jdtrans.c File Reference

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

Include dependency graph for jdtrans.c:

Go to the source code of this file.

Macros
#define	JPEG_INTERNALS

Functions
	LOCAL (void)
	transdecode_master_selection (j_decompress_ptr cinfo)

Macro Definition Documentation

JPEG_INTERNALS

#define JPEG_INTERNALS

Definition at line 14 of file jdtrans.c.

Function Documentation

LOCAL()

LOCAL

(

void

)

Definition at line 20 of file jdtrans.c.

{
  if (cinfo->global_state == DSTATE_READY) {
    /* First call: initialize active modules */
    transdecode_master_selection(cinfo);
    cinfo->global_state = DSTATE_RDCOEFS;
  }
  if (cinfo->global_state == DSTATE_RDCOEFS) {
    /* Absorb whole file into the coef buffer */
    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 NULL;
      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) {
      /* startup underestimated number of scans; ratchet up one scan */
      cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
    }
      }
    }
    /* Set state so that jpeg_finish_decompress does the right thing */
    cinfo->global_state = DSTATE_STOPPING;
  }
  /* At this point we should be in state DSTATE_STOPPING if being used
   * standalone, or in state DSTATE_BUFIMAGE if being invoked to get access
   * to the coefficients during a full buffered-image-mode decompression.
   */
  if ((cinfo->global_state == DSTATE_STOPPING ||
       cinfo->global_state == DSTATE_BUFIMAGE) && cinfo->buffered_image) {
    return cinfo->coef->coef_arrays;
  }
  /* Oops, improper usage */
  ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  return NULL;          /* keep compiler happy */
}

transdecode_master_selection()

transdecode_master_selection

(

j_decompress_ptr

cinfo

)

Definition at line 98 of file jdtrans.c.

{
  /* This is effectively a buffered-image operation. */
  cinfo->buffered_image = TRUE;
 
  /* Compute output image dimensions and related values. */
  jpeg_core_output_dimensions(cinfo);
 
  /* Entropy decoding: either Huffman or arithmetic coding. */
  if (cinfo->arith_code)
    jinit_arith_decoder(cinfo);
  else {
    jinit_huff_decoder(cinfo);
  }
 
  /* Always get a full-image coefficient buffer. */
  jinit_d_coef_controller(cinfo, TRUE);
 
  /* We can now tell the memory manager to allocate virtual arrays. */
  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
 
  /* Initialize input side of decompressor to consume first scan. */
  (*cinfo->inputctl->start_input_pass) (cinfo);
 
  /* Initialize progress monitoring. */
  if (cinfo->progress != NULL) {
    int nscans;
    /* Estimate number of scans to set pass_limit. */
    if (cinfo->progressive_mode) {
      /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
      nscans = 2 + 3 * cinfo->num_components;
    } else if (cinfo->inputctl->has_multiple_scans) {
      /* For a nonprogressive multiscan file, estimate 1 scan per component. */
      nscans = cinfo->num_components;
    } else {
      nscans = 1;
    }
    cinfo->progress->pass_counter = 0L;
    cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
    cinfo->progress->completed_passes = 0;
    cinfo->progress->total_passes = 1;
  }
}