source: trunk/libjpeg/jdapimin.c @ 15

Last change on this file since 15 was 15, checked in by Eugene Romanenko, 15 years ago

needed libs update

File size: 12.7 KB
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
29GLOBAL(void)
30jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
31{
32  int i;
33
34  /* Guard against version mismatches between library and caller. */
35  cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
36  if (version != JPEG_LIB_VERSION)
37    ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
38  if (structsize != SIZEOF(struct jpeg_decompress_struct))
39    ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 
40             (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  {
49    struct jpeg_error_mgr * err = cinfo->err;
50    void * client_data = cinfo->client_data; /* ignore Purify complaint here */
51    MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
52    cinfo->err = err;
53    cinfo->client_data = client_data;
54  }
55  cinfo->is_decompressor = TRUE;
56
57  /* Initialize a memory manager instance for this object */
58  jinit_memory_mgr((j_common_ptr) cinfo);
59
60  /* Zero out pointers to permanent structures. */
61  cinfo->progress = NULL;
62  cinfo->src = NULL;
63
64  for (i = 0; i < NUM_QUANT_TBLS; i++)
65    cinfo->quant_tbl_ptrs[i] = NULL;
66
67  for (i = 0; i < NUM_HUFF_TBLS; i++) {
68    cinfo->dc_huff_tbl_ptrs[i] = NULL;
69    cinfo->ac_huff_tbl_ptrs[i] = NULL;
70  }
71
72  /* Initialize marker processor so application can override methods
73   * for COM, APPn markers before calling jpeg_read_header.
74   */
75  cinfo->marker_list = NULL;
76  jinit_marker_reader(cinfo);
77
78  /* And initialize the overall input controller. */
79  jinit_input_controller(cinfo);
80
81  /* OK, I'm ready */
82  cinfo->global_state = DSTATE_START;
83}
84
85
86/*
87 * Destruction of a JPEG decompression object
88 */
89
90GLOBAL(void)
91jpeg_destroy_decompress (j_decompress_ptr cinfo)
92{
93  jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
94}
95
96
97/*
98 * Abort processing of a JPEG decompression operation,
99 * but don't destroy the object itself.
100 */
101
102GLOBAL(void)
103jpeg_abort_decompress (j_decompress_ptr cinfo)
104{
105  jpeg_abort((j_common_ptr) cinfo); /* use common routine */
106}
107
108
109/*
110 * Set default decompression parameters.
111 */
112
113LOCAL(void)
114default_decompress_parms (j_decompress_ptr cinfo)
115{
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  switch (cinfo->num_components) {
120  case 1:
121    cinfo->jpeg_color_space = JCS_GRAYSCALE;
122    cinfo->out_color_space = JCS_GRAYSCALE;
123    break;
124   
125  case 3:
126    if (cinfo->saw_JFIF_marker) {
127      cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
128    } else if (cinfo->saw_Adobe_marker) {
129      switch (cinfo->Adobe_transform) {
130      case 0:
131        cinfo->jpeg_color_space = JCS_RGB;
132        break;
133      case 1:
134        cinfo->jpeg_color_space = JCS_YCbCr;
135        break;
136      default:
137        WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
138        cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
139        break;
140      }
141    } else {
142      /* Saw no special markers, try to guess from the component IDs */
143      int cid0 = cinfo->comp_info[0].component_id;
144      int cid1 = cinfo->comp_info[1].component_id;
145      int cid2 = cinfo->comp_info[2].component_id;
146
147      if (cid0 == 1 && cid1 == 2 && cid2 == 3)
148        cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
149      else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
150        cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
151      else {
152        TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
153        cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
154      }
155    }
156    /* Always guess RGB is proper output colorspace. */
157    cinfo->out_color_space = JCS_RGB;
158    break;
159   
160  case 4:
161    if (cinfo->saw_Adobe_marker) {
162      switch (cinfo->Adobe_transform) {
163      case 0:
164        cinfo->jpeg_color_space = JCS_CMYK;
165        break;
166      case 2:
167        cinfo->jpeg_color_space = JCS_YCCK;
168        break;
169      default:
170        WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
171        cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
172        break;
173      }
174    } else {
175      /* No special markers, assume straight CMYK. */
176      cinfo->jpeg_color_space = JCS_CMYK;
177    }
178    cinfo->out_color_space = JCS_CMYK;
179    break;
180   
181  default:
182    cinfo->jpeg_color_space = JCS_UNKNOWN;
183    cinfo->out_color_space = JCS_UNKNOWN;
184    break;
185  }
186
187  /* Set defaults for other decompression parameters. */
188  cinfo->scale_num = 1;         /* 1:1 scaling */
189  cinfo->scale_denom = 1;
190  cinfo->output_gamma = 1.0;
191  cinfo->buffered_image = FALSE;
192  cinfo->raw_data_out = FALSE;
193  cinfo->dct_method = JDCT_DEFAULT;
194  cinfo->do_fancy_upsampling = TRUE;
195  cinfo->do_block_smoothing = TRUE;
196  cinfo->quantize_colors = FALSE;
197  /* We set these in case application only sets quantize_colors. */
198  cinfo->dither_mode = JDITHER_FS;
199#ifdef QUANT_2PASS_SUPPORTED
200  cinfo->two_pass_quantize = TRUE;
201#else
202  cinfo->two_pass_quantize = FALSE;
203#endif
204  cinfo->desired_number_of_colors = 256;
205  cinfo->colormap = NULL;
206  /* Initialize for no mode change in buffered-image mode. */
207  cinfo->enable_1pass_quant = FALSE;
208  cinfo->enable_external_quant = FALSE;
209  cinfo->enable_2pass_quant = FALSE;
210}
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
240GLOBAL(int)
241jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
242{
243  int retcode;
244
245  if (cinfo->global_state != DSTATE_START &&
246      cinfo->global_state != DSTATE_INHEADER)
247    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
248
249  retcode = jpeg_consume_input(cinfo);
250
251  switch (retcode) {
252  case JPEG_REACHED_SOS:
253    retcode = JPEG_HEADER_OK;
254    break;
255  case JPEG_REACHED_EOI:
256    if (require_image)          /* Complain if application wanted an image */
257      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    jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
263    retcode = JPEG_HEADER_TABLES_ONLY;
264    break;
265  case JPEG_SUSPENDED:
266    /* no work */
267    break;
268  }
269
270  return retcode;
271}
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
286GLOBAL(int)
287jpeg_consume_input (j_decompress_ptr cinfo)
288{
289  int retcode = JPEG_SUSPENDED;
290
291  /* NB: every possible DSTATE value should be listed in this switch */
292  switch (cinfo->global_state) {
293  case DSTATE_START:
294    /* Start-of-datastream actions: reset appropriate modules */
295    (*cinfo->inputctl->reset_input_controller) (cinfo);
296    /* Initialize application's data source module */
297    (*cinfo->src->init_source) (cinfo);
298    cinfo->global_state = DSTATE_INHEADER;
299    /*FALLTHROUGH*/
300  case DSTATE_INHEADER:
301    retcode = (*cinfo->inputctl->consume_input) (cinfo);
302    if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
303      /* Set up default parameters based on header data */
304      default_decompress_parms(cinfo);
305      /* Set global state: ready for start_decompress */
306      cinfo->global_state = DSTATE_READY;
307    }
308    break;
309  case DSTATE_READY:
310    /* Can't advance past first SOS until start_decompress is called */
311    retcode = JPEG_REACHED_SOS;
312    break;
313  case DSTATE_PRELOAD:
314  case DSTATE_PRESCAN:
315  case DSTATE_SCANNING:
316  case DSTATE_RAW_OK:
317  case DSTATE_BUFIMAGE:
318  case DSTATE_BUFPOST:
319  case DSTATE_STOPPING:
320    retcode = (*cinfo->inputctl->consume_input) (cinfo);
321    break;
322  default:
323    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
324  }
325  return retcode;
326}
327
328
329/*
330 * Have we finished reading the input file?
331 */
332
333GLOBAL(boolean)
334jpeg_input_complete (j_decompress_ptr cinfo)
335{
336  /* Check for valid jpeg object */
337  if (cinfo->global_state < DSTATE_START ||
338      cinfo->global_state > DSTATE_STOPPING)
339    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
340  return cinfo->inputctl->eoi_reached;
341}
342
343
344/*
345 * Is there more than one scan?
346 */
347
348GLOBAL(boolean)
349jpeg_has_multiple_scans (j_decompress_ptr cinfo)
350{
351  /* Only valid after jpeg_read_header completes */
352  if (cinfo->global_state < DSTATE_READY ||
353      cinfo->global_state > DSTATE_STOPPING)
354    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
355  return cinfo->inputctl->has_multiple_scans;
356}
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
368GLOBAL(boolean)
369jpeg_finish_decompress (j_decompress_ptr cinfo)
370{
371  if ((cinfo->global_state == DSTATE_SCANNING ||
372       cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
373    /* Terminate final pass of non-buffered mode */
374    if (cinfo->output_scanline < cinfo->output_height)
375      ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
376    (*cinfo->master->finish_output_pass) (cinfo);
377    cinfo->global_state = DSTATE_STOPPING;
378  } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
379    /* Finishing after a buffered-image operation */
380    cinfo->global_state = DSTATE_STOPPING;
381  } else if (cinfo->global_state != DSTATE_STOPPING) {
382    /* STOPPING = repeat call after a suspension, anything else is error */
383    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
384  }
385  /* Read until EOI */
386  while (! cinfo->inputctl->eoi_reached) {
387    if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
388      return FALSE;             /* Suspend, come back later */
389  }
390  /* Do final cleanup */
391  (*cinfo->src->term_source) (cinfo);
392  /* We can use jpeg_abort to release memory and reset global_state */
393  jpeg_abort((j_common_ptr) cinfo);
394  return TRUE;
395}
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