; michael@0: *whereami = i; michael@0: michael@0: return (state & PNG_FP_SAW_DIGIT) != 0; michael@0: } michael@0: michael@0: michael@0: /* The same but for a complete string. */ michael@0: int michael@0: png_check_fp_string(png_const_charp string, png_size_t size) michael@0: { michael@0: int state=0; michael@0: png_size_t char_index=0; michael@0: michael@0: if (png_check_fp_number(string, size, &state, &char_index) && michael@0: (char_index == size || string[char_index] == 0)) michael@0: return state /* must be non-zero - see above */; michael@0: michael@0: return 0; /* i.e. fail */ michael@0: } michael@0: #endif /* pCAL or sCAL */ michael@0: michael@0: #ifdef PNG_sCAL_SUPPORTED michael@0: # ifdef PNG_FLOATING_POINT_SUPPORTED michael@0: /* Utility used below - a simple accurate power of ten from an integral michael@0: * exponent. michael@0: */ michael@0: static double michael@0: png_pow10(int power) michael@0: { michael@0: int recip = 0; michael@0: double d = 1; michael@0: michael@0: /* Handle negative exponent with a reciprocal at the end because michael@0: * 10 is exact whereas .1 is inexact in base 2 michael@0: */ michael@0: if (power < 0) michael@0: { michael@0: if (power < DBL_MIN_10_EXP) return 0; michael@0: recip = 1, power = -power; michael@0: } michael@0: michael@0: if (power > 0) michael@0: { michael@0: /* Decompose power bitwise. */ michael@0: double mult = 10; michael@0: do michael@0: { michael@0: if (power & 1) d *= mult; michael@0: mult *= mult; michael@0: power >>= 1; michael@0: } michael@0: while (power > 0); michael@0: michael@0: if (recip) d = 1/d; michael@0: } michael@0: /* else power is 0 and d is 1 */ michael@0: michael@0: return d; michael@0: } michael@0: michael@0: /* Function to format a floating point value in ASCII with a given michael@0: * precision. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size, michael@0: double fp, unsigned int precision) michael@0: { michael@0: /* We use standard functions from math.h, but not printf because michael@0: * that would require stdio. The caller must supply a buffer of michael@0: * sufficient size or we will png_error. The tests on size and michael@0: * the space in ascii[] consumed are indicated below. michael@0: */ michael@0: if (precision < 1) michael@0: precision = DBL_DIG; michael@0: michael@0: /* Enforce the limit of the implementation precision too. */ michael@0: if (precision > DBL_DIG+1) michael@0: precision = DBL_DIG+1; michael@0: michael@0: /* Basic sanity checks */ michael@0: if (size >= precision+5) /* See the requirements below. */ michael@0: { michael@0: if (fp < 0) michael@0: { michael@0: fp = -fp; michael@0: *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */ michael@0: --size; michael@0: } michael@0: michael@0: if (fp >= DBL_MIN && fp <= DBL_MAX) michael@0: { michael@0: int exp_b10; /* A base 10 exponent */ michael@0: double base; /* 10^exp_b10 */ michael@0: michael@0: /* First extract a base 10 exponent of the number, michael@0: * the calculation below rounds down when converting michael@0: * from base 2 to base 10 (multiply by log10(2) - michael@0: * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to michael@0: * be increased. Note that the arithmetic shift michael@0: * performs a floor() unlike C arithmetic - using a michael@0: * C multiply would break the following for negative michael@0: * exponents. michael@0: */ michael@0: (void)frexp(fp, &exp_b10); /* exponent to base 2 */ michael@0: michael@0: exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */ michael@0: michael@0: /* Avoid underflow here. */ michael@0: base = png_pow10(exp_b10); /* May underflow */ michael@0: michael@0: while (base < DBL_MIN || base < fp) michael@0: { michael@0: /* And this may overflow. */ michael@0: double test = png_pow10(exp_b10+1); michael@0: michael@0: if (test <= DBL_MAX) michael@0: ++exp_b10, base = test; michael@0: michael@0: else michael@0: break; michael@0: } michael@0: michael@0: /* Normalize fp and correct exp_b10, after this fp is in the michael@0: * range [.1,1) and exp_b10 is both the exponent and the digit michael@0: * *before* which the decimal point should be inserted michael@0: * (starting with 0 for the first digit). Note that this michael@0: * works even if 10^exp_b10 is out of range because of the michael@0: * test on DBL_MAX above. michael@0: */ michael@0: fp /= base; michael@0: while (fp >= 1) fp /= 10, ++exp_b10; michael@0: michael@0: /* Because of the code above fp may, at this point, be michael@0: * less than .1, this is ok because the code below can michael@0: * handle the leading zeros this generates, so no attempt michael@0: * is made to correct that here. michael@0: */ michael@0: michael@0: { michael@0: int czero, clead, cdigits; michael@0: char exponent[10]; michael@0: michael@0: /* Allow up to two leading zeros - this will not lengthen michael@0: * the number compared to using E-n. michael@0: */ michael@0: if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */ michael@0: { michael@0: czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */ michael@0: exp_b10 = 0; /* Dot added below before first output. */ michael@0: } michael@0: else michael@0: czero = 0; /* No zeros to add */ michael@0: michael@0: /* Generate the digit list, stripping trailing zeros and michael@0: * inserting a '.' before a digit if the exponent is 0. michael@0: */ michael@0: clead = czero; /* Count of leading zeros */ michael@0: cdigits = 0; /* Count of digits in list. */ michael@0: michael@0: do michael@0: { michael@0: double d; michael@0: michael@0: fp *= 10; michael@0: /* Use modf here, not floor and subtract, so that michael@0: * the separation is done in one step. At the end michael@0: * of the loop don't break the number into parts so michael@0: * that the final digit is rounded. michael@0: */ michael@0: if (cdigits+czero-clead+1 < (int)precision) michael@0: fp = modf(fp, &d); michael@0: michael@0: else michael@0: { michael@0: d = floor(fp + .5); michael@0: michael@0: if (d > 9) michael@0: { michael@0: /* Rounding up to 10, handle that here. */ michael@0: if (czero > 0) michael@0: { michael@0: --czero, d = 1; michael@0: if (cdigits == 0) --clead; michael@0: } michael@0: else michael@0: { michael@0: while (cdigits > 0 && d > 9) michael@0: { michael@0: int ch = *--ascii; michael@0: michael@0: if (exp_b10 != (-1)) michael@0: ++exp_b10; michael@0: michael@0: else if (ch == 46) michael@0: { michael@0: ch = *--ascii, ++size; michael@0: /* Advance exp_b10 to '1', so that the michael@0: * decimal point happens after the michael@0: * previous digit. michael@0: */ michael@0: exp_b10 = 1; michael@0: } michael@0: michael@0: --cdigits; michael@0: d = ch - 47; /* I.e. 1+(ch-48) */ michael@0: } michael@0: michael@0: /* Did we reach the beginning? If so adjust the michael@0: * exponent but take into account the leading michael@0: * decimal point. michael@0: */ michael@0: if (d > 9) /* cdigits == 0 */ michael@0: { michael@0: if (exp_b10 == (-1)) michael@0: { michael@0: /* Leading decimal point (plus zeros?), if michael@0: * we lose the decimal point here it must michael@0: * be reentered below. michael@0: */ michael@0: int ch = *--ascii; michael@0: michael@0: if (ch == 46) michael@0: ++size, exp_b10 = 1; michael@0: michael@0: /* Else lost a leading zero, so 'exp_b10' is michael@0: * still ok at (-1) michael@0: */ michael@0: } michael@0: else michael@0: ++exp_b10; michael@0: michael@0: /* In all cases we output a '1' */ michael@0: d = 1; michael@0: } michael@0: } michael@0: } michael@0: fp = 0; /* Guarantees termination below. */ michael@0: } michael@0: michael@0: if (d == 0) michael@0: { michael@0: ++czero; michael@0: if (cdigits == 0) ++clead; michael@0: } michael@0: else michael@0: { michael@0: /* Included embedded zeros in the digit count. */ michael@0: cdigits += czero - clead; michael@0: clead = 0; michael@0: michael@0: while (czero > 0) michael@0: { michael@0: /* exp_b10 == (-1) means we just output the decimal michael@0: * place - after the DP don't adjust 'exp_b10' any michael@0: * more! michael@0: */ michael@0: if (exp_b10 != (-1)) michael@0: { michael@0: if (exp_b10 == 0) *ascii++ = 46, --size; michael@0: /* PLUS 1: TOTAL 4 */ michael@0: --exp_b10; michael@0: } michael@0: *ascii++ = 48, --czero; michael@0: } michael@0: michael@0: if (exp_b10 != (-1)) michael@0: { michael@0: if (exp_b10 == 0) *ascii++ = 46, --size; /* counted michael@0: above */ michael@0: --exp_b10; michael@0: } michael@0: *ascii++ = (char)(48 + (int)d), ++cdigits; michael@0: } michael@0: } michael@0: while (cdigits+czero-clead < (int)precision && fp > DBL_MIN); michael@0: michael@0: /* The total output count (max) is now 4+precision */ michael@0: michael@0: /* Check for an exponent, if we don't need one we are michael@0: * done and just need to terminate the string. At michael@0: * this point exp_b10==(-1) is effectively if flag - it got michael@0: * to '-1' because of the decrement after outputing michael@0: * the decimal point above (the exponent required is michael@0: * *not* -1!) michael@0: */ michael@0: if (exp_b10 >= (-1) && exp_b10 <= 2) michael@0: { michael@0: /* The following only happens if we didn't output the michael@0: * leading zeros above for negative exponent, so this michael@0: * doest add to the digit requirement. Note that the michael@0: * two zeros here can only be output if the two leading michael@0: * zeros were *not* output, so this doesn't increase michael@0: * the output count. michael@0: */ michael@0: while (--exp_b10 >= 0) *ascii++ = 48; michael@0: michael@0: *ascii = 0; michael@0: michael@0: /* Total buffer requirement (including the '\0') is michael@0: * 5+precision - see check at the start. michael@0: */ michael@0: return; michael@0: } michael@0: michael@0: /* Here if an exponent is required, adjust size for michael@0: * the digits we output but did not count. The total michael@0: * digit output here so far is at most 1+precision - no michael@0: * decimal point and no leading or trailing zeros have michael@0: * been output. michael@0: */ michael@0: size -= cdigits; michael@0: michael@0: *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */ michael@0: michael@0: /* The following use of an unsigned temporary avoids ambiguities in michael@0: * the signed arithmetic on exp_b10 and permits GCC at least to do michael@0: * better optimization. michael@0: */ michael@0: { michael@0: unsigned int uexp_b10; michael@0: michael@0: if (exp_b10 < 0) michael@0: { michael@0: *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */ michael@0: uexp_b10 = -exp_b10; michael@0: } michael@0: michael@0: else michael@0: uexp_b10 = exp_b10; michael@0: michael@0: cdigits = 0; michael@0: michael@0: while (uexp_b10 > 0) michael@0: { michael@0: exponent[cdigits++] = (char)(48 + uexp_b10 % 10); michael@0: uexp_b10 /= 10; michael@0: } michael@0: } michael@0: michael@0: /* Need another size check here for the exponent digits, so michael@0: * this need not be considered above. michael@0: */ michael@0: if ((int)size > cdigits) michael@0: { michael@0: while (cdigits > 0) *ascii++ = exponent[--cdigits]; michael@0: michael@0: *ascii = 0; michael@0: michael@0: return; michael@0: } michael@0: } michael@0: } michael@0: else if (!(fp >= DBL_MIN)) michael@0: { michael@0: *ascii++ = 48; /* '0' */ michael@0: *ascii = 0; michael@0: return; michael@0: } michael@0: else michael@0: { michael@0: *ascii++ = 105; /* 'i' */ michael@0: *ascii++ = 110; /* 'n' */ michael@0: *ascii++ = 102; /* 'f' */ michael@0: *ascii = 0; michael@0: return; michael@0: } michael@0: } michael@0: michael@0: /* Here on buffer too small. */ michael@0: png_error(png_ptr, "ASCII conversion buffer too small"); michael@0: } michael@0: michael@0: # endif /* FLOATING_POINT */ michael@0: michael@0: # ifdef PNG_FIXED_POINT_SUPPORTED michael@0: /* Function to format a fixed point value in ASCII. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii, michael@0: png_size_t size, png_fixed_point fp) michael@0: { michael@0: /* Require space for 10 decimal digits, a decimal point, a minus sign and a michael@0: * trailing \0, 13 characters: michael@0: */ michael@0: if (size > 12) michael@0: { michael@0: png_uint_32 num; michael@0: michael@0: /* Avoid overflow here on the minimum integer. */ michael@0: if (fp < 0) michael@0: *ascii++ = 45, --size, num = -fp; michael@0: else michael@0: num = fp; michael@0: michael@0: if (num <= 0x80000000) /* else overflowed */ michael@0: { michael@0: unsigned int ndigits = 0, first = 16 /* flag value */; michael@0: char digits[10]; michael@0: michael@0: while (num) michael@0: { michael@0: /* Split the low digit off num: */ michael@0: unsigned int tmp = num/10; michael@0: num -= tmp*10; michael@0: digits[ndigits++] = (char)(48 + num); michael@0: /* Record the first non-zero digit, note that this is a number michael@0: * starting at 1, it's not actually the array index. michael@0: */ michael@0: if (first == 16 && num > 0) michael@0: first = ndigits; michael@0: num = tmp; michael@0: } michael@0: michael@0: if (ndigits > 0) michael@0: { michael@0: while (ndigits > 5) *ascii++ = digits[--ndigits]; michael@0: /* The remaining digits are fractional digits, ndigits is '5' or michael@0: * smaller at this point. It is certainly not zero. Check for a michael@0: * non-zero fractional digit: michael@0: */ michael@0: if (first <= 5) michael@0: { michael@0: unsigned int i; michael@0: *ascii++ = 46; /* decimal point */ michael@0: /* ndigits may be <5 for small numbers, output leading zeros michael@0: * then ndigits digits to first: michael@0: */ michael@0: i = 5; michael@0: while (ndigits < i) *ascii++ = 48, --i; michael@0: while (ndigits >= first) *ascii++ = digits[--ndigits]; michael@0: /* Don't output the trailing zeros! */ michael@0: } michael@0: } michael@0: else michael@0: *ascii++ = 48; michael@0: michael@0: /* And null terminate the string: */ michael@0: *ascii = 0; michael@0: return; michael@0: } michael@0: } michael@0: michael@0: /* Here on buffer too small. */ michael@0: png_error(png_ptr, "ASCII conversion buffer too small"); michael@0: } michael@0: # endif /* FIXED_POINT */ michael@0: #endif /* READ_SCAL */ michael@0: michael@0: #if defined(PNG_FLOATING_POINT_SUPPORTED) && \ michael@0: !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \ michael@0: (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \ michael@0: defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \ michael@0: defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \ michael@0: (defined(PNG_sCAL_SUPPORTED) && \ michael@0: defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)) michael@0: png_fixed_point michael@0: png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text) michael@0: { michael@0: double r = floor(100000 * fp + .5); michael@0: michael@0: if (r > 2147483647. || r < -2147483648.) michael@0: png_fixed_error(png_ptr, text); michael@0: michael@0: # ifndef PNG_ERROR_TEXT_SUPPORTED michael@0: PNG_UNUSED(text) michael@0: # endif michael@0: michael@0: return (png_fixed_point)r; michael@0: } michael@0: #endif michael@0: michael@0: #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\ michael@0: defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED) michael@0: /* muldiv functions */ michael@0: /* This API takes signed arguments and rounds the result to the nearest michael@0: * integer (or, for a fixed point number - the standard argument - to michael@0: * the nearest .00001). Overflow and divide by zero are signalled in michael@0: * the result, a boolean - true on success, false on overflow. michael@0: */ michael@0: int michael@0: png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times, michael@0: png_int_32 divisor) michael@0: { michael@0: /* Return a * times / divisor, rounded. */ michael@0: if (divisor != 0) michael@0: { michael@0: if (a == 0 || times == 0) michael@0: { michael@0: *res = 0; michael@0: return 1; michael@0: } michael@0: else michael@0: { michael@0: #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = a; michael@0: r *= times; michael@0: r /= divisor; michael@0: r = floor(r+.5); michael@0: michael@0: /* A png_fixed_point is a 32-bit integer. */ michael@0: if (r <= 2147483647. && r >= -2147483648.) michael@0: { michael@0: *res = (png_fixed_point)r; michael@0: return 1; michael@0: } michael@0: #else michael@0: int negative = 0; michael@0: png_uint_32 A, T, D; michael@0: png_uint_32 s16, s32, s00; michael@0: michael@0: if (a < 0) michael@0: negative = 1, A = -a; michael@0: else michael@0: A = a; michael@0: michael@0: if (times < 0) michael@0: negative = !negative, T = -times; michael@0: else michael@0: T = times; michael@0: michael@0: if (divisor < 0) michael@0: negative = !negative, D = -divisor; michael@0: else michael@0: D = divisor; michael@0: michael@0: /* Following can't overflow because the arguments only michael@0: * have 31 bits each, however the result may be 32 bits. michael@0: */ michael@0: s16 = (A >> 16) * (T & 0xffff) + michael@0: (A & 0xffff) * (T >> 16); michael@0: /* Can't overflow because the a*times bit is only 30 michael@0: * bits at most. michael@0: */ michael@0: s32 = (A >> 16) * (T >> 16) + (s16 >> 16); michael@0: s00 = (A & 0xffff) * (T & 0xffff); michael@0: michael@0: s16 = (s16 & 0xffff) << 16; michael@0: s00 += s16; michael@0: michael@0: if (s00 < s16) michael@0: ++s32; /* carry */ michael@0: michael@0: if (s32 < D) /* else overflow */ michael@0: { michael@0: /* s32.s00 is now the 64-bit product, do a standard michael@0: * division, we know that s32 < D, so the maximum michael@0: * required shift is 31. michael@0: */ michael@0: int bitshift = 32; michael@0: png_fixed_point result = 0; /* NOTE: signed */ michael@0: michael@0: while (--bitshift >= 0) michael@0: { michael@0: png_uint_32 d32, d00; michael@0: michael@0: if (bitshift > 0) michael@0: d32 = D >> (32-bitshift), d00 = D << bitshift; michael@0: michael@0: else michael@0: d32 = 0, d00 = D; michael@0: michael@0: if (s32 > d32) michael@0: { michael@0: if (s00 < d00) --s32; /* carry */ michael@0: s32 -= d32, s00 -= d00, result += 1<= d00) michael@0: s32 = 0, s00 -= d00, result += 1<= (D >> 1)) michael@0: ++result; michael@0: michael@0: if (negative) michael@0: result = -result; michael@0: michael@0: /* Check for overflow. */ michael@0: if ((negative && result <= 0) || (!negative && result >= 0)) michael@0: { michael@0: *res = result; michael@0: return 1; michael@0: } michael@0: } michael@0: #endif michael@0: } michael@0: } michael@0: michael@0: return 0; michael@0: } michael@0: #endif /* READ_GAMMA || INCH_CONVERSIONS */ michael@0: michael@0: #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED) michael@0: /* The following is for when the caller doesn't much care about the michael@0: * result. michael@0: */ michael@0: png_fixed_point michael@0: png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times, michael@0: png_int_32 divisor) michael@0: { michael@0: png_fixed_point result; michael@0: michael@0: if (png_muldiv(&result, a, times, divisor)) michael@0: return result; michael@0: michael@0: png_warning(png_ptr, "fixed point overflow ignored"); michael@0: return 0; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */ michael@0: /* Calculate a reciprocal, return 0 on div-by-zero or overflow. */ michael@0: png_fixed_point michael@0: png_reciprocal(png_fixed_point a) michael@0: { michael@0: #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = floor(1E10/a+.5); michael@0: michael@0: if (r <= 2147483647. && r >= -2147483648.) michael@0: return (png_fixed_point)r; michael@0: #else michael@0: png_fixed_point res; michael@0: michael@0: if (png_muldiv(&res, 100000, 100000, a)) michael@0: return res; michael@0: #endif michael@0: michael@0: return 0; /* error/overflow */ michael@0: } michael@0: michael@0: /* This is the shared test on whether a gamma value is 'significant' - whether michael@0: * it is worth doing gamma correction. michael@0: */ michael@0: int /* PRIVATE */ michael@0: png_gamma_significant(png_fixed_point gamma_val) michael@0: { michael@0: return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || michael@0: gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; michael@0: } michael@0: #endif michael@0: michael@0: #ifdef PNG_READ_GAMMA_SUPPORTED michael@0: # ifdef PNG_16BIT_SUPPORTED michael@0: /* A local convenience routine. */ michael@0: static png_fixed_point michael@0: png_product2(png_fixed_point a, png_fixed_point b) michael@0: { michael@0: /* The required result is 1/a * 1/b; the following preserves accuracy. */ michael@0: # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = a * 1E-5; michael@0: r *= b; michael@0: r = floor(r+.5); michael@0: michael@0: if (r <= 2147483647. && r >= -2147483648.) michael@0: return (png_fixed_point)r; michael@0: # else michael@0: png_fixed_point res; michael@0: michael@0: if (png_muldiv(&res, a, b, 100000)) michael@0: return res; michael@0: # endif michael@0: michael@0: return 0; /* overflow */ michael@0: } michael@0: # endif /* 16BIT */ michael@0: michael@0: /* The inverse of the above. */ michael@0: png_fixed_point michael@0: png_reciprocal2(png_fixed_point a, png_fixed_point b) michael@0: { michael@0: /* The required result is 1/a * 1/b; the following preserves accuracy. */ michael@0: #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = 1E15/a; michael@0: r /= b; michael@0: r = floor(r+.5); michael@0: michael@0: if (r <= 2147483647. && r >= -2147483648.) michael@0: return (png_fixed_point)r; michael@0: #else michael@0: /* This may overflow because the range of png_fixed_point isn't symmetric, michael@0: * but this API is only used for the product of file and screen gamma so it michael@0: * doesn't matter that the smallest number it can produce is 1/21474, not michael@0: * 1/100000 michael@0: */ michael@0: png_fixed_point res = png_product2(a, b); michael@0: michael@0: if (res != 0) michael@0: return png_reciprocal(res); michael@0: #endif michael@0: michael@0: return 0; /* overflow */ michael@0: } michael@0: #endif /* READ_GAMMA */ michael@0: michael@0: #ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */ michael@0: #ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: /* Fixed point gamma. michael@0: * michael@0: * The code to calculate the tables used below can be found in the shell script michael@0: * contrib/tools/intgamma.sh michael@0: * michael@0: * To calculate gamma this code implements fast log() and exp() calls using only michael@0: * fixed point arithmetic. This code has sufficient precision for either 8-bit michael@0: * or 16-bit sample values. michael@0: * michael@0: * The tables used here were calculated using simple 'bc' programs, but C double michael@0: * precision floating point arithmetic would work fine. michael@0: * michael@0: * 8-bit log table michael@0: * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to michael@0: * 255, so it's the base 2 logarithm of a normalized 8-bit floating point michael@0: * mantissa. The numbers are 32-bit fractions. michael@0: */ michael@0: static const png_uint_32 michael@0: png_8bit_l2[128] = michael@0: { michael@0: 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U, michael@0: 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U, michael@0: 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U, michael@0: 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U, michael@0: 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U, michael@0: 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U, michael@0: 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U, michael@0: 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U, michael@0: 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U, michael@0: 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U, michael@0: 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U, michael@0: 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U, michael@0: 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U, michael@0: 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U, michael@0: 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U, michael@0: 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U, michael@0: 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U, michael@0: 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U, michael@0: 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U, michael@0: 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U, michael@0: 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U, michael@0: 24347096U, 0U michael@0: michael@0: #if 0 michael@0: /* The following are the values for 16-bit tables - these work fine for the michael@0: * 8-bit conversions but produce very slightly larger errors in the 16-bit michael@0: * log (about 1.2 as opposed to 0.7 absolute error in the final value). To michael@0: * use these all the shifts below must be adjusted appropriately. michael@0: */ michael@0: 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054, michael@0: 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803, michael@0: 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068, michael@0: 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782, michael@0: 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887, michael@0: 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339, michael@0: 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098, michael@0: 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132, michael@0: 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415, michael@0: 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523, michael@0: 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495, michael@0: 1119, 744, 372 michael@0: #endif michael@0: }; michael@0: michael@0: static png_int_32 michael@0: png_log8bit(unsigned int x) michael@0: { michael@0: unsigned int lg2 = 0; michael@0: /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log, michael@0: * because the log is actually negate that means adding 1. The final michael@0: * returned value thus has the range 0 (for 255 input) to 7.994 (for 1 michael@0: * input), return -1 for the overflow (log 0) case, - so the result is michael@0: * always at most 19 bits. michael@0: */ michael@0: if ((x &= 0xff) == 0) michael@0: return -1; michael@0: michael@0: if ((x & 0xf0) == 0) michael@0: lg2 = 4, x <<= 4; michael@0: michael@0: if ((x & 0xc0) == 0) michael@0: lg2 += 2, x <<= 2; michael@0: michael@0: if ((x & 0x80) == 0) michael@0: lg2 += 1, x <<= 1; michael@0: michael@0: /* result is at most 19 bits, so this cast is safe: */ michael@0: return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16)); michael@0: } michael@0: michael@0: /* The above gives exact (to 16 binary places) log2 values for 8-bit images, michael@0: * for 16-bit images we use the most significant 8 bits of the 16-bit value to michael@0: * get an approximation then multiply the approximation by a correction factor michael@0: * determined by the remaining up to 8 bits. This requires an additional step michael@0: * in the 16-bit case. michael@0: * michael@0: * We want log2(value/65535), we have log2(v'/255), where: michael@0: * michael@0: * value = v' * 256 + v'' michael@0: * = v' * f michael@0: * michael@0: * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128 michael@0: * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less michael@0: * than 258. The final factor also needs to correct for the fact that our 8-bit michael@0: * value is scaled by 255, whereas the 16-bit values must be scaled by 65535. michael@0: * michael@0: * This gives a final formula using a calculated value 'x' which is value/v' and michael@0: * scaling by 65536 to match the above table: michael@0: * michael@0: * log2(x/257) * 65536 michael@0: * michael@0: * Since these numbers are so close to '1' we can use simple linear michael@0: * interpolation between the two end values 256/257 (result -368.61) and 258/257 michael@0: * (result 367.179). The values used below are scaled by a further 64 to give michael@0: * 16-bit precision in the interpolation: michael@0: * michael@0: * Start (256): -23591 michael@0: * Zero (257): 0 michael@0: * End (258): 23499 michael@0: */ michael@0: static png_int_32 michael@0: png_log16bit(png_uint_32 x) michael@0: { michael@0: unsigned int lg2 = 0; michael@0: michael@0: /* As above, but now the input has 16 bits. */ michael@0: if ((x &= 0xffff) == 0) michael@0: return -1; michael@0: michael@0: if ((x & 0xff00) == 0) michael@0: lg2 = 8, x <<= 8; michael@0: michael@0: if ((x & 0xf000) == 0) michael@0: lg2 += 4, x <<= 4; michael@0: michael@0: if ((x & 0xc000) == 0) michael@0: lg2 += 2, x <<= 2; michael@0: michael@0: if ((x & 0x8000) == 0) michael@0: lg2 += 1, x <<= 1; michael@0: michael@0: /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional michael@0: * value. michael@0: */ michael@0: lg2 <<= 28; michael@0: lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4; michael@0: michael@0: /* Now we need to interpolate the factor, this requires a division by the top michael@0: * 8 bits. Do this with maximum precision. michael@0: */ michael@0: x = ((x << 16) + (x >> 9)) / (x >> 8); michael@0: michael@0: /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24, michael@0: * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly michael@0: * 16 bits to interpolate to get the low bits of the result. Round the michael@0: * answer. Note that the end point values are scaled by 64 to retain overall michael@0: * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust michael@0: * the overall scaling by 6-12. Round at every step. michael@0: */ michael@0: x -= 1U << 24; michael@0: michael@0: if (x <= 65536U) /* <= '257' */ michael@0: lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12); michael@0: michael@0: else michael@0: lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12); michael@0: michael@0: /* Safe, because the result can't have more than 20 bits: */ michael@0: return (png_int_32)((lg2 + 2048) >> 12); michael@0: } michael@0: michael@0: /* The 'exp()' case must invert the above, taking a 20-bit fixed point michael@0: * logarithmic value and returning a 16 or 8-bit number as appropriate. In michael@0: * each case only the low 16 bits are relevant - the fraction - since the michael@0: * integer bits (the top 4) simply determine a shift. michael@0: * michael@0: * The worst case is the 16-bit distinction between 65535 and 65534, this michael@0: * requires perhaps spurious accuracty in the decoding of the logarithm to michael@0: * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance michael@0: * of getting this accuracy in practice. michael@0: * michael@0: * To deal with this the following exp() function works out the exponent of the michael@0: * frational part of the logarithm by using an accurate 32-bit value from the michael@0: * top four fractional bits then multiplying in the remaining bits. michael@0: */ michael@0: static const png_uint_32 michael@0: png_32bit_exp[16] = michael@0: { michael@0: /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */ michael@0: 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U, michael@0: 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U, michael@0: 2553802834U, 2445529972U, 2341847524U, 2242560872U michael@0: }; michael@0: michael@0: /* Adjustment table; provided to explain the numbers in the code below. */ michael@0: #if 0 michael@0: for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"} michael@0: 11 44937.64284865548751208448 michael@0: 10 45180.98734845585101160448 michael@0: 9 45303.31936980687359311872 michael@0: 8 45364.65110595323018870784 michael@0: 7 45395.35850361789624614912 michael@0: 6 45410.72259715102037508096 michael@0: 5 45418.40724413220722311168 michael@0: 4 45422.25021786898173001728 michael@0: 3 45424.17186732298419044352 michael@0: 2 45425.13273269940811464704 michael@0: 1 45425.61317555035558641664 michael@0: 0 45425.85339951654943850496 michael@0: #endif michael@0: michael@0: static png_uint_32 michael@0: png_exp(png_fixed_point x) michael@0: { michael@0: if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */ michael@0: { michael@0: /* Obtain a 4-bit approximation */ michael@0: png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf]; michael@0: michael@0: /* Incorporate the low 12 bits - these decrease the returned value by michael@0: * multiplying by a number less than 1 if the bit is set. The multiplier michael@0: * is determined by the above table and the shift. Notice that the values michael@0: * converge on 45426 and this is used to allow linear interpolation of the michael@0: * low bits. michael@0: */ michael@0: if (x & 0x800) michael@0: e -= (((e >> 16) * 44938U) + 16U) >> 5; michael@0: michael@0: if (x & 0x400) michael@0: e -= (((e >> 16) * 45181U) + 32U) >> 6; michael@0: michael@0: if (x & 0x200) michael@0: e -= (((e >> 16) * 45303U) + 64U) >> 7; michael@0: michael@0: if (x & 0x100) michael@0: e -= (((e >> 16) * 45365U) + 128U) >> 8; michael@0: michael@0: if (x & 0x080) michael@0: e -= (((e >> 16) * 45395U) + 256U) >> 9; michael@0: michael@0: if (x & 0x040) michael@0: e -= (((e >> 16) * 45410U) + 512U) >> 10; michael@0: michael@0: /* And handle the low 6 bits in a single block. */ michael@0: e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9; michael@0: michael@0: /* Handle the upper bits of x. */ michael@0: e >>= x >> 16; michael@0: return e; michael@0: } michael@0: michael@0: /* Check for overflow */ michael@0: if (x <= 0) michael@0: return png_32bit_exp[0]; michael@0: michael@0: /* Else underflow */ michael@0: return 0; michael@0: } michael@0: michael@0: static png_byte michael@0: png_exp8bit(png_fixed_point lg2) michael@0: { michael@0: /* Get a 32-bit value: */ michael@0: png_uint_32 x = png_exp(lg2); michael@0: michael@0: /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the michael@0: * second, rounding, step can't overflow because of the first, subtraction, michael@0: * step. michael@0: */ michael@0: x -= x >> 8; michael@0: return (png_byte)((x + 0x7fffffU) >> 24); michael@0: } michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: static png_uint_16 michael@0: png_exp16bit(png_fixed_point lg2) michael@0: { michael@0: /* Get a 32-bit value: */ michael@0: png_uint_32 x = png_exp(lg2); michael@0: michael@0: /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */ michael@0: x -= x >> 16; michael@0: return (png_uint_16)((x + 32767U) >> 16); michael@0: } michael@0: #endif /* 16BIT */ michael@0: #endif /* FLOATING_ARITHMETIC */ michael@0: michael@0: png_byte michael@0: png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val) michael@0: { michael@0: if (value > 0 && value < 255) michael@0: { michael@0: # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = floor(255*pow(value/255.,gamma_val*.00001)+.5); michael@0: return (png_byte)r; michael@0: # else michael@0: png_int_32 lg2 = png_log8bit(value); michael@0: png_fixed_point res; michael@0: michael@0: if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1)) michael@0: return png_exp8bit(res); michael@0: michael@0: /* Overflow. */ michael@0: value = 0; michael@0: # endif michael@0: } michael@0: michael@0: return (png_byte)value; michael@0: } michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: png_uint_16 michael@0: png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val) michael@0: { michael@0: if (value > 0 && value < 65535) michael@0: { michael@0: # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: double r = floor(65535*pow(value/65535.,gamma_val*.00001)+.5); michael@0: return (png_uint_16)r; michael@0: # else michael@0: png_int_32 lg2 = png_log16bit(value); michael@0: png_fixed_point res; michael@0: michael@0: if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1)) michael@0: return png_exp16bit(res); michael@0: michael@0: /* Overflow. */ michael@0: value = 0; michael@0: # endif michael@0: } michael@0: michael@0: return (png_uint_16)value; michael@0: } michael@0: #endif /* 16BIT */ michael@0: michael@0: /* This does the right thing based on the bit_depth field of the michael@0: * png_struct, interpreting values as 8-bit or 16-bit. While the result michael@0: * is nominally a 16-bit value if bit depth is 8 then the result is michael@0: * 8-bit (as are the arguments.) michael@0: */ michael@0: png_uint_16 /* PRIVATE */ michael@0: png_gamma_correct(png_structrp png_ptr, unsigned int value, michael@0: png_fixed_point gamma_val) michael@0: { michael@0: if (png_ptr->bit_depth == 8) michael@0: return png_gamma_8bit_correct(value, gamma_val); michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: else michael@0: return png_gamma_16bit_correct(value, gamma_val); michael@0: #else michael@0: /* should not reach this */ michael@0: return 0; michael@0: #endif /* 16BIT */ michael@0: } michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: /* Internal function to build a single 16-bit table - the table consists of michael@0: * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount michael@0: * to shift the input values right (or 16-number_of_signifiant_bits). michael@0: * michael@0: * The caller is responsible for ensuring that the table gets cleaned up on michael@0: * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument michael@0: * should be somewhere that will be cleaned. michael@0: */ michael@0: static void michael@0: png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable, michael@0: PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) michael@0: { michael@0: /* Various values derived from 'shift': */ michael@0: PNG_CONST unsigned int num = 1U << (8U - shift); michael@0: PNG_CONST unsigned int max = (1U << (16U - shift))-1U; michael@0: PNG_CONST unsigned int max_by_2 = 1U << (15U-shift); michael@0: unsigned int i; michael@0: michael@0: png_uint_16pp table = *ptable = michael@0: (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); michael@0: michael@0: for (i = 0; i < num; i++) michael@0: { michael@0: png_uint_16p sub_table = table[i] = michael@0: (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16))); michael@0: michael@0: /* The 'threshold' test is repeated here because it can arise for one of michael@0: * the 16-bit tables even if the others don't hit it. michael@0: */ michael@0: if (png_gamma_significant(gamma_val)) michael@0: { michael@0: /* The old code would overflow at the end and this would cause the michael@0: * 'pow' function to return a result >1, resulting in an michael@0: * arithmetic error. This code follows the spec exactly; ig is michael@0: * the recovered input sample, it always has 8-16 bits. michael@0: * michael@0: * We want input * 65535/max, rounded, the arithmetic fits in 32 michael@0: * bits (unsigned) so long as max <= 32767. michael@0: */ michael@0: unsigned int j; michael@0: for (j = 0; j < 256; j++) michael@0: { michael@0: png_uint_32 ig = (j << (8-shift)) + i; michael@0: # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED michael@0: /* Inline the 'max' scaling operation: */ michael@0: double d = floor(65535*pow(ig/(double)max, gamma_val*.00001)+.5); michael@0: sub_table[j] = (png_uint_16)d; michael@0: # else michael@0: if (shift) michael@0: ig = (ig * 65535U + max_by_2)/max; michael@0: michael@0: sub_table[j] = png_gamma_16bit_correct(ig, gamma_val); michael@0: # endif michael@0: } michael@0: } michael@0: else michael@0: { michael@0: /* We must still build a table, but do it the fast way. */ michael@0: unsigned int j; michael@0: michael@0: for (j = 0; j < 256; j++) michael@0: { michael@0: png_uint_32 ig = (j << (8-shift)) + i; michael@0: michael@0: if (shift) michael@0: ig = (ig * 65535U + max_by_2)/max; michael@0: michael@0: sub_table[j] = (png_uint_16)ig; michael@0: } michael@0: } michael@0: } michael@0: } michael@0: michael@0: /* NOTE: this function expects the *inverse* of the overall gamma transformation michael@0: * required. michael@0: */ michael@0: static void michael@0: png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable, michael@0: PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) michael@0: { michael@0: PNG_CONST unsigned int num = 1U << (8U - shift); michael@0: PNG_CONST unsigned int max = (1U << (16U - shift))-1U; michael@0: unsigned int i; michael@0: png_uint_32 last; michael@0: michael@0: png_uint_16pp table = *ptable = michael@0: (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); michael@0: michael@0: /* 'num' is the number of tables and also the number of low bits of low michael@0: * bits of the input 16-bit value used to select a table. Each table is michael@0: * itself index by the high 8 bits of the value. michael@0: */ michael@0: for (i = 0; i < num; i++) michael@0: table[i] = (png_uint_16p)png_malloc(png_ptr, michael@0: 256 * (sizeof (png_uint_16))); michael@0: michael@0: /* 'gamma_val' is set to the reciprocal of the value calculated above, so michael@0: * pow(out,g) is an *input* value. 'last' is the last input value set. michael@0: * michael@0: * In the loop 'i' is used to find output values. Since the output is michael@0: * 8-bit there are only 256 possible values. The tables are set up to michael@0: * select the closest possible output value for each input by finding michael@0: * the input value at the boundary between each pair of output values michael@0: * and filling the table up to that boundary with the lower output michael@0: * value. michael@0: * michael@0: * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit michael@0: * values the code below uses a 16-bit value in i; the values start at michael@0: * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last michael@0: * entries are filled with 255). Start i at 128 and fill all 'last' michael@0: * table entries <= 'max' michael@0: */ michael@0: last = 0; michael@0: for (i = 0; i < 255; ++i) /* 8-bit output value */ michael@0: { michael@0: /* Find the corresponding maximum input value */ michael@0: png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */ michael@0: michael@0: /* Find the boundary value in 16 bits: */ michael@0: png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val); michael@0: michael@0: /* Adjust (round) to (16-shift) bits: */ michael@0: bound = (bound * max + 32768U)/65535U + 1U; michael@0: michael@0: while (last < bound) michael@0: { michael@0: table[last & (0xffU >> shift)][last >> (8U - shift)] = out; michael@0: last++; michael@0: } michael@0: } michael@0: michael@0: /* And fill in the final entries. */ michael@0: while (last < (num << 8)) michael@0: { michael@0: table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U; michael@0: last++; michael@0: } michael@0: } michael@0: #endif /* 16BIT */ michael@0: michael@0: /* Build a single 8-bit table: same as the 16-bit case but much simpler (and michael@0: * typically much faster). Note that libpng currently does no sBIT processing michael@0: * (apparently contrary to the spec) so a 256 entry table is always generated. michael@0: */ michael@0: static void michael@0: png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable, michael@0: PNG_CONST png_fixed_point gamma_val) michael@0: { michael@0: unsigned int i; michael@0: png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256); michael@0: michael@0: if (png_gamma_significant(gamma_val)) for (i=0; i<256; i++) michael@0: table[i] = png_gamma_8bit_correct(i, gamma_val); michael@0: michael@0: else for (i=0; i<256; ++i) michael@0: table[i] = (png_byte)i; michael@0: } michael@0: michael@0: /* Used from png_read_destroy and below to release the memory used by the gamma michael@0: * tables. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_destroy_gamma_table(png_structrp png_ptr) michael@0: { michael@0: png_free(png_ptr, png_ptr->gamma_table); michael@0: png_ptr->gamma_table = NULL; michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: if (png_ptr->gamma_16_table != NULL) michael@0: { michael@0: int i; michael@0: int istop = (1 << (8 - png_ptr->gamma_shift)); michael@0: for (i = 0; i < istop; i++) michael@0: { michael@0: png_free(png_ptr, png_ptr->gamma_16_table[i]); michael@0: } michael@0: png_free(png_ptr, png_ptr->gamma_16_table); michael@0: png_ptr->gamma_16_table = NULL; michael@0: } michael@0: #endif /* 16BIT */ michael@0: michael@0: #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ michael@0: defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ michael@0: defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) michael@0: png_free(png_ptr, png_ptr->gamma_from_1); michael@0: png_ptr->gamma_from_1 = NULL; michael@0: png_free(png_ptr, png_ptr->gamma_to_1); michael@0: png_ptr->gamma_to_1 = NULL; michael@0: michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: if (png_ptr->gamma_16_from_1 != NULL) michael@0: { michael@0: int i; michael@0: int istop = (1 << (8 - png_ptr->gamma_shift)); michael@0: for (i = 0; i < istop; i++) michael@0: { michael@0: png_free(png_ptr, png_ptr->gamma_16_from_1[i]); michael@0: } michael@0: png_free(png_ptr, png_ptr->gamma_16_from_1); michael@0: png_ptr->gamma_16_from_1 = NULL; michael@0: } michael@0: if (png_ptr->gamma_16_to_1 != NULL) michael@0: { michael@0: int i; michael@0: int istop = (1 << (8 - png_ptr->gamma_shift)); michael@0: for (i = 0; i < istop; i++) michael@0: { michael@0: png_free(png_ptr, png_ptr->gamma_16_to_1[i]); michael@0: } michael@0: png_free(png_ptr, png_ptr->gamma_16_to_1); michael@0: png_ptr->gamma_16_to_1 = NULL; michael@0: } michael@0: #endif /* 16BIT */ michael@0: #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ michael@0: } michael@0: michael@0: /* We build the 8- or 16-bit gamma tables here. Note that for 16-bit michael@0: * tables, we don't make a full table if we are reducing to 8-bit in michael@0: * the future. Note also how the gamma_16 tables are segmented so that michael@0: * we don't need to allocate > 64K chunks for a full 16-bit table. michael@0: */ michael@0: void /* PRIVATE */ michael@0: png_build_gamma_table(png_structrp png_ptr, int bit_depth) michael@0: { michael@0: png_debug(1, "in png_build_gamma_table"); michael@0: michael@0: /* Remove any existing table; this copes with multiple calls to michael@0: * png_read_update_info. The warning is because building the gamma tables michael@0: * multiple times is a performance hit - it's harmless but the ability to call michael@0: * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible michael@0: * to warn if the app introduces such a hit. michael@0: */ michael@0: if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL) michael@0: { michael@0: png_warning(png_ptr, "gamma table being rebuilt"); michael@0: png_destroy_gamma_table(png_ptr); michael@0: } michael@0: michael@0: if (bit_depth <= 8) michael@0: { michael@0: png_build_8bit_table(png_ptr, &png_ptr->gamma_table, michael@0: png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, michael@0: png_ptr->screen_gamma) : PNG_FP_1); michael@0: michael@0: #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ michael@0: defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ michael@0: defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) michael@0: if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) michael@0: { michael@0: png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1, michael@0: png_reciprocal(png_ptr->colorspace.gamma)); michael@0: michael@0: png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1, michael@0: png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : michael@0: png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); michael@0: } michael@0: #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ michael@0: } michael@0: #ifdef PNG_16BIT_SUPPORTED michael@0: else michael@0: { michael@0: png_byte shift, sig_bit; michael@0: michael@0: if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) michael@0: { michael@0: sig_bit = png_ptr->sig_bit.red; michael@0: michael@0: if (png_ptr->sig_bit.green > sig_bit) michael@0: sig_bit = png_ptr->sig_bit.green; michael@0: michael@0: if (png_ptr->sig_bit.blue > sig_bit) michael@0: sig_bit = png_ptr->sig_bit.blue; michael@0: } michael@0: else michael@0: sig_bit = png_ptr->sig_bit.gray; michael@0: michael@0: /* 16-bit gamma code uses this equation: michael@0: * michael@0: * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8] michael@0: * michael@0: * Where 'iv' is the input color value and 'ov' is the output value - michael@0: * pow(iv, gamma). michael@0: * michael@0: * Thus the gamma table consists of up to 256 256 entry tables. The table michael@0: * is selected by the (8-gamma_shift) most significant of the low 8 bits of michael@0: * the color value then indexed by the upper 8 bits: michael@0: * michael@0: * table[low bits][high 8 bits] michael@0: * michael@0: * So the table 'n' corresponds to all those 'iv' of: michael@0: * michael@0: * ..<(n+1 << gamma_shift)-1> michael@0: * michael@0: */ michael@0: if (sig_bit > 0 && sig_bit < 16U) michael@0: shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */ michael@0: michael@0: else michael@0: shift = 0; /* keep all 16 bits */ michael@0: michael@0: if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) michael@0: { michael@0: /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively michael@0: * the significant bits in the *input* when the output will michael@0: * eventually be 8 bits. By default it is 11. michael@0: */ michael@0: if (shift < (16U - PNG_MAX_GAMMA_8)) michael@0: shift = (16U - PNG_MAX_GAMMA_8); michael@0: } michael@0: michael@0: if (shift > 8U) michael@0: shift = 8U; /* Guarantees at least one table! */ michael@0: michael@0: png_ptr->gamma_shift = shift; michael@0: michael@0: /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now michael@0: * PNG_COMPOSE). This effectively smashed the background calculation for michael@0: * 16-bit output because the 8-bit table assumes the result will be reduced michael@0: * to 8 bits. michael@0: */ michael@0: if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) michael@0: png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift, michael@0: png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma, michael@0: png_ptr->screen_gamma) : PNG_FP_1); michael@0: michael@0: else michael@0: png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift, michael@0: png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, michael@0: png_ptr->screen_gamma) : PNG_FP_1); michael@0: michael@0: #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ michael@0: defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ michael@0: defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) michael@0: if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) michael@0: { michael@0: png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift, michael@0: png_reciprocal(png_ptr->colorspace.gamma)); michael@0: michael@0: /* Notice that the '16 from 1' table should be full precision, however michael@0: * the lookup on this table still uses gamma_shift, so it can't be. michael@0: * TODO: fix this. michael@0: */ michael@0: png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift, michael@0: png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : michael@0: png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); michael@0: } michael@0: #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ michael@0: } michael@0: #endif /* 16BIT */ michael@0: } michael@0: #endif /* READ_GAMMA */ michael@0: michael@0: /* HARDWARE OPTION SUPPORT */ michael@0: #ifdef PNG_SET_OPTION_SUPPORTED michael@0: int PNGAPI michael@0: png_set_option(png_structrp png_ptr, int option, int onoff) michael@0: { michael@0: if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT && michael@0: (option & 1) == 0) michael@0: { michael@0: int mask = 3 << option; michael@0: int setting = (2 + (onoff != 0)) << option; michael@0: int current = png_ptr->options; michael@0: michael@0: png_ptr->options = (png_byte)((current & ~mask) | setting); michael@0: michael@0: return (current & mask) >> option; michael@0: } michael@0: michael@0: return PNG_OPTION_INVALID; michael@0: } michael@0: #endif michael@0: michael@0: /* sRGB support */ michael@0: #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ michael@0: defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) michael@0: /* sRGB conversion tables; these are machine generated with the code in michael@0: * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the michael@0: * specification (see the article at http://en.wikipedia.org/wiki/SRGB) michael@0: * is used, not the gamma=1/2.2 approximation use elsewhere in libpng. michael@0: * The sRGB to linear table is exact (to the nearest 16 bit linear fraction). michael@0: * The inverse (linear to sRGB) table has accuracies as follows: michael@0: * michael@0: * For all possible (255*65535+1) input values: michael@0: * michael@0: * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact michael@0: * michael@0: * For the input values corresponding to the 65536 16-bit values: michael@0: * michael@0: * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact michael@0: * michael@0: * In all cases the inexact readings are off by one. michael@0: */ michael@0: michael@0: #ifdef PNG_SIMPLIFIED_READ_SUPPORTED michael@0: /* The convert-to-sRGB table is only currently required for read. */ michael@0: const png_uint_16 png_sRGB_table[256] = michael@0: { michael@0: 0,20,40,60,80,99,119,139, michael@0: 159,179,199,219,241,264,288,313, michael@0: 340,367,396,427,458,491,526,562, michael@0: 599,637,677,718,761,805,851,898, michael@0: 947,997,1048,1101,1156,1212,1270,1330, michael@0: 1391,1453,1517,1583,1651,1720,1790,1863, michael@0: 1937,2013,2090,2170,2250,2333,2418,2504, michael@0: 2592,2681,2773,2866,2961,3058,3157,3258, michael@0: 3360,3464,3570,3678,3788,3900,4014,4129, michael@0: 4247,4366,4488,4611,4736,4864,4993,5124, michael@0: 5257,5392,5530,5669,5810,5953,6099,6246, michael@0: 6395,6547,6700,6856,7014,7174,7335,7500, michael@0: 7666,7834,8004,8177,8352,8528,8708,8889, michael@0: 9072,9258,9445,9635,9828,10022,10219,10417, michael@0: 10619,10822,11028,11235,11446,11658,11873,12090, michael@0: 12309,12530,12754,12980,13209,13440,13673,13909, michael@0: 14146,14387,14629,14874,15122,15371,15623,15878, michael@0: 16135,16394,16656,16920,17187,17456,17727,18001, michael@0: 18277,18556,18837,19121,19407,19696,19987,20281, michael@0: 20577,20876,21177,21481,21787,22096,22407,22721, michael@0: 23038,23357,23678,24002,24329,24658,24990,25325, michael@0: 25662,26001,26344,26688,27036,27386,27739,28094, michael@0: 28452,28813,29176,29542,29911,30282,30656,31033, michael@0: 31412,31794,32179,32567,32957,33350,33745,34143, michael@0: 34544,34948,35355,35764,36176,36591,37008,37429, michael@0: 37852,38278,38706,39138,39572,40009,40449,40891, michael@0: 41337,41785,42236,42690,43147,43606,44069,44534, michael@0: 45002,45473,45947,46423,46903,47385,47871,48359, michael@0: 48850,49344,49841,50341,50844,51349,51858,52369, michael@0: 52884,53401,53921,54445,54971,55500,56032,56567, michael@0: 57105,57646,58190,58737,59287,59840,60396,60955, michael@0: 61517,62082,62650,63221,63795,64372,64952,65535 michael@0: }; michael@0: michael@0: #endif /* simplified read only */ michael@0: michael@0: /* The base/delta tables are required for both read and write (but currently michael@0: * only the simplified versions.) michael@0: */ michael@0: const png_uint_16 png_sRGB_base[512] = michael@0: { michael@0: 128,1782,3383,4644,5675,6564,7357,8074, michael@0: 8732,9346,9921,10463,10977,11466,11935,12384, michael@0: 12816,13233,13634,14024,14402,14769,15125,15473, michael@0: 15812,16142,16466,16781,17090,17393,17690,17981, michael@0: 18266,18546,18822,19093,19359,19621,19879,20133, michael@0: 20383,20630,20873,21113,21349,21583,21813,22041, michael@0: 22265,22487,22707,22923,23138,23350,23559,23767, michael@0: 23972,24175,24376,24575,24772,24967,25160,25352, michael@0: 25542,25730,25916,26101,26284,26465,26645,26823, michael@0: 27000,27176,27350,27523,27695,27865,28034,28201, michael@0: 28368,28533,28697,28860,29021,29182,29341,29500, michael@0: 29657,29813,29969,30123,30276,30429,30580,30730, michael@0: 30880,31028,31176,31323,31469,31614,31758,31902, michael@0: 32045,32186,32327,32468,32607,32746,32884,33021, michael@0: 33158,33294,33429,33564,33697,33831,33963,34095, michael@0: 34226,34357,34486,34616,34744,34873,35000,35127, michael@0: 35253,35379,35504,35629,35753,35876,35999,36122, michael@0: 36244,36365,36486,36606,36726,36845,36964,37083, michael@0: 37201,37318,37435,37551,37668,37783,37898,38013, michael@0: 38127,38241,38354,38467,38580,38692,38803,38915, michael@0: 39026,39136,39246,39356,39465,39574,39682,39790, michael@0: 39898,40005,40112,40219,40325,40431,40537,40642, michael@0: 40747,40851,40955,41059,41163,41266,41369,41471, michael@0: 41573,41675,41777,41878,41979,42079,42179,42279, michael@0: 42379,42478,42577,42676,42775,42873,42971,43068, michael@0: 43165,43262,43359,43456,43552,43648,43743,43839, michael@0: 43934,44028,44123,44217,44311,44405,44499,44592, michael@0: 44685,44778,44870,44962,45054,45146,45238,45329, michael@0: 45420,45511,45601,45692,45782,45872,45961,46051, michael@0: 46140,46229,46318,46406,46494,46583,46670,46758, michael@0: 46846,46933,47020,47107,47193,47280,47366,47452, michael@0: 47538,47623,47709,47794,47879,47964,48048,48133, michael@0: 48217,48301,48385,48468,48552,48635,48718,48801, michael@0: 48884,48966,49048,49131,49213,49294,49376,49458, michael@0: 49539,49620,49701,49782,49862,49943,50023,50103, michael@0: 50183,50263,50342,50422,50501,50580,50659,50738, michael@0: 50816,50895,50973,51051,51129,51207,51285,51362, michael@0: 51439,51517,51594,51671,51747,51824,51900,51977, michael@0: 52053,52129,52205,52280,52356,52432,52507,52582, michael@0: 52657,52732,52807,52881,52956,53030,53104,53178, michael@0: 53252,53326,53400,53473,53546,53620,53693,53766, michael@0: 53839,53911,53984,54056,54129,54201,54273,54345, michael@0: 54417,54489,54560,54632,54703,54774,54845,54916, michael@0: 54987,55058,55129,55199,55269,55340,55410,55480, michael@0: 55550,55620,55689,55759,55828,55898,55967,56036, michael@0: 56105,56174,56243,56311,56380,56448,56517,56585, michael@0: 56653,56721,56789,56857,56924,56992,57059,57127, michael@0: 57194,57261,57328,57395,57462,57529,57595,57662, michael@0: 57728,57795,57861,57927,57993,58059,58125,58191, michael@0: 58256,58322,58387,58453,58518,58583,58648,58713, michael@0: 58778,58843,58908,58972,59037,59101,59165,59230, michael@0: 59294,59358,59422,59486,59549,59613,59677,59740, michael@0: 59804,59867,59930,59993,60056,60119,60182,60245, michael@0: 60308,60370,60433,60495,60558,60620,60682,60744, michael@0: 60806,60868,60930,60992,61054,61115,61177,61238, michael@0: 61300,61361,61422,61483,61544,61605,61666,61727, michael@0: 61788,61848,61909,61969,62030,62090,62150,62211, michael@0: 62271,62331,62391,62450,62510,62570,62630,62689, michael@0: 62749,62808,62867,62927,62986,63045,63104,63163, michael@0: 63222,63281,63340,63398,63457,63515,63574,63632, michael@0: 63691,63749,63807,63865,63923,63981,64039,64097, michael@0: 64155,64212,64270,64328,64385,64443,64500,64557, michael@0: 64614,64672,64729,64786,64843,64900,64956,65013, michael@0: 65070,65126,65183,65239,65296,65352,65409,65465 michael@0: }; michael@0: michael@0: const png_byte png_sRGB_delta[512] = michael@0: { michael@0: 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54, michael@0: 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36, michael@0: 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28, michael@0: 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24, michael@0: 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21, michael@0: 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19, michael@0: 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17, michael@0: 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16, michael@0: 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15, michael@0: 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14, michael@0: 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13, michael@0: 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12, michael@0: 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12, michael@0: 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11, michael@0: 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, michael@0: 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, michael@0: 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, michael@0: 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, michael@0: 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, michael@0: 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, michael@0: 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, michael@0: 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, michael@0: 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, michael@0: 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, michael@0: 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, michael@0: 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, michael@0: 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, michael@0: 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, michael@0: 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7, michael@0: 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, michael@0: 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, michael@0: 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 michael@0: }; michael@0: #endif /* SIMPLIFIED READ/WRITE sRGB support */ michael@0: michael@0: /* SIMPLIFIED READ/WRITE SUPPORT */ michael@0: #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ michael@0: defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) michael@0: static int michael@0: png_image_free_function(png_voidp argument) michael@0: { michael@0: png_imagep image = png_voidcast(png_imagep, argument); michael@0: png_controlp cp = image->opaque; michael@0: png_control c; michael@0: michael@0: /* Double check that we have a png_ptr - it should be impossible to get here michael@0: * without one. michael@0: */ michael@0: if (cp->png_ptr == NULL) michael@0: return 0; michael@0: michael@0: /* First free any data held in the control structure. */ michael@0: # ifdef PNG_STDIO_SUPPORTED michael@0: if (cp->owned_file) michael@0: { michael@0: FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr); michael@0: cp->owned_file = 0; michael@0: michael@0: /* Ignore errors here. */ michael@0: if (fp != NULL) michael@0: { michael@0: cp->png_ptr->io_ptr = NULL; michael@0: (void)fclose(fp); michael@0: } michael@0: } michael@0: # endif michael@0: michael@0: /* Copy the control structure so that the original, allocated, version can be michael@0: * safely freed. Notice that a png_error here stops the remainder of the michael@0: * cleanup, but this is probably fine because that would indicate bad memory michael@0: * problems anyway. michael@0: */ michael@0: c = *cp; michael@0: image->opaque = &c; michael@0: png_free(c.png_ptr, cp); michael@0: michael@0: /* Then the structures, calling the correct API. */ michael@0: if (c.for_write) michael@0: { michael@0: # ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED michael@0: png_destroy_write_struct(&c.png_ptr, &c.info_ptr); michael@0: # else michael@0: png_error(c.png_ptr, "simplified write not supported"); michael@0: # endif michael@0: } michael@0: else michael@0: { michael@0: # ifdef PNG_SIMPLIFIED_READ_SUPPORTED michael@0: png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL); michael@0: # else michael@0: png_error(c.png_ptr, "simplified read not supported"); michael@0: # endif michael@0: } michael@0: michael@0: /* Success. */ michael@0: return 1; michael@0: } michael@0: michael@0: void PNGAPI michael@0: png_image_free(png_imagep image) michael@0: { michael@0: /* Safely call the real function, but only if doing so is safe at this point michael@0: * (if not inside an error handling context). Otherwise assume michael@0: * png_safe_execute will call this API after the return. michael@0: */ michael@0: if (image != NULL && image->opaque != NULL && michael@0: image->opaque->error_buf == NULL) michael@0: { michael@0: /* Ignore errors here: */ michael@0: (void)png_safe_execute(image, png_image_free_function, image); michael@0: image->opaque = NULL; michael@0: } michael@0: } michael@0: michael@0: int /* PRIVATE */ michael@0: png_image_error(png_imagep image, png_const_charp error_message) michael@0: { michael@0: /* Utility to log an error. */ michael@0: png_safecat(image->message, (sizeof image->message), 0, error_message); michael@0: image->warning_or_error |= PNG_IMAGE_ERROR; michael@0: png_image_free(image); michael@0: return 0; michael@0: } michael@0: michael@0: #endif /* SIMPLIFIED READ/WRITE */ michael@0: #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */