text: /*
   * jcmarker.c
   *
   * Copyright (C) 1991-1998, Thomas G. Lane.
   * This file is part of the Independent JPEG Group's software.
   * 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"
  
  
  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 index2)
  /* Emit a DQT marker */
  /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
  {
    JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index2];
    int prec;
    int i;
  
    if (qtbl == NULL)
      ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index2);
  
    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, index2 + (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 index2, boolean is_ac)
  /* Emit a DHT marker */
  {
    JHUFF_TBL * htbl;
    int length, i;
    
    if (is_ac) {
      htbl = cinfo->ac_huff_tbl_ptrs[index2];
      index2 += 0x10;              /* output index has AC bit set */
    } else {
      htbl = cinfo->dc_huff_tbl_ptrs[index2];
    }
  
    if (htbl == NULL)
      ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index2);
    
    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, index2);
      
      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_in_use[compptr->dc_tbl_no] = 1;
      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];
    
    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 */
    cinfo = 0;
  }
  
  
  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->image_height > 65535L ||
        (long) cinfo->image_width > 65535L)
      ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
  
    emit_byte(cinfo, cinfo->data_precision);
    emit_2bytes(cinfo, (int) cinfo->image_height);
    emit_2bytes(cinfo, (int) cinfo->image_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);
      td = compptr->dc_tbl_no;
      ta = compptr->ac_tbl_no;
      if (cinfo->progressive_mode) {
        /* Progressive mode: only DC or only AC tables are used in one scan;
         * furthermore, Huffman coding of DC refinement uses no table at all.
         * 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.
         */
        if (cinfo->Ss == 0) {
          ta = 0;                 /* DC scan */
          if (cinfo->Ah != 0 && !cinfo->arith_code)
            td = 0;               /* no DC table either */
        } else {
          td = 0;                 /* AC scan */
        }
      }
      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) {
      emit_sof(cinfo, M_SOF9);    /* SOF code for arithmetic coding */
    } 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];
        if (cinfo->progressive_mode) {
          /* Progressive mode: only DC or only AC tables are used in one scan */
          if (cinfo->Ss == 0) {
            if (cinfo->Ah == 0)   /* DC needs no table for refinement scan */
              emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
          } else {
            emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
          }
        } else {
          /* Sequential mode: need both DC and AC tables */
          emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
          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;
  }
  