276 lines
9.1 KiB
C
276 lines
9.1 KiB
C
|
/*
|
||
|
|
* jdapistd.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 1994-1996, Thomas G. Lane.
|
||
|
|
* This file is part of the Independent JPEG Group's software.
|
||
|
|
* For conditions of distribution and use, see the accompanying README file.
|
||
|
|
*
|
||
|
|
* This file contains application interface code for the decompression half
|
||
|
|
* of the JPEG library. These are the "standard" API routines that are
|
||
|
|
* used in the normal full-decompression case. They are not used by a
|
||
|
|
* transcoding-only application. Note that if an application links in
|
||
|
|
* jpeg_start_decompress, it will end up linking in the entire decompressor.
|
||
|
|
* We thus must separate this file from jdapimin.c to avoid linking the
|
||
|
|
* whole decompression library into a transcoder.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define JPEG_INTERNALS
|
||
|
|
#include "jinclude.h"
|
||
|
|
#include "jpeglib.h"
|
||
|
|
|
||
|
|
|
||
|
|
/* Forward declarations */
|
||
|
|
LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decompression initialization.
|
||
|
|
* jpeg_read_header must be completed before calling this.
|
||
|
|
*
|
||
|
|
* If a multipass operating mode was selected, this will do all but the
|
||
|
|
* last pass, and thus may take a great deal of time.
|
||
|
|
*
|
||
|
|
* Returns FALSE if suspended. The return value need be inspected only if
|
||
|
|
* a suspending data source is used.
|
||
|
|
*/
|
||
|
|
|
||
|
|
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);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set up for an output pass, and perform any dummy pass(es) needed.
|
||
|
|
* Common subroutine for jpeg_start_decompress and jpeg_start_output.
|
||
|
|
* Entry: global_state = DSTATE_PRESCAN only if previously suspended.
|
||
|
|
* Exit: If done, returns TRUE and sets global_state for proper output mode.
|
||
|
|
* If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
|
||
|
|
*/
|
||
|
|
|
||
|
|
LOCAL(boolean)
|
||
|
|
output_pass_setup (j_decompress_ptr cinfo)
|
||
|
|
{
|
||
|
|
if (cinfo->global_state != DSTATE_PRESCAN) {
|
||
|
|
/* First call: do pass setup */
|
||
|
|
(*cinfo->master->prepare_for_output_pass) (cinfo);
|
||
|
|
cinfo->output_scanline = 0;
|
||
|
|
cinfo->global_state = DSTATE_PRESCAN;
|
||
|
|
}
|
||
|
|
/* Loop over any required dummy passes */
|
||
|
|
while (cinfo->master->is_dummy_pass) {
|
||
|
|
#ifdef QUANT_2PASS_SUPPORTED
|
||
|
|
/* Crank through the dummy pass */
|
||
|
|
while (cinfo->output_scanline < cinfo->output_height) {
|
||
|
|
JDIMENSION last_scanline;
|
||
|
|
/* Call progress monitor hook if present */
|
||
|
|
if (cinfo->progress != NULL) {
|
||
|
|
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
|
||
|
|
cinfo->progress->pass_limit = (long) cinfo->output_height;
|
||
|
|
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
|
||
|
|
}
|
||
|
|
/* Process some data */
|
||
|
|
last_scanline = cinfo->output_scanline;
|
||
|
|
(*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
|
||
|
|
&cinfo->output_scanline, (JDIMENSION) 0);
|
||
|
|
if (cinfo->output_scanline == last_scanline)
|
||
|
|
return FALSE; /* No progress made, must suspend */
|
||
|
|
}
|
||
|
|
/* Finish up dummy pass, and set up for another one */
|
||
|
|
(*cinfo->master->finish_output_pass) (cinfo);
|
||
|
|
(*cinfo->master->prepare_for_output_pass) (cinfo);
|
||
|
|
cinfo->output_scanline = 0;
|
||
|
|
#else
|
||
|
|
ERREXIT(cinfo, JERR_NOT_COMPILED);
|
||
|
|
#endif /* QUANT_2PASS_SUPPORTED */
|
||
|
|
}
|
||
|
|
/* Ready for application to drive output pass through
|
||
|
|
* jpeg_read_scanlines or jpeg_read_raw_data.
|
||
|
|
*/
|
||
|
|
cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Read some scanlines of data from the JPEG decompressor.
|
||
|
|
*
|
||
|
|
* The return value will be the number of lines actually read.
|
||
|
|
* This may be less than the number requested in several cases,
|
||
|
|
* including bottom of image, data source suspension, and operating
|
||
|
|
* modes that emit multiple scanlines at a time.
|
||
|
|
*
|
||
|
|
* Note: we warn about excess calls to jpeg_read_scanlines() since
|
||
|
|
* this likely signals an application programmer error. However,
|
||
|
|
* an oversize buffer (max_lines > scanlines remaining) is not an error.
|
||
|
|
*/
|
||
|
|
|
||
|
|
GLOBAL(JDIMENSION)
|
||
|
|
jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
|
||
|
|
JDIMENSION max_lines)
|
||
|
|
{
|
||
|
|
JDIMENSION row_ctr;
|
||
|
|
|
||
|
|
if (cinfo->global_state != DSTATE_SCANNING)
|
||
|
|
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
|
||
|
|
if (cinfo->output_scanline >= cinfo->output_height) {
|
||
|
|
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Call progress monitor hook if present */
|
||
|
|
if (cinfo->progress != NULL) {
|
||
|
|
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
|
||
|
|
cinfo->progress->pass_limit = (long) cinfo->output_height;
|
||
|
|
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Process some data */
|
||
|
|
row_ctr = 0;
|
||
|
|
(*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
|
||
|
|
cinfo->output_scanline += row_ctr;
|
||
|
|
return row_ctr;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Alternate entry point to read raw data.
|
||
|
|
* Processes exactly one iMCU row per call, unless suspended.
|
||
|
|
*/
|
||
|
|
|
||
|
|
GLOBAL(JDIMENSION)
|
||
|
|
jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
|
||
|
|
JDIMENSION max_lines)
|
||
|
|
{
|
||
|
|
JDIMENSION lines_per_iMCU_row;
|
||
|
|
|
||
|
|
if (cinfo->global_state != DSTATE_RAW_OK)
|
||
|
|
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
|
||
|
|
if (cinfo->output_scanline >= cinfo->output_height) {
|
||
|
|
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Call progress monitor hook if present */
|
||
|
|
if (cinfo->progress != NULL) {
|
||
|
|
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
|
||
|
|
cinfo->progress->pass_limit = (long) cinfo->output_height;
|
||
|
|
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Verify that at least one iMCU row can be returned. */
|
||
|
|
lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_v_scaled_size;
|
||
|
|
if (max_lines < lines_per_iMCU_row)
|
||
|
|
ERREXIT(cinfo, JERR_BUFFER_SIZE);
|
||
|
|
|
||
|
|
/* Decompress directly into user's buffer. */
|
||
|
|
if (! (*cinfo->coef->decompress_data) (cinfo, data))
|
||
|
|
return 0; /* suspension forced, can do nothing more */
|
||
|
|
|
||
|
|
/* OK, we processed one iMCU row. */
|
||
|
|
cinfo->output_scanline += lines_per_iMCU_row;
|
||
|
|
return lines_per_iMCU_row;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/* Additional entry points for buffered-image mode. */
|
||
|
|
|
||
|
|
#ifdef D_MULTISCAN_FILES_SUPPORTED
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Initialize for an output pass in buffered-image mode.
|
||
|
|
*/
|
||
|
|
|
||
|
|
GLOBAL(boolean)
|
||
|
|
jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
|
||
|
|
{
|
||
|
|
if (cinfo->global_state != DSTATE_BUFIMAGE &&
|
||
|
|
cinfo->global_state != DSTATE_PRESCAN)
|
||
|
|
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
|
||
|
|
/* Limit scan number to valid range */
|
||
|
|
if (scan_number <= 0)
|
||
|
|
scan_number = 1;
|
||
|
|
if (cinfo->inputctl->eoi_reached &&
|
||
|
|
scan_number > cinfo->input_scan_number)
|
||
|
|
scan_number = cinfo->input_scan_number;
|
||
|
|
cinfo->output_scan_number = scan_number;
|
||
|
|
/* Perform any dummy output passes, and set up for the real pass */
|
||
|
|
return output_pass_setup(cinfo);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Finish up after an output pass in buffered-image mode.
|
||
|
|
*
|
||
|
|
* Returns FALSE if suspended. The return value need be inspected only if
|
||
|
|
* a suspending data source is used.
|
||
|
|
*/
|
||
|
|
|
||
|
|
GLOBAL(boolean)
|
||
|
|
jpeg_finish_output (j_decompress_ptr cinfo)
|
||
|
|
{
|
||
|
|
if ((cinfo->global_state == DSTATE_SCANNING ||
|
||
|
|
cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
|
||
|
|
/* Terminate this pass. */
|
||
|
|
/* We do not require the whole pass to have been completed. */
|
||
|
|
(*cinfo->master->finish_output_pass) (cinfo);
|
||
|
|
cinfo->global_state = DSTATE_BUFPOST;
|
||
|
|
} else if (cinfo->global_state != DSTATE_BUFPOST) {
|
||
|
|
/* BUFPOST = repeat call after a suspension, anything else is error */
|
||
|
|
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
|
||
|
|
}
|
||
|
|
/* Read markers looking for SOS or EOI */
|
||
|
|
while (cinfo->input_scan_number <= cinfo->output_scan_number &&
|
||
|
|
! cinfo->inputctl->eoi_reached) {
|
||
|
|
if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
|
||
|
|
return FALSE; /* Suspend, come back later */
|
||
|
|
}
|
||
|
|
cinfo->global_state = DSTATE_BUFIMAGE;
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* D_MULTISCAN_FILES_SUPPORTED */
|