3rdparty/libjpeg/jdapimin.c

/*
 * jdapimin.c
 *
 * Copyright (C) 1994-1998, Thomas G. Lane.
 * Modified 2009 by Guido Vollbeding.
 * 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 = DCTSIZE;           /* 1:1 scaling */
  cinfo->scale_denom = DCTSIZE;
  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;
}
1	/*
2	* jdapimin.c
3	*
4	* Copyright (C) 1994-1998, Thomas G. Lane.
5	* Modified 2009 by Guido Vollbeding.
6	* This file is part of the Independent JPEG Group's software.
7	* For conditions of distribution and use, see the accompanying README file.
8	*
9	* This file contains application interface code for the decompression half
10	* of the JPEG library. These are the "minimum" API routines that may be
11	* needed in either the normal full-decompression case or the
12	* transcoding-only case.
13	*
14	* Most of the routines intended to be called directly by an application
15	* are in this file or in jdapistd.c. But also see jcomapi.c for routines
16	* shared by compression and decompression, and jdtrans.c for the transcoding
17	* case.
18	*/
19
20	#define JPEG_INTERNALS
21	#include "jinclude.h"
22	#include "jpeglib.h"
23
24
25	/*
26	* Initialization of a JPEG decompression object.
27	* The error manager must already be set up (in case memory manager fails).
28	*/
29
30	GLOBAL(void)
31	jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
32	{
33	int i;
34
35	/* Guard against version mismatches between library and caller. */
36	cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
37	if (version != JPEG_LIB_VERSION)
38	ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
39	if (structsize != SIZEOF(struct jpeg_decompress_struct))
40	ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
41	(int) SIZEOF(struct jpeg_decompress_struct), (int) structsize);
42
43	/* For debugging purposes, we zero the whole master structure.
44	* But the application has already set the err pointer, and may have set
45	* client_data, so we have to save and restore those fields.
46	* Note: if application hasn't set client_data, tools like Purify may
47	* complain here.
48	*/
49	{
50	struct jpeg_error_mgr * err = cinfo->err;
51	void * client_data = cinfo->client_data; /* ignore Purify complaint here */
52	MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
53	cinfo->err = err;
54	cinfo->client_data = client_data;
55	}
56	cinfo->is_decompressor = TRUE;
57
58	/* Initialize a memory manager instance for this object */
59	jinit_memory_mgr((j_common_ptr) cinfo);
60
61	/* Zero out pointers to permanent structures. */
62	cinfo->progress = NULL;
63	cinfo->src = NULL;
64
65	for (i = 0; i < NUM_QUANT_TBLS; i++)
66	cinfo->quant_tbl_ptrs[i] = NULL;
67
68	for (i = 0; i < NUM_HUFF_TBLS; i++) {
69	cinfo->dc_huff_tbl_ptrs[i] = NULL;
70	cinfo->ac_huff_tbl_ptrs[i] = NULL;
71	}
72
73	/* Initialize marker processor so application can override methods
74	* for COM, APPn markers before calling jpeg_read_header.
75	*/
76	cinfo->marker_list = NULL;
77	jinit_marker_reader(cinfo);
78
79	/* And initialize the overall input controller. */
80	jinit_input_controller(cinfo);
81
82	/* OK, I'm ready */
83	cinfo->global_state = DSTATE_START;
84	}
85
86
87	/*
88	* Destruction of a JPEG decompression object
89	*/
90
91	GLOBAL(void)
92	jpeg_destroy_decompress (j_decompress_ptr cinfo)
93	{
94	jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
95	}
96
97
98	/*
99	* Abort processing of a JPEG decompression operation,
100	* but don't destroy the object itself.
101	*/
102
103	GLOBAL(void)
104	jpeg_abort_decompress (j_decompress_ptr cinfo)
105	{
106	jpeg_abort((j_common_ptr) cinfo); /* use common routine */
107	}
108
109
110	/*
111	* Set default decompression parameters.
112	*/
113
114	LOCAL(void)
115	default_decompress_parms (j_decompress_ptr cinfo)
116	{
117	/* Guess the input colorspace, and set output colorspace accordingly. */
118	/* (Wish JPEG committee had provided a real way to specify this...) */
119	/* Note application may override our guesses. */
120	switch (cinfo->num_components) {
121	case 1:
122	cinfo->jpeg_color_space = JCS_GRAYSCALE;
123	cinfo->out_color_space = JCS_GRAYSCALE;
124	break;
125
126	case 3:
127	if (cinfo->saw_JFIF_marker) {
128	cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
129	} else if (cinfo->saw_Adobe_marker) {
130	switch (cinfo->Adobe_transform) {
131	case 0:
132	cinfo->jpeg_color_space = JCS_RGB;
133	break;
134	case 1:
135	cinfo->jpeg_color_space = JCS_YCbCr;
136	break;
137	default:
138	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
139	cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
140	break;
141	}
142	} else {
143	/* Saw no special markers, try to guess from the component IDs */
144	int cid0 = cinfo->comp_info[0].component_id;
145	int cid1 = cinfo->comp_info[1].component_id;
146	int cid2 = cinfo->comp_info[2].component_id;
147
148	if (cid0 == 1 && cid1 == 2 && cid2 == 3)
149	cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
150	else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
151	cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
152	else {
153	TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
154	cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
155	}
156	}
157	/* Always guess RGB is proper output colorspace. */
158	cinfo->out_color_space = JCS_RGB;
159	break;
160
161	case 4:
162	if (cinfo->saw_Adobe_marker) {
163	switch (cinfo->Adobe_transform) {
164	case 0:
165	cinfo->jpeg_color_space = JCS_CMYK;
166	break;
167	case 2:
168	cinfo->jpeg_color_space = JCS_YCCK;
169	break;
170	default:
171	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
172	cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
173	break;
174	}
175	} else {
176	/* No special markers, assume straight CMYK. */
177	cinfo->jpeg_color_space = JCS_CMYK;
178	}
179	cinfo->out_color_space = JCS_CMYK;
180	break;
181
182	default:
183	cinfo->jpeg_color_space = JCS_UNKNOWN;
184	cinfo->out_color_space = JCS_UNKNOWN;
185	break;
186	}
187
188	/* Set defaults for other decompression parameters. */
189	cinfo->scale_num = DCTSIZE; /* 1:1 scaling */
190	cinfo->scale_denom = DCTSIZE;
191	cinfo->output_gamma = 1.0;
192	cinfo->buffered_image = FALSE;
193	cinfo->raw_data_out = FALSE;
194	cinfo->dct_method = JDCT_DEFAULT;
195	cinfo->do_fancy_upsampling = TRUE;
196	cinfo->do_block_smoothing = TRUE;
197	cinfo->quantize_colors = FALSE;
198	/* We set these in case application only sets quantize_colors. */
199	cinfo->dither_mode = JDITHER_FS;
200	#ifdef QUANT_2PASS_SUPPORTED
201	cinfo->two_pass_quantize = TRUE;
202	#else
203	cinfo->two_pass_quantize = FALSE;
204	#endif
205	cinfo->desired_number_of_colors = 256;
206	cinfo->colormap = NULL;
207	/* Initialize for no mode change in buffered-image mode. */
208	cinfo->enable_1pass_quant = FALSE;
209	cinfo->enable_external_quant = FALSE;
210	cinfo->enable_2pass_quant = FALSE;
211	}
212
213
214	/*
215	* Decompression startup: read start of JPEG datastream to see what's there.
216	* Need only initialize JPEG object and supply a data source before calling.
217	*
218	* This routine will read as far as the first SOS marker (ie, actual start of
219	* compressed data), and will save all tables and parameters in the JPEG
220	* object. It will also initialize the decompression parameters to default
221	* values, and finally return JPEG_HEADER_OK. On return, the application may
222	* adjust the decompression parameters and then call jpeg_start_decompress.
223	* (Or, if the application only wanted to determine the image parameters,
224	* the data need not be decompressed. In that case, call jpeg_abort or
225	* jpeg_destroy to release any temporary space.)
226	* If an abbreviated (tables only) datastream is presented, the routine will
227	* return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
228	* re-use the JPEG object to read the abbreviated image datastream(s).
229	* It is unnecessary (but OK) to call jpeg_abort in this case.
230	* The JPEG_SUSPENDED return code only occurs if the data source module
231	* requests suspension of the decompressor. In this case the application
232	* should load more source data and then re-call jpeg_read_header to resume
233	* processing.
234	* If a non-suspending data source is used and require_image is TRUE, then the
235	* return code need not be inspected since only JPEG_HEADER_OK is possible.
236	*
237	* This routine is now just a front end to jpeg_consume_input, with some
238	* extra error checking.
239	*/
240
241	GLOBAL(int)
242	jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
243	{
244	int retcode;
245
246	if (cinfo->global_state != DSTATE_START &&
247	cinfo->global_state != DSTATE_INHEADER)
248	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
249
250	retcode = jpeg_consume_input(cinfo);
251
252	switch (retcode) {
253	case JPEG_REACHED_SOS:
254	retcode = JPEG_HEADER_OK;
255	break;
256	case JPEG_REACHED_EOI:
257	if (require_image) /* Complain if application wanted an image */
258	ERREXIT(cinfo, JERR_NO_IMAGE);
259	/* Reset to start state; it would be safer to require the application to
260	* call jpeg_abort, but we can't change it now for compatibility reasons.
261	* A side effect is to free any temporary memory (there shouldn't be any).
262	*/
263	jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
264	retcode = JPEG_HEADER_TABLES_ONLY;
265	break;
266	case JPEG_SUSPENDED:
267	/* no work */
268	break;
269	}
270
271	return retcode;
272	}
273
274
275	/*
276	* Consume data in advance of what the decompressor requires.
277	* This can be called at any time once the decompressor object has
278	* been created and a data source has been set up.
279	*
280	* This routine is essentially a state machine that handles a couple
281	* of critical state-transition actions, namely initial setup and
282	* transition from header scanning to ready-for-start_decompress.
283	* All the actual input is done via the input controller's consume_input
284	* method.
285	*/
286
287	GLOBAL(int)
288	jpeg_consume_input (j_decompress_ptr cinfo)
289	{
290	int retcode = JPEG_SUSPENDED;
291
292	/* NB: every possible DSTATE value should be listed in this switch */
293	switch (cinfo->global_state) {
294	case DSTATE_START:
295	/* Start-of-datastream actions: reset appropriate modules */
296	(*cinfo->inputctl->reset_input_controller) (cinfo);
297	/* Initialize application's data source module */
298	(*cinfo->src->init_source) (cinfo);
299	cinfo->global_state = DSTATE_INHEADER;
300	/FALLTHROUGH/
301	case DSTATE_INHEADER:
302	retcode = (*cinfo->inputctl->consume_input) (cinfo);
303	if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
304	/* Set up default parameters based on header data */
305	default_decompress_parms(cinfo);
306	/* Set global state: ready for start_decompress */
307	cinfo->global_state = DSTATE_READY;
308	}
309	break;
310	case DSTATE_READY:
311	/* Can't advance past first SOS until start_decompress is called */
312	retcode = JPEG_REACHED_SOS;
313	break;
314	case DSTATE_PRELOAD:
315	case DSTATE_PRESCAN:
316	case DSTATE_SCANNING:
317	case DSTATE_RAW_OK:
318	case DSTATE_BUFIMAGE:
319	case DSTATE_BUFPOST:
320	case DSTATE_STOPPING:
321	retcode = (*cinfo->inputctl->consume_input) (cinfo);
322	break;
323	default:
324	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
325	}
326	return retcode;
327	}
328
329
330	/*
331	* Have we finished reading the input file?
332	*/
333
334	GLOBAL(boolean)
335	jpeg_input_complete (j_decompress_ptr cinfo)
336	{
337	/* Check for valid jpeg object */
338	if (cinfo->global_state < DSTATE_START \|\|
339	cinfo->global_state > DSTATE_STOPPING)
340	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
341	return cinfo->inputctl->eoi_reached;
342	}
343
344
345	/*
346	* Is there more than one scan?
347	*/
348
349	GLOBAL(boolean)
350	jpeg_has_multiple_scans (j_decompress_ptr cinfo)
351	{
352	/* Only valid after jpeg_read_header completes */
353	if (cinfo->global_state < DSTATE_READY \|\|
354	cinfo->global_state > DSTATE_STOPPING)
355	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
356	return cinfo->inputctl->has_multiple_scans;
357	}
358
359
360	/*
361	* Finish JPEG decompression.
362	*
363	* This will normally just verify the file trailer and release temp storage.
364	*
365	* Returns FALSE if suspended. The return value need be inspected only if
366	* a suspending data source is used.
367	*/
368
369	GLOBAL(boolean)
370	jpeg_finish_decompress (j_decompress_ptr cinfo)
371	{
372	if ((cinfo->global_state == DSTATE_SCANNING \|\|
373	cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
374	/* Terminate final pass of non-buffered mode */
375	if (cinfo->output_scanline < cinfo->output_height)
376	ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
377	(*cinfo->master->finish_output_pass) (cinfo);
378	cinfo->global_state = DSTATE_STOPPING;
379	} else if (cinfo->global_state == DSTATE_BUFIMAGE) {
380	/* Finishing after a buffered-image operation */
381	cinfo->global_state = DSTATE_STOPPING;
382	} else if (cinfo->global_state != DSTATE_STOPPING) {
383	/* STOPPING = repeat call after a suspension, anything else is error */
384	ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
385	}
386	/* Read until EOI */
387	while (! cinfo->inputctl->eoi_reached) {
388	if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
389	return FALSE; /* Suspend, come back later */
390	}
391	/* Do final cleanup */
392	(*cinfo->src->term_source) (cinfo);
393	/* We can use jpeg_abort to release memory and reset global_state */
394	jpeg_abort((j_common_ptr) cinfo);
395	return TRUE;
396	}