michael@0: /*
michael@0:  * jdatadst.c
michael@0:  *
michael@0:  * This file was part of the Independent JPEG Group's software:
michael@0:  * Copyright (C) 1994-1996, Thomas G. Lane.
michael@0:  * Modified 2009-2012 by Guido Vollbeding.
michael@0:  * libjpeg-turbo Modifications:
michael@0:  * Copyright (C) 2013, D. R. Commander.
michael@0:  * For conditions of distribution and use, see the accompanying README file.
michael@0:  *
michael@0:  * This file contains compression data destination routines for the case of
michael@0:  * emitting JPEG data to memory or to a file (or any stdio stream).
michael@0:  * While these routines are sufficient for most applications,
michael@0:  * some will want to use a different destination manager.
michael@0:  * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
michael@0:  * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
michael@0:  * than 8 bits on your machine, you may need to do some tweaking.
michael@0:  */
michael@0: 
michael@0: /* this is not a core library module, so it doesn't define JPEG_INTERNALS */
michael@0: #include "jinclude.h"
michael@0: #include "jpeglib.h"
michael@0: #include "jerror.h"
michael@0: 
michael@0: #ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare malloc(),free() */
michael@0: extern void * malloc JPP((size_t size));
michael@0: extern void free JPP((void *ptr));
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /* Expanded data destination object for stdio output */
michael@0: 
michael@0: typedef struct {
michael@0:   struct jpeg_destination_mgr pub; /* public fields */
michael@0: 
michael@0:   FILE * outfile;		/* target stream */
michael@0:   JOCTET * buffer;		/* start of buffer */
michael@0: } my_destination_mgr;
michael@0: 
michael@0: typedef my_destination_mgr * my_dest_ptr;
michael@0: 
michael@0: #define OUTPUT_BUF_SIZE  4096	/* choose an efficiently fwrite'able size */
michael@0: 
michael@0: 
michael@0: #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
michael@0: /* Expanded data destination object for memory output */
michael@0: 
michael@0: typedef struct {
michael@0:   struct jpeg_destination_mgr pub; /* public fields */
michael@0: 
michael@0:   unsigned char ** outbuffer;	/* target buffer */
michael@0:   unsigned long * outsize;
michael@0:   unsigned char * newbuffer;	/* newly allocated buffer */
michael@0:   JOCTET * buffer;		/* start of buffer */
michael@0:   size_t bufsize;
michael@0: } my_mem_destination_mgr;
michael@0: 
michael@0: typedef my_mem_destination_mgr * my_mem_dest_ptr;
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Initialize destination --- called by jpeg_start_compress
michael@0:  * before any data is actually written.
michael@0:  */
michael@0: 
michael@0: METHODDEF(void)
michael@0: init_destination (j_compress_ptr cinfo)
michael@0: {
michael@0:   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
michael@0: 
michael@0:   /* Allocate the output buffer --- it will be released when done with image */
michael@0:   dest->buffer = (JOCTET *)
michael@0:       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
michael@0: 				  OUTPUT_BUF_SIZE * SIZEOF(JOCTET));
michael@0: 
michael@0:   dest->pub.next_output_byte = dest->buffer;
michael@0:   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
michael@0: }
michael@0: 
michael@0: #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
michael@0: METHODDEF(void)
michael@0: init_mem_destination (j_compress_ptr cinfo)
michael@0: {
michael@0:   /* no work necessary here */
michael@0: }
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Empty the output buffer --- called whenever buffer fills up.
michael@0:  *
michael@0:  * In typical applications, this should write the entire output buffer
michael@0:  * (ignoring the current state of next_output_byte & free_in_buffer),
michael@0:  * reset the pointer & count to the start of the buffer, and return TRUE
michael@0:  * indicating that the buffer has been dumped.
michael@0:  *
michael@0:  * In applications that need to be able to suspend compression due to output
michael@0:  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
michael@0:  * In this situation, the compressor will return to its caller (possibly with
michael@0:  * an indication that it has not accepted all the supplied scanlines).  The
michael@0:  * application should resume compression after it has made more room in the
michael@0:  * output buffer.  Note that there are substantial restrictions on the use of
michael@0:  * suspension --- see the documentation.
michael@0:  *
michael@0:  * When suspending, the compressor will back up to a convenient restart point
michael@0:  * (typically the start of the current MCU). next_output_byte & free_in_buffer
michael@0:  * indicate where the restart point will be if the current call returns FALSE.
michael@0:  * Data beyond this point will be regenerated after resumption, so do not
michael@0:  * write it out when emptying the buffer externally.
michael@0:  */
michael@0: 
michael@0: METHODDEF(boolean)
michael@0: empty_output_buffer (j_compress_ptr cinfo)
michael@0: {
michael@0:   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
michael@0: 
michael@0:   if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
michael@0:       (size_t) OUTPUT_BUF_SIZE)
michael@0:     ERREXIT(cinfo, JERR_FILE_WRITE);
michael@0: 
michael@0:   dest->pub.next_output_byte = dest->buffer;
michael@0:   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
michael@0: 
michael@0:   return TRUE;
michael@0: }
michael@0: 
michael@0: #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
michael@0: METHODDEF(boolean)
michael@0: empty_mem_output_buffer (j_compress_ptr cinfo)
michael@0: {
michael@0:   size_t nextsize;
michael@0:   JOCTET * nextbuffer;
michael@0:   my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
michael@0: 
michael@0:   /* Try to allocate new buffer with double size */
michael@0:   nextsize = dest->bufsize * 2;
michael@0:   nextbuffer = (JOCTET *) malloc(nextsize);
michael@0: 
michael@0:   if (nextbuffer == NULL)
michael@0:     ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
michael@0: 
michael@0:   MEMCOPY(nextbuffer, dest->buffer, dest->bufsize);
michael@0: 
michael@0:   if (dest->newbuffer != NULL)
michael@0:     free(dest->newbuffer);
michael@0: 
michael@0:   dest->newbuffer = nextbuffer;
michael@0: 
michael@0:   dest->pub.next_output_byte = nextbuffer + dest->bufsize;
michael@0:   dest->pub.free_in_buffer = dest->bufsize;
michael@0: 
michael@0:   dest->buffer = nextbuffer;
michael@0:   dest->bufsize = nextsize;
michael@0: 
michael@0:   return TRUE;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Terminate destination --- called by jpeg_finish_compress
michael@0:  * after all data has been written.  Usually needs to flush buffer.
michael@0:  *
michael@0:  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
michael@0:  * application must deal with any cleanup that should happen even
michael@0:  * for error exit.
michael@0:  */
michael@0: 
michael@0: METHODDEF(void)
michael@0: term_destination (j_compress_ptr cinfo)
michael@0: {
michael@0:   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
michael@0:   size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
michael@0: 
michael@0:   /* Write any data remaining in the buffer */
michael@0:   if (datacount > 0) {
michael@0:     if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
michael@0:       ERREXIT(cinfo, JERR_FILE_WRITE);
michael@0:   }
michael@0:   fflush(dest->outfile);
michael@0:   /* Make sure we wrote the output file OK */
michael@0:   if (ferror(dest->outfile))
michael@0:     ERREXIT(cinfo, JERR_FILE_WRITE);
michael@0: }
michael@0: 
michael@0: #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
michael@0: METHODDEF(void)
michael@0: term_mem_destination (j_compress_ptr cinfo)
michael@0: {
michael@0:   my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
michael@0: 
michael@0:   *dest->outbuffer = dest->buffer;
michael@0:   *dest->outsize = (unsigned long)(dest->bufsize - dest->pub.free_in_buffer);
michael@0: }
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Prepare for output to a stdio stream.
michael@0:  * The caller must have already opened the stream, and is responsible
michael@0:  * for closing it after finishing compression.
michael@0:  */
michael@0: 
michael@0: GLOBAL(void)
michael@0: jpeg_stdio_dest (j_compress_ptr cinfo, FILE * outfile)
michael@0: {
michael@0:   my_dest_ptr dest;
michael@0: 
michael@0:   /* The destination object is made permanent so that multiple JPEG images
michael@0:    * can be written to the same file without re-executing jpeg_stdio_dest.
michael@0:    * This makes it dangerous to use this manager and a different destination
michael@0:    * manager serially with the same JPEG object, because their private object
michael@0:    * sizes may be different.  Caveat programmer.
michael@0:    */
michael@0:   if (cinfo->dest == NULL) {	/* first time for this JPEG object? */
michael@0:     cinfo->dest = (struct jpeg_destination_mgr *)
michael@0:       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
michael@0: 				  SIZEOF(my_destination_mgr));
michael@0:   }
michael@0: 
michael@0:   dest = (my_dest_ptr) cinfo->dest;
michael@0:   dest->pub.init_destination = init_destination;
michael@0:   dest->pub.empty_output_buffer = empty_output_buffer;
michael@0:   dest->pub.term_destination = term_destination;
michael@0:   dest->outfile = outfile;
michael@0: }
michael@0: 
michael@0: 
michael@0: #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
michael@0: /*
michael@0:  * Prepare for output to a memory buffer.
michael@0:  * The caller may supply an own initial buffer with appropriate size.
michael@0:  * Otherwise, or when the actual data output exceeds the given size,
michael@0:  * the library adapts the buffer size as necessary.
michael@0:  * The standard library functions malloc/free are used for allocating
michael@0:  * larger memory, so the buffer is available to the application after
michael@0:  * finishing compression, and then the application is responsible for
michael@0:  * freeing the requested memory.
michael@0:  */
michael@0: 
michael@0: GLOBAL(void)
michael@0: jpeg_mem_dest (j_compress_ptr cinfo,
michael@0: 	       unsigned char ** outbuffer, unsigned long * outsize)
michael@0: {
michael@0:   my_mem_dest_ptr dest;
michael@0: 
michael@0:   if (outbuffer == NULL || outsize == NULL)	/* sanity check */
michael@0:     ERREXIT(cinfo, JERR_BUFFER_SIZE);
michael@0: 
michael@0:   /* The destination object is made permanent so that multiple JPEG images
michael@0:    * can be written to the same buffer without re-executing jpeg_mem_dest.
michael@0:    */
michael@0:   if (cinfo->dest == NULL) {	/* first time for this JPEG object? */
michael@0:     cinfo->dest = (struct jpeg_destination_mgr *)
michael@0:       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
michael@0: 				  SIZEOF(my_mem_destination_mgr));
michael@0:   }
michael@0: 
michael@0:   dest = (my_mem_dest_ptr) cinfo->dest;
michael@0:   dest->pub.init_destination = init_mem_destination;
michael@0:   dest->pub.empty_output_buffer = empty_mem_output_buffer;
michael@0:   dest->pub.term_destination = term_mem_destination;
michael@0:   dest->outbuffer = outbuffer;
michael@0:   dest->outsize = outsize;
michael@0:   dest->newbuffer = NULL;
michael@0: 
michael@0:   if (*outbuffer == NULL || *outsize == 0) {
michael@0:     /* Allocate initial buffer */
michael@0:     dest->newbuffer = *outbuffer = (unsigned char *) malloc(OUTPUT_BUF_SIZE);
michael@0:     if (dest->newbuffer == NULL)
michael@0:       ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
michael@0:     *outsize = OUTPUT_BUF_SIZE;
michael@0:   }
michael@0: 
michael@0:   dest->pub.next_output_byte = dest->buffer = *outbuffer;
michael@0:   dest->pub.free_in_buffer = dest->bufsize = *outsize;
michael@0: }
michael@0: #endif