GLOBAL boolean

jpeg_start_decompress (j_decompress_ptr cinfo)

{

  if (cinfo->global_state == DSTATE_READY) {

    /* First call: initialize master control, select active modules */

    jinit_master_decompress(cinfo);

    if (cinfo->buffered_image) {

      /* No more work here; expecting jpeg_start_output next */

      cinfo->global_state = DSTATE_BUFIMAGE;

      return TRUE;

    }

    cinfo->global_state = DSTATE_PRELOAD;

  }

  if (cinfo->global_state == DSTATE_PRELOAD) {

    /* If file has multiple scans, absorb them all into the coef buffer */

    if (cinfo->inputctl->has_multiple_scans) {

#ifdef D_MULTISCAN_FILES_SUPPORTED

      for (;;) {

	int retcode;

	/* Call progress monitor hook if present */

	if (cinfo->progress != NULL)

	  (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

	/* Absorb some more input */

	retcode = (*cinfo->inputctl->consume_input) (cinfo);

	if (retcode == JPEG_SUSPENDED)

	  return FALSE;

	if (retcode == JPEG_REACHED_EOI)

	  break;

	/* Advance progress counter if appropriate */

	if (cinfo->progress != NULL &&

	    (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {

	  if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {

	    /* jdmaster underestimated number of scans; ratchet up one scan */

	    cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;

	  }

	}

      }

#else

      ERREXIT(cinfo, JERR_NOT_COMPILED);

#endif /* D_MULTISCAN_FILES_SUPPORTED */

    }

    cinfo->output_scan_number = cinfo->input_scan_number;

  } else if (cinfo->global_state != DSTATE_PRESCAN)

    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* Perform any dummy output passes, and set up for the final pass */

  return output_pass_setup(cinfo);

}

METHODDEF(void) start_pass (j_decompress_ptr cinfo) {
  my_idct_ptr idct = (my_idct_ptr) cinfo->idct;
  int ci, i;
  jpeg_component_info *compptr;
  int method = 0;
  inverse_DCT_method_ptr method_ptr = NULL;
  JQUANT_TBL * qtbl;

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++) {
    /* Select the proper IDCT routine for this component's scaling */
    switch (compptr->DCT_scaled_size) {
#ifdef IDCT_SCALING_SUPPORTED
    case 1:
      method_ptr = jpeg_idct_1x1;
      method = JDCT_ISLOW;	/* jidctred uses islow-style table */
      break;
    case 2:
      method_ptr = jpeg_idct_2x2;
      method = JDCT_ISLOW;	/* jidctred uses islow-style table */
      break;
    case 4:
      method_ptr = jpeg_idct_4x4;
      method = JDCT_ISLOW;	/* jidctred uses islow-style table */
      break;
#endif
    case DCTSIZE:
      switch (cinfo->dct_method) {
#ifdef DCT_ISLOW_SUPPORTED
      case JDCT_ISLOW:
	method_ptr = jpeg_idct_islow;
	method = JDCT_ISLOW;
	break;
#endif
#ifdef DCT_IFAST_SUPPORTED
      case JDCT_IFAST:
	method_ptr = jpeg_idct_ifast;
	method = JDCT_IFAST;
	break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
      case JDCT_FLOAT:
	method_ptr = jpeg_idct_float;
	method = JDCT_FLOAT;
	break;
#endif
      default:
	ERREXIT(cinfo, JERR_NOT_COMPILED);
	break;
      }
      break;
    default:
      ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->DCT_scaled_size);
      break;
    }
    idct->pub.inverse_DCT[ci] = method_ptr;
    /* Create multiplier table from quant table.
     * However, we can skip this if the component is uninteresting
     * or if we already built the table.  Also, if no quant table
     * has yet been saved for the component, we leave the
     * multiplier table all-zero; we'll be reading zeroes from the
     * coefficient controller's buffer anyway.
     */
    if (! compptr->component_needed || idct->cur_method[ci] == method)
      continue;
    qtbl = compptr->quant_table;
    if (qtbl == NULL)		/* happens if no data yet for component */
      continue;
    idct->cur_method[ci] = method;
    switch (method) {
#ifdef PROVIDE_ISLOW_TABLES
    case JDCT_ISLOW:
      {
	/* For LL&M IDCT method, multipliers are equal to raw quantization
	 * coefficients, but are stored as ints to ensure access efficiency.
	 */
	ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table;
	for (i = 0; i < DCTSIZE2; i++) {
	  ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[i];
	}
      }
      break;
#endif
#ifdef DCT_IFAST_SUPPORTED
    case JDCT_IFAST:
      {
	/* For AA&N IDCT method, multipliers are equal to quantization
	 * coefficients scaled by scalefactor[row]*scalefactor[col], where
	 *   scalefactor[0] = 1
	 *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	 * For integer operation, the multiplier table is to be scaled by
	 * IFAST_SCALE_BITS.
	 */
	IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table;
#define CONST_BITS 14
	static const INT16 aanscales[DCTSIZE2] = {
	  /* precomputed values scaled up by 14 bits */
	  16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
	  22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
	  21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
	  19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
//.........这里部分代码省略.........

jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
{
  jpeg_component_info * compptr;
__boundcheck_metadata_store((void *)(&compptr),(void *)((size_t)(&compptr)+sizeof(compptr)*8-1));

  int ci;
__boundcheck_metadata_store((void *)(&ci),(void *)((size_t)(&ci)+sizeof(ci)*8-1));


#define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl)  \
  (compptr = &cinfo->comp_info[index], \
   compptr->component_id = (id), \
   compptr->h_samp_factor = (hsamp), \
   compptr->v_samp_factor = (vsamp), \
   compptr->quant_tbl_no = (quant), \
   compptr->dc_tbl_no = (dctbl), \
   compptr->ac_tbl_no = (actbl) )

  /* Safety check to ensure start_compress not called yet. */
  if (cinfo->global_state != CSTATE_START)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* For all colorspaces, we use Q and Huff tables 0 for luminance components,
   * tables 1 for chrominance components.
   */

  cinfo->jpeg_color_space = colorspace;

  cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
  cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */

  switch (colorspace) {
  case JCS_GRAYSCALE:
    cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
    cinfo->num_components = 1;
    /* JFIF specifies component ID 1 */
    SET_COMP(0, 1, 1,1, 0, 0,0);
    break;
  case JCS_RGB:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
    cinfo->num_components = 3;
    SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
    SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
    SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
    break;
  case JCS_YCbCr:
    cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
    cinfo->num_components = 3;
    /* JFIF specifies component IDs 1,2,3 */
    /* We default to 2x2 subsamples of chrominance */
    SET_COMP(0, 1, 2,2, 0, 0,0);
    SET_COMP(1, 2, 1,1, 1, 1,1);
    SET_COMP(2, 3, 1,1, 1, 1,1);
    break;
  case JCS_CMYK:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
    cinfo->num_components = 4;
    SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
    SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
    SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
    SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
    break;
  case JCS_YCCK:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
    cinfo->num_components = 4;
    SET_COMP(0, 1, 2,2, 0, 0,0);
    SET_COMP(1, 2, 1,1, 1, 1,1);
    SET_COMP(2, 3, 1,1, 1, 1,1);
    SET_COMP(3, 4, 2,2, 0, 0,0);
    break;
  case JCS_UNKNOWN:
    cinfo->num_components = cinfo->input_components;
    if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
	       MAX_COMPONENTS);
    for (ci = 0; ci < cinfo->num_components; ci++) {
      SET_COMP(ci, ci, 1,1, 0, 0,0);
    }
    break;
  default:
    ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
  }
}

start_pass_fdctmgr (j_compress_ptr cinfo)
{
  my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct;
  int ci, qtblno, i;
  jpeg_component_info *compptr;
  JQUANT_TBL * qtbl;
  DCTELEM * dtbl;

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    qtblno = compptr->quant_tbl_no;
    /* Make sure specified quantization table is present */
    if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
	cinfo->quant_tbl_ptrs[qtblno] == NULL)
      ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
    qtbl = cinfo->quant_tbl_ptrs[qtblno];
    /* Compute divisors for this quant table */
    /* We may do this more than once for same table, but it's not a big deal */
    switch (cinfo->dct_method) {
#ifdef DCT_ISLOW_SUPPORTED
    case JDCT_ISLOW:
      /* For LL&M IDCT method, divisors are equal to raw quantization
       * coefficients multiplied by 8 (to counteract scaling).
       */
      if (fdct->divisors[qtblno] == NULL) {
	fdct->divisors[qtblno] = (DCTELEM *)
	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				      DCTSIZE2 * SIZEOF(DCTELEM));
      }
      dtbl = fdct->divisors[qtblno];
      for (i = 0; i < DCTSIZE2; i++) {
	dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3;
      }
      break;
#endif
#ifdef DCT_IFAST_SUPPORTED
    case JDCT_IFAST:
      {
	/* For AA&N IDCT method, divisors are equal to quantization
	 * coefficients scaled by scalefactor[row]*scalefactor[col], where
	 *   scalefactor[0] = 1
	 *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	 * We apply a further scale factor of 8.
	 */
#define CONST_BITS 14
	static const INT16 aanscales[DCTSIZE2] = {
	  /* precomputed values scaled up by 14 bits */
	  16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
	  22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
	  21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
	  19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
	  16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
	  12873, 17855, 16819, 15137, 12873, 10114,  6967,  3552,
	   8867, 12299, 11585, 10426,  8867,  6967,  4799,  2446,
	   4520,  6270,  5906,  5315,  4520,  3552,  2446,  1247
	};
	SHIFT_TEMPS

	if (fdct->divisors[qtblno] == NULL) {
	  fdct->divisors[qtblno] = (DCTELEM *)
	    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
					DCTSIZE2 * SIZEOF(DCTELEM));
	}
	dtbl = fdct->divisors[qtblno];
	for (i = 0; i < DCTSIZE2; i++) {
	  dtbl[i] = (DCTELEM)
	    DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
				  (INT32) aanscales[i]),
		    CONST_BITS-3);
	}
      }
      break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
    case JDCT_FLOAT:
      {
	/* For float AA&N IDCT method, divisors are equal to quantization
	 * coefficients scaled by scalefactor[row]*scalefactor[col], where
	 *   scalefactor[0] = 1
	 *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	 * We apply a further scale factor of 8.
	 * What's actually stored is 1/divisor so that the inner loop can
	 * use a multiplication rather than a division.
	 */
	FAST_FLOAT * fdtbl;
	int row, col;
	static const double aanscalefactor[DCTSIZE] = {
	  1.0, 1.387039845, 1.306562965, 1.175875602,
	  1.0, 0.785694958, 0.541196100, 0.275899379
	};

	if (fdct->float_divisors[qtblno] == NULL) {
	  fdct->float_divisors[qtblno] = (FAST_FLOAT *)
	    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
					DCTSIZE2 * SIZEOF(FAST_FLOAT));
	}
	fdtbl = fdct->float_divisors[qtblno];
	i = 0;
	for (row = 0; row < DCTSIZE; row++) {
	  for (col = 0; col < DCTSIZE; col++) {
//.........这里部分代码省略.........

initial_setup (j_decompress_ptr cinfo)
/* Called once, when first SOS marker is reached */
{
  int ci;
  jpeg_component_info *compptr;

  /* Make sure image isn't bigger than I can handle */
  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);

  /* For now, precision must match compiled-in value... */
  if (cinfo->data_precision != BITS_IN_JSAMPLE)
    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

  /* Check that number of components won't exceed internal array sizes */
  if (cinfo->num_components > MAX_COMPONENTS)
    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
	     MAX_COMPONENTS);

  /* Compute maximum sampling factors; check factor validity */
  cinfo->max_h_samp_factor = 1;
  cinfo->max_v_samp_factor = 1;
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
      ERREXIT(cinfo, JERR_BAD_SAMPLING);
    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
				   compptr->h_samp_factor);
    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
				   compptr->v_samp_factor);
  }

  /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
   * In the full decompressor, this will be overridden by jdmaster.c;
   * but in the transcoder, jdmaster.c is not used, so we must do it here.
   */
  cinfo->min_DCT_scaled_size = DCTSIZE;

  /* Compute dimensions of components */
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    compptr->DCT_scaled_size = DCTSIZE;
    /* Size in DCT blocks */
    compptr->width_in_blocks = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
    compptr->height_in_blocks = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
    /* downsampled_width and downsampled_height will also be overridden by
     * jdmaster.c if we are doing full decompression.  The transcoder library
     * doesn't use these values, but the calling application might.
     */
    /* Size in samples */
    compptr->downsampled_width = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
		    (long) cinfo->max_h_samp_factor);
    compptr->downsampled_height = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
		    (long) cinfo->max_v_samp_factor);
    /* Mark component needed, until color conversion says otherwise */
    compptr->component_needed = true;
    /* Mark no quantization table yet saved for component */
    compptr->quant_table = NULL;
  }

  /* Compute number of fully interleaved MCU rows. */
  cinfo->total_iMCU_rows = (JDIMENSION)
    jdiv_round_up((long) cinfo->image_height,
		  (long) (cinfo->max_v_samp_factor*DCTSIZE));

  /* Decide whether file contains multiple scans */
  if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
    cinfo->inputctl->has_multiple_scans = true;
  else
    cinfo->inputctl->has_multiple_scans = FALSE;
}

//.........这里部分代码省略.........
		JVERSION, JCOPYRIGHT);
	printed_version = TRUE;
      }
      cinfo->err->trace_level++;

    } else if (keymatch(arg, "fast", 1)) {
      /* Select recommended processing options for quick-and-dirty output. */
      cinfo->two_pass_quantize = FALSE;
      cinfo->dither_mode = JDITHER_ORDERED;
      if (! cinfo->quantize_colors) /* don't override an earlier -colors */
	cinfo->desired_number_of_colors = 216;
      cinfo->dct_method = JDCT_FASTEST;
      cinfo->do_fancy_upsampling = FALSE;

    } else if (keymatch(arg, "gif", 1)) {
      /* GIF output format. */
      requested_fmt = FMT_GIF;

    } else if (keymatch(arg, "grayscale", 2) || keymatch(arg, "greyscale",2)) {
      /* Force monochrome output. */
      cinfo->out_color_space = JCS_GRAYSCALE;

    } else if (keymatch(arg, "map", 3)) {
      /* Quantize to a color map taken from an input file. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (for_real) {		/* too expensive to do twice! */
#ifdef QUANT_2PASS_SUPPORTED	/* otherwise can't quantize to supplied map */
	FILE * mapfile;

	if ((mapfile = fopen(argv[argn], READ_BINARY)) == NULL) {
	  fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);
	  exit(EXIT_FAILURE);
	}
	read_color_map(cinfo, mapfile);
	fclose(mapfile);
	cinfo->quantize_colors = TRUE;
#else
	ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
      }

    } else if (keymatch(arg, "maxmemory", 3)) {
      /* Maximum memory in Kb (or Mb with 'm'). */
      long lval;
      char ch = 'x';

      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (sscanf(argv[argn], "%ld%c", &lval, &ch) < 1)
	usage();
      if (ch == 'm' || ch == 'M')
	lval *= 1000L;
      cinfo->mem->max_memory_to_use = lval * 1000L;

    } else if (keymatch(arg, "nosmooth", 3)) {
      /* Suppress fancy upsampling */
      cinfo->do_fancy_upsampling = FALSE;

    } else if (keymatch(arg, "onepass", 3)) {
      /* Use fast one-pass quantization. */
      cinfo->two_pass_quantize = FALSE;

    } else if (keymatch(arg, "os2", 3)) {
      /* BMP output format (OS/2 flavor). */
      requested_fmt = FMT_OS2;

    } else if (keymatch(arg, "outfile", 4)) {
      /* Set output file name. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      outfilename = argv[argn];	/* save it away for later use */

    } else if (keymatch(arg, "pnm", 1) || keymatch(arg, "ppm", 1)) {
      /* PPM/PGM output format. */
      requested_fmt = FMT_PPM;

    } else if (keymatch(arg, "rle", 1)) {
      /* RLE output format. */
      requested_fmt = FMT_RLE;

    } else if (keymatch(arg, "scale", 1)) {
      /* Scale the output image by a fraction M/N. */
      if (++argn >= argc)	/* advance to next argument */
	usage();
      if (sscanf(argv[argn], "%d/%d",
		 &cinfo->scale_num, &cinfo->scale_denom) != 2)
	usage();

    } else if (keymatch(arg, "targa", 1)) {
      /* Targa output format. */
      requested_fmt = FMT_TARGA;

    } else {
      usage();			/* bogus switch */
    }
  }

  return argn;			/* return index of next arg (file name) */
}

jinit_upsampler (j_decompress_ptr cinfo)
{
    my_upsample_ptr upsample;
    int ci;
    jpeg_component_info * compptr;
    boolean need_buffer;
    int h_in_group, v_in_group, h_out_group, v_out_group;

    upsample = (my_upsample_ptr)
               (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                                           SIZEOF(my_upsampler));
    cinfo->upsample = (struct jpeg_upsampler *) upsample;
    upsample->pub.start_pass = start_pass_upsample;
    upsample->pub.upsample = sep_upsample;
    upsample->pub.need_context_rows = FALSE; /* until we find out differently */

    if (cinfo->CCIR601_sampling)	/* this isn't supported */
        ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);

    /* Verify we can handle the sampling factors, select per-component methods,
     * and create storage as needed.
     */
    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
            ci++, compptr++) {
        /* Compute size of an "input group" after IDCT scaling.  This many samples
         * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.
         */
        h_in_group = (compptr->h_samp_factor * compptr->DCT_h_scaled_size) /
                     cinfo->min_DCT_h_scaled_size;
        v_in_group = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
                     cinfo->min_DCT_v_scaled_size;
        h_out_group = cinfo->max_h_samp_factor;
        v_out_group = cinfo->max_v_samp_factor;
        upsample->rowgroup_height[ci] = v_in_group; /* save for use later */
        need_buffer = TRUE;
        if (! compptr->component_needed) {
            /* Don't bother to upsample an uninteresting component. */
            upsample->methods[ci] = noop_upsample;
            need_buffer = FALSE;
        } else if (h_in_group == h_out_group && v_in_group == v_out_group) {
            /* Fullsize components can be processed without any work. */
            upsample->methods[ci] = fullsize_upsample;
            need_buffer = FALSE;
        } else if (h_in_group * 2 == h_out_group &&
                   v_in_group == v_out_group) {
            /* Special case for 2h1v upsampling */
            upsample->methods[ci] = h2v1_upsample;
        } else if (h_in_group * 2 == h_out_group &&
                   v_in_group * 2 == v_out_group) {
            /* Special case for 2h2v upsampling */
            upsample->methods[ci] = h2v2_upsample;
        } else if ((h_out_group % h_in_group) == 0 &&
                   (v_out_group % v_in_group) == 0) {
            /* Generic integral-factors upsampling method */
            upsample->methods[ci] = int_upsample;
            upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);
            upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);
        } else
            ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
        if (need_buffer) {
            upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)
                                      ((j_common_ptr) cinfo, JPOOL_IMAGE,
                                       (JDIMENSION) jround_up((long) cinfo->output_width,
                                               (long) cinfo->max_h_samp_factor),
                                       (JDIMENSION) cinfo->max_v_samp_factor);
        }
    }
}

LOCAL void
per_scan_setup (j_compress_ptr cinfo)
/* Do computations that are needed before processing a JPEG scan */
/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
{
  int ci, mcublks, tmp;
  jpeg_component_info *compptr;
  
  if (cinfo->comps_in_scan == 1) {
    
    /* Noninterleaved (single-component) scan */
    compptr = cinfo->cur_comp_info[0];
    
    /* Overall image size in MCUs */
    cinfo->MCUs_per_row = compptr->width_in_blocks;
    cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
    
    /* For noninterleaved scan, always one block per MCU */
    compptr->MCU_width = 1;
    compptr->MCU_height = 1;
    compptr->MCU_blocks = 1;
    compptr->MCU_sample_width = DCTSIZE;
    compptr->last_col_width = 1;
    compptr->last_row_height = 1;
    
    /* Prepare array describing MCU composition */
    cinfo->blocks_in_MCU = 1;
    cinfo->MCU_membership[0] = 0;
    
  } else {
    
    /* Interleaved (multi-component) scan */
    if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
	       MAX_COMPS_IN_SCAN);
    
    /* Overall image size in MCUs */
    cinfo->MCUs_per_row = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_width,
		    (long) (cinfo->max_h_samp_factor*DCTSIZE));
    cinfo->MCU_rows_in_scan = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_height,
		    (long) (cinfo->max_v_samp_factor*DCTSIZE));
    
    cinfo->blocks_in_MCU = 0;
    
    for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
      compptr = cinfo->cur_comp_info[ci];
      /* Sampling factors give # of blocks of component in each MCU */
      compptr->MCU_width = compptr->h_samp_factor;
      compptr->MCU_height = compptr->v_samp_factor;
      compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
      compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
      /* Figure number of non-dummy blocks in last MCU column & row */
      tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
      if (tmp == 0) tmp = compptr->MCU_width;
      compptr->last_col_width = tmp;
      tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
      if (tmp == 0) tmp = compptr->MCU_height;
      compptr->last_row_height = tmp;
      /* Prepare array describing MCU composition */
      mcublks = compptr->MCU_blocks;
      if (cinfo->blocks_in_MCU + mcublks > MAX_BLOCKS_IN_MCU)
	ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
      while (mcublks-- > 0) {
	cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
      }
    }
    
  }

  /* Convert restart specified in rows to actual MCU count. */
  /* Note that count must fit in 16 bits, so we provide limiting. */
  if (cinfo->restart_in_rows > 0) {
    long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
    cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
  }
}

/*{{{  histogram(transform_info_ptr tinfo) {*/
METHODDEF DATATYPE *
histogram(transform_info_ptr tinfo) {
    struct histogram_local_struct *localp=(struct histogram_local_struct *)tinfo->methods->local_storage;
    transform_argument *args=tinfo->methods->arguments;
    HIST_TYPE *histogram_data=localp->boundaries.histogram;
    DATATYPE hist_min=localp->boundaries.hist_min, hist_resolution=localp->boundaries.hist_resolution;
    int nr_of_bins=localp->boundaries.nr_of_bins;
    int from_x=localp->from_x, to_x=localp->to_x;
    int outliers=args[ARGS_ASSIGN_OUTLIERS].is_set;
    int channels=tinfo->nr_of_channels, itemsize=tinfo->itemsize;
    int channelskip, freqskip, channel, point, points, freq, nfreq;
    int out_binskip, out_freqskip, out_pointskip, out_channelskip, out_shifts;
    int start_freq, end_freq, start_point, end_point;
    int freq_offset, channel_offset, point_offset;
    array tsdata;

    if (itemsize>1) {
        ERREXIT(tinfo->emethods, "histogram: Can't handle multiple items in input data.\n");
    }

    /*{{{  Set up tsdata array: elements=points, vectors=items*/
    tsdata.vector_skip=1;
    tsdata.nr_of_vectors=itemsize;
    if (from_x<0) from_x=0;
    if (tinfo->data_type==FREQ_DATA) {
        nfreq=tinfo->nroffreq;
        freqskip=itemsize;
        channelskip=nfreq*itemsize;
        tsdata.element_skip=channels*channelskip;

        out_shifts=points=tinfo->nrofshifts;
        if (to_x<0 || to_x>nfreq) to_x=nfreq;
        start_freq=from_x;
        end_freq=to_x;
        start_point=0;
        end_point=points;
        if (args[ARGS_COLLAPSE_POINTS].is_set) {
            out_pointskip=0;
        } else {
            out_pointskip=(end_freq-start_freq)*nr_of_bins*(args[ARGS_COLLAPSE_CHANNELS].is_set ? 1 : channels);
        }
    } else {
        nfreq=1;
        freqskip=0;
        points=tinfo->nr_of_points;
        if (tinfo->multiplexed) {
            tsdata.element_skip=channels*itemsize;
            channelskip=itemsize;
        } else {
            tsdata.element_skip=itemsize;
            channelskip=tinfo->nr_of_points*itemsize;
        }

        if (to_x<0 || to_x>points) to_x=points;
        start_freq=0;
        end_freq=1;
        start_point=from_x;
        end_point=to_x;
        out_shifts=1;
        out_pointskip=(args[ARGS_COLLAPSE_POINTS].is_set ? 0: 1);
    }
    tsdata.nr_of_elements=points;
    array_setreadwrite(&tsdata);

    if (to_x<=from_x) {
        ERREXIT(tinfo->emethods, "histogram: minx>=maxx. Please respecify these parameters.\n");
    }
    out_binskip=(args[ARGS_COLLAPSE_POINTS].is_set ? 1 : to_x-from_x);
    out_channelskip=(args[ARGS_COLLAPSE_CHANNELS].is_set ? 0 : out_binskip*nr_of_bins);
    out_freqskip=1;
    /*}}}  */

    if (histogram_data==(HIST_TYPE *)NULL) {
        /*{{{  First incoming epoch: Initialize working memory*/
        memcpy(&localp->tinfo, tinfo, sizeof(struct transform_info_struct));
        /* Protect the memory spaces we may need: */
        tinfo->comment=NULL;
        tinfo->probepos=NULL;
        if (args[ARGS_COLLAPSE_CHANNELS].is_set) {
            localp->tinfo.length_of_output_region=out_binskip*nr_of_bins*out_shifts;
            localp->tinfo.nr_of_channels=1;
        } else {
            tinfo->channelnames=NULL;
            localp->tinfo.length_of_output_region=channels*out_channelskip*out_shifts;
        }
        if ((histogram_data=(HIST_TYPE *)calloc(localp->tinfo.length_of_output_region, sizeof(DATATYPE)))==NULL) {
            ERREXIT(tinfo->emethods, "histogram: Error allocating epoch memory\n");
        }
        localp->tinfo.tsdata=(DATATYPE *)(localp->boundaries.histogram=histogram_data);
        localp->tinfo.itemsize=out_binskip;
        localp->tinfo.leaveright=0;
        if (tinfo->data_type==FREQ_DATA) {
            localp->tinfo.nroffreq=nr_of_bins;
            /* nrofshifts remains unmodified */
        } else {
            localp->tinfo.nr_of_points=nr_of_bins;
        }
        localp->tinfo.multiplexed=FALSE;
        localp->to_x=to_x;
//.........这里部分代码省略.........

GLOBAL void

jpeg_finish_compress (j_compress_ptr cinfo)

{

  JDIMENSION iMCU_row;



  if (cinfo->global_state == CSTATE_SCANNING ||

      cinfo->global_state == CSTATE_RAW_OK) {

    /* Terminate first pass */

    if (cinfo->next_scanline < cinfo->image_height)

      ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);

    (*cinfo->master->finish_pass) (cinfo);

  } else if (cinfo->global_state != CSTATE_WRCOEFS)

    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* Perform any remaining passes */

  while (! cinfo->master->is_last_pass) {

    (*cinfo->master->prepare_for_pass) (cinfo);

    for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {

      if (cinfo->progress != NULL) {

	cinfo->progress->pass_counter = (long) iMCU_row;

	cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;

	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

      }

      /* We bypass the main controller and invoke coef controller directly;

       * all work is being done from the coefficient buffer.

       */

      if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))

	ERREXIT(cinfo, JERR_CANT_SUSPEND);

    }

    (*cinfo->master->finish_pass) (cinfo);

  }

  /* Write EOI, do final cleanup */

  (*cinfo->marker->write_file_trailer) (cinfo);

  (*cinfo->dest->term_destination) (cinfo);

  /* We can use jpeg_abort to release memory and reset global_state */

  jpeg_abort((j_common_ptr) cinfo);

}

jpeg_make_c_derived_tbl (j_compress_ptr cinfo, boolean isDC, int tblno,
             c_derived_tbl ** pdtbl)
{
  JHUFF_TBL *htbl;
  c_derived_tbl *dtbl;
  int p, i, l, lastp, si, maxsymbol;
  char huffsize[257];
  unsigned int huffcode[257];
  unsigned int code;

  /* Note that huffsize[] and huffcode[] are filled in code-length order,
   * paralleling the order of the symbols themselves in htbl->huffval[].
   */

  /* Find the input Huffman table */
  if (tblno < 0 || tblno >= NUM_HUFF_TBLS)
    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);
  htbl =
    isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno];
  if (htbl == NULL)
    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);

  /* Allocate a workspace if we haven't already done so. */
  if (*pdtbl == NULL)
    *pdtbl = (c_derived_tbl *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                  SIZEOF(c_derived_tbl));
  dtbl = *pdtbl;
  
  /* Figure C.1: make table of Huffman code length for each symbol */

  p = 0;
  for (l = 1; l <= 16; l++) {
    i = (int) htbl->bits[l];
    if (i < 0 || p + i > 256)   /* protect against table overrun */
      ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
    while (i--)
      huffsize[p++] = (char) l;
  }
  huffsize[p] = 0;
  lastp = p;
  
  /* Figure C.2: generate the codes themselves */
  /* We also validate that the counts represent a legal Huffman code tree. */

  code = 0;
  si = huffsize[0];
  p = 0;
  while (huffsize[p]) {
    while (((int) huffsize[p]) == si) {
      huffcode[p++] = code;
      code++;
    }
    /* code is now 1 more than the last code used for codelength si; but
     * it must still fit in si bits, since no code is allowed to be all ones.
     * BUG FIX 2001-09-03: Comparison must be >, not >=
     */
    if (((IJG_INT32) code) > (((IJG_INT32) 1) << si))
      ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
    code <<= 1;
    si++;
  }
  
  /* Figure C.3: generate encoding tables */
  /* These are code and size indexed by symbol value */

  /* Set all codeless symbols to have code length 0;
   * this lets us detect duplicate VAL entries here, and later
   * allows emit_bits to detect any attempt to emit such symbols.
   */
  MEMZERO(dtbl->ehufsi, SIZEOF(dtbl->ehufsi));

  /* This is also a convenient place to check for out-of-range
   * and duplicated VAL entries.  We allow 0..255 for AC symbols
   * but only 0..16 for DC.  (We could constrain them further
   * based on data depth and mode, but this seems enough.)
   */
  maxsymbol = isDC ? 16 : 255;

  for (p = 0; p < lastp; p++) {
    i = htbl->huffval[p];
    if (i < 0 || i > maxsymbol || dtbl->ehufsi[i])
      ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
    dtbl->ehufco[i] = huffcode[p];
    dtbl->ehufsi[i] = huffsize[p];
  }
}

jpeg_gen_optimal_table (j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])
{
#define MAX_CLEN 32     /* assumed maximum initial code length */
  UINT8 bits[MAX_CLEN+1];   /* bits[k] = # of symbols with code length k */
  int codesize[257];        /* codesize[k] = code length of symbol k */
  int others[257];      /* next symbol in current branch of tree */
  int c1, c2;
  int p, i, j;
  long v;

  /* This algorithm is explained in section K.2 of the JPEG standard */

  MEMZERO(bits, SIZEOF(bits));
  MEMZERO(codesize, SIZEOF(codesize));
  for (i = 0; i < 257; i++)
    others[i] = -1;     /* init links to empty */
  
  freq[256] = 1;        /* make sure 256 has a nonzero count */
  /* Including the pseudo-symbol 256 in the Huffman procedure guarantees
   * that no real symbol is given code-value of all ones, because 256
   * will be placed last in the largest codeword category.
   */

  /* Huffman's basic algorithm to assign optimal code lengths to symbols */

  for (;;) {
    /* Find the smallest nonzero frequency, set c1 = its symbol */
    /* In case of ties, take the larger symbol number */
    c1 = -1;
    v = 1000000000L;
    for (i = 0; i <= 256; i++) {
      if (freq[i] && freq[i] <= v) {
    v = freq[i];
    c1 = i;
      }
    }

    /* Find the next smallest nonzero frequency, set c2 = its symbol */
    /* In case of ties, take the larger symbol number */
    c2 = -1;
    v = 1000000000L;
    for (i = 0; i <= 256; i++) {
      if (freq[i] && freq[i] <= v && i != c1) {
    v = freq[i];
    c2 = i;
      }
    }

    /* Done if we've merged everything into one frequency */
    if (c2 < 0)
      break;
    
    /* Else merge the two counts/trees */
    freq[c1] += freq[c2];
    freq[c2] = 0;

    /* Increment the codesize of everything in c1's tree branch */
    codesize[c1]++;
    while (others[c1] >= 0) {
      c1 = others[c1];
      codesize[c1]++;
    }
    
    others[c1] = c2;        /* chain c2 onto c1's tree branch */
    
    /* Increment the codesize of everything in c2's tree branch */
    codesize[c2]++;
    while (others[c2] >= 0) {
      c2 = others[c2];
      codesize[c2]++;
    }
  }

  /* Now count the number of symbols of each code length */
  for (i = 0; i <= 256; i++) {
    if (codesize[i]) {
      /* The JPEG standard seems to think that this can't happen, */
      /* but I'm paranoid... */
      if (codesize[i] > MAX_CLEN)
    ERREXIT(cinfo, JERR_HUFF_CLEN_OVERFLOW);

      bits[codesize[i]]++;
    }
  }

  /* JPEG doesn't allow symbols with code lengths over 16 bits, so if the pure
   * Huffman procedure assigned any such lengths, we must adjust the coding.
   * Here is what the JPEG spec says about how this next bit works:
   * Since symbols are paired for the longest Huffman code, the symbols are
   * removed from this length category two at a time.  The prefix for the pair
   * (which is one bit shorter) is allocated to one of the pair; then,
   * skipping the BITS entry for that prefix length, a code word from the next
   * shortest nonzero BITS entry is converted into a prefix for two code words
   * one bit longer.
   */
  
  for (i = MAX_CLEN; i > 16; i--) {
    while (bits[i] > 0) {
      j = i - 2;        /* find length of new prefix to be used */
      while (bits[j] == 0)
//.........这里部分代码省略.........

jpeg_open_backing_store (j_common_ptr cinfo, struct backing_store_struct *,
			 long )
{
  ERREXIT(cinfo, JERR_NO_BACKING_STORE);
}

master_selection (j_decompress_ptr cinfo)
{
  my_master_ptr master = (my_master_ptr) cinfo->master;
  boolean use_c_buffer;
  long samplesperrow;
  JDIMENSION jd_samplesperrow;

  /* Initialize dimensions and other stuff */
  jpeg_calc_output_dimensions(cinfo);
  prepare_range_limit_table(cinfo);

  /* Width of an output scanline must be representable as JDIMENSION. */
  samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
  jd_samplesperrow = (JDIMENSION) samplesperrow;
  if ((long) jd_samplesperrow != samplesperrow)
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);

  /* Initialize my private state */
  master->pass_number = 0;
  master->using_merged_upsample = use_merged_upsample(cinfo);

  /* Color quantizer selection */
  master->quantizer_1pass = NULL;
  master->quantizer_2pass = NULL;
  /* No mode changes if not using buffered-image mode. */
  if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
    cinfo->enable_1pass_quant = FALSE;
    cinfo->enable_external_quant = FALSE;
    cinfo->enable_2pass_quant = FALSE;
  }
  if (cinfo->quantize_colors) {
    if (cinfo->raw_data_out)
      ERREXIT(cinfo, JERR_NOTIMPL);
    /* 2-pass quantizer only works in 3-component color space. */
    if (cinfo->out_color_components != 3) {
      cinfo->enable_1pass_quant = TRUE;
      cinfo->enable_external_quant = FALSE;
      cinfo->enable_2pass_quant = FALSE;
      cinfo->colormap = NULL;
    } else if (cinfo->colormap != NULL) {
      cinfo->enable_external_quant = TRUE;
    } else if (cinfo->two_pass_quantize) {
      cinfo->enable_2pass_quant = TRUE;
    } else {
      cinfo->enable_1pass_quant = TRUE;
    }

    if (cinfo->enable_1pass_quant) {
#ifdef QUANT_1PASS_SUPPORTED
      jinit_1pass_quantizer(cinfo);
      master->quantizer_1pass = cinfo->cquantize;
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
    }

    /* We use the 2-pass code to map to external colormaps. */
    if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
#ifdef QUANT_2PASS_SUPPORTED
      jinit_2pass_quantizer(cinfo);
      master->quantizer_2pass = cinfo->cquantize;
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
    }
    /* If both quantizers are initialized, the 2-pass one is left active;
     * this is necessary for starting with quantization to an external map.
     */
  }

  /* Post-processing: in particular, color conversion first */
  if (! cinfo->raw_data_out) {
    if (master->using_merged_upsample) {
#ifdef UPSAMPLE_MERGING_SUPPORTED
      jinit_merged_upsampler(cinfo); /* does color conversion too */
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
    } else {
      jinit_color_deconverter(cinfo);
      jinit_upsampler(cinfo);
    }
    jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
  }
  /* Inverse DCT */
  jinit_inverse_dct(cinfo);
  /* Entropy decoding: either Huffman or arithmetic coding. */
  if (cinfo->arith_code) {
#ifdef D_ARITH_CODING_SUPPORTED
    jinit_arith_decoder(cinfo);
#else
    ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
#endif
  } else {
    if (cinfo->progressive_mode) {
#ifdef D_PROGRESSIVE_SUPPORTED
      jinit_phuff_decoder(cinfo);
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
//.........这里部分代码省略.........

LOCAL void
initial_setup (j_compress_ptr cinfo)
/* Do computations that are needed before master selection phase */
{
  int ci;
  jpeg_component_info *compptr;
  long samplesperrow;
  JDIMENSION jd_samplesperrow;

  /* Sanity check on image dimensions */
  if (cinfo->image_height <= 0 || cinfo->image_width <= 0
      || cinfo->num_components <= 0 || cinfo->input_components <= 0)
    ERREXIT(cinfo, JERR_EMPTY_IMAGE);

  /* Make sure image isn't bigger than I can handle */
  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);

  /* Width of an input scanline must be representable as JDIMENSION. */
  samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
  jd_samplesperrow = (JDIMENSION) samplesperrow;
  if ((long) jd_samplesperrow != samplesperrow)
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);

  /* For now, precision must match compiled-in value... */
  if (cinfo->data_precision != BITS_IN_JSAMPLE)
    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

  /* Check that number of components won't exceed internal array sizes */
  if (cinfo->num_components > MAX_COMPONENTS)
    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
	     MAX_COMPONENTS);

  /* Compute maximum sampling factors; check factor validity */
  cinfo->max_h_samp_factor = 1;
  cinfo->max_v_samp_factor = 1;
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
      ERREXIT(cinfo, JERR_BAD_SAMPLING);
    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
				   compptr->h_samp_factor);
    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
				   compptr->v_samp_factor);
  }

  /* Compute dimensions of components */
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* For compression, we never do DCT scaling. */
    compptr->DCT_scaled_size = DCTSIZE;
    /* Size in DCT blocks */
    compptr->width_in_blocks = (JDIMENSION)
      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
    compptr-&