text: /*
   * jdmarker.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 decode JPEG datastream markers.
   * Most of the complexity arises from our desire to support input
   * suspension: if not all of the data for a marker is available,
   * we must exit back to the application.  On resumption, we reprocess
   * the marker.
   */
  
  #define JPEG_INTERNALS
  #include "jinclude12.h"
  #include "jpeglib12.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_reader pub; /* public fields */
  
    /* Application-overridable marker processing methods */
    jpeg_marker_parser_method process_COM;
    jpeg_marker_parser_method process_APPn[16];
  
    /* Limit on marker data length to save for each marker type */
    unsigned int length_limit_COM;
    unsigned int length_limit_APPn[16];
  
    /* Status of COM/APPn marker saving */
    jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
    unsigned int bytes_read;      /* data bytes read so far in marker */
    /* Note: cur_marker is not linked into marker_list until it's all read. */
  } my_marker_reader;
  
  typedef my_marker_reader * my_marker_ptr;
  
  
  /*
   * Macros for fetching data from the data source module.
   *
   * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
   * the current restart point; we update them only when we have reached a
   * suitable place to restart if a suspension occurs.
   */
  
  /* Declare and initialize local copies of input pointer/count */
  #define INPUT_VARS(cinfo)  \
      struct jpeg_source_mgr * datasrc = (cinfo)->src;  \
      const JOCTET * next_input_byte = datasrc->next_input_byte;  \
      size_t bytes_in_buffer = datasrc->bytes_in_buffer
  
  /* Unload the local copies --- do this only at a restart boundary */
  #define INPUT_SYNC(cinfo)  \
      ( datasrc->next_input_byte = next_input_byte,  \
        datasrc->bytes_in_buffer = bytes_in_buffer )
  
  /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
  #define INPUT_RELOAD(cinfo)  \
      ( next_input_byte = datasrc->next_input_byte,  \
        bytes_in_buffer = datasrc->bytes_in_buffer )
  
  /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
   * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
   * but we must reload the local copies after a successful fill.
   */
  #define MAKE_BYTE_AVAIL(cinfo,action)  \
      if (bytes_in_buffer == 0) {  \
        if (! (*datasrc->fill_input_buffer) (cinfo))  \
          { action; }  \
        INPUT_RELOAD(cinfo);  \
      }
  
  /* Read a byte into variable V.
   * If must suspend, take the specified action (typically "return FALSE").
   */
  #define INPUT_BYTE(cinfo,V,action)  \
      MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
            bytes_in_buffer--; \
            V = GETJOCTET(*next_input_byte++); )
  
  /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
   * V should be declared unsigned int or perhaps IJG_INT32.
   */
  #define INPUT_2BYTES(cinfo,V,action)  \
      MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
            bytes_in_buffer--; \
            V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
            MAKE_BYTE_AVAIL(cinfo,action); \
            bytes_in_buffer--; \
            V += GETJOCTET(*next_input_byte++); )
  
  
  /*
   * Routines to process JPEG markers.
   *
   * Entry condition: JPEG marker itself has been read and its code saved
   *   in cinfo->unread_marker; input restart point is just after the marker.
   *
   * Exit: if return TRUE, have read and processed any parameters, and have
   *   updated the restart point to point after the parameters.
   *   If return FALSE, was forced to suspend before reaching end of
   *   marker parameters; restart point has not been moved.  Same routine
   *   will be called again after application supplies more input data.
   *
   * This approach to suspension assumes that all of a marker's parameters
   * can fit into a single input bufferload.  This should hold for "normal"
   * markers.  Some COM/APPn markers might have large parameter segments
   * that might not fit.  If we are simply dropping such a marker, we use
   * skip_input_data to get past it, and thereby put the problem on the
   * source manager's shoulders.  If we are saving the marker's contents
   * into memory, we use a slightly different convention: when forced to
   * suspend, the marker processor updates the restart point to the end of
   * what it's consumed (ie, the end of the buffer) before returning FALSE.
   * On resumption, cinfo->unread_marker still contains the marker code,
   * but the data source will point to the next chunk of marker data.
   * The marker processor must retain internal state to deal with this.
   *
   * Note that we don't bother to avoid duplicate trace messages if a
   * suspension occurs within marker parameters.  Other side effects
   * require more care.
   */
  
  
  LOCAL(boolean)
  get_soi (j_decompress_ptr cinfo)
  /* Process an SOI marker */
  {
    int i;
    
    TRACEMS(cinfo, 1, JTRC_SOI);
  
    if (cinfo->marker->saw_SOI)
      ERREXIT(cinfo, JERR_SOI_DUPLICATE);
  
    /* Reset all parameters that are defined to be reset by SOI */
  
    for (i = 0; i < NUM_ARITH_TBLS; i++) {
      cinfo->arith_dc_L[i] = 0;
      cinfo->arith_dc_U[i] = 1;
      cinfo->arith_ac_K[i] = 5;
    }
    cinfo->restart_interval = 0;
  
    /* Set initial assumptions for colorspace etc */
  
    cinfo->jpeg_color_space = JCS_UNKNOWN;
    cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
  
    cinfo->saw_JFIF_marker = FALSE;
    cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
    cinfo->JFIF_minor_version = 1;
    cinfo->density_unit = 0;
    cinfo->X_density = 1;
    cinfo->Y_density = 1;
    cinfo->saw_Adobe_marker = FALSE;
    cinfo->Adobe_transform = 0;
  
    cinfo->marker->saw_SOI = TRUE;
  
    return TRUE;
  }
  
  
  LOCAL(boolean)
  get_sof (j_decompress_ptr cinfo, J_CODEC_PROCESS process, boolean is_arith,
       int data_unit)
  /* Process a SOFn marker */
  {
    IJG_INT32 length;
    int c, ci;
    jpeg_component_info * compptr;
    INPUT_VARS(cinfo);
  
    cinfo->data_unit = data_unit;
    cinfo->process = process;
    cinfo->arith_code = is_arith;
  
    INPUT_2BYTES(cinfo, length, return FALSE);
  
    INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
    INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
    INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
    INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
  
    length -= 8;
  
    TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
         (int) cinfo->image_width, (int) cinfo->image_height,
         cinfo->num_components);
  
    if (cinfo->marker->saw_SOF)
      ERREXIT(cinfo, JERR_SOF_DUPLICATE);
  
    /* We don't support files in which the image height is initially specified */
    /* as 0 and is later redefined by DNL.  As long as we have to check that,  */
    /* might as well have a general sanity check. */
    if (cinfo->image_height <= 0 || cinfo->image_width <= 0
        || cinfo->num_components <= 0)
      ERREXIT(cinfo, JERR_EMPTY_IMAGE);
  
    if (length != (cinfo->num_components * 3))
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    if (cinfo->comp_info == NULL) /* do only once, even if suspend */
      cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
              ((j_common_ptr) cinfo, JPOOL_IMAGE,
               (size_t)cinfo->num_components * SIZEOF(jpeg_component_info));
    
    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         ci++, compptr++) {
      compptr->component_index = ci;
      INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
      INPUT_BYTE(cinfo, c, return FALSE);
      compptr->h_samp_factor = (c >> 4) & 15;
      compptr->v_samp_factor = (c     ) & 15;
      INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
  
      TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
           compptr->component_id, compptr->h_samp_factor,
           compptr->v_samp_factor, compptr->quant_tbl_no);
    }
  
    cinfo->marker->saw_SOF = TRUE;
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  LOCAL(boolean)
  get_sos (j_decompress_ptr cinfo)
  /* Process a SOS marker */
  {
    IJG_INT32 length;
    int i, ci, n, c, cc;
    jpeg_component_info * compptr;
    INPUT_VARS(cinfo);
  
    if (! cinfo->marker->saw_SOF)
      ERREXIT(cinfo, JERR_SOS_NO_SOF);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
  
    INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
  
    TRACEMS1(cinfo, 1, JTRC_SOS, n);
  
    if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    cinfo->comps_in_scan = n;
  
    /* Collect the component-spec parameters */
  
    for (i = 0; i < n; i++) {
      INPUT_BYTE(cinfo, cc, return FALSE);
      INPUT_BYTE(cinfo, c, return FALSE);
      
      for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
        if (cc == compptr->component_id)
      goto id_found;
      }
  
      ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
  
    id_found:
  
      cinfo->cur_comp_info[i] = compptr;
      compptr->dc_tbl_no = (c >> 4) & 15;
      compptr->ac_tbl_no = (c     ) & 15;
      
      TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
           compptr->dc_tbl_no, compptr->ac_tbl_no);
    }
  
    /* Collect the additional scan parameters Ss, Se, Ah/Al. */
    INPUT_BYTE(cinfo, c, return FALSE);
    cinfo->Ss = c;
    INPUT_BYTE(cinfo, c, return FALSE);
    cinfo->Se = c;
    INPUT_BYTE(cinfo, c, return FALSE);
    cinfo->Ah = (c >> 4) & 15;
    cinfo->Al = (c     ) & 15;
  
    TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
         cinfo->Ah, cinfo->Al);
  
    /* Prepare to scan data & restart markers */
    cinfo->marker->next_restart_num = 0;
  
    /* Count another SOS marker */
    cinfo->input_scan_number++;
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  #ifdef D_ARITH_CODING_SUPPORTED
  
  LOCAL(boolean)
  get_dac (j_decompress_ptr cinfo)
  /* Process a DAC marker */
  {
    IJG_INT32 length;
    int idx, val;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    length -= 2;
    
    while (length > 0) {
      INPUT_BYTE(cinfo, idx, return FALSE);
      INPUT_BYTE(cinfo, val, return FALSE);
  
      length -= 2;
  
      TRACEMS2(cinfo, 1, JTRC_DAC, idx, val);
  
      if (idx < 0 || idx >= (2*NUM_ARITH_TBLS))
        ERREXIT1(cinfo, JERR_DAC_INDEX, idx);
  
      if (idx >= NUM_ARITH_TBLS) { /* define AC table */
        cinfo->arith_ac_K[idx-NUM_ARITH_TBLS] = (UINT8) val;
      } else {            /* define DC table */
        cinfo->arith_dc_L[idx] = (UINT8) (val & 0x0F);
        cinfo->arith_dc_U[idx] = (UINT8) (val >> 4);
        if (cinfo->arith_dc_L[idx] > cinfo->arith_dc_U[idx])
      ERREXIT1(cinfo, JERR_DAC_VALUE, val);
      }
    }
  
    if (length != 0)
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  #else /* ! D_ARITH_CODING_SUPPORTED */
  
  #define get_dac(cinfo)  skip_variable(cinfo)
  
  #endif /* D_ARITH_CODING_SUPPORTED */
  
  
  LOCAL(boolean)
  get_dht (j_decompress_ptr cinfo)
  /* Process a DHT marker */
  {
    IJG_INT32 length;
    UINT8 bits[17];
    UINT8 huffval[256];
    int i, idx, count;
    JHUFF_TBL **htblptr;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    length -= 2;
    
    while (length > 16) {
      INPUT_BYTE(cinfo, idx, return FALSE);
  
      TRACEMS1(cinfo, 1, JTRC_DHT, idx);
        
      bits[0] = 0;
      count = 0;
      for (i = 1; i <= 16; i++) {
        INPUT_BYTE(cinfo, bits[i], return FALSE);
        count += bits[i];
      }
  
      length -= 1 + 16;
  
      TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
           bits[1], bits[2], bits[3], bits[4],
           bits[5], bits[6], bits[7], bits[8]);
      TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
           bits[9], bits[10], bits[11], bits[12],
           bits[13], bits[14], bits[15], bits[16]);
  
      /* Here we just do minimal validation of the counts to avoid walking
       * off the end of our table space.  jdhuff.c will check more carefully.
       */
      if (count > 256 || ((IJG_INT32) count) > length)
        ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
  
      for (i = 0; i < count; i++)
        INPUT_BYTE(cinfo, huffval[i], return FALSE);
  
      length -= count;
  
      if (idx & 0x10) {       /* AC table definition */
        idx -= 0x10;
        htblptr = &cinfo->ac_huff_tbl_ptrs[idx];
      } else {            /* DC table definition */
        htblptr = &cinfo->dc_huff_tbl_ptrs[idx];
      }
  
      if (idx < 0 || idx >= NUM_HUFF_TBLS)
        ERREXIT1(cinfo, JERR_DHT_INDEX, idx);
  
      if (*htblptr == NULL)
        *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
    
      MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
      MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
    }
  
    if (length != 0)
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  LOCAL(boolean)
  get_dqt (j_decompress_ptr cinfo)
  /* Process a DQT marker */
  {
    IJG_INT32 length;
    int n, i, prec;
    unsigned int tmp;
    JQUANT_TBL *quant_ptr;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    length -= 2;
  
    while (length > 0) {
      INPUT_BYTE(cinfo, n, return FALSE);
      prec = n >> 4;
      n &= 0x0F;
  
      TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
  
      if (n >= NUM_QUANT_TBLS)
        ERREXIT1(cinfo, JERR_DQT_INDEX, n);
        
      if (cinfo->quant_tbl_ptrs[n] == NULL)
        cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
      quant_ptr = cinfo->quant_tbl_ptrs[n];
  
      for (i = 0; i < DCTSIZE2; i++) {
        if (prec)
      INPUT_2BYTES(cinfo, tmp, return FALSE);
        else
      INPUT_BYTE(cinfo, tmp, return FALSE);
        /* We convert the zigzag-order table to natural array order. */
        quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
      }
  
      if (cinfo->err->trace_level >= 2) {
        for (i = 0; i < DCTSIZE2; i += 8) {
      TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
           quant_ptr->quantval[i],   quant_ptr->quantval[i+1],
           quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
           quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
           quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
        }
      }
  
      length -= DCTSIZE2+1;
      if (prec) length -= DCTSIZE2;
    }
  
    if (length != 0)
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  LOCAL(boolean)
  get_dri (j_decompress_ptr cinfo)
  /* Process a DRI marker */
  {
    IJG_INT32 length;
    unsigned int tmp;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    
    if (length != 4)
      ERREXIT(cinfo, JERR_BAD_LENGTH);
  
    INPUT_2BYTES(cinfo, tmp, return FALSE);
  
    TRACEMS1(cinfo, 1, JTRC_DRI, (int)tmp);
  
    cinfo->restart_interval = tmp;
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  /*
   * Routines for processing APPn and COM markers.
   * These are either saved in memory or discarded, per application request.
   * APP0 and APP14 are specially checked to see if they are
   * JFIF and Adobe markers, respectively.
   */
  
  #define APP0_DATA_LEN   14  /* Length of interesting data in APP0 */
  #define APP14_DATA_LEN  12  /* Length of interesting data in APP14 */
  #define APPN_DATA_LEN   14  /* Must be the largest of the above!! */
  
  
  LOCAL(void)
  examine_app0 (j_decompress_ptr cinfo, const JOCTET FAR * data,
            unsigned int datalen, IJG_INT32 remaining)
  /* Examine first few bytes from an APP0.
   * Take appropriate action if it is a JFIF marker.
   * datalen is # of bytes at data[], remaining is length of rest of marker data.
   */
  {
    IJG_INT32 totallen = (IJG_INT32) datalen + remaining;
  
    if (datalen >= APP0_DATA_LEN &&
        GETJOCTET(data[0]) == 0x4A &&
        GETJOCTET(data[1]) == 0x46 &&
        GETJOCTET(data[2]) == 0x49 &&
        GETJOCTET(data[3]) == 0x46 &&
        GETJOCTET(data[4]) == 0) {
      /* Found JFIF APP0 marker: save info */
      cinfo->saw_JFIF_marker = TRUE;
      cinfo->JFIF_major_version = GETJOCTET(data[5]);
      cinfo->JFIF_minor_version = GETJOCTET(data[6]);
      cinfo->density_unit = GETJOCTET(data[7]);
      cinfo->X_density = (UINT16)((GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]));
      cinfo->Y_density = (UINT16)((GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]));
      /* Check version.
       * Major version must be 1, anything else signals an incompatible change.
       * (We used to treat this as an error, but now it's a nonfatal warning,
       * because some bozo at Hijaak couldn't read the spec.)
       * Minor version should be 0..2, but process anyway if newer.
       */
      if (cinfo->JFIF_major_version != 1)
        WARNMS2(cinfo, JWRN_JFIF_MAJOR,
            cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
      /* Generate trace messages */
      TRACEMS5(cinfo, 1, JTRC_JFIF,
           cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
           cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
      /* Validate thumbnail dimensions and issue appropriate messages */
      if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
        TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
             GETJOCTET(data[12]), GETJOCTET(data[13]));
      totallen -= APP0_DATA_LEN;
      if (totallen !=
      ((IJG_INT32)GETJOCTET(data[12]) * (IJG_INT32)GETJOCTET(data[13]) * (IJG_INT32) 3))
        TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
    } else if (datalen >= 6 &&
        GETJOCTET(data[0]) == 0x4A &&
        GETJOCTET(data[1]) == 0x46 &&
        GETJOCTET(data[2]) == 0x58 &&
        GETJOCTET(data[3]) == 0x58 &&
        GETJOCTET(data[4]) == 0) {
      /* Found JFIF "JFXX" extension APP0 marker */
      /* The library doesn't actually do anything with these,
       * but we try to produce a helpful trace message.
       */
      switch (GETJOCTET(data[5])) {
      case 0x10:
        TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
        break;
      case 0x11:
        TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
        break;
      case 0x13:
        TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
        break;
      default:
        TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
             GETJOCTET(data[5]), (int) totallen);
        break;
      }
    } else {
      /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
      TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
    }
  }
  
  
  LOCAL(void)
  examine_app14 (j_decompress_ptr cinfo, const JOCTET FAR * data,
             unsigned int datalen, IJG_INT32 remaining)
  /* Examine first few bytes from an APP14.
   * Take appropriate action if it is an Adobe marker.
   * datalen is # of bytes at data[], remaining is length of rest of marker data.
   */
  {
    unsigned int version, flags0, flags1, transform;
  
    if (datalen >= APP14_DATA_LEN &&
        GETJOCTET(data[0]) == 0x41 &&
        GETJOCTET(data[1]) == 0x64 &&
        GETJOCTET(data[2]) == 0x6F &&
        GETJOCTET(data[3]) == 0x62 &&
        GETJOCTET(data[4]) == 0x65) {
      /* Found Adobe APP14 marker */
      version = (unsigned int)((GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]));
      flags0 = (unsigned int)((GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]));
      flags1 = (unsigned int)((GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]));
      transform = GETJOCTET(data[11]);
      TRACEMS4(cinfo, 1, JTRC_ADOBE, (int)version, (int)flags0, (int)flags1, (int)transform);
      cinfo->saw_Adobe_marker = TRUE;
      cinfo->Adobe_transform = (UINT8) transform;
    } else {
      /* Start of APP14 does not match "Adobe", or too short */
      TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
    }
  }
  
  
  METHODDEF(boolean)
  get_interesting_appn (j_decompress_ptr cinfo)
  /* Process an APP0 or APP14 marker without saving it */
  {
    IJG_INT32 length;
    JOCTET b[APPN_DATA_LEN];
    unsigned int i, numtoread;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    length -= 2;
  
    /* get the interesting part of the marker data */
    if (length >= APPN_DATA_LEN)
      numtoread = APPN_DATA_LEN;
    else if (length > 0)
      numtoread = (unsigned int) length;
    else
      numtoread = 0;
    for (i = 0; i < numtoread; i++)
      INPUT_BYTE(cinfo, b[i], return FALSE);
    length -= numtoread;
  
    /* process it */
    switch (cinfo->unread_marker) {
    case M_APP0:
      examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
      break;
    case M_APP14:
      examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
      break;
    default:
      /* can't get here unless jpeg_save_markers chooses wrong processor */
      ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
      break;
    }
  
    /* skip any remaining data -- could be lots */
    INPUT_SYNC(cinfo);
    if (length > 0)
      (*cinfo->src->skip_input_data) (cinfo, (long) length);
  
    return TRUE;
  }
  
  
  #ifdef SAVE_MARKERS_SUPPORTED
  
  METHODDEF(boolean)
  save_marker (j_decompress_ptr cinfo)
  /* Save an APPn or COM marker into the marker list */
  {
    my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
    jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
    unsigned int bytes_read, data_length;
    JOCTET FAR * data;
    IJG_INT32 length = 0;
    INPUT_VARS(cinfo);
  
    if (cur_marker == NULL) {
      /* begin reading a marker */
      INPUT_2BYTES(cinfo, length, return FALSE);
      length -= 2;
      if (length >= 0) {      /* watch out for bogus length word */
        /* figure out how much we want to save */
        unsigned int limit;
        if (cinfo->unread_marker == (int) M_COM)
      limit = marker->length_limit_COM;
        else
      limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
        if ((unsigned int) length < limit)
      limit = (unsigned int) length;
        /* allocate and initialize the marker item */
        cur_marker = (jpeg_saved_marker_ptr)
      (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                      SIZEOF(struct jpeg_marker_struct) + limit);
        cur_marker->next = NULL;
        cur_marker->marker = (UINT8) cinfo->unread_marker;
        cur_marker->original_length = (unsigned int) length;
        cur_marker->data_length = limit;
        /* data area is just beyond the jpeg_marker_struct */
        data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
        marker->cur_marker = cur_marker;
        marker->bytes_read = 0;
        bytes_read = 0;
        data_length = limit;
      } else {
        /* deal with bogus length word */
        bytes_read = data_length = 0;
        data = NULL;
      }
    } else {
      /* resume reading a marker */
      bytes_read = marker->bytes_read;
      data_length = cur_marker->data_length;
      data = cur_marker->data + bytes_read;
    }
  
    while (bytes_read < data_length) {
      INPUT_SYNC(cinfo);      /* move the restart point to here */
      marker->bytes_read = bytes_read;
      /* If there's not at least one byte in buffer, suspend */
      MAKE_BYTE_AVAIL(cinfo, return FALSE);
      /* Copy bytes with reasonable rapidity */
      while (bytes_read < data_length && bytes_in_buffer > 0) {
        *data++ = *next_input_byte++;
        bytes_in_buffer--;
        bytes_read++;
      }
    }
  
    /* Done reading what we want to read */
    if (cur_marker != NULL) { /* will be NULL if bogus length word */
      /* Add new marker to end of list */
      if (cinfo->marker_list == NULL) {
        cinfo->marker_list = cur_marker;
      } else {
        jpeg_saved_marker_ptr prev = cinfo->marker_list;
        while (prev->next != NULL)
      prev = prev->next;
        prev->next = cur_marker;
      }
      /* Reset pointer & calc remaining data length */
      data = cur_marker->data;
      length = cur_marker->original_length - data_length;
    }
    /* Reset to initial state for next marker */
    marker->cur_marker = NULL;
  
    /* Process the marker if interesting; else just make a generic trace msg */
    switch (cinfo->unread_marker) {
    case M_APP0:
      examine_app0(cinfo, data, data_length, length);
      break;
    case M_APP14:
      examine_app14(cinfo, data, data_length, length);
      break;
    default:
      TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
           (int) (data_length + length));
      break;
    }
  
    /* skip any remaining data -- could be lots */
    INPUT_SYNC(cinfo);        /* do before skip_input_data */
    if (length > 0)
      (*cinfo->src->skip_input_data) (cinfo, (long) length);
  
    return TRUE;
  }
  
  #endif /* SAVE_MARKERS_SUPPORTED */
  
  
  METHODDEF(boolean)
  skip_variable (j_decompress_ptr cinfo)
  /* Skip over an unknown or uninteresting variable-length marker */
  {
    IJG_INT32 length;
    INPUT_VARS(cinfo);
  
    INPUT_2BYTES(cinfo, length, return FALSE);
    length -= 2;
    
    TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
  
    INPUT_SYNC(cinfo);        /* do before skip_input_data */
    if (length > 0)
      (*cinfo->src->skip_input_data) (cinfo, (long) length);
  
    return TRUE;
  }
  
  
  /*
   * Find the next JPEG marker, save it in cinfo->unread_marker.
   * Returns FALSE if had to suspend before reaching a marker;
   * in that case cinfo->unread_marker is unchanged.
   *
   * Note that the result might not be a valid marker code,
   * but it will never be 0 or FF.
   */
  
  LOCAL(boolean)
  next_marker (j_decompress_ptr cinfo)
  {
    int c;
    INPUT_VARS(cinfo);
  
    for (;;) {
      INPUT_BYTE(cinfo, c, return FALSE);
      /* Skip any non-FF bytes.
       * This may look a bit inefficient, but it will not occur in a valid file.
       * We sync after each discarded byte so that a suspending data source
       * can discard the byte from its buffer.
       */
      while (c != 0xFF) {
        cinfo->marker->discarded_bytes++;
        INPUT_SYNC(cinfo);
        INPUT_BYTE(cinfo, c, return FALSE);
      }
      /* This loop swallows any duplicate FF bytes.  Extra FFs are legal as
       * pad bytes, so don't count them in discarded_bytes.  We assume there
       * will not be so many consecutive FF bytes as to overflow a suspending
       * data source's input buffer.
       */
      do {
        INPUT_BYTE(cinfo, c, return FALSE);
      } while (c == 0xFF);
      if (c != 0)
        break;            /* found a valid marker, exit loop */
      /* Reach here if we found a stuffed-zero data sequence (FF/00).
       * Discard it and loop back to try again.
       */
      cinfo->marker->discarded_bytes += 2;
      INPUT_SYNC(cinfo);
    }
  
    if (cinfo->marker->discarded_bytes != 0) {
      WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, (int)cinfo->marker->discarded_bytes, c);
      cinfo->marker->discarded_bytes = 0;
    }
  
    cinfo->unread_marker = c;
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  LOCAL(boolean)
  first_marker (j_decompress_ptr cinfo)
  /* Like next_marker, but used to obtain the initial SOI marker. */
  /* For this marker, we do not allow preceding garbage or fill; otherwise,
   * we might well scan an entire input file before realizing it ain't JPEG.
   * If an application wants to process non-JFIF files, it must seek to the
   * SOI before calling the JPEG library.
   */
  {
    int c, c2;
    INPUT_VARS(cinfo);
  
    INPUT_BYTE(cinfo, c, return FALSE);
    INPUT_BYTE(cinfo, c2, return FALSE);
    if (c != 0xFF || c2 != (int) M_SOI)
      ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
  
    cinfo->unread_marker = c2;
  
    INPUT_SYNC(cinfo);
    return TRUE;
  }
  
  
  /*
   * Read markers until SOS or EOI.
   *
   * Returns same codes as are defined for jpeg_consume_input:
   * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
   */
  
  METHODDEF(int)
  read_markers (j_decompress_ptr cinfo)
  {
    /* Outer loop repeats once for each marker. */
    for (;;) {
      /* Collect the marker proper, unless we already did. */
      /* NB: first_marker() enforces the requirement that SOI appear first. */
      if (cinfo->unread_marker == 0) {
        if (! cinfo->marker->saw_SOI) {
      if (! first_marker(cinfo))
        return JPEG_SUSPENDED;
        } else {
      if (! next_marker(cinfo))
        return JPEG_SUSPENDED;
        }
      }
      /* At this point cinfo->unread_marker contains the marker code and the
       * input point is just past the marker proper, but before any parameters.
       * A suspension will cause us to return with this state still true.
       */
      switch (cinfo->unread_marker) {
      case M_SOI:
        if (! get_soi(cinfo))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF0:        /* Baseline */
      case M_SOF1:        /* Extended sequential, Huffman */
        if (! get_sof(cinfo, JPROC_SEQUENTIAL, FALSE, DCTSIZE))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF2:        /* Progressive, Huffman */
        if (! get_sof(cinfo, JPROC_PROGRESSIVE, FALSE, DCTSIZE))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF3:        /* Lossless, Huffman */
        if (! get_sof(cinfo, JPROC_LOSSLESS, FALSE, 1))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF9:        /* Extended sequential, arithmetic */
        if (! get_sof(cinfo, JPROC_SEQUENTIAL, TRUE, DCTSIZE))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF10:       /* Progressive, arithmetic */
        if (! get_sof(cinfo, JPROC_PROGRESSIVE, TRUE, DCTSIZE))
      return JPEG_SUSPENDED;
        break;
  
      case M_SOF11:       /* Lossless, arithmetic */
        if (! get_sof(cinfo, JPROC_LOSSLESS, TRUE, 1))
      return JPEG_SUSPENDED;
        break;
  
      /* Currently unsupported SOFn types */
      case M_SOF5:        /* Differential sequential, Huffman */
      case M_SOF6:        /* Differential progressive, Huffman */
      case M_SOF7:        /* Differential lossless, Huffman */
      case M_JPG:         /* Reserved for JPEG extensions */
      case M_SOF13:       /* Differential sequential, arithmetic */
      case M_SOF14:       /* Differential progressive, arithmetic */
      case M_SOF15:       /* Differential lossless, arithmetic */
        ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
        break;
  
      case M_SOS:
        if (! get_sos(cinfo))
      return JPEG_SUSPENDED;
        cinfo->unread_marker = 0; /* processed the marker */
        return JPEG_REACHED_SOS;
      
      case M_EOI:
        TRACEMS(cinfo, 1, JTRC_EOI);
        cinfo->unread_marker = 0; /* processed the marker */
        return JPEG_REACHED_EOI;
        
      case M_DAC:
        if (! get_dac(cinfo))
      return JPEG_SUSPENDED;
        break;
        
      case M_DHT:
        if (! get_dht(cinfo))
      return JPEG_SUSPENDED;
        break;
        
      case M_DQT:
        if (! get_dqt(cinfo))
      return JPEG_SUSPENDED;
        break;
        
      case M_DRI:
        if (! get_dri(cinfo))
      return JPEG_SUSPENDED;
        break;
        
      case M_APP0:
      case M_APP1:
      case M_APP2:
      case M_APP3:
      case M_APP4:
      case M_APP5:
      case M_APP6:
      case M_APP7:
      case M_APP8:
      case M_APP9:
      case M_APP10:
      case M_APP11:
      case M_APP12:
      case M_APP13:
      case M_APP14:
      case M_APP15:
        if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
          cinfo->unread_marker - (int) M_APP0]) (cinfo))
      return JPEG_SUSPENDED;
        break;
        
      case M_COM:
        if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
      return JPEG_SUSPENDED;
        break;
  
      case M_RST0:        /* these are all parameterless */
      case M_RST1:
      case M_RST2:
      case M_RST3:
      case M_RST4:
      case M_RST5:
      case M_RST6:
      case M_RST7:
      case M_TEM:
        TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
        break;
  
      case M_DNL:         /* Ignore DNL ... perhaps the wrong thing */
        if (! skip_variable(cinfo))
      return JPEG_SUSPENDED;
        break;
  
      default:            /* must be DHP, EXP, JPGn, or RESn */
        /* For now, we treat the reserved markers as fatal errors since they are
         * likely to be used to signal incompatible JPEG Part 3 extensions.
         * Once the JPEG 3 version-number marker is well defined, this code
         * ought to change!
         */
        ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
        break;
      }
      /* Successfully processed marker, so reset state variable */
      cinfo->unread_marker = 0;
    } /* end loop */
  }
  
  
  /*
   * Read a restart marker, which is expected to appear next in the datastream;
   * if the marker is not there, take appropriate recovery action.
   * Returns FALSE if suspension is required.
   *
   * This is called by the entropy decoder after it has read an appropriate
   * number of MCUs.  cinfo->unread_marker may be nonzero if the entropy decoder
   * has already read a marker from the data source.  Under normal conditions
   * cinfo->unread_marker will be reset to 0 before returning; if not reset,
   * it holds a marker which the decoder will be unable to read past.
   */
  
  METHODDEF(boolean)
  read_restart_marker (j_decompress_ptr cinfo)
  {
    /* Obtain a marker unless we already did. */
    /* Note that next_marker will complain if it skips any data. */
    if (cinfo->unread_marker == 0) {
      if (! next_marker(cinfo))
        return FALSE;
    }
  
    if (cinfo->unread_marker ==
        ((int) M_RST0 + cinfo->marker->next_restart_num)) {
      /* Normal case --- swallow the marker and let entropy decoder continue */
      TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
      cinfo->unread_marker = 0;
    } else {
      /* Uh-oh, the restart markers have been messed up. */
      /* Let the data source manager determine how to resync. */
      if (! (*cinfo->src->resync_to_restart) (cinfo,
                          cinfo->marker->next_restart_num))
        return FALSE;
    }
  
    /* Update next-restart state */
    cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
  
    return TRUE;
  }
  
  
  /*
   * This is the default resync_to_restart method for data source managers
   * to use if they don't have any better approach.  Some data source managers
   * may be able to back up, or may have additional knowledge about the data
   * which permits a more intelligent recovery strategy; such managers would
   * presumably supply their own resync method.
   *
   * read_restart_marker calls resync_to_restart if it finds a marker other than
   * the restart marker it was expecting.  (This code is *not* used unless
   * a nonzero restart interval has been declared.)  cinfo->unread_marker is
   * the marker code actually found (might be anything, except 0 or FF).
   * The desired restart marker number (0..7) is passed as a parameter.
   * This routine is supposed to apply whatever error recovery strategy seems
   * appropriate in order to position the input stream to the next data segment.
   * Note that cinfo->unread_marker is treated as a marker appearing before
   * the current data-source input point; usually it should be reset to zero
   * before returning.
   * Returns FALSE if suspension is required.
   *
   * This implementation is substantially constrained by wanting to treat the
   * input as a data stream; this means we can't back up.  Therefore, we have
   * only the following actions to work with:
   *   1. Simply discard the marker and let the entropy decoder resume at next
   *      byte of file.
   *   2. Read forward until we find another marker, discarding intervening
   *      data.  (In theory we could look ahead within the current bufferload,
   *      without having to discard data if we don't find the desired marker.
   *      This idea is not implemented here, in part because it makes behavior
   *      dependent on buffer size and chance buffer-boundary positions.)
   *   3. Leave the marker unread (by failing to zero cinfo->unread_marker).
   *      This will cause the entropy decoder to process an empty data segment,
   *      inserting dummy zeroes, and then we will reprocess the marker.
   *
   * #2 is appropriate if we think the desired marker lies ahead, while #3 is
   * appropriate if the found marker is a future restart marker (indicating
   * that we have missed the desired restart marker, probably because it got
   * corrupted).
   * We apply #2 or #3 if the found marker is a restart marker no more than
   * two counts behind or ahead of the expected one.  We also apply #2 if the
   * found marker is not a legal JPEG marker code (it's certainly bogus data).
   * If the found marker is a restart marker more than 2 counts away, we do #1
   * (too much risk that the marker is erroneous; with luck we will be able to
   * resync at some future point).
   * For any valid non-restart JPEG marker, we apply #3.  This keeps us from
   * overrunning the end of a scan.  An implementation limited to single-scan
   * files might find it better to apply #2 for markers other than EOI, since
   * any other marker would have to be bogus data in that case.
   */
  
  GLOBAL(boolean)
  jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
  {
    int marker = cinfo->unread_marker;
    int action = 1;
    
    /* Always put up a warning. */
    WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
    
    /* Outer loop handles repeated decision after scanning forward. */
    for (;;) {
      if (marker < (int) M_SOF0)
        action = 2;       /* invalid marker */
      else if (marker < (int) M_RST0 || marker > (int) M_RST7)
        action = 3;       /* valid non-restart marker */
      else {
        if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
        marker == ((int) M_RST0 + ((desired+2) & 7)))
      action = 3;     /* one of the next two expected restarts */
        else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
             marker == ((int) M_RST0 + ((desired-2) & 7)))
      action = 2;     /* a prior restart, so advance */
        else
      action = 1;     /* desired restart or too far away */
      }
      TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
      switch (action) {
      case 1:
        /* Discard marker and let entropy decoder resume processing. */
        cinfo->unread_marker = 0;
        return TRUE;
      case 2:
        /* Scan to the next marker, and repeat the decision loop. */
        if (! next_marker(cinfo))
      return FALSE;
        marker = cinfo->unread_marker;
        break;
      case 3:
        /* Return without advancing past this marker. */
        /* Entropy decoder will be forced to process an empty segment. */
        return TRUE;
      }
    } /* end loop */
  }
  
  
  /*
   * Reset marker processing state to begin a fresh datastream.
   */
  
  METHODDEF(void)
  reset_marker_reader (j_decompress_ptr cinfo)
  {
    my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
  
    cinfo->comp_info = NULL;      /* until allocated by get_sof */
    cinfo->input_scan_number = 0;     /* no SOS seen yet */
    cinfo->unread_marker = 0;     /* no pending marker */
    marker->pub.saw_SOI = FALSE;      /* set internal state too */
    marker->pub.saw_SOF = FALSE;
    marker->pub.discarded_bytes = 0;
    marker->cur_marker = NULL;
  }
  
  
  /*
   * Initialize the marker reader module.
   * This is called only once, when the decompression object is created.
   */
  
  GLOBAL(void)
  jinit_marker_reader (j_decompress_ptr cinfo)
  {
    my_marker_ptr marker;
    int i;
  
    /* Create subobject in permanent pool */
    marker = (my_marker_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
                  SIZEOF(my_marker_reader));
    cinfo->marker = (struct jpeg_marker_reader *) marker;
    /* Initialize public method pointers */
    marker->pub.reset_marker_reader = reset_marker_reader;
    marker->pub.read_markers = read_markers;
    marker->pub.read_restart_marker = read_restart_marker;
    /* Initialize COM/APPn processing.
     * By default, we examine and then discard APP0 and APP14,
     * but simply discard COM and all other APPn.
     */
    marker->process_COM = skip_variable;
    marker->length_limit_COM = 0;
    for (i = 0; i < 16; i++) {
      marker->process_APPn[i] = skip_variable;
      marker->length_limit_APPn[i] = 0;
    }
    marker->process_APPn[0] = get_interesting_appn;
    marker->process_APPn[14] = get_interesting_appn;
    /* Reset marker processing state */
    reset_marker_reader(cinfo);
  }
  
  
  /*
   * Control saving of COM and APPn markers into marker_list.
   */
  
  #ifdef SAVE_MARKERS_SUPPORTED
  
  GLOBAL(void)
  jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
             unsigned int length_limit)
  {
    my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
    long maxlength;
    jpeg_marker_parser_method processor;
  
    /* Length limit mustn't be larger than what we can allocate
     * (should only be a concern in a 16-bit environment).
     */
    maxlength = cinfo->mem->max_alloc_chunk - (long)SIZEOF(struct jpeg_marker_struct);
    if (((long) length_limit) > maxlength)
      length_limit = (unsigned int) maxlength;
  
    /* Choose processor routine to use.
     * APP0/APP14 have special requirements.
     */
    if (length_limit) {
      processor = save_marker;
      /* If saving APP0/APP14, save at least enough for our internal use. */
      if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
        length_limit = APP0_DATA_LEN;
      else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
        length_limit = APP14_DATA_LEN;
    } else {
      processor = skip_variable;
      /* If discarding APP0/APP14, use our regular on-the-fly processor. */
      if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
        processor = get_interesting_appn;
    }
  
    if (marker_code == (int) M_COM) {
      marker->process_COM = processor;
      marker->length_limit_COM = length_limit;
    } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
      marker->process_APPn[marker_code - (int) M_APP0] = processor;
      marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
    } else
      ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
  }
  
  #endif /* SAVE_MARKERS_SUPPORTED */
  
  
  /*
   * Install a special processing method for COM or APPn markers.
   */
  
  GLOBAL(void)
  jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
                 jpeg_marker_parser_method routine)
  {
    my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
  
    if (marker_code == (int) M_COM)
      marker->process_COM = routine;
    else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
      marker->process_APPn[marker_code - (int) M_APP0] = routine;
    else
      ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
  }
  