src/jpeg/jdapistd.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_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 */
Commit	Line	Data
	1	/*
	2	* jdapistd.c
	3	*
	4	* Copyright (C) 1994-1996, Thomas G. Lane.
	5	* This file is part of the Independent JPEG Group's software.
	6	* For conditions of distribution and use, see the accompanying README file.
	7	*
	8	* This file contains application interface code for the decompression half
	9	* of the JPEG library. These are the "standard" API routines that are
	10	* used in the normal full-decompression case. They are not used by a
	11	* transcoding-only application. Note that if an application links in
	12	* jpeg_start_decompress, it will end up linking in the entire decompressor.
	13	* We thus must separate this file from jdapimin.c to avoid linking the
	14	* whole decompression library into a transcoder.
	15	*/
	16
	17	#define JPEG_INTERNALS
	18	#include "jinclude.h"
	19	#include "jpeglib.h"
	20
	21
	22	/* Forward declarations */
	23	LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
	24
	25
	26	/*
	27	* Decompression initialization.
	28	* jpeg_read_header must be completed before calling this.
	29	*
	30	* If a multipass operating mode was selected, this will do all but the
	31	* last pass, and thus may take a great deal of time.
	32	*
	33	* Returns FALSE if suspended. The return value need be inspected only if
	34	* a suspending data source is used.
	35	*/
	36
	37	GLOBAL(boolean)
	38	jpeg_start_decompress (j_decompress_ptr cinfo)
	39	{
	40	if (cinfo->global_state == DSTATE_READY) {
	41	/* First call: initialize master control, select active modules */
	42	jinit_master_decompress(cinfo);
	43	if (cinfo->buffered_image) {
	44	/* No more work here; expecting jpeg_start_output next */
	45	cinfo->global_state = DSTATE_BUFIMAGE;
	46	return TRUE;
	47	}
	48	cinfo->global_state = DSTATE_PRELOAD;
	49	}
	50	if (cinfo->global_state == DSTATE_PRELOAD) {
	51	/* If file has multiple scans, absorb them all into the coef buffer */
	52	if (cinfo->inputctl->has_multiple_scans) {
	53	#ifdef D_MULTISCAN_FILES_SUPPORTED
	54	for (;;) {
	55	int retcode;
	56	/* Call progress monitor hook if present */
	57	if (cinfo->progress != NULL)
	58	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
	59	/* Absorb some more input */
	60	retcode = (*cinfo->inputctl->consume_input) (cinfo);
	61	if (retcode == JPEG_SUSPENDED)
	62	return FALSE;
	63	if (retcode == JPEG_REACHED_EOI)
	64	break;
	65	/* Advance progress counter if appropriate */
	66	if (cinfo->progress != NULL &&
	67	(retcode == JPEG_ROW_COMPLETED \|\| retcode == JPEG_REACHED_SOS)) {
	68	if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
	69	/* jdmaster underestimated number of scans; ratchet up one scan */
	70	cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
	71	}
	72	}
	73	}
	74	#else
	75	ERREXIT(cinfo, JERR_NOT_COMPILED);
	76	#endif /* D_MULTISCAN_FILES_SUPPORTED */
	77	}
	78	cinfo->output_scan_number = cinfo->input_scan_number;
	79	} else if (cinfo->global_state != DSTATE_PRESCAN)
	80	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
	81	/* Perform any dummy output passes, and set up for the final pass */
	82	return output_pass_setup(cinfo);
	83	}
	84
	85
	86	/*
	87	* Set up for an output pass, and perform any dummy pass(es) needed.
	88	* Common subroutine for jpeg_start_decompress and jpeg_start_output.
	89	* Entry: global_state = DSTATE_PRESCAN only if previously suspended.
	90	* Exit: If done, returns TRUE and sets global_state for proper output mode.
	91	* If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
	92	*/
	93
	94	LOCAL(boolean)
	95	output_pass_setup (j_decompress_ptr cinfo)
	96	{
	97	if (cinfo->global_state != DSTATE_PRESCAN) {
	98	/* First call: do pass setup */
	99	(*cinfo->master->prepare_for_output_pass) (cinfo);
	100	cinfo->output_scanline = 0;
	101	cinfo->global_state = DSTATE_PRESCAN;
	102	}
	103	/* Loop over any required dummy passes */
	104	while (cinfo->master->is_dummy_pass) {
	105	#ifdef QUANT_2PASS_SUPPORTED
	106	/* Crank through the dummy pass */
	107	while (cinfo->output_scanline < cinfo->output_height) {
	108	JDIMENSION last_scanline;
	109	/* Call progress monitor hook if present */
	110	if (cinfo->progress != NULL) {
	111	cinfo->progress->pass_counter = (long) cinfo->output_scanline;
	112	cinfo->progress->pass_limit = (long) cinfo->output_height;
	113	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
	114	}
	115	/* Process some data */
	116	last_scanline = cinfo->output_scanline;
	117	(*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
	118	&cinfo->output_scanline, (JDIMENSION) 0);
	119	if (cinfo->output_scanline == last_scanline)
	120	return FALSE; /* No progress made, must suspend */
	121	}
	122	/* Finish up dummy pass, and set up for another one */
	123	(*cinfo->master->finish_output_pass) (cinfo);
	124	(*cinfo->master->prepare_for_output_pass) (cinfo);
	125	cinfo->output_scanline = 0;
	126	#else
	127	ERREXIT(cinfo, JERR_NOT_COMPILED);
	128	#endif /* QUANT_2PASS_SUPPORTED */
	129	}
	130	/* Ready for application to drive output pass through
	131	* jpeg_read_scanlines or jpeg_read_raw_data.
	132	*/
	133	cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
	134	return TRUE;
	135	}
	136
	137
	138	/*
	139	* Read some scanlines of data from the JPEG decompressor.
	140	*
	141	* The return value will be the number of lines actually read.
	142	* This may be less than the number requested in several cases,
	143	* including bottom of image, data source suspension, and operating
	144	* modes that emit multiple scanlines at a time.
	145	*
	146	* Note: we warn about excess calls to jpeg_read_scanlines() since
	147	* this likely signals an application programmer error. However,
	148	* an oversize buffer (max_lines > scanlines remaining) is not an error.
	149	*/
	150
	151	GLOBAL(JDIMENSION)
	152	jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
	153	JDIMENSION max_lines)
	154	{
	155	JDIMENSION row_ctr;
	156
	157	if (cinfo->global_state != DSTATE_SCANNING)
	158	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
	159	if (cinfo->output_scanline >= cinfo->output_height) {
	160	WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
	161	return 0;
	162	}
	163
	164	/* Call progress monitor hook if present */
	165	if (cinfo->progress != NULL) {
	166	cinfo->progress->pass_counter = (long) cinfo->output_scanline;
	167	cinfo->progress->pass_limit = (long) cinfo->output_height;
	168	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
	169	}
	170
	171	/* Process some data */
	172	row_ctr = 0;
	173	(*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
	174	cinfo->output_scanline += row_ctr;
	175	return row_ctr;
	176	}
	177
	178
	179	/*
	180	* Alternate entry point to read raw data.
	181	* Processes exactly one iMCU row per call, unless suspended.
	182	*/
	183
	184	GLOBAL(JDIMENSION)
	185	jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
	186	JDIMENSION max_lines)
	187	{
	188	JDIMENSION lines_per_iMCU_row;
	189
	190	if (cinfo->global_state != DSTATE_RAW_OK)
	191	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
	192	if (cinfo->output_scanline >= cinfo->output_height) {
	193	WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
	194	return 0;
	195	}
	196
	197	/* Call progress monitor hook if present */
	198	if (cinfo->progress != NULL) {
	199	cinfo->progress->pass_counter = (long) cinfo->output_scanline;
	200	cinfo->progress->pass_limit = (long) cinfo->output_height;
	201	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
	202	}
	203
	204	/* Verify that at least one iMCU row can be returned. */
	205	lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
	206	if (max_lines < lines_per_iMCU_row)
	207	ERREXIT(cinfo, JERR_BUFFER_SIZE);
	208
	209	/* Decompress directly into user's buffer. */
	210	if (! (*cinfo->coef->decompress_data) (cinfo, data))
	211	return 0; /* suspension forced, can do nothing more */
	212
	213	/* OK, we processed one iMCU row. */
	214	cinfo->output_scanline += lines_per_iMCU_row;
	215	return lines_per_iMCU_row;
	216	}
	217
	218
	219	/* Additional entry points for buffered-image mode. */
	220
	221	#ifdef D_MULTISCAN_FILES_SUPPORTED
	222
	223	/*
	224	* Initialize for an output pass in buffered-image mode.
	225	*/
	226
	227	GLOBAL(boolean)
	228	jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
	229	{
	230	if (cinfo->global_state != DSTATE_BUFIMAGE &&
	231	cinfo->global_state != DSTATE_PRESCAN)
	232	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
	233	/* Limit scan number to valid range */
	234	if (scan_number <= 0)
	235	scan_number = 1;
	236	if (cinfo->inputctl->eoi_reached &&
	237	scan_number > cinfo->input_scan_number)
	238	scan_number = cinfo->input_scan_number;
	239	cinfo->output_scan_number = scan_number;
	240	/* Perform any dummy output passes, and set up for the real pass */
	241	return output_pass_setup(cinfo);
	242	}
	243
	244
	245	/*
	246	* Finish up after an output pass in buffered-image mode.
	247	*
	248	* Returns FALSE if suspended. The return value need be inspected only if
	249	* a suspending data source is used.
	250	*/
	251
	252	GLOBAL(boolean)
	253	jpeg_finish_output (j_decompress_ptr cinfo)
	254	{
	255	if ((cinfo->global_state == DSTATE_SCANNING \|\|
	256	cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
	257	/* Terminate this pass. */
	258	/* We do not require the whole pass to have been completed. */
	259	(*cinfo->master->finish_output_pass) (cinfo);
	260	cinfo->global_state = DSTATE_BUFPOST;
	261	} else if (cinfo->global_state != DSTATE_BUFPOST) {
	262	/* BUFPOST = repeat call after a suspension, anything else is error */
	263	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
	264	}
	265	/* Read markers looking for SOS or EOI */
	266	while (cinfo->input_scan_number <= cinfo->output_scan_number &&
	267	! cinfo->inputctl->eoi_reached) {
	268	if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
	269	return FALSE; /* Suspend, come back later */
	270	}
	271	cinfo->global_state = DSTATE_BUFIMAGE;
	272	return TRUE;
	273	}
	274
	275	#endif /* D_MULTISCAN_FILES_SUPPORTED */