workbench/libs/jpeg/jcmaster.c

   1 /*
   2  * jcmaster.c
   3  *
   4  * Copyright (C) 1991-1997, Thomas G. Lane.
   5  * Modified 2003-2013 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 master control logic for the JPEG compressor.
  10  * These routines are concerned with parameter validation, initial setup,
  11  * and inter-pass control (determining the number of passes and the work
  12  * to be done in each pass).
  13  */
  14
  15 #define JPEG_INTERNALS
  16 #include "jinclude.h"
  17 #include "jpeglib.h"
  18
  19
  20 /* Private state */
  21
  22 typedef enum {
  23         main_pass,              /* input data, also do first output step */
  24         huff_opt_pass,          /* Huffman code optimization pass */
  25         output_pass             /* data output pass */
  26 } c_pass_type;
  27
  28 typedef struct {
  29   struct jpeg_comp_master pub;  /* public fields */
  30
  31   c_pass_type pass_type;        /* the type of the current pass */
  32
  33   int pass_number;              /* # of passes completed */
  34   int total_passes;             /* total # of passes needed */
  35
  36   int scan_number;              /* current index in scan_info[] */
  37 } my_comp_master;
  38
  39 typedef my_comp_master * my_master_ptr;
  40
  41
  42 /*
  43  * Support routines that do various essential calculations.
  44  */
  45
  46 /*
  47  * Compute JPEG image dimensions and related values.
  48  * NOTE: this is exported for possible use by application.
  49  * Hence it mustn't do anything that can't be done twice.
  50  */
  51
  52 GLOBAL(void)
  53 jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
  54 /* Do computations that are needed before master selection phase */
  55 {
  56 #ifdef DCT_SCALING_SUPPORTED
  57
  58   /* Sanity check on input image dimensions to prevent overflow in
  59    * following calculation.
  60    * We do check jpeg_width and jpeg_height in initial_setup below,
  61    * but image_width and image_height can come from arbitrary data,
  62    * and we need some space for multiplication by block_size.
  63    */
  64   if (((long) cinfo->image_width >> 24) || ((long) cinfo->image_height >> 24))
  65     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
  66
  67   /* Compute actual JPEG image dimensions and DCT scaling choices. */
  68   if (cinfo->scale_num >= cinfo->scale_denom * cinfo->block_size) {
  69     /* Provide block_size/1 scaling */
  70     cinfo->jpeg_width = cinfo->image_width * cinfo->block_size;
  71     cinfo->jpeg_height = cinfo->image_height * cinfo->block_size;
  72     cinfo->min_DCT_h_scaled_size = 1;
  73     cinfo->min_DCT_v_scaled_size = 1;
  74   } else if (cinfo->scale_num * 2 >= cinfo->scale_denom * cinfo->block_size) {
  75     /* Provide block_size/2 scaling */
  76     cinfo->jpeg_width = (JDIMENSION)
  77       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 2L);
  78     cinfo->jpeg_height = (JDIMENSION)
  79       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 2L);
  80     cinfo->min_DCT_h_scaled_size = 2;
  81     cinfo->min_DCT_v_scaled_size = 2;
  82   } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * cinfo->block_size) {
  83     /* Provide block_size/3 scaling */
  84     cinfo->jpeg_width = (JDIMENSION)
  85       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 3L);
  86     cinfo->jpeg_height = (JDIMENSION)
  87       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 3L);
  88     cinfo->min_DCT_h_scaled_size = 3;
  89     cinfo->min_DCT_v_scaled_size = 3;
  90   } else if (cinfo->scale_num * 4 >= cinfo->scale_denom * cinfo->block_size) {
  91     /* Provide block_size/4 scaling */
  92     cinfo->jpeg_width = (JDIMENSION)
  93       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 4L);
  94     cinfo->jpeg_height = (JDIMENSION)
  95       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 4L);
  96     cinfo->min_DCT_h_scaled_size = 4;
  97     cinfo->min_DCT_v_scaled_size = 4;
  98   } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * cinfo->block_size) {
  99     /* Provide block_size/5 scaling */
 100     cinfo->jpeg_width = (JDIMENSION)
 101       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 5L);
 102     cinfo->jpeg_height = (JDIMENSION)
 103       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 5L);
 104     cinfo->min_DCT_h_scaled_size = 5;
 105     cinfo->min_DCT_v_scaled_size = 5;
 106   } else if (cinfo->scale_num * 6 >= cinfo->scale_denom * cinfo->block_size) {
 107     /* Provide block_size/6 scaling */
 108     cinfo->jpeg_width = (JDIMENSION)
 109       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 6L);
 110     cinfo->jpeg_height = (JDIMENSION)
 111       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 6L);
 112     cinfo->min_DCT_h_scaled_size = 6;
 113     cinfo->min_DCT_v_scaled_size = 6;
 114   } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * cinfo->block_size) {
 115     /* Provide block_size/7 scaling */
 116     cinfo->jpeg_width = (JDIMENSION)
 117       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 7L);
 118     cinfo->jpeg_height = (JDIMENSION)
 119       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 7L);
 120     cinfo->min_DCT_h_scaled_size = 7;
 121     cinfo->min_DCT_v_scaled_size = 7;
 122   } else if (cinfo->scale_num * 8 >= cinfo->scale_denom * cinfo->block_size) {
 123     /* Provide block_size/8 scaling */
 124     cinfo->jpeg_width = (JDIMENSION)
 125       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 8L);
 126     cinfo->jpeg_height = (JDIMENSION)
 127       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 8L);
 128     cinfo->min_DCT_h_scaled_size = 8;
 129     cinfo->min_DCT_v_scaled_size = 8;
 130   } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * cinfo->block_size) {
 131     /* Provide block_size/9 scaling */
 132     cinfo->jpeg_width = (JDIMENSION)
 133       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 9L);
 134     cinfo->jpeg_height = (JDIMENSION)
 135       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 9L);
 136     cinfo->min_DCT_h_scaled_size = 9;
 137     cinfo->min_DCT_v_scaled_size = 9;
 138   } else if (cinfo->scale_num * 10 >= cinfo->scale_denom * cinfo->block_size) {
 139     /* Provide block_size/10 scaling */
 140     cinfo->jpeg_width = (JDIMENSION)
 141       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 10L);
 142     cinfo->jpeg_height = (JDIMENSION)
 143       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 10L);
 144     cinfo->min_DCT_h_scaled_size = 10;
 145     cinfo->min_DCT_v_scaled_size = 10;
 146   } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * cinfo->block_size) {
 147     /* Provide block_size/11 scaling */
 148     cinfo->jpeg_width = (JDIMENSION)
 149       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 11L);
 150     cinfo->jpeg_height = (JDIMENSION)
 151       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 11L);
 152     cinfo->min_DCT_h_scaled_size = 11;
 153     cinfo->min_DCT_v_scaled_size = 11;
 154   } else if (cinfo->scale_num * 12 >= cinfo->scale_denom * cinfo->block_size) {
 155     /* Provide block_size/12 scaling */
 156     cinfo->jpeg_width = (JDIMENSION)
 157       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 12L);
 158     cinfo->jpeg_height = (JDIMENSION)
 159       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 12L);
 160     cinfo->min_DCT_h_scaled_size = 12;
 161     cinfo->min_DCT_v_scaled_size = 12;
 162   } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * cinfo->block_size) {
 163     /* Provide block_size/13 scaling */
 164     cinfo->jpeg_width = (JDIMENSION)
 165       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 13L);
 166     cinfo->jpeg_height = (JDIMENSION)
 167       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 13L);
 168     cinfo->min_DCT_h_scaled_size = 13;
 169     cinfo->min_DCT_v_scaled_size = 13;
 170   } else if (cinfo->scale_num * 14 >= cinfo->scale_denom * cinfo->block_size) {
 171     /* Provide block_size/14 scaling */
 172     cinfo->jpeg_width = (JDIMENSION)
 173       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 14L);
 174     cinfo->jpeg_height = (JDIMENSION)
 175       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 14L);
 176     cinfo->min_DCT_h_scaled_size = 14;
 177     cinfo->min_DCT_v_scaled_size = 14;
 178   } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * cinfo->block_size) {
 179     /* Provide block_size/15 scaling */
 180     cinfo->jpeg_width = (JDIMENSION)
 181       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 15L);
 182     cinfo->jpeg_height = (JDIMENSION)
 183       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 15L);
 184     cinfo->min_DCT_h_scaled_size = 15;
 185     cinfo->min_DCT_v_scaled_size = 15;
 186   } else {
 187     /* Provide block_size/16 scaling */
 188     cinfo->jpeg_width = (JDIMENSION)
 189       jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 16L);
 190     cinfo->jpeg_height = (JDIMENSION)
 191       jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 16L);
 192     cinfo->min_DCT_h_scaled_size = 16;
 193     cinfo->min_DCT_v_scaled_size = 16;
 194   }
 195
 196 #else /* !DCT_SCALING_SUPPORTED */
 197
 198   /* Hardwire it to "no scaling" */
 199   cinfo->jpeg_width = cinfo->image_width;
 200   cinfo->jpeg_height = cinfo->image_height;
 201   cinfo->min_DCT_h_scaled_size = DCTSIZE;
 202   cinfo->min_DCT_v_scaled_size = DCTSIZE;
 203
 204 #endif /* DCT_SCALING_SUPPORTED */
 205 }
 206
 207
 208 LOCAL(void)
 209 jpeg_calc_trans_dimensions (j_compress_ptr cinfo)
 210 {
 211   if (cinfo->min_DCT_h_scaled_size != cinfo->min_DCT_v_scaled_size)
 212     ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
 213              cinfo->min_DCT_h_scaled_size, cinfo->min_DCT_v_scaled_size);
 214
 215   cinfo->block_size = cinfo->min_DCT_h_scaled_size;
 216 }
 217
 218
 219 LOCAL(void)
 220 initial_setup (j_compress_ptr cinfo, boolean transcode_only)
 221 /* Do computations that are needed before master selection phase */
 222 {
 223   int ci, ssize;
 224   jpeg_component_info *compptr;
 225
 226   if (transcode_only)
 227     jpeg_calc_trans_dimensions(cinfo);
 228   else
 229     jpeg_calc_jpeg_dimensions(cinfo);
 230
 231   /* Sanity check on block_size */
 232   if (cinfo->block_size < 1 || cinfo->block_size > 16)
 233     ERREXIT2(cinfo, JERR_BAD_DCTSIZE, cinfo->block_size, cinfo->block_size);
 234
 235   /* Derive natural_order from block_size */
 236   switch (cinfo->block_size) {
 237   case 2: cinfo->natural_order = jpeg_natural_order2; break;
 238   case 3: cinfo->natural_order = jpeg_natural_order3; break;
 239   case 4: cinfo->natural_order = jpeg_natural_order4; break;
 240   case 5: cinfo->natural_order = jpeg_natural_order5; break;
 241   case 6: cinfo->natural_order = jpeg_natural_order6; break;
 242   case 7: cinfo->natural_order = jpeg_natural_order7; break;
 243   default: cinfo->natural_order = jpeg_natural_order; break;
 244   }
 245
 246   /* Derive lim_Se from block_size */
 247   cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
 248     cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
 249
 250   /* Sanity check on image dimensions */
 251   if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
 252       cinfo->num_components <= 0)
 253     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
 254
 255   /* Make sure image isn't bigger than I can handle */
 256   if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
 257       (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
 258     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
 259
 260   /* Only 8 to 12 bits data precision are supported for DCT based JPEG */
 261   if (cinfo->data_precision < 8 || cinfo->data_precision > 12)
 262     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
 263
 264   /* Check that number of components won't exceed internal array sizes */
 265   if (cinfo->num_components > MAX_COMPONENTS)
 266     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 267              MAX_COMPONENTS);
 268
 269   /* Compute maximum sampling factors; check factor validity */
 270   cinfo->max_h_samp_factor = 1;
 271   cinfo->max_v_samp_factor = 1;
 272   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 273        ci++, compptr++) {
 274     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
 275         compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
 276       ERREXIT(cinfo, JERR_BAD_SAMPLING);
 277     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
 278                                    compptr->h_samp_factor);
 279     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
 280                                    compptr->v_samp_factor);
 281   }
 282
 283   /* Compute dimensions of components */
 284   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 285        ci++, compptr++) {
 286     /* Fill in the correct component_index value; don't rely on application */
 287     compptr->component_index = ci;
 288     /* In selecting the actual DCT scaling for each component, we try to
 289      * scale down the chroma components via DCT scaling rather than downsampling.
 290      * This saves time if the downsampler gets to use 1:1 scaling.
 291      * Note this code adapts subsampling ratios which are powers of 2.
 292      */
 293     ssize = 1;
 294 #ifdef DCT_SCALING_SUPPORTED
 295     while (cinfo->min_DCT_h_scaled_size * ssize <=
 296            (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
 297            (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
 298       ssize = ssize * 2;
 299     }
 300 #endif
 301     compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
 302     ssize = 1;
 303 #ifdef DCT_SCALING_SUPPORTED
 304     while (cinfo->min_DCT_v_scaled_size * ssize <=
 305            (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
 306            (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
 307       ssize = ssize * 2;
 308     }
 309 #endif
 310     compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
 311
 312     /* We don't support DCT ratios larger than 2. */
 313     if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
 314         compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
 315     else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
 316         compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
 317
 318     /* Size in DCT blocks */
 319     compptr->width_in_blocks = (JDIMENSION)
 320       jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
 321                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 322     compptr->height_in_blocks = (JDIMENSION)
 323       jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
 324                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 325     /* Size in samples */
 326     compptr->downsampled_width = (JDIMENSION)
 327       jdiv_round_up((long) cinfo->jpeg_width *
 328                     (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
 329                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 330     compptr->downsampled_height = (JDIMENSION)
 331       jdiv_round_up((long) cinfo->jpeg_height *
 332                     (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
 333                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 334     /* Don't need quantization scale after DCT,
 335      * until color conversion says otherwise.
 336      */
 337     compptr->component_needed = FALSE;
 338   }
 339
 340   /* Compute number of fully interleaved MCU rows (number of times that
 341    * main controller will call coefficient controller).
 342    */
 343   cinfo->total_iMCU_rows = (JDIMENSION)
 344     jdiv_round_up((long) cinfo->jpeg_height,
 345                   (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 346 }
 347
 348
 349 #ifdef C_MULTISCAN_FILES_SUPPORTED
 350
 351 LOCAL(void)
 352 validate_script (j_compress_ptr cinfo)
 353 /* Verify that the scan script in cinfo->scan_info[] is valid; also
 354  * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
 355  */
 356 {
 357   const jpeg_scan_info * scanptr;
 358   int scanno, ncomps, ci, coefi, thisi;
 359   int Ss, Se, Ah, Al;
 360   boolean component_sent[MAX_COMPONENTS];
 361 #ifdef C_PROGRESSIVE_SUPPORTED
 362   int * last_bitpos_ptr;
 363   int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
 364   /* -1 until that coefficient has been seen; then last Al for it */
 365 #endif
 366
 367   if (cinfo->num_scans <= 0)
 368     ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
 369
 370   /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
 371    * for progressive JPEG, no scan can have this.
 372    */
 373   scanptr = cinfo->scan_info;
 374   if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
 375 #ifdef C_PROGRESSIVE_SUPPORTED
 376     cinfo->progressive_mode = TRUE;
 377     last_bitpos_ptr = & last_bitpos[0][0];
 378     for (ci = 0; ci < cinfo->num_components; ci++)
 379       for (coefi = 0; coefi < DCTSIZE2; coefi++)
 380         *last_bitpos_ptr++ = -1;
 381 #else
 382     ERREXIT(cinfo, JERR_NOT_COMPILED);
 383 #endif
 384   } else {
 385     cinfo->progressive_mode = FALSE;
 386     for (ci = 0; ci < cinfo->num_components; ci++)
 387       component_sent[ci] = FALSE;
 388   }
 389
 390   for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
 391     /* Validate component indexes */
 392     ncomps = scanptr->comps_in_scan;
 393     if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
 394       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
 395     for (ci = 0; ci < ncomps; ci++) {
 396       thisi = scanptr->component_index[ci];
 397       if (thisi < 0 || thisi >= cinfo->num_components)
 398         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 399       /* Components must appear in SOF order within each scan */
 400       if (ci > 0 && thisi <= scanptr->component_index[ci-1])
 401         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 402     }
 403     /* Validate progression parameters */
 404     Ss = scanptr->Ss;
 405     Se = scanptr->Se;
 406     Ah = scanptr->Ah;
 407     Al = scanptr->Al;
 408     if (cinfo->progressive_mode) {
 409 #ifdef C_PROGRESSIVE_SUPPORTED
 410       /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
 411        * seems wrong: the upper bound ought to depend on data precision.
 412        * Perhaps they really meant 0..N+1 for N-bit precision.
 413        * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
 414        * out-of-range reconstructed DC values during the first DC scan,
 415        * which might cause problems for some decoders.
 416        */
 417 #if BITS_IN_JSAMPLE == 8
 418 #define MAX_AH_AL 10
 419 #else
 420 #define MAX_AH_AL 13
 421 #endif
 422       if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
 423           Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
 424         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 425       if (Ss == 0) {
 426         if (Se != 0)            /* DC and AC together not OK */
 427           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 428       } else {
 429         if (ncomps != 1)        /* AC scans must be for only one component */
 430           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 431       }
 432       for (ci = 0; ci < ncomps; ci++) {
 433         last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
 434         if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
 435           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 436         for (coefi = Ss; coefi <= Se; coefi++) {
 437           if (last_bitpos_ptr[coefi] < 0) {
 438             /* first scan of this coefficient */
 439             if (Ah != 0)
 440               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 441           } else {
 442             /* not first scan */
 443             if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
 444               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 445           }
 446           last_bitpos_ptr[coefi] = Al;
 447         }
 448       }
 449 #endif
 450     } else {
 451       /* For sequential JPEG, all progression parameters must be these: */
 452       if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
 453         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 454       /* Make sure components are not sent twice */
 455       for (ci = 0; ci < ncomps; ci++) {
 456         thisi = scanptr->component_index[ci];
 457         if (component_sent[thisi])
 458           ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 459         component_sent[thisi] = TRUE;
 460       }
 461     }
 462   }
 463
 464   /* Now verify that everything got sent. */
 465   if (cinfo->progressive_mode) {
 466 #ifdef C_PROGRESSIVE_SUPPORTED
 467     /* For progressive mode, we only check that at least some DC data
 468      * got sent for each component; the spec does not require that all bits
 469      * of all coefficients be transmitted.  Would it be wiser to enforce
 470      * transmission of all coefficient bits??
 471      */
 472     for (ci = 0; ci < cinfo->num_components; ci++) {
 473       if (last_bitpos[ci][0] < 0)
 474         ERREXIT(cinfo, JERR_MISSING_DATA);
 475     }
 476 #endif
 477   } else {
 478     for (ci = 0; ci < cinfo->num_components; ci++) {
 479       if (! component_sent[ci])
 480         ERREXIT(cinfo, JERR_MISSING_DATA);
 481     }
 482   }
 483 }
 484
 485
 486 LOCAL(void)
 487 reduce_script (j_compress_ptr cinfo)
 488 /* Adapt scan script for use with reduced block size;
 489  * assume that script has been validated before.
 490  */
 491 {
 492   jpeg_scan_info * scanptr;
 493   int idxout, idxin;
 494
 495   /* Circumvent const declaration for this function */
 496   scanptr = (jpeg_scan_info *) cinfo->scan_info;
 497   idxout = 0;
 498
 499   for (idxin = 0; idxin < cinfo->num_scans; idxin++) {
 500     /* After skipping, idxout becomes smaller than idxin */
 501     if (idxin != idxout)
 502       /* Copy rest of data;
 503        * note we stay in given chunk of allocated memory.
 504        */
 505       scanptr[idxout] = scanptr[idxin];
 506     if (scanptr[idxout].Ss > cinfo->lim_Se)
 507       /* Entire scan out of range - skip this entry */
 508       continue;
 509     if (scanptr[idxout].Se > cinfo->lim_Se)
 510       /* Limit scan to end of block */
 511       scanptr[idxout].Se = cinfo->lim_Se;
 512     idxout++;
 513   }
 514
 515   cinfo->num_scans = idxout;
 516 }
 517
 518 #endif /* C_MULTISCAN_FILES_SUPPORTED */
 519
 520
 521 LOCAL(void)
 522 select_scan_parameters (j_compress_ptr cinfo)
 523 /* Set up the scan parameters for the current scan */
 524 {
 525   int ci;
 526
 527 #ifdef C_MULTISCAN_FILES_SUPPORTED
 528   if (cinfo->scan_info != NULL) {
 529     /* Prepare for current scan --- the script is already validated */
 530     my_master_ptr master = (my_master_ptr) cinfo->master;
 531     const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
 532
 533     cinfo->comps_in_scan = scanptr->comps_in_scan;
 534     for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
 535       cinfo->cur_comp_info[ci] =
 536         &cinfo->comp_info[scanptr->component_index[ci]];
 537     }
 538     if (cinfo->progressive_mode) {
 539       cinfo->Ss = scanptr->Ss;
 540       cinfo->Se = scanptr->Se;
 541       cinfo->Ah = scanptr->Ah;
 542       cinfo->Al = scanptr->Al;
 543       return;
 544     }
 545   }
 546   else
 547 #endif
 548   {
 549     /* Prepare for single sequential-JPEG scan containing all components */
 550     if (cinfo->num_components > MAX_COMPS_IN_SCAN)
 551       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 552                MAX_COMPS_IN_SCAN);
 553     cinfo->comps_in_scan = cinfo->num_components;
 554     for (ci = 0; ci < cinfo->num_components; ci++) {
 555       cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
 556     }
 557   }
 558   cinfo->Ss = 0;
 559   cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
 560   cinfo->Ah = 0;
 561   cinfo->Al = 0;
 562 }
 563
 564
 565 LOCAL(void)
 566 per_scan_setup (j_compress_ptr cinfo)
 567 /* Do computations that are needed before processing a JPEG scan */
 568 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
 569 {
 570   int ci, mcublks, tmp;
 571   jpeg_component_info *compptr;
 572
 573   if (cinfo->comps_in_scan == 1) {
 574
 575     /* Noninterleaved (single-component) scan */
 576     compptr = cinfo->cur_comp_info[0];
 577
 578     /* Overall image size in MCUs */
 579     cinfo->MCUs_per_row = compptr->width_in_blocks;
 580     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
 581
 582     /* For noninterleaved scan, always one block per MCU */
 583     compptr->MCU_width = 1;
 584     compptr->MCU_height = 1;
 585     compptr->MCU_blocks = 1;
 586     compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
 587     compptr->last_col_width = 1;
 588     /* For noninterleaved scans, it is convenient to define last_row_height
 589      * as the number of block rows present in the last iMCU row.
 590      */
 591     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
 592     if (tmp == 0) tmp = compptr->v_samp_factor;
 593     compptr->last_row_height = tmp;
 594
 595     /* Prepare array describing MCU composition */
 596     cinfo->blocks_in_MCU = 1;
 597     cinfo->MCU_membership[0] = 0;
 598
 599   } else {
 600
 601     /* Interleaved (multi-component) scan */
 602     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
 603       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
 604                MAX_COMPS_IN_SCAN);
 605
 606     /* Overall image size in MCUs */
 607     cinfo->MCUs_per_row = (JDIMENSION)
 608       jdiv_round_up((long) cinfo->jpeg_width,
 609                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 610     cinfo->MCU_rows_in_scan = (JDIMENSION)
 611       jdiv_round_up((long) cinfo->jpeg_height,
 612                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 613
 614     cinfo->blocks_in_MCU = 0;
 615
 616     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 617       compptr = cinfo->cur_comp_info[ci];
 618       /* Sampling factors give # of blocks of component in each MCU */
 619       compptr->MCU_width = compptr->h_samp_factor;
 620       compptr->MCU_height = compptr->v_samp_factor;
 621       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
 622       compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
 623       /* Figure number of non-dummy blocks in last MCU column & row */
 624       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
 625       if (tmp == 0) tmp = compptr->MCU_width;
 626       compptr->last_col_width = tmp;
 627       tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
 628       if (tmp == 0) tmp = compptr->MCU_height;
 629       compptr->last_row_height = tmp;
 630       /* Prepare array describing MCU composition */
 631       mcublks = compptr->MCU_blocks;
 632       if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
 633         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
 634       while (mcublks-- > 0) {
 635         cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
 636       }
 637     }
 638
 639   }
 640
 641   /* Convert restart specified in rows to actual MCU count. */
 642   /* Note that count must fit in 16 bits, so we provide limiting. */
 643   if (cinfo->restart_in_rows > 0) {
 644     long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
 645     cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
 646   }
 647 }
 648
 649
 650 /*
 651  * Per-pass setup.
 652  * This is called at the beginning of each pass.  We determine which modules
 653  * will be active during this pass and give them appropriate start_pass calls.
 654  * We also set is_last_pass to indicate whether any more passes will be
 655  * required.
 656  */
 657
 658 METHODDEF(void)
 659 prepare_for_pass (j_compress_ptr cinfo)
 660 {
 661   my_master_ptr master = (my_master_ptr) cinfo->master;
 662
 663   switch (master->pass_type) {
 664   case main_pass:
 665     /* Initial pass: will collect input data, and do either Huffman
 666      * optimization or data output for the first scan.
 667      */
 668     select_scan_parameters(cinfo);
 669     per_scan_setup(cinfo);
 670     if (! cinfo->raw_data_in) {
 671       (*cinfo->cconvert->start_pass) (cinfo);
 672       (*cinfo->downsample->start_pass) (cinfo);
 673       (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
 674     }
 675     (*cinfo->fdct->start_pass) (cinfo);
 676     (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
 677     (*cinfo->coef->start_pass) (cinfo,
 678                                 (master->total_passes > 1 ?
 679                                  JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
 680     (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
 681     if (cinfo->optimize_coding) {
 682       /* No immediate data output; postpone writing frame/scan headers */
 683       master->pub.call_pass_startup = FALSE;
 684     } else {
 685       /* Will write frame/scan headers at first jpeg_write_scanlines call */
 686       master->pub.call_pass_startup = TRUE;
 687     }
 688     break;
 689 #ifdef ENTROPY_OPT_SUPPORTED
 690   case huff_opt_pass:
 691     /* Do Huffman optimization for a scan after the first one. */
 692     select_scan_parameters(cinfo);
 693     per_scan_setup(cinfo);
 694     if (cinfo->Ss != 0 || cinfo->Ah == 0) {
 695       (*cinfo->entropy->start_pass) (cinfo, TRUE);
 696       (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
 697       master->pub.call_pass_startup = FALSE;
 698       break;
 699     }
 700     /* Special case: Huffman DC refinement scans need no Huffman table
 701      * and therefore we can skip the optimization pass for them.
 702      */
 703     master->pass_type = output_pass;
 704     master->pass_number++;
 705     /*FALLTHROUGH*/
 706 #endif
 707   case output_pass:
 708     /* Do a data-output pass. */
 709     /* We need not repeat per-scan setup if prior optimization pass did it. */
 710     if (! cinfo->optimize_coding) {
 711       select_scan_parameters(cinfo);
 712       per_scan_setup(cinfo);
 713     }
 714     (*cinfo->entropy->start_pass) (cinfo, FALSE);
 715     (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
 716     /* We emit frame/scan headers now */
 717     if (master->scan_number == 0)
 718       (*cinfo->marker->write_frame_header) (cinfo);
 719     (*cinfo->marker->write_scan_header) (cinfo);
 720     master->pub.call_pass_startup = FALSE;
 721     break;
 722   default:
 723     ERREXIT(cinfo, JERR_NOT_COMPILED);
 724   }
 725
 726   master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
 727
 728   /* Set up progress monitor's pass info if present */
 729   if (cinfo->progress != NULL) {
 730     cinfo->progress->completed_passes = master->pass_number;
 731     cinfo->progress->total_passes = master->total_passes;
 732   }
 733 }
 734
 735
 736 /*
 737  * Special start-of-pass hook.
 738  * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
 739  * In single-pass processing, we need this hook because we don't want to
 740  * write frame/scan headers during jpeg_start_compress; we want to let the
 741  * application write COM markers etc. between jpeg_start_compress and the
 742  * jpeg_write_scanlines loop.
 743  * In multi-pass processing, this routine is not used.
 744  */
 745
 746 METHODDEF(void)
 747 pass_startup (j_compress_ptr cinfo)
 748 {
 749   cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
 750
 751   (*cinfo->marker->write_frame_header) (cinfo);
 752   (*cinfo->marker->write_scan_header) (cinfo);
 753 }
 754
 755
 756 /*
 757  * Finish up at end of pass.
 758  */
 759
 760 METHODDEF(void)
 761 finish_pass_master (j_compress_ptr cinfo)
 762 {
 763   my_master_ptr master = (my_master_ptr) cinfo->master;
 764
 765   /* The entropy coder always needs an end-of-pass call,
 766    * either to analyze statistics or to flush its output buffer.
 767    */
 768   (*cinfo->entropy->finish_pass) (cinfo);
 769
 770   /* Update state for next pass */
 771   switch (master->pass_type) {
 772   case main_pass:
 773     /* next pass is either output of scan 0 (after optimization)
 774      * or output of scan 1 (if no optimization).
 775      */
 776     master->pass_type = output_pass;
 777     if (! cinfo->optimize_coding)
 778       master->scan_number++;
 779     break;
 780   case huff_opt_pass:
 781     /* next pass is always output of current scan */
 782     master->pass_type = output_pass;
 783     break;
 784   case output_pass:
 785     /* next pass is either optimization or output of next scan */
 786     if (cinfo->optimize_coding)
 787       master->pass_type = huff_opt_pass;
 788     master->scan_number++;
 789     break;
 790   }
 791
 792   master->pass_number++;
 793 }
 794
 795
 796 /*
 797  * Initialize master compression control.
 798  */
 799
 800 GLOBAL(void)
 801 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
 802 {
 803   my_master_ptr master;
 804
 805   master = (my_master_ptr)
 806       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 807                                   SIZEOF(my_comp_master));
 808   cinfo->master = &master->pub;
 809   master->pub.prepare_for_pass = prepare_for_pass;
 810   master->pub.pass_startup = pass_startup;
 811   master->pub.finish_pass = finish_pass_master;
 812   master->pub.is_last_pass = FALSE;
 813
 814   /* Validate parameters, determine derived values */
 815   initial_setup(cinfo, transcode_only);
 816
 817   if (cinfo->scan_info != NULL) {
 818 #ifdef C_MULTISCAN_FILES_SUPPORTED
 819     validate_script(cinfo);
 820     if (cinfo->block_size < DCTSIZE)
 821       reduce_script(cinfo);
 822 #else
 823     ERREXIT(cinfo, JERR_NOT_COMPILED);
 824 #endif
 825   } else {
 826     cinfo->progressive_mode = FALSE;
 827     cinfo->num_scans = 1;
 828   }
 829
 830   if (cinfo->optimize_coding)
 831     cinfo->arith_code = FALSE; /* disable arithmetic coding */
 832   else if (! cinfo->arith_code &&
 833            (cinfo->progressive_mode ||
 834             (cinfo->block_size > 1 && cinfo->block_size < DCTSIZE)))
 835     /* TEMPORARY HACK ??? */
 836     /* assume default tables no good for progressive or reduced AC mode */
 837     cinfo->optimize_coding = TRUE; /* force Huffman optimization */
 838
 839   /* Initialize my private state */
 840   if (transcode_only) {
 841     /* no main pass in transcoding */
 842     if (cinfo->optimize_coding)
 843       master->pass_type = huff_opt_pass;
 844     else
 845       master->pass_type = output_pass;
 846   } else {
 847     /* for normal compression, first pass is always this type: */
 848     master->pass_type = main_pass;
 849   }
 850   master->scan_number = 0;
 851   master->pass_number = 0;
 852   if (cinfo->optimize_coding)
 853     master->total_passes = cinfo->num_scans * 2;
 854   else
 855     master->total_passes = cinfo->num_scans;
 856 }