jdmainct.c File Reference

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

Include dependency graph for jdmainct.c:

Go to the source code of this file.

Classes
struct	my_main_controller

Macros
#define	JPEG_INTERNALS
#define	CTX_PREPARE_FOR_IMCU   0 /* need to prepare for MCU row */
#define	CTX_PROCESS_IMCU   1 /* feeding iMCU to postprocessor */
#define	CTX_POSTPONED_ROW   2 /* feeding postponed row group */

Typedefs
typedef my_main_controller *	my_main_ptr

Functions
	METHODDEF (void)
	make_funny_pointers (j_decompress_ptr cinfo)
	set_wraparound_pointers (j_decompress_ptr cinfo)
	set_bottom_pointers (j_decompress_ptr cinfo)
	start_pass_main (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
	process_data_simple_main (j_decompress_ptr cinfo, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
	process_data_context_main (j_decompress_ptr cinfo, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
	jinit_d_main_controller (j_decompress_ptr cinfo, boolean need_full_buffer)

Macro Definition Documentation

CTX_POSTPONED_ROW

#define CTX_POSTPONED_ROW   2 /* feeding postponed row group */

Definition at line 141 of file jdmainct.c.

CTX_PREPARE_FOR_IMCU

#define CTX_PREPARE_FOR_IMCU   0 /* need to prepare for MCU row */

Definition at line 139 of file jdmainct.c.

CTX_PROCESS_IMCU

#define CTX_PROCESS_IMCU   1 /* feeding iMCU to postprocessor */

Definition at line 140 of file jdmainct.c.

JPEG_INTERNALS

#define JPEG_INTERNALS

Definition at line 17 of file jdmainct.c.

Typedef Documentation

my_main_ptr

typedef my_main_controller* my_main_ptr

Definition at line 136 of file jdmainct.c.

Function Documentation

jinit_d_main_controller()

jinit_d_main_controller	(	j_decompress_ptr	cinfo,
		boolean	need_full_buffer
	)

Definition at line 472 of file jdmainct.c.

{
  my_main_ptr mainp;
  int ci, rgroup, ngroups;
  jpeg_component_info *compptr;
 
  mainp = (my_main_ptr) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_main_controller));
  cinfo->main = &mainp->pub;
  mainp->pub.start_pass = start_pass_main;
 
  if (need_full_buffer)     /* shouldn't happen */
    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 
  /* Allocate the workspace.
   * ngroups is the number of row groups we need.
   */
  if (cinfo->upsample->need_context_rows) {
    if (cinfo->min_DCT_v_scaled_size < 2) /* unsupported, see comments above */
      ERREXIT(cinfo, JERR_NOTIMPL);
    alloc_funny_pointers(cinfo); /* Alloc space for xbuffer[] lists */
    ngroups = cinfo->min_DCT_v_scaled_size + 2;
  } else {
    /* There are always min_DCT_v_scaled_size row groups in an iMCU row. */
    ngroups = cinfo->min_DCT_v_scaled_size;
    mainp->rowgroups_avail = (JDIMENSION) ngroups;
  }
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (! compptr->component_needed)
      continue;         /* skip uninteresting component */
    rgroup = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
      cinfo->min_DCT_v_scaled_size; /* height of a row group of component */
    mainp->buffer[ci] = (*cinfo->mem->alloc_sarray)
      ((j_common_ptr) cinfo, JPOOL_IMAGE,
       compptr->width_in_blocks * ((JDIMENSION) compptr->DCT_h_scaled_size),
       (JDIMENSION) (rgroup * ngroups));
  }
}

Referenced by master_selection().

make_funny_pointers()

make_funny_pointers

(

j_decompress_ptr

cinfo

)

Definition at line 198 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
  int ci, i, rgroup;
  int M = cinfo->min_DCT_v_scaled_size;
  jpeg_component_info *compptr;
  JSAMPARRAY buf, xbuf0, xbuf1;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (! compptr->component_needed)
      continue;         /* skip uninteresting component */
    rgroup = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
      cinfo->min_DCT_v_scaled_size; /* height of a row group of component */
    xbuf0 = mainp->xbuffer[0][ci];
    xbuf1 = mainp->xbuffer[1][ci];
    /* First copy the workspace pointers as-is */
    buf = mainp->buffer[ci];
    for (i = 0; i < rgroup * (M + 2); i++) {
      xbuf0[i] = xbuf1[i] = buf[i];
    }
    /* In the second list, put the last four row groups in swapped order */
    for (i = 0; i < rgroup * 2; i++) {
      xbuf1[rgroup*(M-2) + i] = buf[rgroup*M + i];
      xbuf1[rgroup*M + i] = buf[rgroup*(M-2) + i];
    }
    /* The wraparound pointers at top and bottom will be filled later
     * (see set_wraparound_pointers, below).  Initially we want the "above"
     * pointers to duplicate the first actual data line.  This only needs
     * to happen in xbuffer[0].
     */
    for (i = 0; i < rgroup; i++) {
      xbuf0[i - rgroup] = xbuf0[0];
    }
  }
}

Referenced by start_pass_main().

METHODDEF()

METHODDEF

(

void

)

Definition at line 145 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
  int ci, rgroup;
  int M = cinfo->min_DCT_v_scaled_size;
  jpeg_component_info *compptr;
  JSAMPARRAY xbuf;
 
  /* Get top-level space for component array pointers.
   * We alloc both arrays with one call to save a few cycles.
   */
  mainp->xbuffer[0] = (JSAMPIMAGE) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE,
     cinfo->num_components * 2 * SIZEOF(JSAMPARRAY));
  mainp->xbuffer[1] = mainp->xbuffer[0] + cinfo->num_components;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (! compptr->component_needed)
      continue;         /* skip uninteresting component */
    rgroup = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
      cinfo->min_DCT_v_scaled_size; /* height of a row group of component */
    /* Get space for pointer lists --- M+4 row groups in each list.
     * We alloc both pointer lists with one call to save a few cycles.
     */
    xbuf = (JSAMPARRAY) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo,
      JPOOL_IMAGE, 2 * (rgroup * (M + 4)) * SIZEOF(JSAMPROW));
    xbuf += rgroup;     /* want one row group at negative offsets */
    mainp->xbuffer[0][ci] = xbuf;
    xbuf += rgroup * (M + 4);
    mainp->xbuffer[1][ci] = xbuf;
  }
}

process_data_context_main()

process_data_context_main	(	j_decompress_ptr	cinfo,
		JSAMPARRAY	output_buf,
		JDIMENSION *	out_row_ctr,
		JDIMENSION	out_rows_avail
	)

Definition at line 383 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
 
  /* Read input data if we haven't filled the main buffer yet */
  if (! mainp->buffer_full) {
    if (! (*cinfo->coef->decompress_data) (cinfo,
                       mainp->xbuffer[mainp->whichptr]))
      return;           /* suspension forced, can do nothing more */
    mainp->buffer_full = TRUE;  /* OK, we have an iMCU row to work with */
    mainp->iMCU_row_ctr++;  /* count rows received */
  }
 
  /* Postprocessor typically will not swallow all the input data it is handed
   * in one call (due to filling the output buffer first).  Must be prepared
   * to exit and restart.  This switch lets us keep track of how far we got.
   * Note that each case falls through to the next on successful completion.
   */
  switch (mainp->context_state) {
  case CTX_POSTPONED_ROW:
    /* Call postprocessor using previously set pointers for postponed row */
    (*cinfo->post->post_process_data) (cinfo, mainp->xbuffer[mainp->whichptr],
            &mainp->rowgroup_ctr, mainp->rowgroups_avail,
            output_buf, out_row_ctr, out_rows_avail);
    if (mainp->rowgroup_ctr < mainp->rowgroups_avail)
      return;           /* Need to suspend */
    mainp->context_state = CTX_PREPARE_FOR_IMCU;
    if (*out_row_ctr >= out_rows_avail)
      return;           /* Postprocessor exactly filled output buf */
    /*FALLTHROUGH*/
  case CTX_PREPARE_FOR_IMCU:
    /* Prepare to process first M-1 row groups of this iMCU row */
    mainp->rowgroup_ctr = 0;
    mainp->rowgroups_avail = (JDIMENSION) (cinfo->min_DCT_v_scaled_size - 1);
    /* Check for bottom of image: if so, tweak pointers to "duplicate"
     * the last sample row, and adjust rowgroups_avail to ignore padding rows.
     */
    if (mainp->iMCU_row_ctr == cinfo->total_iMCU_rows)
      set_bottom_pointers(cinfo);
    mainp->context_state = CTX_PROCESS_IMCU;
    /*FALLTHROUGH*/
  case CTX_PROCESS_IMCU:
    /* Call postprocessor using previously set pointers */
    (*cinfo->post->post_process_data) (cinfo, mainp->xbuffer[mainp->whichptr],
            &mainp->rowgroup_ctr, mainp->rowgroups_avail,
            output_buf, out_row_ctr, out_rows_avail);
    if (mainp->rowgroup_ctr < mainp->rowgroups_avail)
      return;           /* Need to suspend */
    /* After the first iMCU, change wraparound pointers to normal state */
    if (mainp->iMCU_row_ctr == 1)
      set_wraparound_pointers(cinfo);
    /* Prepare to load new iMCU row using other xbuffer list */
    mainp->whichptr ^= 1;   /* 0=>1 or 1=>0 */
    mainp->buffer_full = FALSE;
    /* Still need to process last row group of this iMCU row, */
    /* which is saved at index M+1 of the other xbuffer */
    mainp->rowgroup_ctr = (JDIMENSION) (cinfo->min_DCT_v_scaled_size + 1);
    mainp->rowgroups_avail = (JDIMENSION) (cinfo->min_DCT_v_scaled_size + 2);
    mainp->context_state = CTX_POSTPONED_ROW;
  }
}

Referenced by start_pass_main().

process_data_simple_main()

process_data_simple_main	(	j_decompress_ptr	cinfo,
		JSAMPARRAY	output_buf,
		JDIMENSION *	out_row_ctr,
		JDIMENSION	out_rows_avail
	)

Definition at line 353 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
 
  /* Read input data if we haven't filled the main buffer yet */
  if (mainp->rowgroup_ctr >= mainp->rowgroups_avail) {
    if (! (*cinfo->coef->decompress_data) (cinfo, mainp->buffer))
      return;           /* suspension forced, can do nothing more */
    mainp->rowgroup_ctr = 0;    /* OK, we have an iMCU row to work with */
  }
 
  /* Note: at the bottom of the image, we may pass extra garbage row groups
   * to the postprocessor.  The postprocessor has to check for bottom
   * of image anyway (at row resolution), so no point in us doing it too.
   */
 
  /* Feed the postprocessor */
  (*cinfo->post->post_process_data) (cinfo, mainp->buffer,
            &mainp->rowgroup_ctr, mainp->rowgroups_avail,
            output_buf, out_row_ctr, out_rows_avail);
}

Referenced by start_pass_main().

set_bottom_pointers()

set_bottom_pointers

(

j_decompress_ptr

cinfo

)

Definition at line 273 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
  int ci, i, rgroup, iMCUheight, rows_left;
  jpeg_component_info *compptr;
  JSAMPARRAY xbuf;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (! compptr->component_needed)
      continue;         /* skip uninteresting component */
    /* Count sample rows in one iMCU row and in one row group */
    iMCUheight = compptr->v_samp_factor * compptr->DCT_v_scaled_size;
    rgroup = iMCUheight / cinfo->min_DCT_v_scaled_size;
    /* Count nondummy sample rows remaining for this component */
    rows_left = (int) (compptr->downsampled_height % (JDIMENSION) iMCUheight);
    if (rows_left == 0) rows_left = iMCUheight;
    /* Count nondummy row groups.  Should get same answer for each component,
     * so we need only do it once.
     */
    if (ci == 0) {
      mainp->rowgroups_avail = (JDIMENSION) ((rows_left-1) / rgroup + 1);
    }
    /* Duplicate the last real sample row rgroup*2 times; this pads out the
     * last partial rowgroup and ensures at least one full rowgroup of context.
     */
    xbuf = mainp->xbuffer[mainp->whichptr][ci];
    for (i = 0; i < rgroup * 2; i++) {
      xbuf[rows_left + i] = xbuf[rows_left-1];
    }
  }
}

Referenced by process_data_context_main().

set_wraparound_pointers()

set_wraparound_pointers

(

j_decompress_ptr

cinfo

)

Definition at line 243 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
  int ci, i, rgroup;
  int M = cinfo->min_DCT_v_scaled_size;
  jpeg_component_info *compptr;
  JSAMPARRAY xbuf0, xbuf1;
 
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    if (! compptr->component_needed)
      continue;         /* skip uninteresting component */
    rgroup = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
      cinfo->min_DCT_v_scaled_size; /* height of a row group of component */
    xbuf0 = mainp->xbuffer[0][ci];
    xbuf1 = mainp->xbuffer[1][ci];
    for (i = 0; i < rgroup; i++) {
      xbuf0[i - rgroup] = xbuf0[rgroup*(M+1) + i];
      xbuf1[i - rgroup] = xbuf1[rgroup*(M+1) + i];
      xbuf0[rgroup*(M+2) + i] = xbuf0[i];
      xbuf1[rgroup*(M+2) + i] = xbuf1[i];
    }
  }
}

Referenced by process_data_context_main().

start_pass_main()

start_pass_main	(	j_decompress_ptr	cinfo,
		J_BUF_MODE	pass_mode
	)

Definition at line 316 of file jdmainct.c.

{
  my_main_ptr mainp = (my_main_ptr) cinfo->main;
 
  switch (pass_mode) {
  case JBUF_PASS_THRU:
    if (cinfo->upsample->need_context_rows) {
      mainp->pub.process_data = process_data_context_main;
      make_funny_pointers(cinfo); /* Create the xbuffer[] lists */
      mainp->whichptr = 0;  /* Read first iMCU row into xbuffer[0] */
      mainp->context_state = CTX_PREPARE_FOR_IMCU;
      mainp->iMCU_row_ctr = 0;
      mainp->buffer_full = FALSE; /* Mark buffer empty */
    } else {
      /* Simple case with no context needed */
      mainp->pub.process_data = process_data_simple_main;
      mainp->rowgroup_ctr = mainp->rowgroups_avail; /* Mark buffer empty */
    }
    break;
#ifdef QUANT_2PASS_SUPPORTED
  case JBUF_CRANK_DEST:
    /* For last pass of 2-pass quantization, just crank the postprocessor */
    mainp->pub.process_data = process_data_crank_post;
    break;
#endif
  default:
    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
  }
}

Referenced by jinit_c_main_controller(), and jinit_d_main_controller().