/src/gdal/build/frmts/jpeg/libjpeg12/jdapimin12.c

Source (jump to first uncovered line)
/*
 * jdapimin.c
 *
 * Copyright (C) 1994-1998, 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 "minimum" API routines that may be
 * needed in either the normal full-decompression case or the
 * transcoding-only case.
 *
 * Most of the routines intended to be called directly by an application
 * are in this file or in jdapistd.c.  But also see jcomapi.c for routines
 * shared by compression and decompression, and jdtrans.c for the transcoding
 * case.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"


/*
 * Initialization of a JPEG decompression object.
 * The error manager must already be set up (in case memory manager fails).
 */

GLOBAL(void)
jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
{
  int i;

  /* Guard against version mismatches between library and caller. */
  cinfo->mem = NULL;    /* so jpeg_destroy knows mem mgr not called */
  if (version != JPEG_LIB_VERSION)
    ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
  if (structsize != SIZEOF(struct jpeg_decompress_struct))
    ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 
       (int) SIZEOF(struct jpeg_decompress_struct), (int) structsize);

  /* For debugging purposes, we zero the whole master structure.
   * But the application has already set the err pointer, and may have set
   * client_data, so we have to save and restore those fields.
   * Note: if application hasn't set client_data, tools like Purify may
   * complain here.
   */
  {
    struct jpeg_error_mgr * err = cinfo->err;
    void * client_data = cinfo->client_data; /* ignore Purify complaint here */
    MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
    cinfo->err = err;
    cinfo->client_data = client_data;
  }
  cinfo->is_decompressor = TRUE;

  /* Initialize a memory manager instance for this object */
  jinit_memory_mgr((j_common_ptr) cinfo);

  /* Zero out pointers to permanent structures. */
  cinfo->progress = NULL;
  cinfo->src = NULL;

  for (i = 0; i < NUM_QUANT_TBLS; i++)
    cinfo->quant_tbl_ptrs[i] = NULL;

  for (i = 0; i < NUM_HUFF_TBLS; i++) {
    cinfo->dc_huff_tbl_ptrs[i] = NULL;
    cinfo->ac_huff_tbl_ptrs[i] = NULL;
  }

  /* Initialize marker processor so application can override methods
   * for COM, APPn markers before calling jpeg_read_header.
   */
  cinfo->marker_list = NULL;
  jinit_marker_reader(cinfo);

  /* And initialize the overall input controller. */
  jinit_input_controller(cinfo);

  /* OK, I'm ready */
  cinfo->global_state = DSTATE_START;
}


/*
 * Destruction of a JPEG decompression object
 */

GLOBAL(void)
jpeg_destroy_decompress (j_decompress_ptr cinfo)
{
  jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
}


/*
 * Abort processing of a JPEG decompression operation,
 * but don't destroy the object itself.
 */

GLOBAL(void)
jpeg_abort_decompress (j_decompress_ptr cinfo)
{
  jpeg_abort((j_common_ptr) cinfo); /* use common routine */
}


/*
 * Set default decompression parameters.
 */

LOCAL(void)
default_decompress_parms (j_decompress_ptr cinfo)
{
  /* Guess the input colorspace, and set output colorspace accordingly. */
  /* (Wish JPEG committee had provided a real way to specify this...) */
  /* Note application may override our guesses. */
  switch (cinfo->num_components) {
  case 1:
    cinfo->jpeg_color_space = JCS_GRAYSCALE;
    cinfo->out_color_space = JCS_GRAYSCALE;
    break;
    
  case 3:
    if (cinfo->saw_JFIF_marker) {
      cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
    } else if (cinfo->saw_Adobe_marker) {
      switch (cinfo->Adobe_transform) {
      case 0:
  cinfo->jpeg_color_space = JCS_RGB;
  break;
      case 1:
  cinfo->jpeg_color_space = JCS_YCbCr;
  break;
      default:
  WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
  cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
  break;
      }
    } else {
      /* Saw no special markers, try to guess from the component IDs */
      int cid0 = cinfo->comp_info[0].component_id;
      int cid1 = cinfo->comp_info[1].component_id;
      int cid2 = cinfo->comp_info[2].component_id;

      if (cid0 == 1 && cid1 == 2 && cid2 == 3)
  cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
      else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
  cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
      else {
  TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
  cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
      }
    }
    /* Always guess RGB is proper output colorspace. */
    cinfo->out_color_space = JCS_RGB;
    break;
    
  case 4:
    if (cinfo->saw_Adobe_marker) {
      switch (cinfo->Adobe_transform) {
      case 0:
  cinfo->jpeg_color_space = JCS_CMYK;
  break;
      case 2:
  cinfo->jpeg_color_space = JCS_YCCK;
  break;
      default:
  WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
  cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
  break;
      }
    } else {
      /* No special markers, assume straight CMYK. */
      cinfo->jpeg_color_space = JCS_CMYK;
    }
    cinfo->out_color_space = JCS_CMYK;
    break;
    
  default:
    cinfo->jpeg_color_space = JCS_UNKNOWN;
    cinfo->out_color_space = JCS_UNKNOWN;
    break;
  }

  /* Set defaults for other decompression parameters. */
  cinfo->scale_num = 1;   /* 1:1 scaling */
  cinfo->scale_denom = 1;
  cinfo->output_gamma = 1.0;
  cinfo->buffered_image = FALSE;
  cinfo->raw_data_out = FALSE;
  cinfo->dct_method = JDCT_DEFAULT;
  cinfo->do_fancy_upsampling = TRUE;
  cinfo->do_block_smoothing = TRUE;
  cinfo->quantize_colors = FALSE;
  /* We set these in case application only sets quantize_colors. */
  cinfo->dither_mode = JDITHER_FS;
#ifdef QUANT_2PASS_SUPPORTED
  cinfo->two_pass_quantize = TRUE;
#else
  cinfo->two_pass_quantize = FALSE;
#endif
  cinfo->desired_number_of_colors = 256;
  cinfo->colormap = NULL;
  /* Initialize for no mode change in buffered-image mode. */
  cinfo->enable_1pass_quant = FALSE;
  cinfo->enable_external_quant = FALSE;
  cinfo->enable_2pass_quant = FALSE;
}


/*
 * Decompression startup: read start of JPEG datastream to see what's there.
 * Need only initialize JPEG object and supply a data source before calling.
 *
 * This routine will read as far as the first SOS marker (ie, actual start of
 * compressed data), and will save all tables and parameters in the JPEG
 * object.  It will also initialize the decompression parameters to default
 * values, and finally return JPEG_HEADER_OK.  On return, the application may
 * adjust the decompression parameters and then call jpeg_start_decompress.
 * (Or, if the application only wanted to determine the image parameters,
 * the data need not be decompressed.  In that case, call jpeg_abort or
 * jpeg_destroy to release any temporary space.)
 * If an abbreviated (tables only) datastream is presented, the routine will
 * return JPEG_HEADER_TABLES_ONLY upon reaching EOI.  The application may then
 * re-use the JPEG object to read the abbreviated image datastream(s).
 * It is unnecessary (but OK) to call jpeg_abort in this case.
 * The JPEG_SUSPENDED return code only occurs if the data source module
 * requests suspension of the decompressor.  In this case the application
 * should load more source data and then re-call jpeg_read_header to resume
 * processing.
 * If a non-suspending data source is used and require_image is TRUE, then the
 * return code need not be inspected since only JPEG_HEADER_OK is possible.
 *
 * This routine is now just a front end to jpeg_consume_input, with some
 * extra error checking.
 */

GLOBAL(int)
jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
{
  int retcode;

  if (cinfo->global_state != DSTATE_START &&
      cinfo->global_state != DSTATE_INHEADER)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  retcode = jpeg_consume_input(cinfo);

  switch (retcode) {
  case JPEG_REACHED_SOS:
    retcode = JPEG_HEADER_OK;
    break;
  case JPEG_REACHED_EOI:
    if (require_image)   /* Complain if application wanted an image */
      ERREXIT(cinfo, JERR_NO_IMAGE);
    /* Reset to start state; it would be safer to require the application to
     * call jpeg_abort, but we can't change it now for compatibility reasons.
     * A side effect is to free any temporary memory (there shouldn't be any).
     */
    jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
    retcode = JPEG_HEADER_TABLES_ONLY;
    break;
  case JPEG_SUSPENDED:
    /* no work */
    break;
  }

  return retcode;
}


/*
 * Consume data in advance of what the decompressor requires.
 * This can be called at any time once the decompressor object has
 * been created and a data source has been set up.
 *
 * This routine is essentially a state machine that handles a couple
 * of critical state-transition actions, namely initial setup and
 * transition from header scanning to ready-for-start_decompress.
 * All the actual input is done via the input controller's consume_input
 * method.
 */

GLOBAL(int)
jpeg_consume_input (j_decompress_ptr cinfo)
{
  int retcode = JPEG_SUSPENDED;

  /* NB: every possible DSTATE value should be listed in this switch */
  switch (cinfo->global_state) {
  case DSTATE_START:
    /* Start-of-datastream actions: reset appropriate modules */
    (*cinfo->inputctl->reset_input_controller) (cinfo);
    /* Initialize application's data source module */
    (*cinfo->src->init_source) (cinfo);
    cinfo->global_state = DSTATE_INHEADER;
    /*FALLTHROUGH*/
  case DSTATE_INHEADER:
    retcode = (*cinfo->inputctl->consume_input) (cinfo);
    if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
      /* Set up default parameters based on header data */
      default_decompress_parms(cinfo);
      /* Set global state: ready for start_decompress */
      cinfo->global_state = DSTATE_READY;
    }
    break;
  case DSTATE_READY:
    /* Can't advance past first SOS until start_decompress is called */
    retcode = JPEG_REACHED_SOS;
    break;
  case DSTATE_PRELOAD:
  case DSTATE_PRESCAN:
  case DSTATE_SCANNING:
  case DSTATE_RAW_OK:
  case DSTATE_BUFIMAGE:
  case DSTATE_BUFPOST:
  case DSTATE_STOPPING:
    retcode = (*cinfo->inputctl->consume_input) (cinfo);
    break;
  default:
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  }
  return retcode;
}


/*
 * Have we finished reading the input file?
 */

GLOBAL(boolean)
jpeg_input_complete (j_decompress_ptr cinfo)
{
  /* Check for valid jpeg object */
  if (cinfo->global_state < DSTATE_START ||
      cinfo->global_state > DSTATE_STOPPING)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  return cinfo->inputctl->eoi_reached;
}


/*
 * Is there more than one scan?
 */

GLOBAL(boolean)
jpeg_has_multiple_scans (j_decompress_ptr cinfo)
{
  /* Only valid after jpeg_read_header completes */
  if (cinfo->global_state < DSTATE_READY ||
      cinfo->global_state > DSTATE_STOPPING)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  return cinfo->inputctl->has_multiple_scans;
}


/*
 * Finish JPEG decompression.
 *
 * This will normally just verify the file trailer and release temp storage.
 *
 * Returns FALSE if suspended.  The return value need be inspected only if
 * a suspending data source is used.
 */

GLOBAL(boolean)
jpeg_finish_decompress (j_decompress_ptr cinfo)
{
  if ((cinfo->global_state == DSTATE_SCANNING ||
       cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
    /* Terminate final pass of non-buffered mode */
    if (cinfo->output_scanline < cinfo->output_height)
      ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
    (*cinfo->master->finish_output_pass) (cinfo);
    cinfo->global_state = DSTATE_STOPPING;
  } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
    /* Finishing after a buffered-image operation */
    cinfo->global_state = DSTATE_STOPPING;
  } else if (cinfo->global_state != DSTATE_STOPPING) {
    /* STOPPING = repeat call after a suspension, anything else is error */
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  }
  /* Read until EOI */
  while (! cinfo->inputctl->eoi_reached) {
    if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
      return FALSE;   /* Suspend, come back later */
  }
  /* Do final cleanup */
  (*cinfo->src->term_source) (cinfo);
  /* We can use jpeg_abort to release memory and reset global_state */
  jpeg_abort((j_common_ptr) cinfo);
  return TRUE;
}

Coverage Report

Created: 2025-06-13 06:18

Line	Count	Source (jump to first uncovered line)
1		/*
2		* jdapimin.c
3		*
4		* Copyright (C) 1994-1998, 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 "minimum" API routines that may be
10		* needed in either the normal full-decompression case or the
11		* transcoding-only case.
12		*
13		* Most of the routines intended to be called directly by an application
14		* are in this file or in jdapistd.c. But also see jcomapi.c for routines
15		* shared by compression and decompression, and jdtrans.c for the transcoding
16		* case.
17		*/
18
19		#define JPEG_INTERNALS
20		#include "jinclude.h"
21		#include "jpeglib.h"
22
23
24		/*
25		* Initialization of a JPEG decompression object.
26		* The error manager must already be set up (in case memory manager fails).
27		*/
28
29		GLOBAL(void)
30		jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
31	0	{
32	0	int i;
33
34		/* Guard against version mismatches between library and caller. */
35	0	cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
36	0	if (version != JPEG_LIB_VERSION)
37	0	ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
38	0	if (structsize != SIZEOF(struct jpeg_decompress_struct))
39	0	ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
40	0	(int) SIZEOF(struct jpeg_decompress_struct), (int) structsize);
41
42		/* For debugging purposes, we zero the whole master structure.
43		* But the application has already set the err pointer, and may have set
44		* client_data, so we have to save and restore those fields.
45		* Note: if application hasn't set client_data, tools like Purify may
46		* complain here.
47		*/
48	0	{
49	0	struct jpeg_error_mgr * err = cinfo->err;
50	0	void * client_data = cinfo->client_data; /* ignore Purify complaint here */
51	0	MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
52	0	cinfo->err = err;
53	0	cinfo->client_data = client_data;
54	0	}
55	0	cinfo->is_decompressor = TRUE;
56
57		/* Initialize a memory manager instance for this object */
58	0	jinit_memory_mgr((j_common_ptr) cinfo);
59
60		/* Zero out pointers to permanent structures. */
61	0	cinfo->progress = NULL;
62	0	cinfo->src = NULL;
63
64	0	for (i = 0; i < NUM_QUANT_TBLS; i++)
65	0	cinfo->quant_tbl_ptrs[i] = NULL;
66
67	0	for (i = 0; i < NUM_HUFF_TBLS; i++) {
68	0	cinfo->dc_huff_tbl_ptrs[i] = NULL;
69	0	cinfo->ac_huff_tbl_ptrs[i] = NULL;
70	0	}
71
72		/* Initialize marker processor so application can override methods
73		* for COM, APPn markers before calling jpeg_read_header.
74		*/
75	0	cinfo->marker_list = NULL;
76	0	jinit_marker_reader(cinfo);
77
78		/* And initialize the overall input controller. */
79	0	jinit_input_controller(cinfo);
80
81		/* OK, I'm ready */
82	0	cinfo->global_state = DSTATE_START;
83	0	}
84
85
86		/*
87		* Destruction of a JPEG decompression object
88		*/
89
90		GLOBAL(void)
91		jpeg_destroy_decompress (j_decompress_ptr cinfo)
92	0	{
93	0	jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
94	0	}
95
96
97		/*
98		* Abort processing of a JPEG decompression operation,
99		* but don't destroy the object itself.
100		*/
101
102		GLOBAL(void)
103		jpeg_abort_decompress (j_decompress_ptr cinfo)
104	0	{
105	0	jpeg_abort((j_common_ptr) cinfo); /* use common routine */
106	0	}
107
108
109		/*
110		* Set default decompression parameters.
111		*/
112
113		LOCAL(void)
114		default_decompress_parms (j_decompress_ptr cinfo)
115	0	{
116		/* Guess the input colorspace, and set output colorspace accordingly. */
117		/* (Wish JPEG committee had provided a real way to specify this...) */
118		/* Note application may override our guesses. */
119	0	switch (cinfo->num_components) {
120	0	case 1:
121	0	cinfo->jpeg_color_space = JCS_GRAYSCALE;
122	0	cinfo->out_color_space = JCS_GRAYSCALE;
123	0	break;
124
125	0	case 3:
126	0	if (cinfo->saw_JFIF_marker) {
127	0	cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
128	0	} else if (cinfo->saw_Adobe_marker) {
129	0	switch (cinfo->Adobe_transform) {
130	0	case 0:
131	0	cinfo->jpeg_color_space = JCS_RGB;
132	0	break;
133	0	case 1:
134	0	cinfo->jpeg_color_space = JCS_YCbCr;
135	0	break;
136	0	default:
137	0	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
138	0	cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
139	0	break;
140	0	}
141	0	} else {
142		/* Saw no special markers, try to guess from the component IDs */
143	0	int cid0 = cinfo->comp_info[0].component_id;
144	0	int cid1 = cinfo->comp_info[1].component_id;
145	0	int cid2 = cinfo->comp_info[2].component_id;
146
147	0	if (cid0 == 1 && cid1 == 2 && cid2 == 3)
148	0	cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
149	0	else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
150	0	cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
151	0	else {
152	0	TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
153	0	cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
154	0	}
155	0	}
156		/* Always guess RGB is proper output colorspace. */
157	0	cinfo->out_color_space = JCS_RGB;
158	0	break;
159
160	0	case 4:
161	0	if (cinfo->saw_Adobe_marker) {
162	0	switch (cinfo->Adobe_transform) {
163	0	case 0:
164	0	cinfo->jpeg_color_space = JCS_CMYK;
165	0	break;
166	0	case 2:
167	0	cinfo->jpeg_color_space = JCS_YCCK;
168	0	break;
169	0	default:
170	0	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
171	0	cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
172	0	break;
173	0	}
174	0	} else {
175		/* No special markers, assume straight CMYK. */
176	0	cinfo->jpeg_color_space = JCS_CMYK;
177	0	}
178	0	cinfo->out_color_space = JCS_CMYK;
179	0	break;
180
181	0	default:
182	0	cinfo->jpeg_color_space = JCS_UNKNOWN;
183	0	cinfo->out_color_space = JCS_UNKNOWN;
184	0	break;
185	0	}
186
187		/* Set defaults for other decompression parameters. */
188	0	cinfo->scale_num = 1; /* 1:1 scaling */
189	0	cinfo->scale_denom = 1;
190	0	cinfo->output_gamma = 1.0;
191	0	cinfo->buffered_image = FALSE;
192	0	cinfo->raw_data_out = FALSE;
193	0	cinfo->dct_method = JDCT_DEFAULT;
194	0	cinfo->do_fancy_upsampling = TRUE;
195	0	cinfo->do_block_smoothing = TRUE;
196	0	cinfo->quantize_colors = FALSE;
197		/* We set these in case application only sets quantize_colors. */
198	0	cinfo->dither_mode = JDITHER_FS;
199	0	#ifdef QUANT_2PASS_SUPPORTED
200	0	cinfo->two_pass_quantize = TRUE;
201		#else
202		cinfo->two_pass_quantize = FALSE;
203		#endif
204	0	cinfo->desired_number_of_colors = 256;
205	0	cinfo->colormap = NULL;
206		/* Initialize for no mode change in buffered-image mode. */
207	0	cinfo->enable_1pass_quant = FALSE;
208	0	cinfo->enable_external_quant = FALSE;
209	0	cinfo->enable_2pass_quant = FALSE;
210	0	}
211
212
213		/*
214		* Decompression startup: read start of JPEG datastream to see what's there.
215		* Need only initialize JPEG object and supply a data source before calling.
216		*
217		* This routine will read as far as the first SOS marker (ie, actual start of
218		* compressed data), and will save all tables and parameters in the JPEG
219		* object. It will also initialize the decompression parameters to default
220		* values, and finally return JPEG_HEADER_OK. On return, the application may
221		* adjust the decompression parameters and then call jpeg_start_decompress.
222		* (Or, if the application only wanted to determine the image parameters,
223		* the data need not be decompressed. In that case, call jpeg_abort or
224		* jpeg_destroy to release any temporary space.)
225		* If an abbreviated (tables only) datastream is presented, the routine will
226		* return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
227		* re-use the JPEG object to read the abbreviated image datastream(s).
228		* It is unnecessary (but OK) to call jpeg_abort in this case.
229		* The JPEG_SUSPENDED return code only occurs if the data source module
230		* requests suspension of the decompressor. In this case the application
231		* should load more source data and then re-call jpeg_read_header to resume
232		* processing.
233		* If a non-suspending data source is used and require_image is TRUE, then the
234		* return code need not be inspected since only JPEG_HEADER_OK is possible.
235		*
236		* This routine is now just a front end to jpeg_consume_input, with some
237		* extra error checking.
238		*/
239
240		GLOBAL(int)
241		jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
242	0	{
243	0	int retcode;
244
245	0	if (cinfo->global_state != DSTATE_START &&
246	0	cinfo->global_state != DSTATE_INHEADER)
247	0	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
248
249	0	retcode = jpeg_consume_input(cinfo);
250
251	0	switch (retcode) {
252	0	case JPEG_REACHED_SOS:
253	0	retcode = JPEG_HEADER_OK;
254	0	break;
255	0	case JPEG_REACHED_EOI:
256	0	if (require_image) /* Complain if application wanted an image */
257	0	ERREXIT(cinfo, JERR_NO_IMAGE);
258		/* Reset to start state; it would be safer to require the application to
259		* call jpeg_abort, but we can't change it now for compatibility reasons.
260		* A side effect is to free any temporary memory (there shouldn't be any).
261		*/
262	0	jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
263	0	retcode = JPEG_HEADER_TABLES_ONLY;
264	0	break;
265	0	case JPEG_SUSPENDED:
266		/* no work */
267	0	break;
268	0	}
269
270	0	return retcode;
271	0	}
272
273
274		/*
275		* Consume data in advance of what the decompressor requires.
276		* This can be called at any time once the decompressor object has
277		* been created and a data source has been set up.
278		*
279		* This routine is essentially a state machine that handles a couple
280		* of critical state-transition actions, namely initial setup and
281		* transition from header scanning to ready-for-start_decompress.
282		* All the actual input is done via the input controller's consume_input
283		* method.
284		*/
285
286		GLOBAL(int)
287		jpeg_consume_input (j_decompress_ptr cinfo)
288	0	{
289	0	int retcode = JPEG_SUSPENDED;
290
291		/* NB: every possible DSTATE value should be listed in this switch */
292	0	switch (cinfo->global_state) {
293	0	case DSTATE_START:
294		/* Start-of-datastream actions: reset appropriate modules */
295	0	(*cinfo->inputctl->reset_input_controller) (cinfo);
296		/* Initialize application's data source module */
297	0	(*cinfo->src->init_source) (cinfo);
298	0	cinfo->global_state = DSTATE_INHEADER;
299		/FALLTHROUGH/
300	0	case DSTATE_INHEADER:
301	0	retcode = (*cinfo->inputctl->consume_input) (cinfo);
302	0	if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
303		/* Set up default parameters based on header data */
304	0	default_decompress_parms(cinfo);
305		/* Set global state: ready for start_decompress */
306	0	cinfo->global_state = DSTATE_READY;
307	0	}
308	0	break;
309	0	case DSTATE_READY:
310		/* Can't advance past first SOS until start_decompress is called */
311	0	retcode = JPEG_REACHED_SOS;
312	0	break;
313	0	case DSTATE_PRELOAD:
314	0	case DSTATE_PRESCAN:
315	0	case DSTATE_SCANNING:
316	0	case DSTATE_RAW_OK:
317	0	case DSTATE_BUFIMAGE:
318	0	case DSTATE_BUFPOST:
319	0	case DSTATE_STOPPING:
320	0	retcode = (*cinfo->inputctl->consume_input) (cinfo);
321	0	break;
322	0	default:
323	0	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
324	0	}
325	0	return retcode;
326	0	}
327
328
329		/*
330		* Have we finished reading the input file?
331		*/
332
333		GLOBAL(boolean)
334		jpeg_input_complete (j_decompress_ptr cinfo)
335	0	{
336		/* Check for valid jpeg object */
337	0	if (cinfo->global_state < DSTATE_START \|\|
338	0	cinfo->global_state > DSTATE_STOPPING)
339	0	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
340	0	return cinfo->inputctl->eoi_reached;
341	0	}
342
343
344		/*
345		* Is there more than one scan?
346		*/
347
348		GLOBAL(boolean)
349		jpeg_has_multiple_scans (j_decompress_ptr cinfo)
350	0	{
351		/* Only valid after jpeg_read_header completes */
352	0	if (cinfo->global_state < DSTATE_READY \|\|
353	0	cinfo->global_state > DSTATE_STOPPING)
354	0	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
355	0	return cinfo->inputctl->has_multiple_scans;
356	0	}
357
358
359		/*
360		* Finish JPEG decompression.
361		*
362		* This will normally just verify the file trailer and release temp storage.
363		*
364		* Returns FALSE if suspended. The return value need be inspected only if
365		* a suspending data source is used.
366		*/
367
368		GLOBAL(boolean)
369		jpeg_finish_decompress (j_decompress_ptr cinfo)
370	0	{
371	0	if ((cinfo->global_state == DSTATE_SCANNING \|\|
372	0	cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
373		/* Terminate final pass of non-buffered mode */
374	0	if (cinfo->output_scanline < cinfo->output_height)
375	0	ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
376	0	(*cinfo->master->finish_output_pass) (cinfo);
377	0	cinfo->global_state = DSTATE_STOPPING;
378	0	} else if (cinfo->global_state == DSTATE_BUFIMAGE) {
379		/* Finishing after a buffered-image operation */
380	0	cinfo->global_state = DSTATE_STOPPING;
381	0	} else if (cinfo->global_state != DSTATE_STOPPING) {
382		/* STOPPING = repeat call after a suspension, anything else is error */
383	0	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
384	0	}
385		/* Read until EOI */
386	0	while (! cinfo->inputctl->eoi_reached) {
387	0	if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
388	0	return FALSE; /* Suspend, come back later */
389	0	}
390		/* Do final cleanup */
391	0	(*cinfo->src->term_source) (cinfo);
392		/* We can use jpeg_abort to release memory and reset global_state */
393	0	jpeg_abort((j_common_ptr) cinfo);
394	0	return TRUE;
395	0	}