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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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