1 /*
2 * jdapimin.c
3 *
4 * Copyright (C) 1994-1998, Thomas G. Lane.
5 * Modified 2009-2013 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 int cid0, cid1, cid2;
118
119 /* Guess the input colorspace, and set output colorspace accordingly. */
120 /* Note application may override our guesses. */
121 switch (cinfo->num_components) {
122 case 1:
123 cinfo->jpeg_color_space = JCS_GRAYSCALE;
124 cinfo->out_color_space = JCS_GRAYSCALE;
125 break;
126
127 case 3:
128 cid0 = cinfo->comp_info[0].component_id;
129 cid1 = cinfo->comp_info[1].component_id;
130 cid2 = cinfo->comp_info[2].component_id;
131
132 /* First try to guess from the component IDs */
133 if (cid0 == 0x01 && cid1 == 0x02 && cid2 == 0x03)
134 cinfo->jpeg_color_space = JCS_YCbCr;
135 else if (cid0 == 0x01 && cid1 == 0x22 && cid2 == 0x23)
136 cinfo->jpeg_color_space = JCS_BG_YCC;
137 else if (cid0 == 0x52 && cid1 == 0x47 && cid2 == 0x42)
138 cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
139 else if (cid0 == 0x72 && cid1 == 0x67 && cid2 == 0x62)
140 cinfo->jpeg_color_space = JCS_BG_RGB; /* ASCII 'r', 'g', 'b' */
141 else if (cinfo->saw_JFIF_marker)
142 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
143 else if (cinfo->saw_Adobe_marker) {
144 switch (cinfo->Adobe_transform) {
145 case 0:
146 cinfo->jpeg_color_space = JCS_RGB;
147 break;
148 case 1:
149 cinfo->jpeg_color_space = JCS_YCbCr;
150 break;
151 default:
152 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
153 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
154 break;
155 }
156 } else {
157 TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
158 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
159 }
160 /* Always guess RGB is proper output colorspace. */
161 cinfo->out_color_space = JCS_RGB;
162 break;
163
164 case 4:
165 if (cinfo->saw_Adobe_marker) {
166 switch (cinfo->Adobe_transform) {
167 case 0:
168 cinfo->jpeg_color_space = JCS_CMYK;
169 break;
170 case 2:
171 cinfo->jpeg_color_space = JCS_YCCK;
172 break;
173 default:
174 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
175 cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
176 break;
177 }
178 } else {
179 /* No special markers, assume straight CMYK. */
180 cinfo->jpeg_color_space = JCS_CMYK;
181 }
182 cinfo->out_color_space = JCS_CMYK;
183 break;
184
185 default:
186 cinfo->jpeg_color_space = JCS_UNKNOWN;
187 cinfo->out_color_space = JCS_UNKNOWN;
188 break;
189 }
190
191 /* Set defaults for other decompression parameters. */
192 cinfo->scale_num = cinfo->block_size; /* 1:1 scaling */
193 cinfo->scale_denom = cinfo->block_size;
194 cinfo->output_gamma = 1.0;
195 cinfo->buffered_image = FALSE;
196 cinfo->raw_data_out = FALSE;
197 cinfo->dct_method = JDCT_DEFAULT;
198 cinfo->do_fancy_upsampling = TRUE;
199 cinfo->do_block_smoothing = TRUE;
200 cinfo->quantize_colors = FALSE;
201 /* We set these in case application only sets quantize_colors. */
202 cinfo->dither_mode = JDITHER_FS;
203 #ifdef QUANT_2PASS_SUPPORTED
204 cinfo->two_pass_quantize = TRUE;
205 #else
206 cinfo->two_pass_quantize = FALSE;
207 #endif
208 cinfo->desired_number_of_colors = 256;
209 cinfo->colormap = NULL;
210 /* Initialize for no mode change in buffered-image mode. */
211 cinfo->enable_1pass_quant = FALSE;
212 cinfo->enable_external_quant = FALSE;
213 cinfo->enable_2pass_quant = FALSE;
214 }
215
216
217 /*
218 * Decompression startup: read start of JPEG datastream to see what's there.
219 * Need only initialize JPEG object and supply a data source before calling.
220 *
221 * This routine will read as far as the first SOS marker (ie, actual start of
222 * compressed data), and will save all tables and parameters in the JPEG
223 * object. It will also initialize the decompression parameters to default
224 * values, and finally return JPEG_HEADER_OK. On return, the application may
225 * adjust the decompression parameters and then call jpeg_start_decompress.
226 * (Or, if the application only wanted to determine the image parameters,
227 * the data need not be decompressed. In that case, call jpeg_abort or
228 * jpeg_destroy to release any temporary space.)
229 * If an abbreviated (tables only) datastream is presented, the routine will
230 * return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
231 * re-use the JPEG object to read the abbreviated image datastream(s).
232 * It is unnecessary (but OK) to call jpeg_abort in this case.
233 * The JPEG_SUSPENDED return code only occurs if the data source module
234 * requests suspension of the decompressor. In this case the application
235 * should load more source data and then re-call jpeg_read_header to resume
236 * processing.
237 * If a non-suspending data source is used and require_image is TRUE, then the
238 * return code need not be inspected since only JPEG_HEADER_OK is possible.
239 *
240 * This routine is now just a front end to jpeg_consume_input, with some
241 * extra error checking.
242 */
243
244 GLOBAL(int)
245 jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
246 {
247 int retcode;
248
249 if (cinfo->global_state != DSTATE_START &&
250 cinfo->global_state != DSTATE_INHEADER)
251 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
252
253 retcode = jpeg_consume_input(cinfo);
254
255 switch (retcode) {
256 case JPEG_REACHED_SOS:
257 retcode = JPEG_HEADER_OK;
258 break;
259 case JPEG_REACHED_EOI:
260 if (require_image) /* Complain if application wanted an image */
261 ERREXIT(cinfo, JERR_NO_IMAGE);
262 /* Reset to start state; it would be safer to require the application to
263 * call jpeg_abort, but we can't change it now for compatibility reasons.
264 * A side effect is to free any temporary memory (there shouldn't be any).
265 */
266 jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
267 retcode = JPEG_HEADER_TABLES_ONLY;
268 break;
269 case JPEG_SUSPENDED:
270 /* no work */
271 break;
272 }
273
274 return retcode;
275 }
276
277
278 /*
279 * Consume data in advance of what the decompressor requires.
280 * This can be called at any time once the decompressor object has
281 * been created and a data source has been set up.
282 *
283 * This routine is essentially a state machine that handles a couple
284 * of critical state-transition actions, namely initial setup and
285 * transition from header scanning to ready-for-start_decompress.
286 * All the actual input is done via the input controller's consume_input
287 * method.
288 */
289
290 GLOBAL(int)
291 jpeg_consume_input (j_decompress_ptr cinfo)
292 {
293 int retcode = JPEG_SUSPENDED;
294
295 /* NB: every possible DSTATE value should be listed in this switch */
296 switch (cinfo->global_state) {
297 case DSTATE_START:
298 /* Start-of-datastream actions: reset appropriate modules */
299 (*cinfo->inputctl->reset_input_controller) (cinfo);
300 /* Initialize application's data source module */
301 (*cinfo->src->init_source) (cinfo);
302 cinfo->global_state = DSTATE_INHEADER;
303 /*FALLTHROUGH*/
304 case DSTATE_INHEADER:
305 retcode = (*cinfo->inputctl->consume_input) (cinfo);
306 if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
307 /* Set up default parameters based on header data */
308 default_decompress_parms(cinfo);
309 /* Set global state: ready for start_decompress */
310 cinfo->global_state = DSTATE_READY;
311 }
312 break;
313 case DSTATE_READY:
314 /* Can't advance past first SOS until start_decompress is called */
315 retcode = JPEG_REACHED_SOS;
316 break;
317 case DSTATE_PRELOAD:
318 case DSTATE_PRESCAN:
319 case DSTATE_SCANNING:
320 case DSTATE_RAW_OK:
321 case DSTATE_BUFIMAGE:
322 case DSTATE_BUFPOST:
323 case DSTATE_STOPPING:
324 retcode = (*cinfo->inputctl->consume_input) (cinfo);
325 break;
326 default:
327 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
328 }
329 return retcode;
330 }
331
332
333 /*
334 * Have we finished reading the input file?
335 */
336
337 GLOBAL(boolean)
338 jpeg_input_complete (j_decompress_ptr cinfo)
339 {
340 /* Check for valid jpeg object */
341 if (cinfo->global_state < DSTATE_START ||
342 cinfo->global_state > DSTATE_STOPPING)
343 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
344 return cinfo->inputctl->eoi_reached;
345 }
346
347
348 /*
349 * Is there more than one scan?
350 */
351
352 GLOBAL(boolean)
353 jpeg_has_multiple_scans (j_decompress_ptr cinfo)
354 {
355 /* Only valid after jpeg_read_header completes */
356 if (cinfo->global_state < DSTATE_READY ||
357 cinfo->global_state > DSTATE_STOPPING)
358 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
359 return cinfo->inputctl->has_multiple_scans;
360 }
361
362
363 /*
364 * Finish JPEG decompression.
365 *
366 * This will normally just verify the file trailer and release temp storage.
367 *
368 * Returns FALSE if suspended. The return value need be inspected only if
369 * a suspending data source is used.
370 */
371
372 GLOBAL(boolean)
373 jpeg_finish_decompress (j_decompress_ptr cinfo)
374 {
375 if ((cinfo->global_state == DSTATE_SCANNING ||
376 cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
377 /* Terminate final pass of non-buffered mode */
378 if (cinfo->output_scanline < cinfo->output_height)
379 ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
380 (*cinfo->master->finish_output_pass) (cinfo);
381 cinfo->global_state = DSTATE_STOPPING;
382 } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
383 /* Finishing after a buffered-image operation */
384 cinfo->global_state = DSTATE_STOPPING;
385 } else if (cinfo->global_state != DSTATE_STOPPING) {
386 /* STOPPING = repeat call after a suspension, anything else is error */
387 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
388 }
389 /* Read until EOI */
390 while (! cinfo->inputctl->eoi_reached) {
391 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
392 return FALSE; /* Suspend, come back later */
393 }
394 /* Do final cleanup */
395 (*cinfo->src->term_source) (cinfo);
396 /* We can use jpeg_abort to release memory and reset global_state */
397 jpeg_abort((j_common_ptr) cinfo);
398 return TRUE;
399 }