compiler/libjpeg/main/jcmaster.c

   1 /*
   2     $Id$
   3 */
   4
   5 /*
   6  * jcmaster.c
   7  *
   8  * Copyright (C) 1991-1998, 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 master control logic for the JPEG compressor.
  13  * These routines are concerned with parameter validation, initial setup,
  14  * and inter-pass control (determining the number of passes and the work
  15  * to be done in each pass).
  16  */
  17
  18 #define JPEG_INTERNALS
  19 #include "jinclude.h"
  20 #include "jpeglib.h"
  21 #include "jlossy.h"             /* Private declarations for lossy codec */
  22
  23
  24 /* Private state */
  25
  26 typedef enum {
  27         main_pass,              /* input data, also do first output step */
  28         huff_opt_pass,          /* Huffman code optimization pass */
  29         output_pass             /* data output pass */
  30 } c_pass_type;
  31
  32 typedef struct {
  33   struct jpeg_comp_master pub;  /* public fields */
  34
  35   c_pass_type pass_type;        /* the type of the current pass */
  36
  37   int pass_number;              /* # of passes completed */
  38   int total_passes;             /* total # of passes needed */
  39
  40   int scan_number;              /* current index in scan_info[] */
  41 } my_comp_master;
  42
  43 typedef my_comp_master * my_master_ptr;
  44
  45
  46 /*
  47  * Support routines that do various essential calculations.
  48  */
  49
  50 LOCAL(void)
  51 initial_setup (j_compress_ptr cinfo)
  52 /* Do computations that are needed before master selection phase */
  53 {
  54   int ci;
  55   jpeg_component_info *compptr;
  56   long samplesperrow;
  57   JDIMENSION jd_samplesperrow;
  58   int data_unit = cinfo->data_unit;
  59
  60   /* Sanity check on image dimensions */
  61   if (cinfo->image_height <= 0 || cinfo->image_width <= 0
  62       || cinfo->num_components <= 0 || cinfo->input_components <= 0)
  63     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
  64
  65   /* Make sure image isn't bigger than I can handle */
  66   if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
  67       (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
  68     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
  69
  70   /* Width of an input scanline must be representable as JDIMENSION. */
  71   samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
  72   jd_samplesperrow = (JDIMENSION) samplesperrow;
  73   if ((long) jd_samplesperrow != samplesperrow)
  74     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
  75
  76   /* For now, precision must match compiled-in value... */
  77   if (cinfo->data_precision != BITS_IN_JSAMPLE)
  78     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
  79
  80   /* Check that number of components won't exceed internal array sizes */
  81   if (cinfo->num_components > MAX_COMPONENTS)
  82     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
  83              MAX_COMPONENTS);
  84
  85   /* Compute maximum sampling factors; check factor validity */
  86   cinfo->max_h_samp_factor = 1;
  87   cinfo->max_v_samp_factor = 1;
  88   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
  89        ci++, compptr++) {
  90     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
  91         compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
  92       ERREXIT(cinfo, JERR_BAD_SAMPLING);
  93     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
  94                                    compptr->h_samp_factor);
  95     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
  96                                    compptr->v_samp_factor);
  97   }
  98
  99   /* Compute dimensions of components */
 100   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 101        ci++, compptr++) {
 102     /* Fill in the correct component_index value; don't rely on application */
 103     compptr->component_index = ci;
 104     /* For compression, we never do any codec-based processing. */
 105     compptr->codec_data_unit = data_unit;
 106     /* Size in data units */
 107     compptr->width_in_data_units = (JDIMENSION)
 108       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 109                     (long) (cinfo->max_h_samp_factor * data_unit));
 110     compptr->height_in_data_units = (JDIMENSION)
 111       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 112                     (long) (cinfo->max_v_samp_factor * data_unit));
 113     /* Size in samples */
 114     compptr->downsampled_width = (JDIMENSION)
 115       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 116                     (long) cinfo->max_h_samp_factor);
 117     compptr->downsampled_height = (JDIMENSION)
 118       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 119                     (long) cinfo->max_v_samp_factor);
 120     /* Mark component needed (this flag isn't actually used for compression) */
 121     compptr->component_needed = TRUE;
 122   }
 123
 124   /* Compute number of fully interleaved MCU rows (number of times that
 125    * main controller will call coefficient controller).
 126    */
 127   cinfo->total_iMCU_rows = (JDIMENSION)
 128     jdiv_round_up((long) cinfo->image_height,
 129                   (long) (cinfo->max_v_samp_factor*data_unit));
 130 }
 131
 132 #ifdef C_MULTISCAN_FILES_SUPPORTED
 133 #define NEED_SCAN_SCRIPT
 134 #else
 135 #ifdef C_LOSSLESS_SUPPORTED
 136 #define NEED_SCAN_SCRIPT
 137 #endif
 138 #endif
 139
 140 #ifdef NEED_SCAN_SCRIPT
 141
 142 LOCAL(void)
 143 validate_script (j_compress_ptr cinfo)
 144 /* Verify that the scan script in cinfo->scan_info[] is valid; also
 145  * determine whether it uses progressive JPEG, and set cinfo->process.
 146  */
 147 {
 148   const jpeg_scan_info * scanptr;
 149   int scanno, ncomps, ci, coefi, thisi;
 150   int Ss, Se, Ah, Al;
 151   boolean component_sent[MAX_COMPONENTS];
 152 #ifdef C_PROGRESSIVE_SUPPORTED
 153   int * last_bitpos_ptr;
 154   int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
 155   /* -1 until that coefficient has been seen; then last Al for it */
 156 #endif
 157
 158   if (cinfo->num_scans <= 0)
 159     ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
 160
 161 #ifndef C_MULTISCAN_FILES_SUPPORTED
 162   if (cinfo->num_scans > 1)
 163     ERREXIT(cinfo, JERR_NOT_COMPILED);
 164 #endif
 165
 166   scanptr = cinfo->scan_info;
 167   if (cinfo->lossless) {
 168 #ifdef C_LOSSLESS_SUPPORTED
 169     cinfo->process = JPROC_LOSSLESS;
 170     for (ci = 0; ci < cinfo->num_components; ci++)
 171       component_sent[ci] = FALSE;
 172 #else
 173     ERREXIT(cinfo, JERR_NOT_COMPILED);
 174 #endif
 175   }
 176   /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
 177    * for progressive JPEG, no scan can have this.
 178    */
 179   else if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
 180 #ifdef C_PROGRESSIVE_SUPPORTED
 181     cinfo->process = JPROC_PROGRESSIVE;
 182     last_bitpos_ptr = & last_bitpos[0][0];
 183     for (ci = 0; ci < cinfo->num_components; ci++)
 184       for (coefi = 0; coefi < DCTSIZE2; coefi++)
 185         *last_bitpos_ptr++ = -1;
 186 #else
 187     ERREXIT(cinfo, JERR_NOT_COMPILED);
 188 #endif
 189   } else {
 190     cinfo->process = JPROC_SEQUENTIAL;
 191     for (ci = 0; ci < cinfo->num_components; ci++)
 192       component_sent[ci] = FALSE;
 193   }
 194
 195   for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
 196     /* Validate component indexes */
 197     ncomps = scanptr->comps_in_scan;
 198     if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
 199       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
 200     for (ci = 0; ci < ncomps; ci++) {
 201       thisi = scanptr->component_index[ci];
 202       if (thisi < 0 || thisi >= cinfo->num_components)
 203         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 204       /* Components must appear in SOF order within each scan */
 205       if (ci > 0 && thisi <= scanptr->component_index[ci-1])
 206         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 207     }
 208     /* Validate progression parameters */
 209     Ss = scanptr->Ss;
 210     Se = scanptr->Se;
 211     Ah = scanptr->Ah;
 212     Al = scanptr->Al;
 213     if (cinfo->process == JPROC_LOSSLESS) {
 214 #ifdef C_LOSSLESS_SUPPORTED
 215       /* The JPEG spec simply gives the range 0..15 for Al (Pt), but that
 216        * seems wrong: the upper bound ought to depend on data precision.
 217        * Perhaps they really meant 0..N-1 for N-bit precision, which is what
 218        * we allow here.
 219        */
 220       if (Ss < 1 || Ss > 7 ||                   /* predictor selector */
 221           Se != 0 || Ah != 0 ||
 222           Al < 0 || Al >= cinfo->data_precision) /* point transform */
 223         ERREXIT1(cinfo, JERR_BAD_LOSSLESS_SCRIPT, scanno);
 224       /* Make sure components are not sent twice */
 225       for (ci = 0; ci < ncomps; ci++) {
 226         thisi = scanptr->component_index[ci];
 227         if (component_sent[thisi])
 228           ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 229         component_sent[thisi] = TRUE;
 230       }
 231 #endif
 232     } else if (cinfo->process == JPROC_PROGRESSIVE) {
 233 #ifdef C_PROGRESSIVE_SUPPORTED
 234       /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
 235        * seems wrong: the upper bound ought to depend on data precision.
 236        * Perhaps they really meant 0..N+1 for N-bit precision.
 237        * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
 238        * out-of-range reconstructed DC values during the first DC scan,
 239        * which might cause problems for some decoders.
 240        */
 241 #if BITS_IN_JSAMPLE == 8
 242 #define MAX_AH_AL 10
 243 #else
 244 #define MAX_AH_AL 13
 245 #endif
 246       if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
 247           Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
 248         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 249       if (Ss == 0) {
 250         if (Se != 0)            /* DC and AC together not OK */
 251           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 252       } else {
 253         if (ncomps != 1)        /* AC scans must be for only one component */
 254           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 255       }
 256       for (ci = 0; ci < ncomps; ci++) {
 257         last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
 258         if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
 259           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 260         for (coefi = Ss; coefi <= Se; coefi++) {
 261           if (last_bitpos_ptr[coefi] < 0) {
 262             /* first scan of this coefficient */
 263             if (Ah != 0)
 264               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 265           } else {
 266             /* not first scan */
 267             if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
 268               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 269           }
 270           last_bitpos_ptr[coefi] = Al;
 271         }
 272       }
 273 #endif
 274     } else {
 275       /* For sequential JPEG, all progression parameters must be these: */
 276       if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
 277         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 278       /* Make sure components are not sent twice */
 279       for (ci = 0; ci < ncomps; ci++) {
 280         thisi = scanptr->component_index[ci];
 281         if (component_sent[thisi])
 282           ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 283         component_sent[thisi] = TRUE;
 284       }
 285     }
 286   }
 287
 288   /* Now verify that everything got sent. */
 289   if (cinfo->process == JPROC_PROGRESSIVE) {
 290 #ifdef C_PROGRESSIVE_SUPPORTED
 291     /* For progressive mode, we only check that at least some DC data
 292      * got sent for each component; the spec does not require that all bits
 293      * of all coefficients be transmitted.  Would it be wiser to enforce
 294      * transmission of all coefficient bits??
 295      */
 296     for (ci = 0; ci < cinfo->num_components; ci++) {
 297       if (last_bitpos[ci][0] < 0)
 298         ERREXIT(cinfo, JERR_MISSING_DATA);
 299     }
 300 #endif
 301   } else {
 302     for (ci = 0; ci < cinfo->num_components; ci++) {
 303       if (! component_sent[ci])
 304         ERREXIT(cinfo, JERR_MISSING_DATA);
 305     }
 306   }
 307 }
 308
 309 #endif /* NEED_SCAN_SCRIPT */
 310
 311
 312 LOCAL(void)
 313 select_scan_parameters (j_compress_ptr cinfo)
 314 /* Set up the scan parameters for the current scan */
 315 {
 316   int ci;
 317
 318 #ifdef NEED_SCAN_SCRIPT
 319   if (cinfo->scan_info != NULL) {
 320     /* Prepare for current scan --- the script is already validated */
 321     my_master_ptr master = (my_master_ptr) cinfo->master;
 322     const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
 323
 324     cinfo->comps_in_scan = scanptr->comps_in_scan;
 325     for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
 326       cinfo->cur_comp_info[ci] =
 327         &cinfo->comp_info[scanptr->component_index[ci]];
 328     }
 329     cinfo->Ss = scanptr->Ss;
 330     cinfo->Se = scanptr->Se;
 331     cinfo->Ah = scanptr->Ah;
 332     cinfo->Al = scanptr->Al;
 333   } else
 334 #endif
 335   {
 336     /* Prepare for single sequential-JPEG scan containing all components */
 337     if (cinfo->num_components > MAX_COMPS_IN_SCAN)
 338       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 339                MAX_COMPS_IN_SCAN);
 340     cinfo->comps_in_scan = cinfo->num_components;
 341     for (ci = 0; ci < cinfo->num_components; ci++) {
 342       cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
 343     }
 344     if (cinfo->lossless) {
 345 #ifdef C_LOSSLESS_SUPPORTED
 346     /* If we fall through to here, the user specified lossless, but did not
 347      * provide a scan script.
 348      */
 349       ERREXIT(cinfo, JERR_NO_LOSSLESS_SCRIPT);
 350 #endif
 351     } else {
 352       cinfo->process = JPROC_SEQUENTIAL;
 353       cinfo->Ss = 0;
 354       cinfo->Se = DCTSIZE2-1;
 355       cinfo->Ah = 0;
 356       cinfo->Al = 0;
 357     }
 358   }
 359 }
 360
 361
 362 LOCAL(void)
 363 per_scan_setup (j_compress_ptr cinfo)
 364 /* Do computations that are needed before processing a JPEG scan */
 365 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
 366 {
 367   int ci, mcublks, tmp;
 368   jpeg_component_info *compptr;
 369   int data_unit = cinfo->data_unit;
 370
 371   if (cinfo->comps_in_scan == 1) {
 372
 373     /* Noninterleaved (single-component) scan */
 374     compptr = cinfo->cur_comp_info[0];
 375
 376     /* Overall image size in MCUs */
 377     cinfo->MCUs_per_row = compptr->width_in_data_units;
 378     cinfo->MCU_rows_in_scan = compptr->height_in_data_units;
 379
 380     /* For noninterleaved scan, always one block per MCU */
 381     compptr->MCU_width = 1;
 382     compptr->MCU_height = 1;
 383     compptr->MCU_data_units = 1;
 384     compptr->MCU_sample_width = data_unit;
 385     compptr->last_col_width = 1;
 386     /* For noninterleaved scans, it is convenient to define last_row_height
 387      * as the number of block rows present in the last iMCU row.
 388      */
 389     tmp = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
 390     if (tmp == 0) tmp = compptr->v_samp_factor;
 391     compptr->last_row_height = tmp;
 392
 393     /* Prepare array describing MCU composition */
 394     cinfo->data_units_in_MCU = 1;
 395     cinfo->MCU_membership[0] = 0;
 396
 397   } else {
 398
 399     /* Interleaved (multi-component) scan */
 400     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
 401       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
 402                MAX_COMPS_IN_SCAN);
 403
 404     /* Overall image size in MCUs */
 405     cinfo->MCUs_per_row = (JDIMENSION)
 406       jdiv_round_up((long) cinfo->image_width,
 407                     (long) (cinfo->max_h_samp_factor*data_unit));
 408     cinfo->MCU_rows_in_scan = (JDIMENSION)
 409       jdiv_round_up((long) cinfo->image_height,
 410                     (long) (cinfo->max_v_samp_factor*data_unit));
 411
 412     cinfo->data_units_in_MCU = 0;
 413
 414     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 415       compptr = cinfo->cur_comp_info[ci];
 416       /* Sampling factors give # of blocks of component in each MCU */
 417       compptr->MCU_width = compptr->h_samp_factor;
 418       compptr->MCU_height = compptr->v_samp_factor;
 419       compptr->MCU_data_units = compptr->MCU_width * compptr->MCU_height;
 420       compptr->MCU_sample_width = compptr->MCU_width * data_unit;
 421       /* Figure number of non-dummy blocks in last MCU column & row */
 422       tmp = (int) (compptr->width_in_data_units % compptr->MCU_width);
 423       if (tmp == 0) tmp = compptr->MCU_width;
 424       compptr->last_col_width = tmp;
 425       tmp = (int) (compptr->height_in_data_units % compptr->MCU_height);
 426       if (tmp == 0) tmp = compptr->MCU_height;
 427       compptr->last_row_height = tmp;
 428       /* Prepare array describing MCU composition */
 429       mcublks = compptr->MCU_data_units;
 430       if (cinfo->data_units_in_MCU + mcublks > C_MAX_DATA_UNITS_IN_MCU)
 431         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
 432       while (mcublks-- > 0) {
 433         cinfo->MCU_membership[cinfo->data_units_in_MCU++] = ci;
 434       }
 435     }
 436
 437   }
 438
 439   /* Convert restart specified in rows to actual MCU count. */
 440   /* Note that count must fit in 16 bits, so we provide limiting. */
 441   if (cinfo->restart_in_rows > 0) {
 442     long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
 443     cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
 444   }
 445 }
 446
 447
 448 /*
 449  * Per-pass setup.
 450  * This is called at the beginning of each pass.  We determine which modules
 451  * will be active during this pass and give them appropriate start_pass calls.
 452  * We also set is_last_pass to indicate whether any more passes will be
 453  * required.
 454  */
 455
 456 METHODDEF(void)
 457 prepare_for_pass (j_compress_ptr cinfo)
 458 {
 459   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 460   my_master_ptr master = (my_master_ptr) cinfo->master;
 461
 462   switch (master->pass_type) {
 463   case main_pass:
 464     /* Initial pass: will collect input data, and do either Huffman
 465      * optimization or data output for the first scan.
 466      */
 467     select_scan_parameters(cinfo);
 468     per_scan_setup(cinfo);
 469     if (! cinfo->raw_data_in) {
 470       (*cinfo->cconvert->start_pass) (cinfo);
 471       (*cinfo->downsample->start_pass) (cinfo);
 472       (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
 473     }
 474     (*cinfo->codec->entropy_start_pass) (cinfo, cinfo->optimize_coding);
 475     (*cinfo->codec->start_pass) (cinfo,
 476                                  (master->total_passes > 1 ?
 477                                   JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
 478     (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
 479     if (cinfo->optimize_coding) {
 480       /* No immediate data output; postpone writing frame/scan headers */
 481       master->pub.call_pass_startup = FALSE;
 482     } else {
 483       /* Will write frame/scan headers at first jpeg_write_scanlines call */
 484       master->pub.call_pass_startup = TRUE;
 485     }
 486     break;
 487 #ifdef ENTROPY_OPT_SUPPORTED
 488   case huff_opt_pass:
 489     /* Do Huffman optimization for a scan after the first one. */
 490     select_scan_parameters(cinfo);
 491     per_scan_setup(cinfo);
 492     if ((*cinfo->codec->need_optimization_pass) (cinfo) || cinfo->arith_code) {
 493       (*cinfo->codec->entropy_start_pass) (cinfo, TRUE);
 494       (*cinfo->codec->start_pass) (cinfo, JBUF_CRANK_DEST);
 495       master->pub.call_pass_startup = FALSE;
 496       break;
 497     }
 498     /* Special case: Huffman DC refinement scans need no Huffman table
 499      * and therefore we can skip the optimization pass for them.
 500      */
 501     master->pass_type = output_pass;
 502     master->pass_number++;
 503     /*FALLTHROUGH*/
 504 #endif
 505   case output_pass:
 506     /* Do a data-output pass. */
 507     /* We need not repeat per-scan setup if prior optimization pass did it. */
 508     if (! cinfo->optimize_coding) {
 509       select_scan_parameters(cinfo);
 510       per_scan_setup(cinfo);
 511     }
 512     (*cinfo->codec->entropy_start_pass) (cinfo, FALSE);
 513     (*cinfo->codec->start_pass) (cinfo, JBUF_CRANK_DEST);
 514     /* We emit frame/scan headers now */
 515     if (master->scan_number == 0)
 516       (*cinfo->marker->write_frame_header) (cinfo);
 517     (*cinfo->marker->write_scan_header) (cinfo);
 518     master->pub.call_pass_startup = FALSE;
 519     break;
 520   default:
 521     ERREXIT(cinfo, JERR_NOT_COMPILED);
 522   }
 523
 524   master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
 525
 526   /* Set up progress monitor's pass info if present */
 527   if (cinfo->progress != NULL) {
 528     cinfo->progress->completed_passes = master->pass_number;
 529     cinfo->progress->total_passes = master->total_passes;
 530   }
 531 }
 532
 533
 534 /*
 535  * Special start-of-pass hook.
 536  * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
 537  * In single-pass processing, we need this hook because we don't want to
 538  * write frame/scan headers during jpeg_start_compress; we want to let the
 539  * application write COM markers etc. between jpeg_start_compress and the
 540  * jpeg_write_scanlines loop.
 541  * In multi-pass processing, this routine is not used.
 542  */
 543
 544 METHODDEF(void)
 545 pass_startup (j_compress_ptr cinfo)
 546 {
 547   cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
 548
 549   (*cinfo->marker->write_frame_header) (cinfo);
 550   (*cinfo->marker->write_scan_header) (cinfo);
 551 }
 552
 553
 554 /*
 555  * Finish up at end of pass.
 556  */
 557
 558 METHODDEF(void)
 559 finish_pass_master (j_compress_ptr cinfo)
 560 {
 561   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 562   my_master_ptr master = (my_master_ptr) cinfo->master;
 563
 564   /* The entropy coder always needs an end-of-pass call,
 565    * either to analyze statistics or to flush its output buffer.
 566    */
 567   (*lossyc->pub.entropy_finish_pass) (cinfo);
 568
 569   /* Update state for next pass */
 570   switch (master->pass_type) {
 571   case main_pass:
 572     /* next pass is either output of scan 0 (after optimization)
 573      * or output of scan 1 (if no optimization).
 574      */
 575     master->pass_type = output_pass;
 576     if (! cinfo->optimize_coding)
 577       master->scan_number++;
 578     break;
 579   case huff_opt_pass:
 580     /* next pass is always output of current scan */
 581     master->pass_type = output_pass;
 582     break;
 583   case output_pass:
 584     /* next pass is either optimization or output of next scan */
 585     if (cinfo->optimize_coding)
 586       master->pass_type = huff_opt_pass;
 587     master->scan_number++;
 588     break;
 589   }
 590
 591   master->pass_number++;
 592 }
 593
 594
 595 /*
 596  * Initialize master compression control.
 597  */
 598
 599 JGLOBAL(void)
 600 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
 601 {
 602   my_master_ptr master;
 603
 604   master = (my_master_ptr)
 605       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 606                                   SIZEOF(my_comp_master));
 607   cinfo->master = (struct jpeg_comp_master *) master;
 608   master->pub.prepare_for_pass = prepare_for_pass;
 609   master->pub.pass_startup = pass_startup;
 610   master->pub.finish_pass = finish_pass_master;
 611   master->pub.is_last_pass = FALSE;
 612
 613   cinfo->data_unit = cinfo->lossless ? 1 : DCTSIZE;
 614
 615   /* Validate parameters, determine derived values */
 616   initial_setup(cinfo);
 617
 618   if (cinfo->scan_info != NULL) {
 619 #ifdef NEED_SCAN_SCRIPT
 620     validate_script(cinfo);
 621 #else
 622     ERREXIT(cinfo, JERR_NOT_COMPILED);
 623 #endif
 624   } else {
 625     cinfo->process = JPROC_SEQUENTIAL;
 626     cinfo->num_scans = 1;
 627   }
 628
 629   if (cinfo->process == JPROC_PROGRESSIVE ||    /*  TEMPORARY HACK ??? */
 630       cinfo->process == JPROC_LOSSLESS)
 631     cinfo->optimize_coding = TRUE; /* assume default tables no good for
 632                                     * progressive mode or lossless mode */
 633
 634   /* Initialize my private state */
 635   if (transcode_only) {
 636     /* no main pass in transcoding */
 637     if (cinfo->optimize_coding)
 638       master->pass_type = huff_opt_pass;
 639     else
 640       master->pass_type = output_pass;
 641   } else {
 642     /* for normal compression, first pass is always this type: */
 643     master->pass_type = main_pass;
 644   }
 645   master->scan_number = 0;
 646   master->pass_number = 0;
 647   if (cinfo->optimize_coding)
 648     master->total_passes = cinfo->num_scans * 2;
 649   else
 650     master->total_passes = cinfo->num_scans;
 651 }