compiler/libjpeg/main/jdapimin.c

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