tor-browser

jcmarker.c (17896B)

---

/*
* 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.
* Lossless JPEG Modifications:
* Copyright (C) 1999, Ken Murchison.
* libjpeg-turbo Modifications:
* Copyright (C) 2010, 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
* This file contains routines to write JPEG datastream markers.
*/

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jpegapicomp.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 = 0;
 boolean is_baseline;
 jpeg_component_info *compptr;

 if (!cinfo->master->lossless) {
   /* Emit DQT for each quantization table.
    * Note that emit_dqt() suppresses any duplicate tables.
    */
   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->master->lossless || 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 (cinfo->master->lossless)
     emit_sof(cinfo, M_SOF3);  /* SOF code for lossless 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) || cinfo->master->lossless)
       emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
     /* AC needs no table when not present, and lossless mode uses only DC
        tables. */
     if (cinfo->Se && !cinfo->master->lossless)
       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;
}