libs/jpeg/jdapistd.c

   1 /*
   2  * jdapistd.c
   3  *
   4  * Copyright (C) 1994-1996, Thomas G. Lane.
   5  * Modified 2002-2013 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 "standard" API routines that are
  11  * used in the normal full-decompression case.  They are not used by a
  12  * transcoding-only application.  Note that if an application links in
  13  * jpeg_start_decompress, it will end up linking in the entire decompressor.
  14  * We thus must separate this file from jdapimin.c to avoid linking the
  15  * whole decompression library into a transcoder.
  16  */
  17
  18 #define JPEG_INTERNALS
  19 #include "jinclude.h"
  20 #include "jpeglib.h"
  21
  22
  23 /* Forward declarations */
  24 LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
  25
  26
  27 /*
  28  * Decompression initialization.
  29  * jpeg_read_header must be completed before calling this.
  30  *
  31  * If a multipass operating mode was selected, this will do all but the
  32  * last pass, and thus may take a great deal of time.
  33  *
  34  * Returns FALSE if suspended.  The return value need be inspected only if
  35  * a suspending data source is used.
  36  */
  37
  38 GLOBAL(boolean)
  39 jpeg_start_decompress (j_decompress_ptr cinfo)
  40 {
  41   if (cinfo->global_state == DSTATE_READY) {
  42     /* First call: initialize master control, select active modules */
  43     jinit_master_decompress(cinfo);
  44     if (cinfo->buffered_image) {
  45       /* No more work here; expecting jpeg_start_output next */
  46       cinfo->global_state = DSTATE_BUFIMAGE;
  47       return TRUE;
  48     }
  49     cinfo->global_state = DSTATE_PRELOAD;
  50   }
  51   if (cinfo->global_state == DSTATE_PRELOAD) {
  52     /* If file has multiple scans, absorb them all into the coef buffer */
  53     if (cinfo->inputctl->has_multiple_scans) {
  54 #ifdef D_MULTISCAN_FILES_SUPPORTED
  55       for (;;) {
  56         int retcode;
  57         /* Call progress monitor hook if present */
  58         if (cinfo->progress != NULL)
  59           (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
  60         /* Absorb some more input */
  61         retcode = (*cinfo->inputctl->consume_input) (cinfo);
  62         if (retcode == JPEG_SUSPENDED)
  63           return FALSE;
  64         if (retcode == JPEG_REACHED_EOI)
  65           break;
  66         /* Advance progress counter if appropriate */
  67         if (cinfo->progress != NULL &&
  68             (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
  69           if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
  70             /* jdmaster underestimated number of scans; ratchet up one scan */
  71             cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
  72           }
  73         }
  74       }
  75 #else
  76       ERREXIT(cinfo, JERR_NOT_COMPILED);
  77 #endif /* D_MULTISCAN_FILES_SUPPORTED */
  78     }
  79     cinfo->output_scan_number = cinfo->input_scan_number;
  80   } else if (cinfo->global_state != DSTATE_PRESCAN)
  81     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  82   /* Perform any dummy output passes, and set up for the final pass */
  83   return output_pass_setup(cinfo);
  84 }
  85
  86
  87 /*
  88  * Set up for an output pass, and perform any dummy pass(es) needed.
  89  * Common subroutine for jpeg_start_decompress and jpeg_start_output.
  90  * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
  91  * Exit: If done, returns TRUE and sets global_state for proper output mode.
  92  *       If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
  93  */
  94
  95 LOCAL(boolean)
  96 output_pass_setup (j_decompress_ptr cinfo)
  97 {
  98   if (cinfo->global_state != DSTATE_PRESCAN) {
  99     /* First call: do pass setup */
 100     (*cinfo->master->prepare_for_output_pass) (cinfo);
 101     cinfo->output_scanline = 0;
 102     cinfo->global_state = DSTATE_PRESCAN;
 103   }
 104   /* Loop over any required dummy passes */
 105   while (cinfo->master->is_dummy_pass) {
 106 #ifdef QUANT_2PASS_SUPPORTED
 107     /* Crank through the dummy pass */
 108     while (cinfo->output_scanline < cinfo->output_height) {
 109       JDIMENSION last_scanline;
 110       /* Call progress monitor hook if present */
 111       if (cinfo->progress != NULL) {
 112         cinfo->progress->pass_counter = (long) cinfo->output_scanline;
 113         cinfo->progress->pass_limit = (long) cinfo->output_height;
 114         (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
 115       }
 116       /* Process some data */
 117       last_scanline = cinfo->output_scanline;
 118       (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
 119                                     &cinfo->output_scanline, (JDIMENSION) 0);
 120       if (cinfo->output_scanline == last_scanline)
 121         return FALSE;           /* No progress made, must suspend */
 122     }
 123     /* Finish up dummy pass, and set up for another one */
 124     (*cinfo->master->finish_output_pass) (cinfo);
 125     (*cinfo->master->prepare_for_output_pass) (cinfo);
 126     cinfo->output_scanline = 0;
 127 #else
 128     ERREXIT(cinfo, JERR_NOT_COMPILED);
 129 #endif /* QUANT_2PASS_SUPPORTED */
 130   }
 131   /* Ready for application to drive output pass through
 132    * jpeg_read_scanlines or jpeg_read_raw_data.
 133    */
 134   cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
 135   return TRUE;
 136 }
 137
 138
 139 /*
 140  * Read some scanlines of data from the JPEG decompressor.
 141  *
 142  * The return value will be the number of lines actually read.
 143  * This may be less than the number requested in several cases,
 144  * including bottom of image, data source suspension, and operating
 145  * modes that emit multiple scanlines at a time.
 146  *
 147  * Note: we warn about excess calls to jpeg_read_scanlines() since
 148  * this likely signals an application programmer error.  However,
 149  * an oversize buffer (max_lines > scanlines remaining) is not an error.
 150  */
 151
 152 GLOBAL(JDIMENSION)
 153 jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
 154                      JDIMENSION max_lines)
 155 {
 156   JDIMENSION row_ctr;
 157
 158   if (cinfo->global_state != DSTATE_SCANNING)
 159     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 160   if (cinfo->output_scanline >= cinfo->output_height) {
 161     WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
 162     return 0;
 163   }
 164
 165   /* Call progress monitor hook if present */
 166   if (cinfo->progress != NULL) {
 167     cinfo->progress->pass_counter = (long) cinfo->output_scanline;
 168     cinfo->progress->pass_limit = (long) cinfo->output_height;
 169     (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
 170   }
 171
 172   /* Process some data */
 173   row_ctr = 0;
 174   (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
 175   cinfo->output_scanline += row_ctr;
 176   return row_ctr;
 177 }
 178
 179
 180 /*
 181  * Alternate entry point to read raw data.
 182  * Processes exactly one iMCU row per call, unless suspended.
 183  */
 184
 185 GLOBAL(JDIMENSION)
 186 jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
 187                     JDIMENSION max_lines)
 188 {
 189   JDIMENSION lines_per_iMCU_row;
 190
 191   if (cinfo->global_state != DSTATE_RAW_OK)
 192     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 193   if (cinfo->output_scanline >= cinfo->output_height) {
 194     WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
 195     return 0;
 196   }
 197
 198   /* Call progress monitor hook if present */
 199   if (cinfo->progress != NULL) {
 200     cinfo->progress->pass_counter = (long) cinfo->output_scanline;
 201     cinfo->progress->pass_limit = (long) cinfo->output_height;
 202     (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
 203   }
 204
 205   /* Verify that at least one iMCU row can be returned. */
 206   lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_v_scaled_size;
 207   if (max_lines < lines_per_iMCU_row)
 208     ERREXIT(cinfo, JERR_BUFFER_SIZE);
 209
 210   /* Decompress directly into user's buffer. */
 211   if (! (*cinfo->coef->decompress_data) (cinfo, data))
 212     return 0;                   /* suspension forced, can do nothing more */
 213
 214   /* OK, we processed one iMCU row. */
 215   cinfo->output_scanline += lines_per_iMCU_row;
 216   return lines_per_iMCU_row;
 217 }
 218
 219
 220 /* Additional entry points for buffered-image mode. */
 221
 222 #ifdef D_MULTISCAN_FILES_SUPPORTED
 223
 224 /*
 225  * Initialize for an output pass in buffered-image mode.
 226  */
 227
 228 GLOBAL(boolean)
 229 jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
 230 {
 231   if (cinfo->global_state != DSTATE_BUFIMAGE &&
 232       cinfo->global_state != DSTATE_PRESCAN)
 233     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 234   /* Limit scan number to valid range */
 235   if (scan_number <= 0)
 236     scan_number = 1;
 237   if (cinfo->inputctl->eoi_reached &&
 238       scan_number > cinfo->input_scan_number)
 239     scan_number = cinfo->input_scan_number;
 240   cinfo->output_scan_number = scan_number;
 241   /* Perform any dummy output passes, and set up for the real pass */
 242   return output_pass_setup(cinfo);
 243 }
 244
 245
 246 /*
 247  * Finish up after an output pass in buffered-image mode.
 248  *
 249  * Returns FALSE if suspended.  The return value need be inspected only if
 250  * a suspending data source is used.
 251  */
 252
 253 GLOBAL(boolean)
 254 jpeg_finish_output (j_decompress_ptr cinfo)
 255 {
 256   if ((cinfo->global_state == DSTATE_SCANNING ||
 257        cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
 258     /* Terminate this pass. */
 259     /* We do not require the whole pass to have been completed. */
 260     (*cinfo->master->finish_output_pass) (cinfo);
 261     cinfo->global_state = DSTATE_BUFPOST;
 262   } else if (cinfo->global_state != DSTATE_BUFPOST) {
 263     /* BUFPOST = repeat call after a suspension, anything else is error */
 264     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 265   }
 266   /* Read markers looking for SOS or EOI */
 267   while (cinfo->input_scan_number <= cinfo->output_scan_number &&
 268          ! cinfo->inputctl->eoi_reached) {
 269     if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
 270       return FALSE;             /* Suspend, come back later */
 271   }
 272   cinfo->global_state = DSTATE_BUFIMAGE;
 273   return TRUE;
 274 }
 275
 276 #endif /* D_MULTISCAN_FILES_SUPPORTED */