compiler/libjpeg/jcmaster.c

   1 /*
   2  * jcmaster.c
   3  *
   4  * Copyright (C) 1991-1997, Thomas G. Lane.
   5  * Modified 2003-2010 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   /* Compute actual JPEG image dimensions and DCT scaling choices. */
  59   if (cinfo->scale_num >= cinfo->scale_denom * 8) {
  60     /* Provide 8/1 scaling */
  61     cinfo->jpeg_width = cinfo->image_width << 3;
  62     cinfo->jpeg_height = cinfo->image_height << 3;
  63     cinfo->min_DCT_h_scaled_size = 1;
  64     cinfo->min_DCT_v_scaled_size = 1;
  65   } else if (cinfo->scale_num >= cinfo->scale_denom * 4) {
  66     /* Provide 4/1 scaling */
  67     cinfo->jpeg_width = cinfo->image_width << 2;
  68     cinfo->jpeg_height = cinfo->image_height << 2;
  69     cinfo->min_DCT_h_scaled_size = 2;
  70     cinfo->min_DCT_v_scaled_size = 2;
  71   } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 8) {
  72     /* Provide 8/3 scaling */
  73     cinfo->jpeg_width = (cinfo->image_width << 1) + (JDIMENSION)
  74       jdiv_round_up((long) cinfo->image_width * 2, 3L);
  75     cinfo->jpeg_height = (cinfo->image_height << 1) + (JDIMENSION)
  76       jdiv_round_up((long) cinfo->image_height * 2, 3L);
  77     cinfo->min_DCT_h_scaled_size = 3;
  78     cinfo->min_DCT_v_scaled_size = 3;
  79   } else if (cinfo->scale_num >= cinfo->scale_denom * 2) {
  80     /* Provide 2/1 scaling */
  81     cinfo->jpeg_width = cinfo->image_width << 1;
  82     cinfo->jpeg_height = cinfo->image_height << 1;
  83     cinfo->min_DCT_h_scaled_size = 4;
  84     cinfo->min_DCT_v_scaled_size = 4;
  85   } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 8) {
  86     /* Provide 8/5 scaling */
  87     cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
  88       jdiv_round_up((long) cinfo->image_width * 3, 5L);
  89     cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
  90       jdiv_round_up((long) cinfo->image_height * 3, 5L);
  91     cinfo->min_DCT_h_scaled_size = 5;
  92     cinfo->min_DCT_v_scaled_size = 5;
  93   } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 4) {
  94     /* Provide 4/3 scaling */
  95     cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
  96       jdiv_round_up((long) cinfo->image_width, 3L);
  97     cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
  98       jdiv_round_up((long) cinfo->image_height, 3L);
  99     cinfo->min_DCT_h_scaled_size = 6;
 100     cinfo->min_DCT_v_scaled_size = 6;
 101   } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 8) {
 102     /* Provide 8/7 scaling */
 103     cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
 104       jdiv_round_up((long) cinfo->image_width, 7L);
 105     cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
 106       jdiv_round_up((long) cinfo->image_height, 7L);
 107     cinfo->min_DCT_h_scaled_size = 7;
 108     cinfo->min_DCT_v_scaled_size = 7;
 109   } else if (cinfo->scale_num >= cinfo->scale_denom) {
 110     /* Provide 1/1 scaling */
 111     cinfo->jpeg_width = cinfo->image_width;
 112     cinfo->jpeg_height = cinfo->image_height;
 113     cinfo->min_DCT_h_scaled_size = 8;
 114     cinfo->min_DCT_v_scaled_size = 8;
 115   } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * 8) {
 116     /* Provide 8/9 scaling */
 117     cinfo->jpeg_width = (JDIMENSION)
 118       jdiv_round_up((long) cinfo->image_width * 8, 9L);
 119     cinfo->jpeg_height = (JDIMENSION)
 120       jdiv_round_up((long) cinfo->image_height * 8, 9L);
 121     cinfo->min_DCT_h_scaled_size = 9;
 122     cinfo->min_DCT_v_scaled_size = 9;
 123   } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 4) {
 124     /* Provide 4/5 scaling */
 125     cinfo->jpeg_width = (JDIMENSION)
 126       jdiv_round_up((long) cinfo->image_width * 4, 5L);
 127     cinfo->jpeg_height = (JDIMENSION)
 128       jdiv_round_up((long) cinfo->image_height * 4, 5L);
 129     cinfo->min_DCT_h_scaled_size = 10;
 130     cinfo->min_DCT_v_scaled_size = 10;
 131   } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * 8) {
 132     /* Provide 8/11 scaling */
 133     cinfo->jpeg_width = (JDIMENSION)
 134       jdiv_round_up((long) cinfo->image_width * 8, 11L);
 135     cinfo->jpeg_height = (JDIMENSION)
 136       jdiv_round_up((long) cinfo->image_height * 8, 11L);
 137     cinfo->min_DCT_h_scaled_size = 11;
 138     cinfo->min_DCT_v_scaled_size = 11;
 139   } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 2) {
 140     /* Provide 2/3 scaling */
 141     cinfo->jpeg_width = (JDIMENSION)
 142       jdiv_round_up((long) cinfo->image_width * 2, 3L);
 143     cinfo->jpeg_height = (JDIMENSION)
 144       jdiv_round_up((long) cinfo->image_height * 2, 3L);
 145     cinfo->min_DCT_h_scaled_size = 12;
 146     cinfo->min_DCT_v_scaled_size = 12;
 147   } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * 8) {
 148     /* Provide 8/13 scaling */
 149     cinfo->jpeg_width = (JDIMENSION)
 150       jdiv_round_up((long) cinfo->image_width * 8, 13L);
 151     cinfo->jpeg_height = (JDIMENSION)
 152       jdiv_round_up((long) cinfo->image_height * 8, 13L);
 153     cinfo->min_DCT_h_scaled_size = 13;
 154     cinfo->min_DCT_v_scaled_size = 13;
 155   } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 4) {
 156     /* Provide 4/7 scaling */
 157     cinfo->jpeg_width = (JDIMENSION)
 158       jdiv_round_up((long) cinfo->image_width * 4, 7L);
 159     cinfo->jpeg_height = (JDIMENSION)
 160       jdiv_round_up((long) cinfo->image_height * 4, 7L);
 161     cinfo->min_DCT_h_scaled_size = 14;
 162     cinfo->min_DCT_v_scaled_size = 14;
 163   } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * 8) {
 164     /* Provide 8/15 scaling */
 165     cinfo->jpeg_width = (JDIMENSION)
 166       jdiv_round_up((long) cinfo->image_width * 8, 15L);
 167     cinfo->jpeg_height = (JDIMENSION)
 168       jdiv_round_up((long) cinfo->image_height * 8, 15L);
 169     cinfo->min_DCT_h_scaled_size = 15;
 170     cinfo->min_DCT_v_scaled_size = 15;
 171   } else {
 172     /* Provide 1/2 scaling */
 173     cinfo->jpeg_width = (JDIMENSION)
 174       jdiv_round_up((long) cinfo->image_width, 2L);
 175     cinfo->jpeg_height = (JDIMENSION)
 176       jdiv_round_up((long) cinfo->image_height, 2L);
 177     cinfo->min_DCT_h_scaled_size = 16;
 178     cinfo->min_DCT_v_scaled_size = 16;
 179   }
 180
 181 #else /* !DCT_SCALING_SUPPORTED */
 182
 183   /* Hardwire it to "no scaling" */
 184   cinfo->jpeg_width = cinfo->image_width;
 185   cinfo->jpeg_height = cinfo->image_height;
 186   cinfo->min_DCT_h_scaled_size = DCTSIZE;
 187   cinfo->min_DCT_v_scaled_size = DCTSIZE;
 188
 189 #endif /* DCT_SCALING_SUPPORTED */
 190 }
 191
 192
 193 LOCAL(void)
 194 jpeg_calc_trans_dimensions (j_compress_ptr cinfo)
 195 {
 196   if (cinfo->min_DCT_h_scaled_size < 1 || cinfo->min_DCT_h_scaled_size > 16
 197       || cinfo->min_DCT_h_scaled_size != cinfo->min_DCT_v_scaled_size)
 198     ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
 199              cinfo->min_DCT_h_scaled_size, cinfo->min_DCT_v_scaled_size);
 200
 201   cinfo->block_size = cinfo->min_DCT_h_scaled_size;
 202
 203   switch (cinfo->block_size) {
 204   case 2: cinfo->natural_order = jpeg_natural_order2; break;
 205   case 3: cinfo->natural_order = jpeg_natural_order3; break;
 206   case 4: cinfo->natural_order = jpeg_natural_order4; break;
 207   case 5: cinfo->natural_order = jpeg_natural_order5; break;
 208   case 6: cinfo->natural_order = jpeg_natural_order6; break;
 209   case 7: cinfo->natural_order = jpeg_natural_order7; break;
 210   default: cinfo->natural_order = jpeg_natural_order; break;
 211   }
 212
 213   cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
 214     cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
 215 }
 216
 217
 218 LOCAL(void)
 219 initial_setup (j_compress_ptr cinfo, boolean transcode_only)
 220 /* Do computations that are needed before master selection phase */
 221 {
 222   int ci, ssize;
 223   jpeg_component_info *compptr;
 224   long samplesperrow;
 225   JDIMENSION jd_samplesperrow;
 226
 227   if (transcode_only)
 228     jpeg_calc_trans_dimensions(cinfo);
 229   else
 230     jpeg_calc_jpeg_dimensions(cinfo);
 231
 232   /* Sanity check on image dimensions */
 233   if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
 234       cinfo->num_components <= 0 || cinfo->input_components <= 0)
 235     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
 236
 237   /* Make sure image isn't bigger than I can handle */
 238   if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
 239       (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
 240     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
 241
 242   /* Width of an input scanline must be representable as JDIMENSION. */
 243   samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
 244   jd_samplesperrow = (JDIMENSION) samplesperrow;
 245   if ((long) jd_samplesperrow != samplesperrow)
 246     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
 247
 248   /* For now, precision must match compiled-in value... */
 249   if (cinfo->data_precision != BITS_IN_JSAMPLE)
 250     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
 251
 252   /* Check that number of components won't exceed internal array sizes */
 253   if (cinfo->num_components > MAX_COMPONENTS)
 254     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 255              MAX_COMPONENTS);
 256
 257   /* Compute maximum sampling factors; check factor validity */
 258   cinfo->max_h_samp_factor = 1;
 259   cinfo->max_v_samp_factor = 1;
 260   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 261        ci++, compptr++) {
 262     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
 263         compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
 264       ERREXIT(cinfo, JERR_BAD_SAMPLING);
 265     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
 266                                    compptr->h_samp_factor);
 267     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
 268                                    compptr->v_samp_factor);
 269   }
 270
 271   /* Compute dimensions of components */
 272   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 273        ci++, compptr++) {
 274     /* Fill in the correct component_index value; don't rely on application */
 275     compptr->component_index = ci;
 276     /* In selecting the actual DCT scaling for each component, we try to
 277      * scale down the chroma components via DCT scaling rather than downsampling.
 278      * This saves time if the downsampler gets to use 1:1 scaling.
 279      * Note this code adapts subsampling ratios which are powers of 2.
 280      */
 281     ssize = 1;
 282 #ifdef DCT_SCALING_SUPPORTED
 283     while (cinfo->min_DCT_h_scaled_size * ssize <=
 284            (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
 285            (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
 286       ssize = ssize * 2;
 287     }
 288 #endif
 289     compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
 290     ssize = 1;
 291 #ifdef DCT_SCALING_SUPPORTED
 292     while (cinfo->min_DCT_v_scaled_size * ssize <=
 293            (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
 294            (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
 295       ssize = ssize * 2;
 296     }
 297 #endif
 298     compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
 299
 300     /* We don't support DCT ratios larger than 2. */
 301     if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
 302         compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
 303     else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
 304         compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
 305
 306     /* Size in DCT blocks */
 307     compptr->width_in_blocks = (JDIMENSION)
 308       jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
 309                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 310     compptr->height_in_blocks = (JDIMENSION)
 311       jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
 312                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 313     /* Size in samples */
 314     compptr->downsampled_width = (JDIMENSION)
 315       jdiv_round_up((long) cinfo->jpeg_width *
 316                     (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
 317                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 318     compptr->downsampled_height = (JDIMENSION)
 319       jdiv_round_up((long) cinfo->jpeg_height *
 320                     (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
 321                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 322     /* Mark component needed (this flag isn't actually used for compression) */
 323     compptr->component_needed = TRUE;
 324   }
 325
 326   /* Compute number of fully interleaved MCU rows (number of times that
 327    * main controller will call coefficient controller).
 328    */
 329   cinfo->total_iMCU_rows = (JDIMENSION)
 330     jdiv_round_up((long) cinfo->jpeg_height,
 331                   (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 332 }
 333
 334
 335 #ifdef C_MULTISCAN_FILES_SUPPORTED
 336
 337 LOCAL(void)
 338 validate_script (j_compress_ptr cinfo)
 339 /* Verify that the scan script in cinfo->scan_info[] is valid; also
 340  * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
 341  */
 342 {
 343   const jpeg_scan_info * scanptr;
 344   int scanno, ncomps, ci, coefi, thisi;
 345   int Ss, Se, Ah, Al;
 346   boolean component_sent[MAX_COMPONENTS];
 347 #ifdef C_PROGRESSIVE_SUPPORTED
 348   int * last_bitpos_ptr;
 349   int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
 350   /* -1 until that coefficient has been seen; then last Al for it */
 351 #endif
 352
 353   if (cinfo->num_scans <= 0)
 354     ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
 355
 356   /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
 357    * for progressive JPEG, no scan can have this.
 358    */
 359   scanptr = cinfo->scan_info;
 360   if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
 361 #ifdef C_PROGRESSIVE_SUPPORTED
 362     cinfo->progressive_mode = TRUE;
 363     last_bitpos_ptr = & last_bitpos[0][0];
 364     for (ci = 0; ci < cinfo->num_components; ci++)
 365       for (coefi = 0; coefi < DCTSIZE2; coefi++)
 366         *last_bitpos_ptr++ = -1;
 367 #else
 368     ERREXIT(cinfo, JERR_NOT_COMPILED);
 369 #endif
 370   } else {
 371     cinfo->progressive_mode = FALSE;
 372     for (ci = 0; ci < cinfo->num_components; ci++)
 373       component_sent[ci] = FALSE;
 374   }
 375
 376   for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
 377     /* Validate component indexes */
 378     ncomps = scanptr->comps_in_scan;
 379     if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
 380       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
 381     for (ci = 0; ci < ncomps; ci++) {
 382       thisi = scanptr->component_index[ci];
 383       if (thisi < 0 || thisi >= cinfo->num_components)
 384         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 385       /* Components must appear in SOF order within each scan */
 386       if (ci > 0 && thisi <= scanptr->component_index[ci-1])
 387         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 388     }
 389     /* Validate progression parameters */
 390     Ss = scanptr->Ss;
 391     Se = scanptr->Se;
 392     Ah = scanptr->Ah;
 393     Al = scanptr->Al;
 394     if (cinfo->progressive_mode) {
 395 #ifdef C_PROGRESSIVE_SUPPORTED
 396       /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
 397        * seems wrong: the upper bound ought to depend on data precision.
 398        * Perhaps they really meant 0..N+1 for N-bit precision.
 399        * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
 400        * out-of-range reconstructed DC values during the first DC scan,
 401        * which might cause problems for some decoders.
 402        */
 403 #if BITS_IN_JSAMPLE == 8
 404 #define MAX_AH_AL 10
 405 #else
 406 #define MAX_AH_AL 13
 407 #endif
 408       if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
 409           Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
 410         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 411       if (Ss == 0) {
 412         if (Se != 0)            /* DC and AC together not OK */
 413           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 414       } else {
 415         if (ncomps != 1)        /* AC scans must be for only one component */
 416           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 417       }
 418       for (ci = 0; ci < ncomps; ci++) {
 419         last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
 420         if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
 421           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 422         for (coefi = Ss; coefi <= Se; coefi++) {
 423           if (last_bitpos_ptr[coefi] < 0) {
 424             /* first scan of this coefficient */
 425             if (Ah != 0)
 426               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 427           } else {
 428             /* not first scan */
 429             if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
 430               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 431           }
 432           last_bitpos_ptr[coefi] = Al;
 433         }
 434       }
 435 #endif
 436     } else {
 437       /* For sequential JPEG, all progression parameters must be these: */
 438       if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
 439         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
 440       /* Make sure components are not sent twice */
 441       for (ci = 0; ci < ncomps; ci++) {
 442         thisi = scanptr->component_index[ci];
 443         if (component_sent[thisi])
 444           ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
 445         component_sent[thisi] = TRUE;
 446       }
 447     }
 448   }
 449
 450   /* Now verify that everything got sent. */
 451   if (cinfo->progressive_mode) {
 452 #ifdef C_PROGRESSIVE_SUPPORTED
 453     /* For progressive mode, we only check that at least some DC data
 454      * got sent for each component; the spec does not require that all bits
 455      * of all coefficients be transmitted.  Would it be wiser to enforce
 456      * transmission of all coefficient bits??
 457      */
 458     for (ci = 0; ci < cinfo->num_components; ci++) {
 459       if (last_bitpos[ci][0] < 0)
 460         ERREXIT(cinfo, JERR_MISSING_DATA);
 461     }
 462 #endif
 463   } else {
 464     for (ci = 0; ci < cinfo->num_components; ci++) {
 465       if (! component_sent[ci])
 466         ERREXIT(cinfo, JERR_MISSING_DATA);
 467     }
 468   }
 469 }
 470
 471
 472 LOCAL(void)
 473 reduce_script (j_compress_ptr cinfo)
 474 /* Adapt scan script for use with reduced block size;
 475  * assume that script has been validated before.
 476  */
 477 {
 478   jpeg_scan_info * scanptr;
 479   int idxout, idxin;
 480
 481   /* Circumvent const declaration for this function */
 482   scanptr = (jpeg_scan_info *) cinfo->scan_info;
 483   idxout = 0;
 484
 485   for (idxin = 0; idxin < cinfo->num_scans; idxin++) {
 486     /* After skipping, idxout becomes smaller than idxin */
 487     if (idxin != idxout)
 488       /* Copy rest of data;
 489        * note we stay in given chunk of allocated memory.
 490        */
 491       scanptr[idxout] = scanptr[idxin];
 492     if (scanptr[idxout].Ss > cinfo->lim_Se)
 493       /* Entire scan out of range - skip this entry */
 494       continue;
 495     if (scanptr[idxout].Se > cinfo->lim_Se)
 496       /* Limit scan to end of block */
 497       scanptr[idxout].Se = cinfo->lim_Se;
 498     idxout++;
 499   }
 500
 501   cinfo->num_scans = idxout;
 502 }
 503
 504 #endif /* C_MULTISCAN_FILES_SUPPORTED */
 505
 506
 507 LOCAL(void)
 508 select_scan_parameters (j_compress_ptr cinfo)
 509 /* Set up the scan parameters for the current scan */
 510 {
 511   int ci;
 512
 513 #ifdef C_MULTISCAN_FILES_SUPPORTED
 514   if (cinfo->scan_info != NULL) {
 515     /* Prepare for current scan --- the script is already validated */
 516     my_master_ptr master = (my_master_ptr) cinfo->master;
 517     const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
 518
 519     cinfo->comps_in_scan = scanptr->comps_in_scan;
 520     for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
 521       cinfo->cur_comp_info[ci] =
 522         &cinfo->comp_info[scanptr->component_index[ci]];
 523     }
 524     if (cinfo->progressive_mode) {
 525       cinfo->Ss = scanptr->Ss;
 526       cinfo->Se = scanptr->Se;
 527       cinfo->Ah = scanptr->Ah;
 528       cinfo->Al = scanptr->Al;
 529       return;
 530     }
 531   }
 532   else
 533 #endif
 534   {
 535     /* Prepare for single sequential-JPEG scan containing all components */
 536     if (cinfo->num_components > MAX_COMPS_IN_SCAN)
 537       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 538                MAX_COMPS_IN_SCAN);
 539     cinfo->comps_in_scan = cinfo->num_components;
 540     for (ci = 0; ci < cinfo->num_components; ci++) {
 541       cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
 542     }
 543   }
 544   cinfo->Ss = 0;
 545   cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
 546   cinfo->Ah = 0;
 547   cinfo->Al = 0;
 548 }
 549
 550
 551 LOCAL(void)
 552 per_scan_setup (j_compress_ptr cinfo)
 553 /* Do computations that are needed before processing a JPEG scan */
 554 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
 555 {
 556   int ci, mcublks, tmp;
 557   jpeg_component_info *compptr;
 558
 559   if (cinfo->comps_in_scan == 1) {
 560
 561     /* Noninterleaved (single-component) scan */
 562     compptr = cinfo->cur_comp_info[0];
 563
 564     /* Overall image size in MCUs */
 565     cinfo->MCUs_per_row = compptr->width_in_blocks;
 566     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
 567
 568     /* For noninterleaved scan, always one block per MCU */
 569     compptr->MCU_width = 1;
 570     compptr->MCU_height = 1;
 571     compptr->MCU_blocks = 1;
 572     compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
 573     compptr->last_col_width = 1;
 574     /* For noninterleaved scans, it is convenient to define last_row_height
 575      * as the number of block rows present in the last iMCU row.
 576      */
 577     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
 578     if (tmp == 0) tmp = compptr->v_samp_factor;
 579     compptr->last_row_height = tmp;
 580
 581     /* Prepare array describing MCU composition */
 582     cinfo->blocks_in_MCU = 1;
 583     cinfo->MCU_membership[0] = 0;
 584
 585   } else {
 586
 587     /* Interleaved (multi-component) scan */
 588     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
 589       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
 590                MAX_COMPS_IN_SCAN);
 591
 592     /* Overall image size in MCUs */
 593     cinfo->MCUs_per_row = (JDIMENSION)
 594       jdiv_round_up((long) cinfo->jpeg_width,
 595                     (long) (cinfo->max_h_samp_factor * cinfo->block_size));
 596     cinfo->MCU_rows_in_scan = (JDIMENSION)
 597       jdiv_round_up((long) cinfo->jpeg_height,
 598                     (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 599
 600     cinfo->blocks_in_MCU = 0;
 601
 602     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 603       compptr = cinfo->cur_comp_info[ci];
 604       /* Sampling factors give # of blocks of component in each MCU */
 605       compptr->MCU_width = compptr->h_samp_factor;
 606       compptr->MCU_height = compptr->v_samp_factor;
 607       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
 608       compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
 609       /* Figure number of non-dummy blocks in last MCU column & row */
 610       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
 611       if (tmp == 0) tmp = compptr->MCU_width;
 612       compptr->last_col_width = tmp;
 613       tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
 614       if (tmp == 0) tmp = compptr->MCU_height;
 615       compptr->last_row_height = tmp;
 616       /* Prepare array describing MCU composition */
 617       mcublks = compptr->MCU_blocks;
 618       if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
 619         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
 620       while (mcublks-- > 0) {
 621         cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
 622       }
 623     }
 624
 625   }
 626
 627   /* Convert restart specified in rows to actual MCU count. */
 628   /* Note that count must fit in 16 bits, so we provide limiting. */
 629   if (cinfo->restart_in_rows > 0) {
 630     long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
 631     cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
 632   }
 633 }
 634
 635
 636 /*
 637  * Per-pass setup.
 638  * This is called at the beginning of each pass.  We determine which modules
 639  * will be active during this pass and give them appropriate start_pass calls.
 640  * We also set is_last_pass to indicate whether any more passes will be
 641  * required.
 642  */
 643
 644 METHODDEF(void)
 645 prepare_for_pass (j_compress_ptr cinfo)
 646 {
 647   my_master_ptr master = (my_master_ptr) cinfo->master;
 648
 649   switch (master->pass_type) {
 650   case main_pass:
 651     /* Initial pass: will collect input data, and do either Huffman
 652      * optimization or data output for the first scan.
 653      */
 654     select_scan_parameters(cinfo);
 655     per_scan_setup(cinfo);
 656     if (! cinfo->raw_data_in) {
 657       (*cinfo->cconvert->start_pass) (cinfo);
 658       (*cinfo->downsample->start_pass) (cinfo);
 659       (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
 660     }
 661     (*cinfo->fdct->start_pass) (cinfo);
 662     (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
 663     (*cinfo->coef->start_pass) (cinfo,
 664                                 (master->total_passes > 1 ?
 665                                  JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
 666     (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
 667     if (cinfo->optimize_coding) {
 668       /* No immediate data output; postpone writing frame/scan headers */
 669       master->pub.call_pass_startup = FALSE;
 670     } else {
 671       /* Will write frame/scan headers at first jpeg_write_scanlines call */
 672       master->pub.call_pass_startup = TRUE;
 673     }
 674     break;
 675 #ifdef ENTROPY_OPT_SUPPORTED
 676   case huff_opt_pass:
 677     /* Do Huffman optimization for a scan after the first one. */
 678     select_scan_parameters(cinfo);
 679     per_scan_setup(cinfo);
 680     if (cinfo->Ss != 0 || cinfo->Ah == 0) {
 681       (*cinfo->entropy->start_pass) (cinfo, TRUE);
 682       (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
 683       master->pub.call_pass_startup = FALSE;
 684       break;
 685     }
 686     /* Special case: Huffman DC refinement scans need no Huffman table
 687      * and therefore we can skip the optimization pass for them.
 688      */
 689     master->pass_type = output_pass;
 690     master->pass_number++;
 691     /*FALLTHROUGH*/
 692 #endif
 693   case output_pass:
 694     /* Do a data-output pass. */
 695     /* We need not repeat per-scan setup if prior optimization pass did it. */
 696     if (! cinfo->optimize_coding) {
 697       select_scan_parameters(cinfo);
 698       per_scan_setup(cinfo);
 699     }
 700     (*cinfo->entropy->start_pass) (cinfo, FALSE);
 701     (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
 702     /* We emit frame/scan headers now */
 703     if (master->scan_number == 0)
 704       (*cinfo->marker->write_frame_header) (cinfo);
 705     (*cinfo->marker->write_scan_header) (cinfo);
 706     master->pub.call_pass_startup = FALSE;
 707     break;
 708   default:
 709     ERREXIT(cinfo, JERR_NOT_COMPILED);
 710   }
 711
 712   master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
 713
 714   /* Set up progress monitor's pass info if present */
 715   if (cinfo->progress != NULL) {
 716     cinfo->progress->completed_passes = master->pass_number;
 717     cinfo->progress->total_passes = master->total_passes;
 718   }
 719 }
 720
 721
 722 /*
 723  * Special start-of-pass hook.
 724  * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
 725  * In single-pass processing, we need this hook because we don't want to
 726  * write frame/scan headers during jpeg_start_compress; we want to let the
 727  * application write COM markers etc. between jpeg_start_compress and the
 728  * jpeg_write_scanlines loop.
 729  * In multi-pass processing, this routine is not used.
 730  */
 731
 732 METHODDEF(void)
 733 pass_startup (j_compress_ptr cinfo)
 734 {
 735   cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
 736
 737   (*cinfo->marker->write_frame_header) (cinfo);
 738   (*cinfo->marker->write_scan_header) (cinfo);
 739 }
 740
 741
 742 /*
 743  * Finish up at end of pass.
 744  */
 745
 746 METHODDEF(void)
 747 finish_pass_master (j_compress_ptr cinfo)
 748 {
 749   my_master_ptr master = (my_master_ptr) cinfo->master;
 750
 751   /* The entropy coder always needs an end-of-pass call,
 752    * either to analyze statistics or to flush its output buffer.
 753    */
 754   (*cinfo->entropy->finish_pass) (cinfo);
 755
 756   /* Update state for next pass */
 757   switch (master->pass_type) {
 758   case main_pass:
 759     /* next pass is either output of scan 0 (after optimization)
 760      * or output of scan 1 (if no optimization).
 761      */
 762     master->pass_type = output_pass;
 763     if (! cinfo->optimize_coding)
 764       master->scan_number++;
 765     break;
 766   case huff_opt_pass:
 767     /* next pass is always output of current scan */
 768     master->pass_type = output_pass;
 769     break;
 770   case output_pass:
 771     /* next pass is either optimization or output of next scan */
 772     if (cinfo->optimize_coding)
 773       master->pass_type = huff_opt_pass;
 774     master->scan_number++;
 775     break;
 776   }
 777
 778   master->pass_number++;
 779 }
 780
 781
 782 /*
 783  * Initialize master compression control.
 784  */
 785
 786 GLOBAL(void)
 787 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
 788 {
 789   my_master_ptr master;
 790
 791   master = (my_master_ptr)
 792       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 793                                   SIZEOF(my_comp_master));
 794   cinfo->master = (struct jpeg_comp_master *) master;
 795   master->pub.prepare_for_pass = prepare_for_pass;
 796   master->pub.pass_startup = pass_startup;
 797   master->pub.finish_pass = finish_pass_master;
 798   master->pub.is_last_pass = FALSE;
 799
 800   /* Validate parameters, determine derived values */
 801   initial_setup(cinfo, transcode_only);
 802
 803   if (cinfo->scan_info != NULL) {
 804 #ifdef C_MULTISCAN_FILES_SUPPORTED
 805     validate_script(cinfo);
 806     if (cinfo->block_size < DCTSIZE)
 807       reduce_script(cinfo);
 808 #else
 809     ERREXIT(cinfo, JERR_NOT_COMPILED);
 810 #endif
 811   } else {
 812     cinfo->progressive_mode = FALSE;
 813     cinfo->num_scans = 1;
 814   }
 815
 816   if ((cinfo->progressive_mode || cinfo->block_size < DCTSIZE) &&
 817       !cinfo->arith_code)                       /*  TEMPORARY HACK ??? */
 818     /* assume default tables no good for progressive or downscale mode */
 819     cinfo->optimize_coding = TRUE;
 820
 821   /* Initialize my private state */
 822   if (transcode_only) {
 823     /* no main pass in transcoding */
 824     if (cinfo->optimize_coding)
 825       master->pass_type = huff_opt_pass;
 826     else
 827       master->pass_type = output_pass;
 828   } else {
 829     /* for normal compression, first pass is always this type: */
 830     master->pass_type = main_pass;
 831   }
 832   master->scan_number = 0;
 833   master->pass_number = 0;
 834   if (cinfo->optimize_coding)
 835     master->total_passes = cinfo->num_scans * 2;
 836   else
 837     master->total_passes = cinfo->num_scans;
 838 }