jdapimin.c (13610B)
1 /* 2 * jdapimin.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1994-1998, Thomas G. Lane. 6 * Lossless JPEG Modifications: 7 * Copyright (C) 1999, Ken Murchison. 8 * libjpeg-turbo Modifications: 9 * Copyright (C) 2016, 2022, 2024, D. R. Commander. 10 * For conditions of distribution and use, see the accompanying README.ijg 11 * file. 12 * 13 * This file contains application interface code for the decompression half 14 * of the JPEG library. These are the "minimum" API routines that may be 15 * needed in either the normal full-decompression case or the 16 * transcoding-only case. 17 * 18 * Most of the routines intended to be called directly by an application 19 * are in this file or in jdapistd.c. But also see jcomapi.c for routines 20 * shared by compression and decompression, and jdtrans.c for the transcoding 21 * case. 22 */ 23 24 #define JPEG_INTERNALS 25 #include "jinclude.h" 26 #include "jpeglib.h" 27 #include "jdmaster.h" 28 29 30 /* 31 * Initialization of a JPEG decompression object. 32 * The error manager must already be set up (in case memory manager fails). 33 */ 34 35 GLOBAL(void) 36 jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, size_t structsize) 37 { 38 int i; 39 40 /* Guard against version mismatches between library and caller. */ 41 cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */ 42 if (version != JPEG_LIB_VERSION) 43 ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version); 44 if (structsize != sizeof(struct jpeg_decompress_struct)) 45 ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 46 (int)sizeof(struct jpeg_decompress_struct), (int)structsize); 47 48 /* For debugging purposes, we zero the whole master structure. 49 * But the application has already set the err pointer, and may have set 50 * client_data, so we have to save and restore those fields. 51 * Note: if application hasn't set client_data, tools like Purify may 52 * complain here. 53 */ 54 { 55 struct jpeg_error_mgr *err = cinfo->err; 56 void *client_data = cinfo->client_data; /* ignore Purify complaint here */ 57 memset(cinfo, 0, sizeof(struct jpeg_decompress_struct)); 58 cinfo->err = err; 59 cinfo->client_data = client_data; 60 } 61 cinfo->is_decompressor = TRUE; 62 63 /* Initialize a memory manager instance for this object */ 64 jinit_memory_mgr((j_common_ptr)cinfo); 65 66 /* Zero out pointers to permanent structures. */ 67 cinfo->progress = NULL; 68 cinfo->src = NULL; 69 70 for (i = 0; i < NUM_QUANT_TBLS; i++) 71 cinfo->quant_tbl_ptrs[i] = NULL; 72 73 for (i = 0; i < NUM_HUFF_TBLS; i++) { 74 cinfo->dc_huff_tbl_ptrs[i] = NULL; 75 cinfo->ac_huff_tbl_ptrs[i] = NULL; 76 } 77 78 /* Initialize marker processor so application can override methods 79 * for COM, APPn markers before calling jpeg_read_header. 80 */ 81 cinfo->marker_list = NULL; 82 jinit_marker_reader(cinfo); 83 84 /* And initialize the overall input controller. */ 85 jinit_input_controller(cinfo); 86 87 cinfo->data_precision = BITS_IN_JSAMPLE; 88 89 /* OK, I'm ready */ 90 cinfo->global_state = DSTATE_START; 91 92 /* The master struct is used to store extension parameters, so we allocate it 93 * here. 94 */ 95 cinfo->master = (struct jpeg_decomp_master *) 96 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT, 97 sizeof(my_decomp_master)); 98 memset(cinfo->master, 0, sizeof(my_decomp_master)); 99 } 100 101 102 /* 103 * Destruction of a JPEG decompression object 104 */ 105 106 GLOBAL(void) 107 jpeg_destroy_decompress(j_decompress_ptr cinfo) 108 { 109 jpeg_destroy((j_common_ptr)cinfo); /* use common routine */ 110 } 111 112 113 /* 114 * Abort processing of a JPEG decompression operation, 115 * but don't destroy the object itself. 116 */ 117 118 GLOBAL(void) 119 jpeg_abort_decompress(j_decompress_ptr cinfo) 120 { 121 jpeg_abort((j_common_ptr)cinfo); /* use common routine */ 122 } 123 124 125 /* 126 * Set default decompression parameters. 127 */ 128 129 LOCAL(void) 130 default_decompress_parms(j_decompress_ptr cinfo) 131 { 132 /* Guess the input colorspace, and set output colorspace accordingly. */ 133 /* (Wish JPEG committee had provided a real way to specify this...) */ 134 /* Note application may override our guesses. */ 135 switch (cinfo->num_components) { 136 case 1: 137 cinfo->jpeg_color_space = JCS_GRAYSCALE; 138 cinfo->out_color_space = JCS_GRAYSCALE; 139 break; 140 141 case 3: 142 if (cinfo->saw_JFIF_marker) { 143 cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */ 144 } else if (cinfo->saw_Adobe_marker) { 145 switch (cinfo->Adobe_transform) { 146 case 0: 147 cinfo->jpeg_color_space = JCS_RGB; 148 break; 149 case 1: 150 cinfo->jpeg_color_space = JCS_YCbCr; 151 break; 152 default: 153 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); 154 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ 155 break; 156 } 157 } else { 158 /* Saw no special markers, try to guess from the component IDs */ 159 int cid0 = cinfo->comp_info[0].component_id; 160 int cid1 = cinfo->comp_info[1].component_id; 161 int cid2 = cinfo->comp_info[2].component_id; 162 163 if (cid0 == 1 && cid1 == 2 && cid2 == 3) { 164 if (cinfo->master->lossless) 165 cinfo->jpeg_color_space = JCS_RGB; /* assume RGB w/out marker */ 166 else 167 cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */ 168 } else if (cid0 == 82 && cid1 == 71 && cid2 == 66) 169 cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */ 170 else { 171 TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2); 172 if (cinfo->master->lossless) 173 cinfo->jpeg_color_space = JCS_RGB; /* assume it's RGB */ 174 else 175 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ 176 } 177 } 178 /* Always guess RGB is proper output colorspace. */ 179 cinfo->out_color_space = JCS_RGB; 180 break; 181 182 case 4: 183 if (cinfo->saw_Adobe_marker) { 184 switch (cinfo->Adobe_transform) { 185 case 0: 186 cinfo->jpeg_color_space = JCS_CMYK; 187 break; 188 case 2: 189 cinfo->jpeg_color_space = JCS_YCCK; 190 break; 191 default: 192 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); 193 cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */ 194 break; 195 } 196 } else { 197 /* No special markers, assume straight CMYK. */ 198 cinfo->jpeg_color_space = JCS_CMYK; 199 } 200 cinfo->out_color_space = JCS_CMYK; 201 break; 202 203 default: 204 cinfo->jpeg_color_space = JCS_UNKNOWN; 205 cinfo->out_color_space = JCS_UNKNOWN; 206 break; 207 } 208 209 /* Set defaults for other decompression parameters. */ 210 cinfo->scale_num = 1; /* 1:1 scaling */ 211 cinfo->scale_denom = 1; 212 cinfo->output_gamma = 1.0; 213 cinfo->buffered_image = FALSE; 214 cinfo->raw_data_out = FALSE; 215 cinfo->dct_method = JDCT_DEFAULT; 216 cinfo->do_fancy_upsampling = TRUE; 217 cinfo->do_block_smoothing = TRUE; 218 cinfo->quantize_colors = FALSE; 219 /* We set these in case application only sets quantize_colors. */ 220 cinfo->dither_mode = JDITHER_FS; 221 #ifdef QUANT_2PASS_SUPPORTED 222 cinfo->two_pass_quantize = TRUE; 223 #else 224 cinfo->two_pass_quantize = FALSE; 225 #endif 226 cinfo->desired_number_of_colors = 256; 227 cinfo->colormap = NULL; 228 /* Initialize for no mode change in buffered-image mode. */ 229 cinfo->enable_1pass_quant = FALSE; 230 cinfo->enable_external_quant = FALSE; 231 cinfo->enable_2pass_quant = FALSE; 232 } 233 234 235 /* 236 * Decompression startup: read start of JPEG datastream to see what's there. 237 * Need only initialize JPEG object and supply a data source before calling. 238 * 239 * This routine will read as far as the first SOS marker (ie, actual start of 240 * compressed data), and will save all tables and parameters in the JPEG 241 * object. It will also initialize the decompression parameters to default 242 * values, and finally return JPEG_HEADER_OK. On return, the application may 243 * adjust the decompression parameters and then call jpeg_start_decompress. 244 * (Or, if the application only wanted to determine the image parameters, 245 * the data need not be decompressed. In that case, call jpeg_abort or 246 * jpeg_destroy to release any temporary space.) 247 * If an abbreviated (tables only) datastream is presented, the routine will 248 * return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then 249 * re-use the JPEG object to read the abbreviated image datastream(s). 250 * It is unnecessary (but OK) to call jpeg_abort in this case. 251 * The JPEG_SUSPENDED return code only occurs if the data source module 252 * requests suspension of the decompressor. In this case the application 253 * should load more source data and then re-call jpeg_read_header to resume 254 * processing. 255 * If a non-suspending data source is used and require_image is TRUE, then the 256 * return code need not be inspected since only JPEG_HEADER_OK is possible. 257 * 258 * This routine is now just a front end to jpeg_consume_input, with some 259 * extra error checking. 260 */ 261 262 GLOBAL(int) 263 jpeg_read_header(j_decompress_ptr cinfo, boolean require_image) 264 { 265 int retcode; 266 267 if (cinfo->global_state != DSTATE_START && 268 cinfo->global_state != DSTATE_INHEADER) 269 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 270 271 retcode = jpeg_consume_input(cinfo); 272 273 switch (retcode) { 274 case JPEG_REACHED_SOS: 275 retcode = JPEG_HEADER_OK; 276 break; 277 case JPEG_REACHED_EOI: 278 if (require_image) /* Complain if application wanted an image */ 279 ERREXIT(cinfo, JERR_NO_IMAGE); 280 /* Reset to start state; it would be safer to require the application to 281 * call jpeg_abort, but we can't change it now for compatibility reasons. 282 * A side effect is to free any temporary memory (there shouldn't be any). 283 */ 284 jpeg_abort((j_common_ptr)cinfo); /* sets state = DSTATE_START */ 285 retcode = JPEG_HEADER_TABLES_ONLY; 286 break; 287 case JPEG_SUSPENDED: 288 /* no work */ 289 break; 290 } 291 292 return retcode; 293 } 294 295 296 /* 297 * Consume data in advance of what the decompressor requires. 298 * This can be called at any time once the decompressor object has 299 * been created and a data source has been set up. 300 * 301 * This routine is essentially a state machine that handles a couple 302 * of critical state-transition actions, namely initial setup and 303 * transition from header scanning to ready-for-start_decompress. 304 * All the actual input is done via the input controller's consume_input 305 * method. 306 */ 307 308 GLOBAL(int) 309 jpeg_consume_input(j_decompress_ptr cinfo) 310 { 311 int retcode = JPEG_SUSPENDED; 312 313 /* NB: every possible DSTATE value should be listed in this switch */ 314 switch (cinfo->global_state) { 315 case DSTATE_START: 316 /* Start-of-datastream actions: reset appropriate modules */ 317 (*cinfo->inputctl->reset_input_controller) (cinfo); 318 /* Initialize application's data source module */ 319 (*cinfo->src->init_source) (cinfo); 320 cinfo->global_state = DSTATE_INHEADER; 321 FALLTHROUGH /*FALLTHROUGH*/ 322 case DSTATE_INHEADER: 323 retcode = (*cinfo->inputctl->consume_input) (cinfo); 324 if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */ 325 /* Set up default parameters based on header data */ 326 default_decompress_parms(cinfo); 327 /* Set global state: ready for start_decompress */ 328 cinfo->global_state = DSTATE_READY; 329 } 330 break; 331 case DSTATE_READY: 332 /* Can't advance past first SOS until start_decompress is called */ 333 retcode = JPEG_REACHED_SOS; 334 break; 335 case DSTATE_PRELOAD: 336 case DSTATE_PRESCAN: 337 case DSTATE_SCANNING: 338 case DSTATE_RAW_OK: 339 case DSTATE_BUFIMAGE: 340 case DSTATE_BUFPOST: 341 case DSTATE_STOPPING: 342 retcode = (*cinfo->inputctl->consume_input) (cinfo); 343 break; 344 default: 345 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 346 } 347 return retcode; 348 } 349 350 351 /* 352 * Have we finished reading the input file? 353 */ 354 355 GLOBAL(boolean) 356 jpeg_input_complete(j_decompress_ptr cinfo) 357 { 358 /* Check for valid jpeg object */ 359 if (cinfo->global_state < DSTATE_START || 360 cinfo->global_state > DSTATE_STOPPING) 361 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 362 return cinfo->inputctl->eoi_reached; 363 } 364 365 366 /* 367 * Is there more than one scan? 368 */ 369 370 GLOBAL(boolean) 371 jpeg_has_multiple_scans(j_decompress_ptr cinfo) 372 { 373 /* Only valid after jpeg_read_header completes */ 374 if (cinfo->global_state < DSTATE_READY || 375 cinfo->global_state > DSTATE_STOPPING) 376 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 377 return cinfo->inputctl->has_multiple_scans; 378 } 379 380 381 /* 382 * Finish JPEG decompression. 383 * 384 * This will normally just verify the file trailer and release temp storage. 385 * 386 * Returns FALSE if suspended. The return value need be inspected only if 387 * a suspending data source is used. 388 */ 389 390 GLOBAL(boolean) 391 jpeg_finish_decompress(j_decompress_ptr cinfo) 392 { 393 if ((cinfo->global_state == DSTATE_SCANNING || 394 cinfo->global_state == DSTATE_RAW_OK) && !cinfo->buffered_image) { 395 /* Terminate final pass of non-buffered mode */ 396 if (cinfo->output_scanline < cinfo->output_height) 397 ERREXIT(cinfo, JERR_TOO_LITTLE_DATA); 398 (*cinfo->master->finish_output_pass) (cinfo); 399 cinfo->global_state = DSTATE_STOPPING; 400 } else if (cinfo->global_state == DSTATE_BUFIMAGE) { 401 /* Finishing after a buffered-image operation */ 402 cinfo->global_state = DSTATE_STOPPING; 403 } else if (cinfo->global_state != DSTATE_STOPPING) { 404 /* STOPPING = repeat call after a suspension, anything else is error */ 405 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 406 } 407 /* Read until EOI */ 408 while (!cinfo->inputctl->eoi_reached) { 409 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) 410 return FALSE; /* Suspend, come back later */ 411 } 412 /* Do final cleanup */ 413 (*cinfo->src->term_source) (cinfo); 414 /* We can use jpeg_abort to release memory and reset global_state */ 415 jpeg_abort((j_common_ptr)cinfo); 416 return TRUE; 417 }