jcmaster.c File Reference

#include "jinclude.h"
#include "jpeglib.h"

Include dependency graph for jcmaster.c:

Go to the source code of this file.

Classes
struct	my_comp_master

Macros
#define	JPEG_INTERNALS

Typedefs
typedef my_comp_master *	my_master_ptr

Enumerations
enum	c_pass_type { main_pass , huff_opt_pass , output_pass }

Functions
	initial_setup (j_compress_ptr cinfo)
	select_scan_parameters (j_compress_ptr cinfo)
	per_scan_setup (j_compress_ptr cinfo)
	prepare_for_pass (j_compress_ptr cinfo)
	pass_startup (j_compress_ptr cinfo)
	finish_pass_master (j_compress_ptr cinfo)
	jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)

Macro Definition Documentation

JPEG_INTERNALS

#define JPEG_INTERNALS

Definition at line 15 of file jcmaster.c.

Typedef Documentation

my_master_ptr

typedef my_comp_master* my_master_ptr

Definition at line 39 of file jcmaster.c.

Enumeration Type Documentation

c_pass_type

enum c_pass_type

Enumerator
main_pass
huff_opt_pass
output_pass

Definition at line 22 of file jcmaster.c.

             {
    main_pass,      /* input data, also do first output step */
    huff_opt_pass,      /* Huffman code optimization pass */
    output_pass     /* data output pass */
} c_pass_type;

Function Documentation

finish_pass_master()

finish_pass_master

(

j_compress_ptr

cinfo

)

Definition at line 581 of file jcmaster.c.

{
  my_master_ptr master = (my_master_ptr) cinfo->master;
 
  /* The entropy coder always needs an end-of-pass call,
   * either to analyze statistics or to flush its output buffer.
   */
  (*cinfo->entropy->finish_pass) (cinfo);
 
  /* Update state for next pass */
  switch (master->pass_type) {
  case main_pass:
    /* next pass is either output of scan 0 (after optimization)
     * or output of scan 1 (if no optimization).
     */
    master->pass_type = output_pass;
    if (! cinfo->optimize_coding)
      master->scan_number++;
    break;
  case huff_opt_pass:
    /* next pass is always output of current scan */
    master->pass_type = output_pass;
    break;
  case output_pass:
    /* next pass is either optimization or output of next scan */
    if (cinfo->optimize_coding)
      master->pass_type = huff_opt_pass;
    master->scan_number++;
    break;
  }
 
  master->pass_number++;
}

Referenced by jinit_c_master_control().

initial_setup()

initial_setup

(

j_compress_ptr

cinfo

)

Definition at line 47 of file jcmaster.c.

{
  int ci, ssize;
  jpeg_component_info *compptr;
 
  /* Sanity check on block_size */
  if (cinfo->block_size < 1 || cinfo->block_size > 16)
    ERREXIT2(cinfo, JERR_BAD_DCTSIZE, cinfo->block_size, cinfo->block_size);
 
  /* Derive natural_order from block_size */
  switch (cinfo->block_size) {
  case 2: cinfo->natural_order = jpeg_natural_order2; break;
  case 3: cinfo->natural_order = jpeg_natural_order3; break;
  case 4: cinfo->natural_order = jpeg_natural_order4; break;
  case 5: cinfo->natural_order = jpeg_natural_order5; break;
  case 6: cinfo->natural_order = jpeg_natural_order6; break;
  case 7: cinfo->natural_order = jpeg_natural_order7; break;
  default: cinfo->natural_order = jpeg_natural_order;
  }
 
  /* Derive lim_Se from block_size */
  cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
    cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
 
  /* Sanity check on image dimensions */
  if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
      cinfo->num_components <= 0)
    ERREXIT(cinfo, JERR_EMPTY_IMAGE);
 
  /* Make sure image isn't bigger than I can handle */
  if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
      (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
 
  /* Only 8 to 12 bits data precision are supported for DCT based JPEG */
  if (cinfo->data_precision < 8 || cinfo->data_precision > 12)
    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++) {
    /* Fill in the correct component_index value; don't rely on application */
    compptr->component_index = ci;
    /* In selecting the actual DCT scaling for each component, we try to
     * scale down the chroma components via DCT scaling rather than downsampling.
     * This saves time if the downsampler gets to use 1:1 scaling.
     * Note this code adapts subsampling ratios which are powers of 2.
     */
    ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
    if (! cinfo->raw_data_in)
      while (cinfo->min_DCT_h_scaled_size * ssize <=
         (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
         (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) ==
         0) {
    ssize = ssize * 2;
      }
#endif
    compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
    ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
    if (! cinfo->raw_data_in)
      while (cinfo->min_DCT_v_scaled_size * ssize <=
         (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
         (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) ==
         0) {
    ssize = ssize * 2;
      }
#endif
    compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
 
    /* We don't support DCT ratios larger than 2. */
    if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
    compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
    else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
    compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
 
    /* Size in DCT blocks */
    compptr->width_in_blocks = (JDIMENSION)
      jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
            (long) (cinfo->max_h_samp_factor * cinfo->block_size));
    compptr->height_in_blocks = (JDIMENSION)
      jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
            (long) (cinfo->max_v_samp_factor * cinfo->block_size));
    /* Size in samples */
    compptr->downsampled_width = (JDIMENSION)
      jdiv_round_up((long) cinfo->jpeg_width *
            (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
            (long) (cinfo->max_h_samp_factor * cinfo->block_size));
    compptr->downsampled_height = (JDIMENSION)
      jdiv_round_up((long) cinfo->jpeg_height *
            (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
            (long) (cinfo->max_v_samp_factor * cinfo->block_size));
    /* Don't need quantization scale after DCT,
     * until color conversion says otherwise.
     */
    compptr->component_needed = FALSE;
  }
 
  /* Compute number of fully interleaved MCU rows (number of times that
   * main controller will call coefficient controller).
   */
  cinfo->total_iMCU_rows = (JDIMENSION)
    jdiv_round_up((long) cinfo->jpeg_height,
          (long) (cinfo->max_v_samp_factor * cinfo->block_size));
}

Referenced by jinit_c_master_control().

jinit_c_master_control()

jinit_c_master_control	(	j_compress_ptr	cinfo,
		boolean	transcode_only
	)

Definition at line 621 of file jcmaster.c.

{
  my_master_ptr master;
 
  master = (my_master_ptr) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_comp_master));
  cinfo->master = &master->pub;
  master->pub.prepare_for_pass = prepare_for_pass;
  master->pub.pass_startup = pass_startup;
  master->pub.finish_pass = finish_pass_master;
  master->pub.is_last_pass = FALSE;
 
  /* Validate parameters, determine derived values */
  initial_setup(cinfo);
 
  if (cinfo->scan_info != NULL) {
#ifdef C_MULTISCAN_FILES_SUPPORTED
    validate_script(cinfo);
    if (cinfo->block_size < DCTSIZE)
      reduce_script(cinfo);
#else
    ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
  } else {
    cinfo->progressive_mode = FALSE;
    cinfo->num_scans = 1;
  }
 
  if (cinfo->optimize_coding)
    cinfo->arith_code = FALSE; /* disable arithmetic coding */
  else if (! cinfo->arith_code &&
       (cinfo->progressive_mode ||
        (cinfo->block_size > 1 && cinfo->block_size < DCTSIZE)))
    /* TEMPORARY HACK ??? */
    /* assume default tables no good for progressive or reduced AC mode */
    cinfo->optimize_coding = TRUE; /* force Huffman optimization */
 
  /* Initialize my private state */
  if (transcode_only) {
    /* no main pass in transcoding */
    if (cinfo->optimize_coding)
      master->pass_type = huff_opt_pass;
    else
      master->pass_type = output_pass;
  } else {
    /* for normal compression, first pass is always this type: */
    master->pass_type = main_pass;
  }
  master->scan_number = 0;
  master->pass_number = 0;
  if (cinfo->optimize_coding)
    master->total_passes = cinfo->num_scans * 2;
  else
    master->total_passes = cinfo->num_scans;
}

Referenced by jinit_compress_master(), and transencode_master_selection().

pass_startup()

pass_startup

(

j_compress_ptr

cinfo

)

Definition at line 567 of file jcmaster.c.

{
  cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
 
  (*cinfo->marker->write_frame_header) (cinfo);
  (*cinfo->marker->write_scan_header) (cinfo);
}

Referenced by jinit_c_master_control().

per_scan_setup()

per_scan_setup

(

j_compress_ptr

cinfo

)

Definition at line 388 of file jcmaster.c.

{
  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 = compptr->DCT_h_scaled_size;
    compptr->last_col_width = 1;
    /* For noninterleaved scans, it is convenient to define last_row_height
     * as the number of block rows present in the last iMCU row.
     */
    tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
    if (tmp == 0) tmp = compptr->v_samp_factor;
    compptr->last_row_height = tmp;
 
    /* 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->jpeg_width,
            (long) (cinfo->max_h_samp_factor * cinfo->block_size));
    cinfo->MCU_rows_in_scan = cinfo->total_iMCU_rows;
 
    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 * compptr->DCT_h_scaled_size;
      /* 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 > C_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);
  }
}

Referenced by prepare_for_pass().

prepare_for_pass()

prepare_for_pass

(

j_compress_ptr

cinfo

)

Definition at line 479 of file jcmaster.c.

{
  my_master_ptr master = (my_master_ptr) cinfo->master;
 
  switch (master->pass_type) {
  case main_pass:
    /* Initial pass: will collect input data, and do either Huffman
     * optimization or data output for the first scan.
     */
    select_scan_parameters(cinfo);
    per_scan_setup(cinfo);
    if (! cinfo->raw_data_in) {
      (*cinfo->cconvert->start_pass) (cinfo);
      (*cinfo->downsample->start_pass) (cinfo);
      (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
    }
    (*cinfo->fdct->start_pass) (cinfo);
    (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
    (*cinfo->coef->start_pass) (cinfo,
                (master->total_passes > 1 ?
                 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
    (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
    if (cinfo->optimize_coding) {
      /* No immediate data output; postpone writing frame/scan headers */
      master->pub.call_pass_startup = FALSE;
    } else {
      /* Will write frame/scan headers at first jpeg_write_scanlines call */
      master->pub.call_pass_startup = TRUE;
    }
    break;
#ifdef ENTROPY_OPT_SUPPORTED
  case huff_opt_pass:
    /* Do Huffman optimization for a scan after the first one. */
    select_scan_parameters(cinfo);
    per_scan_setup(cinfo);
    if (cinfo->Ss != 0 || cinfo->Ah == 0) {
      (*cinfo->entropy->start_pass) (cinfo, TRUE);
      (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
      master->pub.call_pass_startup = FALSE;
      break;
    }
    /* Special case: Huffman DC refinement scans need no Huffman table
     * and therefore we can skip the optimization pass for them.
     */
    master->pass_type = output_pass;
    master->pass_number++;
    /*FALLTHROUGH*/
#endif
  case output_pass:
    /* Do a data-output pass. */
    /* We need not repeat per-scan setup if prior optimization pass did it. */
    if (! cinfo->optimize_coding) {
      select_scan_parameters(cinfo);
      per_scan_setup(cinfo);
    }
    (*cinfo->entropy->start_pass) (cinfo, FALSE);
    (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
    /* We emit frame/scan headers now */
    if (master->scan_number == 0)
      (*cinfo->marker->write_frame_header) (cinfo);
    (*cinfo->marker->write_scan_header) (cinfo);
    master->pub.call_pass_startup = FALSE;
    break;
  default:
    ERREXIT(cinfo, JERR_NOT_COMPILED);
  }
 
  master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
 
  /* Set up progress monitor's pass info if present */
  if (cinfo->progress != NULL) {
    cinfo->progress->completed_passes = master->pass_number;
    cinfo->progress->total_passes = master->total_passes;
  }
}

Referenced by jinit_c_master_control().

select_scan_parameters()

select_scan_parameters

(

j_compress_ptr

cinfo

)

Definition at line 344 of file jcmaster.c.

{
  int ci;
 
#ifdef C_MULTISCAN_FILES_SUPPORTED
  if (cinfo->scan_info != NULL) {
    /* Prepare for current scan --- the script is already validated */
    my_master_ptr master = (my_master_ptr) cinfo->master;
    const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
 
    cinfo->comps_in_scan = scanptr->comps_in_scan;
    for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
      cinfo->cur_comp_info[ci] =
    &cinfo->comp_info[scanptr->component_index[ci]];
    }
    if (cinfo->progressive_mode) {
      cinfo->Ss = scanptr->Ss;
      cinfo->Se = scanptr->Se;
      cinfo->Ah = scanptr->Ah;
      cinfo->Al = scanptr->Al;
      return;
    }
  }
  else
#endif
  {
    /* Prepare for single sequential-JPEG scan containing all components */
    if (cinfo->num_components > MAX_COMPS_IN_SCAN)
      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
           MAX_COMPS_IN_SCAN);
    cinfo->comps_in_scan = cinfo->num_components;
    for (ci = 0; ci < cinfo->num_components; ci++) {
      cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
    }
  }
  cinfo->Ss = 0;
  cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
  cinfo->Ah = 0;
  cinfo->Al = 0;
}

Referenced by prepare_for_pass().