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 cinfo->tile_decode = FALSE; 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 /* Guess the input colorspace, and set output colorspace accordingly. */ 118 /* (Wish JPEG committee had provided a real way to specify this...) */ 119 /* Note application may override our guesses. */ 120 switch (cinfo->num_components) { 121 case 1: 122 cinfo->jpeg_color_space = JCS_GRAYSCALE; 123 cinfo->out_color_space = JCS_GRAYSCALE; 124 break; 125 126 case 3: 127 if (cinfo->saw_JFIF_marker) { 128 cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */ 129 } else if (cinfo->saw_Adobe_marker) { 130 switch (cinfo->Adobe_transform) { 131 case 0: 132 cinfo->jpeg_color_space = JCS_RGB; 133 break; 134 case 1: 135 cinfo->jpeg_color_space = JCS_YCbCr; 136 break; 137 default: 138 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); 139 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ 140 break; 141 } 142 } else { 143 /* Saw no special markers, try to guess from the component IDs */ 144 int cid0 = cinfo->comp_info[0].component_id; 145 int cid1 = cinfo->comp_info[1].component_id; 146 int cid2 = cinfo->comp_info[2].component_id; 147 148 if (cid0 == 1 && cid1 == 2 && cid2 == 3) 149 cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */ 150 else if (cid0 == 82 && cid1 == 71 && cid2 == 66) 151 cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */ 152 else { 153 TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2); 154 cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */ 155 } 156 } 157 /* Always guess RGB is proper output colorspace. */ 158 cinfo->out_color_space = JCS_RGB; 159 break; 160 161 case 4: 162 if (cinfo->saw_Adobe_marker) { 163 switch (cinfo->Adobe_transform) { 164 case 0: 165 cinfo->jpeg_color_space = JCS_CMYK; 166 break; 167 case 2: 168 cinfo->jpeg_color_space = JCS_YCCK; 169 break; 170 default: 171 WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform); 172 cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */ 173 break; 174 } 175 } else { 176 /* No special markers, assume straight CMYK. */ 177 cinfo->jpeg_color_space = JCS_CMYK; 178 } 179 cinfo->out_color_space = JCS_CMYK; 180 break; 181 182 default: 183 cinfo->jpeg_color_space = JCS_UNKNOWN; 184 cinfo->out_color_space = JCS_UNKNOWN; 185 break; 186 } 187 188 /* Set defaults for other decompression parameters. */ 189 cinfo->scale_num = 1; /* 1:1 scaling */ 190 cinfo->scale_denom = 1; 191 cinfo->output_gamma = 1.0; 192 cinfo->buffered_image = FALSE; 193 cinfo->raw_data_out = FALSE; 194 cinfo->dct_method = JDCT_DEFAULT; 195 cinfo->do_fancy_upsampling = TRUE; 196 cinfo->do_block_smoothing = TRUE; 197 cinfo->quantize_colors = FALSE; 198 /* We set these in case application only sets quantize_colors. */ 199 cinfo->dither_mode = JDITHER_FS; 200 #ifdef QUANT_2PASS_SUPPORTED 201 cinfo->two_pass_quantize = TRUE; 202 #else 203 cinfo->two_pass_quantize = FALSE; 204 #endif 205 cinfo->desired_number_of_colors = 256; 206 cinfo->colormap = NULL; 207 /* Initialize for no mode change in buffered-image mode. */ 208 cinfo->enable_1pass_quant = FALSE; 209 cinfo->enable_external_quant = FALSE; 210 cinfo->enable_2pass_quant = FALSE; 211 } 212 213 214 /* 215 * Decompression startup: read start of JPEG datastream to see what's there. 216 * Need only initialize JPEG object and supply a data source before calling. 217 * 218 * This routine will read as far as the first SOS marker (ie, actual start of 219 * compressed data), and will save all tables and parameters in the JPEG 220 * object. It will also initialize the decompression parameters to default 221 * values, and finally return JPEG_HEADER_OK. On return, the application may 222 * adjust the decompression parameters and then call jpeg_start_decompress. 223 * (Or, if the application only wanted to determine the image parameters, 224 * the data need not be decompressed. In that case, call jpeg_abort or 225 * jpeg_destroy to release any temporary space.) 226 * If an abbreviated (tables only) datastream is presented, the routine will 227 * return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then 228 * re-use the JPEG object to read the abbreviated image datastream(s). 229 * It is unnecessary (but OK) to call jpeg_abort in this case. 230 * The JPEG_SUSPENDED return code only occurs if the data source module 231 * requests suspension of the decompressor. In this case the application 232 * should load more source data and then re-call jpeg_read_header to resume 233 * processing. 234 * If a non-suspending data source is used and require_image is TRUE, then the 235 * return code need not be inspected since only JPEG_HEADER_OK is possible. 236 * 237 * This routine is now just a front end to jpeg_consume_input, with some 238 * extra error checking. 239 */ 240 241 GLOBAL(int) 242 jpeg_read_header (j_decompress_ptr cinfo, boolean require_image) 243 { 244 int retcode; 245 246 if (cinfo->global_state != DSTATE_START && 247 cinfo->global_state != DSTATE_INHEADER) 248 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 249 250 retcode = jpeg_consume_input(cinfo); 251 252 switch (retcode) { 253 case JPEG_REACHED_SOS: 254 retcode = JPEG_HEADER_OK; 255 break; 256 case JPEG_REACHED_EOI: 257 if (require_image) /* Complain if application wanted an image */ 258 ERREXIT(cinfo, JERR_NO_IMAGE); 259 /* Reset to start state; it would be safer to require the application to 260 * call jpeg_abort, but we can't change it now for compatibility reasons. 261 * A side effect is to free any temporary memory (there shouldn't be any). 262 */ 263 jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */ 264 retcode = JPEG_HEADER_TABLES_ONLY; 265 break; 266 case JPEG_SUSPENDED: 267 /* no work */ 268 break; 269 } 270 271 return retcode; 272 } 273 274 275 /* 276 * Consume data in advance of what the decompressor requires. 277 * This can be called at any time once the decompressor object has 278 * been created and a data source has been set up. 279 * 280 * This routine is essentially a state machine that handles a couple 281 * of critical state-transition actions, namely initial setup and 282 * transition from header scanning to ready-for-start_decompress. 283 * All the actual input is done via the input controller's consume_input 284 * method. 285 */ 286 287 GLOBAL(int) 288 jpeg_consume_input (j_decompress_ptr cinfo) 289 { 290 int retcode = JPEG_SUSPENDED; 291 292 /* NB: every possible DSTATE value should be listed in this switch */ 293 switch (cinfo->global_state) { 294 case DSTATE_START: 295 /* Start-of-datastream actions: reset appropriate modules */ 296 (*cinfo->inputctl->reset_input_controller) (cinfo); 297 /* Initialize application's data source module */ 298 (*cinfo->src->init_source) (cinfo); 299 cinfo->global_state = DSTATE_INHEADER; 300 /*FALLTHROUGH*/ 301 case DSTATE_INHEADER: 302 retcode = (*cinfo->inputctl->consume_input) (cinfo); 303 if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */ 304 /* Set up default parameters based on header data */ 305 default_decompress_parms(cinfo); 306 /* Set global state: ready for start_decompress */ 307 cinfo->global_state = DSTATE_READY; 308 } 309 break; 310 case DSTATE_READY: 311 /* Can't advance past first SOS until start_decompress is called */ 312 retcode = JPEG_REACHED_SOS; 313 break; 314 case DSTATE_PRELOAD: 315 case DSTATE_PRESCAN: 316 case DSTATE_SCANNING: 317 case DSTATE_RAW_OK: 318 case DSTATE_BUFIMAGE: 319 case DSTATE_BUFPOST: 320 case DSTATE_STOPPING: 321 retcode = (*cinfo->inputctl->consume_input) (cinfo); 322 break; 323 default: 324 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 325 } 326 return retcode; 327 } 328 329 330 /* 331 * Have we finished reading the input file? 332 */ 333 334 GLOBAL(boolean) 335 jpeg_input_complete (j_decompress_ptr cinfo) 336 { 337 /* Check for valid jpeg object */ 338 if (cinfo->global_state < DSTATE_START || 339 cinfo->global_state > DSTATE_STOPPING) 340 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 341 return cinfo->inputctl->eoi_reached; 342 } 343 344 345 /* 346 * Is there more than one scan? 347 */ 348 349 GLOBAL(boolean) 350 jpeg_has_multiple_scans (j_decompress_ptr cinfo) 351 { 352 /* Only valid after jpeg_read_header completes */ 353 if (cinfo->global_state < DSTATE_READY || 354 cinfo->global_state > DSTATE_STOPPING) 355 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 356 return cinfo->inputctl->has_multiple_scans; 357 } 358 359 360 /* 361 * Finish JPEG decompression. 362 * 363 * This will normally just verify the file trailer and release temp storage. 364 * 365 * Returns FALSE if suspended. The return value need be inspected only if 366 * a suspending data source is used. 367 */ 368 369 GLOBAL(boolean) 370 jpeg_finish_decompress (j_decompress_ptr cinfo) 371 { 372 if ((cinfo->global_state == DSTATE_SCANNING || 373 cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) { 374 /* Terminate final pass of non-buffered mode */ 375 #ifdef ANDROID_TILE_BASED_DECODE 376 cinfo->output_scanline = cinfo->output_height; 377 #endif 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 #ifndef ANDROID_TILE_BASED_DECODE 391 while (! cinfo->inputctl->eoi_reached) { 392 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) 393 return FALSE; /* Suspend, come back later */ 394 } 395 #endif 396 /* Do final cleanup */ 397 (*cinfo->src->term_source) (cinfo); 398 /* We can use jpeg_abort to release memory and reset global_state */ 399 jpeg_abort((j_common_ptr) cinfo); 400 return TRUE; 401 } 402
