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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 { | |
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 | |
90 GLOBAL(void) | |
91 jpeg_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 | |
102 GLOBAL(void) | |
103 jpeg_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 | |
113 LOCAL(void) | |
114 default_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 | |
240 GLOBAL(int) | |
241 jpeg_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 | |
286 GLOBAL(int) | |
287 jpeg_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 | |
333 GLOBAL(boolean) | |
334 jpeg_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 | |
348 GLOBAL(boolean) | |
349 jpeg_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 | |
368 GLOBAL(boolean) | |
369 jpeg_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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