jdmarker.c

linux下的flash播放器源程序

     */
    if (count > 256 || ((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 (index & 0x10) {		/* AC table definition */
      index -= 0x10;
      htblptr = &cinfo->ac_huff_tbl_ptrs[index];
    } else {			/* DC table definition */
      htblptr = &cinfo->dc_huff_tbl_ptrs[index];
    }

    if (index < 0 || index >= NUM_HUFF_TBLS)
      ERREXIT1(cinfo, JERR_DHT_INDEX, index);

    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 */
{
  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 */
{
  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, 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, JOCTET FAR * data,
	      unsigned int datalen, 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.
 */
{
  INT32 totallen = (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 = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
    cinfo->Y_density = (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 !=
	((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (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, JOCTET FAR * data,
	       unsigned int datalen, 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 = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
    flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
    flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
    transform = GETJOCTET(data[11]);
    TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, 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 */
{
  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;
  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 */
{
  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) {