The Tor Browser / file revision

 /*

  * jcmarker.c

  *

  * This file was part of the Independent JPEG Group's software:

  * Copyright (C) 1991-1998, Thomas G. Lane.

  * Modified 2003-2010 by Guido Vollbeding.

  * libjpeg-turbo Modifications:

  * Copyright (C) 2010, D. R. Commander.

  * For conditions of distribution and use, see the accompanying README file.

  *

  * This file contains routines to write JPEG datastream markers.

  */

 #define JPEG_INTERNALS

 #include "jinclude.h"

 #include "jpeglib.h"

 #include "jpegcomp.h"

 typedef enum {			/* JPEG marker codes */

   M_SOF0  = 0xc0,

   M_SOF1  = 0xc1,

   M_SOF2  = 0xc2,

   M_SOF3  = 0xc3,

   M_SOF5  = 0xc5,

   M_SOF6  = 0xc6,

   M_SOF7  = 0xc7,

   M_JPG   = 0xc8,

   M_SOF9  = 0xc9,

   M_SOF10 = 0xca,

   M_SOF11 = 0xcb,

   M_SOF13 = 0xcd,

   M_SOF14 = 0xce,

   M_SOF15 = 0xcf,

   M_DHT   = 0xc4,

   M_DAC   = 0xcc,

   M_RST0  = 0xd0,

   M_RST1  = 0xd1,

   M_RST2  = 0xd2,

   M_RST3  = 0xd3,

   M_RST4  = 0xd4,

   M_RST5  = 0xd5,

   M_RST6  = 0xd6,

   M_RST7  = 0xd7,

   M_SOI   = 0xd8,

   M_EOI   = 0xd9,

   M_SOS   = 0xda,

   M_DQT   = 0xdb,

   M_DNL   = 0xdc,

   M_DRI   = 0xdd,

   M_DHP   = 0xde,

   M_EXP   = 0xdf,

   M_APP0  = 0xe0,

   M_APP1  = 0xe1,

   M_APP2  = 0xe2,

   M_APP3  = 0xe3,

   M_APP4  = 0xe4,

   M_APP5  = 0xe5,

   M_APP6  = 0xe6,

   M_APP7  = 0xe7,

   M_APP8  = 0xe8,

   M_APP9  = 0xe9,

   M_APP10 = 0xea,

   M_APP11 = 0xeb,

   M_APP12 = 0xec,

   M_APP13 = 0xed,

   M_APP14 = 0xee,

   M_APP15 = 0xef,

   M_JPG0  = 0xf0,

   M_JPG13 = 0xfd,

   M_COM   = 0xfe,

   M_TEM   = 0x01,

   M_ERROR = 0x100

 } JPEG_MARKER;

 /* Private state */

 typedef struct {

   struct jpeg_marker_writer pub; /* public fields */

   unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */

 } my_marker_writer;

 typedef my_marker_writer * my_marker_ptr;

 /*

  * Basic output routines.

  *

  * Note that we do not support suspension while writing a marker.

  * Therefore, an application using suspension must ensure that there is

  * enough buffer space for the initial markers (typ. 600-700 bytes) before

  * calling jpeg_start_compress, and enough space to write the trailing EOI

  * (a few bytes) before calling jpeg_finish_compress.  Multipass compression

  * modes are not supported at all with suspension, so those two are the only

  * points where markers will be written.

  */

 LOCAL(void)

 emit_byte (j_compress_ptr cinfo, int val)

 /* Emit a byte */

 {

   struct jpeg_destination_mgr * dest = cinfo->dest;

   *(dest->next_output_byte)++ = (JOCTET) val;

   if (--dest->free_in_buffer == 0) {

     if (! (*dest->empty_output_buffer) (cinfo))

       ERREXIT(cinfo, JERR_CANT_SUSPEND);

   }

 }

 LOCAL(void)

 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)

 /* Emit a marker code */

 {

   emit_byte(cinfo, 0xFF);

   emit_byte(cinfo, (int) mark);

 }

 LOCAL(void)

 emit_2bytes (j_compress_ptr cinfo, int value)

 /* Emit a 2-byte integer; these are always MSB first in JPEG files */

 {

   emit_byte(cinfo, (value >> 8) & 0xFF);

   emit_byte(cinfo, value & 0xFF);

 }

 /*

  * Routines to write specific marker types.

  */

 LOCAL(int)

 emit_dqt (j_compress_ptr cinfo, int index)

 /* Emit a DQT marker */

 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */

 {

   JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];

   int prec;

   int i;

   if (qtbl == NULL)

     ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);

   prec = 0;

   for (i = 0; i < DCTSIZE2; i++) {

     if (qtbl->quantval[i] > 255)

       prec = 1;

   }

   if (! qtbl->sent_table) {

     emit_marker(cinfo, M_DQT);

     emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);

     emit_byte(cinfo, index + (prec<<4));

     for (i = 0; i < DCTSIZE2; i++) {

       /* The table entries must be emitted in zigzag order. */

       unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];

       if (prec)

 	emit_byte(cinfo, (int) (qval >> 8));

       emit_byte(cinfo, (int) (qval & 0xFF));

     }

     qtbl->sent_table = TRUE;

   }

   return prec;

 }

 LOCAL(void)

 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)

 /* Emit a DHT marker */

 {

   JHUFF_TBL * htbl;

   int length, i;

   if (is_ac) {

     htbl = cinfo->ac_huff_tbl_ptrs[index];

     index += 0x10;		/* output index has AC bit set */

   } else {

     htbl = cinfo->dc_huff_tbl_ptrs[index];

   }

   if (htbl == NULL)

     ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);

   if (! htbl->sent_table) {

     emit_marker(cinfo, M_DHT);

     length = 0;

     for (i = 1; i <= 16; i++)

       length += htbl->bits[i];

     emit_2bytes(cinfo, length + 2 + 1 + 16);

     emit_byte(cinfo, index);

     for (i = 1; i <= 16; i++)

       emit_byte(cinfo, htbl->bits[i]);

     for (i = 0; i < length; i++)

       emit_byte(cinfo, htbl->huffval[i]);

     htbl->sent_table = TRUE;

   }

 }

 LOCAL(void)

 emit_dac (j_compress_ptr cinfo)

 /* Emit a DAC marker */

 /* Since the useful info is so small, we want to emit all the tables in */

 /* one DAC marker.  Therefore this routine does its own scan of the table. */

 {

 #ifdef C_ARITH_CODING_SUPPORTED

   char dc_in_use[NUM_ARITH_TBLS];

   char ac_in_use[NUM_ARITH_TBLS];

   int length, i;

   jpeg_component_info *compptr;

   for (i = 0; i < NUM_ARITH_TBLS; i++)

     dc_in_use[i] = ac_in_use[i] = 0;

   for (i = 0; i < cinfo->comps_in_scan; i++) {

     compptr = cinfo->cur_comp_info[i];

     /* DC needs no table for refinement scan */

     if (cinfo->Ss == 0 && cinfo->Ah == 0)

       dc_in_use[compptr->dc_tbl_no] = 1;

     /* AC needs no table when not present */

     if (cinfo->Se)

       ac_in_use[compptr->ac_tbl_no] = 1;

   }

   length = 0;

   for (i = 0; i < NUM_ARITH_TBLS; i++)

     length += dc_in_use[i] + ac_in_use[i];

   if (length) {

     emit_marker(cinfo, M_DAC);

     emit_2bytes(cinfo, length*2 + 2);

     for (i = 0; i < NUM_ARITH_TBLS; i++) {

       if (dc_in_use[i]) {

 	emit_byte(cinfo, i);

 	emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));

       }

       if (ac_in_use[i]) {

 	emit_byte(cinfo, i + 0x10);

 	emit_byte(cinfo, cinfo->arith_ac_K[i]);

       }

     }

   }

 #endif /* C_ARITH_CODING_SUPPORTED */

 }

 LOCAL(void)

 emit_dri (j_compress_ptr cinfo)

 /* Emit a DRI marker */

 {

   emit_marker(cinfo, M_DRI);

   emit_2bytes(cinfo, 4);	/* fixed length */

   emit_2bytes(cinfo, (int) cinfo->restart_interval);

 }

 LOCAL(void)

 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)

 /* Emit a SOF marker */

 {

   int ci;

   jpeg_component_info *compptr;

   emit_marker(cinfo, code);

   emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */

   /* Make sure image isn't bigger than SOF field can handle */

   if ((long) cinfo->_jpeg_height > 65535L ||

       (long) cinfo->_jpeg_width > 65535L)

     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);

   emit_byte(cinfo, cinfo->data_precision);

   emit_2bytes(cinfo, (int) cinfo->_jpeg_height);

   emit_2bytes(cinfo, (int) cinfo->_jpeg_width);

   emit_byte(cinfo, cinfo->num_components);

   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

        ci++, compptr++) {

     emit_byte(cinfo, compptr->component_id);

     emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);

     emit_byte(cinfo, compptr->quant_tbl_no);

   }

 }

 LOCAL(void)

 emit_sos (j_compress_ptr cinfo)

 /* Emit a SOS marker */

 {

   int i, td, ta;

   jpeg_component_info *compptr;

   emit_marker(cinfo, M_SOS);

   emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */

   emit_byte(cinfo, cinfo->comps_in_scan);

   for (i = 0; i < cinfo->comps_in_scan; i++) {

     compptr = cinfo->cur_comp_info[i];

     emit_byte(cinfo, compptr->component_id);

     /* We emit 0 for unused field(s); this is recommended by the P&M text

      * but does not seem to be specified in the standard.

      */

     /* DC needs no table for refinement scan */

     td = cinfo->Ss == 0 && cinfo->Ah == 0 ? compptr->dc_tbl_no : 0;

     /* AC needs no table when not present */

     ta = cinfo->Se ? compptr->ac_tbl_no : 0;

     emit_byte(cinfo, (td << 4) + ta);

   }

   emit_byte(cinfo, cinfo->Ss);

   emit_byte(cinfo, cinfo->Se);

   emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);

 }

 LOCAL(void)

 emit_jfif_app0 (j_compress_ptr cinfo)

 /* Emit a JFIF-compliant APP0 marker */

 {

   /*

    * Length of APP0 block	(2 bytes)

    * Block ID			(4 bytes - ASCII "JFIF")

    * Zero byte			(1 byte to terminate the ID string)

    * Version Major, Minor	(2 bytes - major first)

    * Units			(1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)

    * Xdpu			(2 bytes - dots per unit horizontal)

    * Ydpu			(2 bytes - dots per unit vertical)

    * Thumbnail X size		(1 byte)

    * Thumbnail Y size		(1 byte)

    */

   emit_marker(cinfo, M_APP0);

   emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */

   emit_byte(cinfo, 0x4A);	/* Identifier: ASCII "JFIF" */

   emit_byte(cinfo, 0x46);

   emit_byte(cinfo, 0x49);

   emit_byte(cinfo, 0x46);

   emit_byte(cinfo, 0);

   emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */

   emit_byte(cinfo, cinfo->JFIF_minor_version);

   emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */

   emit_2bytes(cinfo, (int) cinfo->X_density);

   emit_2bytes(cinfo, (int) cinfo->Y_density);

   emit_byte(cinfo, 0);		/* No thumbnail image */

   emit_byte(cinfo, 0);

 }

 LOCAL(void)

 emit_adobe_app14 (j_compress_ptr cinfo)

 /* Emit an Adobe APP14 marker */

 {

   /*

    * Length of APP14 block	(2 bytes)

    * Block ID			(5 bytes - ASCII "Adobe")

    * Version Number		(2 bytes - currently 100)

    * Flags0			(2 bytes - currently 0)

    * Flags1			(2 bytes - currently 0)

    * Color transform		(1 byte)

    *

    * Although Adobe TN 5116 mentions Version = 101, all the Adobe files

    * now in circulation seem to use Version = 100, so that's what we write.

    *

    * We write the color transform byte as 1 if the JPEG color space is

    * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with

    * whether the encoder performed a transformation, which is pretty useless.

    */

   emit_marker(cinfo, M_APP14);

   emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */

   emit_byte(cinfo, 0x41);	/* Identifier: ASCII "Adobe" */

   emit_byte(cinfo, 0x64);

   emit_byte(cinfo, 0x6F);

   emit_byte(cinfo, 0x62);

   emit_byte(cinfo, 0x65);

   emit_2bytes(cinfo, 100);	/* Version */

   emit_2bytes(cinfo, 0);	/* Flags0 */

   emit_2bytes(cinfo, 0);	/* Flags1 */

   switch (cinfo->jpeg_color_space) {

   case JCS_YCbCr:

     emit_byte(cinfo, 1);	/* Color transform = 1 */

     break;

   case JCS_YCCK:

     emit_byte(cinfo, 2);	/* Color transform = 2 */

     break;

   default:

     emit_byte(cinfo, 0);	/* Color transform = 0 */

     break;

   }

 }

 /*

  * These routines allow writing an arbitrary marker with parameters.

  * The only intended use is to emit COM or APPn markers after calling

  * write_file_header and before calling write_frame_header.

  * Other uses are not guaranteed to produce desirable results.

  * Counting the parameter bytes properly is the caller's responsibility.

  */

 METHODDEF(void)

 write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)

 /* Emit an arbitrary marker header */

 {

   if (datalen > (unsigned int) 65533)		/* safety check */

     ERREXIT(cinfo, JERR_BAD_LENGTH);

   emit_marker(cinfo, (JPEG_MARKER) marker);

   emit_2bytes(cinfo, (int) (datalen + 2));	/* total length */

 }

 METHODDEF(void)

 write_marker_byte (j_compress_ptr cinfo, int val)

 /* Emit one byte of marker parameters following write_marker_header */

 {

   emit_byte(cinfo, val);

 }

 /*

  * Write datastream header.

  * This consists of an SOI and optional APPn markers.

  * We recommend use of the JFIF marker, but not the Adobe marker,

  * when using YCbCr or grayscale data.  The JFIF marker should NOT

  * be used for any other JPEG colorspace.  The Adobe marker is helpful

  * to distinguish RGB, CMYK, and YCCK colorspaces.

  * Note that an application can write additional header markers after

  * jpeg_start_compress returns.

  */

 METHODDEF(void)

 write_file_header (j_compress_ptr cinfo)

 {

   my_marker_ptr marker = (my_marker_ptr) cinfo->marker;

   emit_marker(cinfo, M_SOI);	/* first the SOI */

   /* SOI is defined to reset restart interval to 0 */

   marker->last_restart_interval = 0;

   if (cinfo->write_JFIF_header)	/* next an optional JFIF APP0 */

     emit_jfif_app0(cinfo);

   if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */

     emit_adobe_app14(cinfo);

 }

 /*

  * Write frame header.

  * This consists of DQT and SOFn markers.

  * Note that we do not emit the SOF until we have emitted the DQT(s).

  * This avoids compatibility problems with incorrect implementations that

  * try to error-check the quant table numbers as soon as they see the SOF.

  */

 METHODDEF(void)

 write_frame_header (j_compress_ptr cinfo)

 {

   int ci, prec;

   boolean is_baseline;

   jpeg_component_info *compptr;

   /* Emit DQT for each quantization table.

    * Note that emit_dqt() suppresses any duplicate tables.

    */

   prec = 0;

   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

        ci++, compptr++) {

     prec += emit_dqt(cinfo, compptr->quant_tbl_no);

   }

   /* now prec is nonzero iff there are any 16-bit quant tables. */

   /* Check for a non-baseline specification.

    * Note we assume that Huffman table numbers won't be changed later.

    */

   if (cinfo->arith_code || cinfo->progressive_mode ||

       cinfo->data_precision != 8) {

     is_baseline = FALSE;

   } else {

     is_baseline = TRUE;

     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

 	 ci++, compptr++) {

       if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)

 	is_baseline = FALSE;

     }

     if (prec && is_baseline) {

       is_baseline = FALSE;

       /* If it's baseline except for quantizer size, warn the user */

       TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);

     }

   }

   /* Emit the proper SOF marker */

   if (cinfo->arith_code) {

     if (cinfo->progressive_mode)

       emit_sof(cinfo, M_SOF10); /* SOF code for progressive arithmetic */

     else

       emit_sof(cinfo, M_SOF9);  /* SOF code for sequential arithmetic */

   } else {

     if (cinfo->progressive_mode)

       emit_sof(cinfo, M_SOF2);	/* SOF code for progressive Huffman */

     else if (is_baseline)

       emit_sof(cinfo, M_SOF0);	/* SOF code for baseline implementation */

     else

       emit_sof(cinfo, M_SOF1);	/* SOF code for non-baseline Huffman file */

   }

 }

 /*

  * Write scan header.

  * This consists of DHT or DAC markers, optional DRI, and SOS.

  * Compressed data will be written following the SOS.

  */

 METHODDEF(void)

 write_scan_header (j_compress_ptr cinfo)

 {

   my_marker_ptr marker = (my_marker_ptr) cinfo->marker;

   int i;

   jpeg_component_info *compptr;

   if (cinfo->arith_code) {

     /* Emit arith conditioning info.  We may have some duplication

      * if the file has multiple scans, but it's so small it's hardly

      * worth worrying about.

      */

     emit_dac(cinfo);

   } else {

     /* Emit Huffman tables.

      * Note that emit_dht() suppresses any duplicate tables.

      */

     for (i = 0; i < cinfo->comps_in_scan; i++) {

       compptr = cinfo->cur_comp_info[i];

       /* DC needs no table for refinement scan */

       if (cinfo->Ss == 0 && cinfo->Ah == 0)

 	emit_dht(cinfo, compptr->dc_tbl_no, FALSE);

       /* AC needs no table when not present */

       if (cinfo->Se)

 	emit_dht(cinfo, compptr->ac_tbl_no, TRUE);

     }

   }

   /* Emit DRI if required --- note that DRI value could change for each scan.

    * We avoid wasting space with unnecessary DRIs, however.

    */

   if (cinfo->restart_interval != marker->last_restart_interval) {

     emit_dri(cinfo);

     marker->last_restart_interval = cinfo->restart_interval;

   }

   emit_sos(cinfo);

 }

 /*

  * Write datastream trailer.

  */

 METHODDEF(void)

 write_file_trailer (j_compress_ptr cinfo)

 {

   emit_marker(cinfo, M_EOI);

 }

 /*

  * Write an abbreviated table-specification datastream.

  * This consists of SOI, DQT and DHT tables, and EOI.

  * Any table that is defined and not marked sent_table = TRUE will be

  * emitted.  Note that all tables will be marked sent_table = TRUE at exit.

  */

 METHODDEF(void)

 write_tables_only (j_compress_ptr cinfo)

 {

   int i;

   emit_marker(cinfo, M_SOI);

   for (i = 0; i < NUM_QUANT_TBLS; i++) {

     if (cinfo->quant_tbl_ptrs[i] != NULL)

       (void) emit_dqt(cinfo, i);

   }

   if (! cinfo->arith_code) {

     for (i = 0; i < NUM_HUFF_TBLS; i++) {

       if (cinfo->dc_huff_tbl_ptrs[i] != NULL)

 	emit_dht(cinfo, i, FALSE);

       if (cinfo->ac_huff_tbl_ptrs[i] != NULL)

 	emit_dht(cinfo, i, TRUE);

     }

   }

   emit_marker(cinfo, M_EOI);

 }

 /*

  * Initialize the marker writer module.

  */

 GLOBAL(void)

 jinit_marker_writer (j_compress_ptr cinfo)

 {

   my_marker_ptr marker;

   /* Create the subobject */

   marker = (my_marker_ptr)

     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

 				SIZEOF(my_marker_writer));

   cinfo->marker = (struct jpeg_marker_writer *) marker;

   /* Initialize method pointers */

   marker->pub.write_file_header = write_file_header;

   marker->pub.write_frame_header = write_frame_header;

   marker->pub.write_scan_header = write_scan_header;

   marker->pub.write_file_trailer = write_file_trailer;

   marker->pub.write_tables_only = write_tables_only;

   marker->pub.write_marker_header = write_marker_header;

   marker->pub.write_marker_byte = write_marker_byte;

   /* Initialize private state */

   marker->last_restart_interval = 0;

 }