compiler/libjpeg/jdapimin.c

   1 /*
   2  * jdapimin.c
   3  *
   4  * Copyright (C) 1994-1998, Thomas G. Lane.
   5  * Modified 2009 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   /* 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 = cinfo->block_size;         /* 1:1 scaling */
 190   cinfo->scale_denom = cinfo->block_size;
 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     if (cinfo->output_scanline < cinfo->output_height)
 376       ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
 377     (*cinfo->master->finish_output_pass) (cinfo);
 378     cinfo->global_state = DSTATE_STOPPING;
 379   } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
 380     /* Finishing after a buffered-image operation */
 381     cinfo->global_state = DSTATE_STOPPING;
 382   } else if (cinfo->global_state != DSTATE_STOPPING) {
 383     /* STOPPING = repeat call after a suspension, anything else is error */
 384     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 385   }
 386   /* Read until EOI */
 387   while (! cinfo->inputctl->eoi_reached) {
 388     if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
 389       return FALSE;             /* Suspend, come back later */
 390   }
 391   /* Do final cleanup */
 392   (*cinfo->src->term_source) (cinfo);
 393   /* We can use jpeg_abort to release memory and reset global_state */
 394   jpeg_abort((j_common_ptr) cinfo);
 395   return TRUE;
 396 }