LCOV - code coverage report
Current view: directory - media/libjpeg - jdmaster.c (source / functions) Found Hit Coverage
Test: app.info Lines: 225 110 48.9 %
Date: 2012-06-02 Functions: 8 7 87.5 %

       1                 : /*
       2                 :  * jdmaster.c
       3                 :  *
       4                 :  * Copyright (C) 1991-1997, Thomas G. Lane.
       5                 :  * Copyright (C) 2009-2011, D. R. Commander.
       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 decompressor.
      10                 :  * These routines are concerned with selecting the modules to be executed
      11                 :  * and with determining the number of passes and the work to be done in each
      12                 :  * pass.
      13                 :  */
      14                 : 
      15                 : #define JPEG_INTERNALS
      16                 : #include "jinclude.h"
      17                 : #include "jpeglib.h"
      18                 : #include "jpegcomp.h"
      19                 : 
      20                 : 
      21                 : /* Private state */
      22                 : 
      23                 : typedef struct {
      24                 :   struct jpeg_decomp_master pub; /* public fields */
      25                 : 
      26                 :   int pass_number;              /* # of passes completed */
      27                 : 
      28                 :   boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
      29                 : 
      30                 :   /* Saved references to initialized quantizer modules,
      31                 :    * in case we need to switch modes.
      32                 :    */
      33                 :   struct jpeg_color_quantizer * quantizer_1pass;
      34                 :   struct jpeg_color_quantizer * quantizer_2pass;
      35                 : } my_decomp_master;
      36                 : 
      37                 : typedef my_decomp_master * my_master_ptr;
      38                 : 
      39                 : 
      40                 : /*
      41                 :  * Determine whether merged upsample/color conversion should be used.
      42                 :  * CRUCIAL: this must match the actual capabilities of jdmerge.c!
      43                 :  */
      44                 : 
      45                 : LOCAL(boolean)
      46              15 : use_merged_upsample (j_decompress_ptr cinfo)
      47                 : {
      48                 : #ifdef UPSAMPLE_MERGING_SUPPORTED
      49                 :   /* Merging is the equivalent of plain box-filter upsampling */
      50              15 :   if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
      51              15 :     return FALSE;
      52                 :   /* jdmerge.c only supports YCC=>RGB color conversion */
      53               0 :   if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
      54               0 :       (cinfo->out_color_space != JCS_RGB &&
      55               0 :       cinfo->out_color_space != JCS_EXT_RGB &&
      56               0 :       cinfo->out_color_space != JCS_EXT_RGBX &&
      57               0 :       cinfo->out_color_space != JCS_EXT_BGR &&
      58               0 :       cinfo->out_color_space != JCS_EXT_BGRX &&
      59               0 :       cinfo->out_color_space != JCS_EXT_XBGR &&
      60               0 :       cinfo->out_color_space != JCS_EXT_XRGB &&
      61               0 :       cinfo->out_color_space != JCS_EXT_RGBA &&
      62               0 :       cinfo->out_color_space != JCS_EXT_BGRA &&
      63               0 :       cinfo->out_color_space != JCS_EXT_ABGR &&
      64               0 :       cinfo->out_color_space != JCS_EXT_ARGB) ||
      65               0 :       cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space])
      66               0 :     return FALSE;
      67                 :   /* and it only handles 2h1v or 2h2v sampling ratios */
      68               0 :   if (cinfo->comp_info[0].h_samp_factor != 2 ||
      69               0 :       cinfo->comp_info[1].h_samp_factor != 1 ||
      70               0 :       cinfo->comp_info[2].h_samp_factor != 1 ||
      71               0 :       cinfo->comp_info[0].v_samp_factor >  2 ||
      72               0 :       cinfo->comp_info[1].v_samp_factor != 1 ||
      73               0 :       cinfo->comp_info[2].v_samp_factor != 1)
      74               0 :     return FALSE;
      75                 :   /* furthermore, it doesn't work if we've scaled the IDCTs differently */
      76               0 :   if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
      77               0 :       cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
      78               0 :       cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size)
      79               0 :     return FALSE;
      80                 :   /* ??? also need to test for upsample-time rescaling, when & if supported */
      81               0 :   return TRUE;                  /* by golly, it'll work... */
      82                 : #else
      83                 :   return FALSE;
      84                 : #endif
      85                 : }
      86                 : 
      87                 : 
      88                 : /*
      89                 :  * Compute output image dimensions and related values.
      90                 :  * NOTE: this is exported for possible use by application.
      91                 :  * Hence it mustn't do anything that can't be done twice.
      92                 :  * Also note that it may be called before the master module is initialized!
      93                 :  */
      94                 : 
      95                 : GLOBAL(void)
      96              10 : jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
      97                 : /* Do computations that are needed before master selection phase */
      98                 : {
      99                 : #ifdef IDCT_SCALING_SUPPORTED
     100                 :   int ci;
     101                 :   jpeg_component_info *compptr;
     102                 : #endif
     103                 : 
     104                 :   /* Prevent application from calling me at wrong times */
     105              10 :   if (cinfo->global_state != DSTATE_READY)
     106               0 :     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
     107                 : 
     108                 : #ifdef IDCT_SCALING_SUPPORTED
     109                 : 
     110                 :   /* Compute actual output image dimensions and DCT scaling choices. */
     111              10 :   if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
     112                 :     /* Provide 1/8 scaling */
     113               0 :     cinfo->output_width = (JDIMENSION)
     114               0 :       jdiv_round_up((long) cinfo->image_width, 8L);
     115               0 :     cinfo->output_height = (JDIMENSION)
     116               0 :       jdiv_round_up((long) cinfo->image_height, 8L);
     117                 : #if JPEG_LIB_VERSION >= 70
     118                 :     cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 1;
     119                 : #else
     120               0 :     cinfo->min_DCT_scaled_size = 1;
     121                 : #endif
     122              10 :   } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
     123                 :     /* Provide 1/4 scaling */
     124               0 :     cinfo->output_width = (JDIMENSION)
     125               0 :       jdiv_round_up((long) cinfo->image_width, 4L);
     126               0 :     cinfo->output_height = (JDIMENSION)
     127               0 :       jdiv_round_up((long) cinfo->image_height, 4L);
     128                 : #if JPEG_LIB_VERSION >= 70
     129                 :     cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 2;
     130                 : #else
     131               0 :     cinfo->min_DCT_scaled_size = 2;
     132                 : #endif
     133              10 :   } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
     134                 :     /* Provide 1/2 scaling */
     135               0 :     cinfo->output_width = (JDIMENSION)
     136               0 :       jdiv_round_up((long) cinfo->image_width, 2L);
     137               0 :     cinfo->output_height = (JDIMENSION)
     138               0 :       jdiv_round_up((long) cinfo->image_height, 2L);
     139                 : #if JPEG_LIB_VERSION >= 70
     140                 :     cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 4;
     141                 : #else
     142               0 :     cinfo->min_DCT_scaled_size = 4;
     143                 : #endif
     144                 :   } else {
     145                 :     /* Provide 1/1 scaling */
     146              10 :     cinfo->output_width = cinfo->image_width;
     147              10 :     cinfo->output_height = cinfo->image_height;
     148                 : #if JPEG_LIB_VERSION >= 70
     149                 :     cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
     150                 : #else
     151              10 :     cinfo->min_DCT_scaled_size = DCTSIZE;
     152                 : #endif
     153                 :   }
     154                 :   /* In selecting the actual DCT scaling for each component, we try to
     155                 :    * scale up the chroma components via IDCT scaling rather than upsampling.
     156                 :    * This saves time if the upsampler gets to use 1:1 scaling.
     157                 :    * Note this code assumes that the supported DCT scalings are powers of 2.
     158                 :    */
     159              50 :   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
     160              30 :        ci++, compptr++) {
     161              30 :     int ssize = cinfo->_min_DCT_scaled_size;
     162              60 :     while (ssize < DCTSIZE &&
     163               0 :            (compptr->h_samp_factor * ssize * 2 <=
     164               0 :             cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) &&
     165               0 :            (compptr->v_samp_factor * ssize * 2 <=
     166               0 :             cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size)) {
     167               0 :       ssize = ssize * 2;
     168                 :     }
     169                 : #if JPEG_LIB_VERSION >= 70
     170                 :     compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize;
     171                 : #else
     172              30 :     compptr->DCT_scaled_size = ssize;
     173                 : #endif
     174                 :   }
     175                 : 
     176                 :   /* Recompute downsampled dimensions of components;
     177                 :    * application needs to know these if using raw downsampled data.
     178                 :    */
     179              50 :   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
     180              30 :        ci++, compptr++) {
     181                 :     /* Size in samples, after IDCT scaling */
     182              30 :     compptr->downsampled_width = (JDIMENSION)
     183              60 :       jdiv_round_up((long) cinfo->image_width *
     184              30 :                     (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size),
     185              30 :                     (long) (cinfo->max_h_samp_factor * DCTSIZE));
     186              30 :     compptr->downsampled_height = (JDIMENSION)
     187              60 :       jdiv_round_up((long) cinfo->image_height *
     188              30 :                     (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size),
     189              30 :                     (long) (cinfo->max_v_samp_factor * DCTSIZE));
     190                 :   }
     191                 : 
     192                 : #else /* !IDCT_SCALING_SUPPORTED */
     193                 : 
     194                 :   /* Hardwire it to "no scaling" */
     195                 :   cinfo->output_width = cinfo->image_width;
     196                 :   cinfo->output_height = cinfo->image_height;
     197                 :   /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
     198                 :    * and has computed unscaled downsampled_width and downsampled_height.
     199                 :    */
     200                 : 
     201                 : #endif /* IDCT_SCALING_SUPPORTED */
     202                 : 
     203                 :   /* Report number of components in selected colorspace. */
     204                 :   /* Probably this should be in the color conversion module... */
     205              10 :   switch (cinfo->out_color_space) {
     206                 :   case JCS_GRAYSCALE:
     207               0 :     cinfo->out_color_components = 1;
     208               0 :     break;
     209                 :   case JCS_RGB:
     210                 :   case JCS_EXT_RGB:
     211                 :   case JCS_EXT_RGBX:
     212                 :   case JCS_EXT_BGR:
     213                 :   case JCS_EXT_BGRX:
     214                 :   case JCS_EXT_XBGR:
     215                 :   case JCS_EXT_XRGB:
     216                 :   case JCS_EXT_RGBA:
     217                 :   case JCS_EXT_BGRA:
     218                 :   case JCS_EXT_ABGR:
     219                 :   case JCS_EXT_ARGB:
     220              10 :     cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space];
     221              10 :     break;
     222                 :   case JCS_YCbCr:
     223               0 :     cinfo->out_color_components = 3;
     224               0 :     break;
     225                 :   case JCS_CMYK:
     226                 :   case JCS_YCCK:
     227               0 :     cinfo->out_color_components = 4;
     228               0 :     break;
     229                 :   default:                      /* else must be same colorspace as in file */
     230               0 :     cinfo->out_color_components = cinfo->num_components;
     231               0 :     break;
     232                 :   }
     233              10 :   cinfo->output_components = (cinfo->quantize_colors ? 1 :
     234                 :                               cinfo->out_color_components);
     235                 : 
     236                 :   /* See if upsampler will want to emit more than one row at a time */
     237              10 :   if (use_merged_upsample(cinfo))
     238               0 :     cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
     239                 :   else
     240              10 :     cinfo->rec_outbuf_height = 1;
     241              10 : }
     242                 : 
     243                 : 
     244                 : /*
     245                 :  * Several decompression processes need to range-limit values to the range
     246                 :  * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
     247                 :  * due to noise introduced by quantization, roundoff error, etc.  These
     248                 :  * processes are inner loops and need to be as fast as possible.  On most
     249                 :  * machines, particularly CPUs with pipelines or instruction prefetch,
     250                 :  * a (subscript-check-less) C table lookup
     251                 :  *              x = sample_range_limit[x];
     252                 :  * is faster than explicit tests
     253                 :  *              if (x < 0)  x = 0;
     254                 :  *              else if (x > MAXJSAMPLE)  x = MAXJSAMPLE;
     255                 :  * These processes all use a common table prepared by the routine below.
     256                 :  *
     257                 :  * For most steps we can mathematically guarantee that the initial value
     258                 :  * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
     259                 :  * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient.  But for the initial
     260                 :  * limiting step (just after the IDCT), a wildly out-of-range value is 
     261                 :  * possible if the input data is corrupt.  To avoid any chance of indexing
     262                 :  * off the end of memory and getting a bad-pointer trap, we perform the
     263                 :  * post-IDCT limiting thus:
     264                 :  *              x = range_limit[x & MASK];
     265                 :  * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
     266                 :  * samples.  Under normal circumstances this is more than enough range and
     267                 :  * a correct output will be generated; with bogus input data the mask will
     268                 :  * cause wraparound, and we will safely generate a bogus-but-in-range output.
     269                 :  * For the post-IDCT step, we want to convert the data from signed to unsigned
     270                 :  * representation by adding CENTERJSAMPLE at the same time that we limit it.
     271                 :  * So the post-IDCT limiting table ends up looking like this:
     272                 :  *   CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
     273                 :  *   MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
     274                 :  *   0          (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
     275                 :  *   0,1,...,CENTERJSAMPLE-1
     276                 :  * Negative inputs select values from the upper half of the table after
     277                 :  * masking.
     278                 :  *
     279                 :  * We can save some space by overlapping the start of the post-IDCT table
     280                 :  * with the simpler range limiting table.  The post-IDCT table begins at
     281                 :  * sample_range_limit + CENTERJSAMPLE.
     282                 :  *
     283                 :  * Note that the table is allocated in near data space on PCs; it's small
     284                 :  * enough and used often enough to justify this.
     285                 :  */
     286                 : 
     287                 : LOCAL(void)
     288               5 : prepare_range_limit_table (j_decompress_ptr cinfo)
     289                 : /* Allocate and fill in the sample_range_limit table */
     290                 : {
     291                 :   JSAMPLE * table;
     292                 :   int i;
     293                 : 
     294               5 :   table = (JSAMPLE *)
     295               5 :     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
     296                 :                 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
     297               5 :   table += (MAXJSAMPLE+1);      /* allow negative subscripts of simple table */
     298               5 :   cinfo->sample_range_limit = table;
     299                 :   /* First segment of "simple" table: limit[x] = 0 for x < 0 */
     300               5 :   MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
     301                 :   /* Main part of "simple" table: limit[x] = x */
     302            1285 :   for (i = 0; i <= MAXJSAMPLE; i++)
     303            1280 :     table[i] = (JSAMPLE) i;
     304               5 :   table += CENTERJSAMPLE;       /* Point to where post-IDCT table starts */
     305                 :   /* End of simple table, rest of first half of post-IDCT table */
     306            1925 :   for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
     307            1920 :     table[i] = MAXJSAMPLE;
     308                 :   /* Second half of post-IDCT table */
     309               5 :   MEMZERO(table + (2 * (MAXJSAMPLE+1)),
     310                 :           (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
     311               5 :   MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
     312                 :           cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
     313               5 : }
     314                 : 
     315                 : 
     316                 : /*
     317                 :  * Master selection of decompression modules.
     318                 :  * This is done once at jpeg_start_decompress time.  We determine
     319                 :  * which modules will be used and give them appropriate initialization calls.
     320                 :  * We also initialize the decompressor input side to begin consuming data.
     321                 :  *
     322                 :  * Since jpeg_read_header has finished, we know what is in the SOF
     323                 :  * and (first) SOS markers.  We also have all the application parameter
     324                 :  * settings.
     325                 :  */
     326                 : 
     327                 : LOCAL(void)
     328               5 : master_selection (j_decompress_ptr cinfo)
     329                 : {
     330               5 :   my_master_ptr master = (my_master_ptr) cinfo->master;
     331                 :   boolean use_c_buffer;
     332                 :   long samplesperrow;
     333                 :   JDIMENSION jd_samplesperrow;
     334                 : 
     335                 :   /* Initialize dimensions and other stuff */
     336               5 :   jpeg_calc_output_dimensions(cinfo);
     337               5 :   prepare_range_limit_table(cinfo);
     338                 : 
     339                 :   /* Width of an output scanline must be representable as JDIMENSION. */
     340               5 :   samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
     341               5 :   jd_samplesperrow = (JDIMENSION) samplesperrow;
     342               5 :   if ((long) jd_samplesperrow != samplesperrow)
     343               0 :     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
     344                 : 
     345                 :   /* Initialize my private state */
     346               5 :   master->pass_number = 0;
     347               5 :   master->using_merged_upsample = use_merged_upsample(cinfo);
     348                 : 
     349                 :   /* Color quantizer selection */
     350               5 :   master->quantizer_1pass = NULL;
     351               5 :   master->quantizer_2pass = NULL;
     352                 :   /* No mode changes if not using buffered-image mode. */
     353               5 :   if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
     354               5 :     cinfo->enable_1pass_quant = FALSE;
     355               5 :     cinfo->enable_external_quant = FALSE;
     356               5 :     cinfo->enable_2pass_quant = FALSE;
     357                 :   }
     358               5 :   if (cinfo->quantize_colors) {
     359               0 :     if (cinfo->raw_data_out)
     360               0 :       ERREXIT(cinfo, JERR_NOTIMPL);
     361                 :     /* 2-pass quantizer only works in 3-component color space. */
     362               0 :     if (cinfo->out_color_components != 3) {
     363               0 :       cinfo->enable_1pass_quant = TRUE;
     364               0 :       cinfo->enable_external_quant = FALSE;
     365               0 :       cinfo->enable_2pass_quant = FALSE;
     366               0 :       cinfo->colormap = NULL;
     367               0 :     } else if (cinfo->colormap != NULL) {
     368               0 :       cinfo->enable_external_quant = TRUE;
     369               0 :     } else if (cinfo->two_pass_quantize) {
     370               0 :       cinfo->enable_2pass_quant = TRUE;
     371                 :     } else {
     372               0 :       cinfo->enable_1pass_quant = TRUE;
     373                 :     }
     374                 : 
     375               0 :     if (cinfo->enable_1pass_quant) {
     376                 : #ifdef QUANT_1PASS_SUPPORTED
     377               0 :       jinit_1pass_quantizer(cinfo);
     378               0 :       master->quantizer_1pass = cinfo->cquantize;
     379                 : #else
     380                 :       ERREXIT(cinfo, JERR_NOT_COMPILED);
     381                 : #endif
     382                 :     }
     383                 : 
     384                 :     /* We use the 2-pass code to map to external colormaps. */
     385               0 :     if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
     386                 : #ifdef QUANT_2PASS_SUPPORTED
     387               0 :       jinit_2pass_quantizer(cinfo);
     388               0 :       master->quantizer_2pass = cinfo->cquantize;
     389                 : #else
     390                 :       ERREXIT(cinfo, JERR_NOT_COMPILED);
     391                 : #endif
     392                 :     }
     393                 :     /* If both quantizers are initialized, the 2-pass one is left active;
     394                 :      * this is necessary for starting with quantization to an external map.
     395                 :      */
     396                 :   }
     397                 : 
     398                 :   /* Post-processing: in particular, color conversion first */
     399               5 :   if (! cinfo->raw_data_out) {
     400               5 :     if (master->using_merged_upsample) {
     401                 : #ifdef UPSAMPLE_MERGING_SUPPORTED
     402               0 :       jinit_merged_upsampler(cinfo); /* does color conversion too */
     403                 : #else
     404                 :       ERREXIT(cinfo, JERR_NOT_COMPILED);
     405                 : #endif
     406                 :     } else {
     407               5 :       jinit_color_deconverter(cinfo);
     408               5 :       jinit_upsampler(cinfo);
     409                 :     }
     410               5 :     jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
     411                 :   }
     412                 :   /* Inverse DCT */
     413               5 :   jinit_inverse_dct(cinfo);
     414                 :   /* Entropy decoding: either Huffman or arithmetic coding. */
     415               5 :   if (cinfo->arith_code) {
     416                 : #ifdef D_ARITH_CODING_SUPPORTED
     417                 :     jinit_arith_decoder(cinfo);
     418                 : #else
     419               0 :     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
     420                 : #endif
     421                 :   } else {
     422               5 :     if (cinfo->progressive_mode) {
     423                 : #ifdef D_PROGRESSIVE_SUPPORTED
     424               0 :       jinit_phuff_decoder(cinfo);
     425                 : #else
     426                 :       ERREXIT(cinfo, JERR_NOT_COMPILED);
     427                 : #endif
     428                 :     } else
     429               5 :       jinit_huff_decoder(cinfo);
     430                 :   }
     431                 : 
     432                 :   /* Initialize principal buffer controllers. */
     433               5 :   use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
     434               5 :   jinit_d_coef_controller(cinfo, use_c_buffer);
     435                 : 
     436               5 :   if (! cinfo->raw_data_out)
     437               5 :     jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
     438                 : 
     439                 :   /* We can now tell the memory manager to allocate virtual arrays. */
     440               5 :   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
     441                 : 
     442                 :   /* Initialize input side of decompressor to consume first scan. */
     443               5 :   (*cinfo->inputctl->start_input_pass) (cinfo);
     444                 : 
     445                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
     446                 :   /* If jpeg_start_decompress will read the whole file, initialize
     447                 :    * progress monitoring appropriately.  The input step is counted
     448                 :    * as one pass.
     449                 :    */
     450               5 :   if (cinfo->progress != NULL && ! cinfo->buffered_image &&
     451               0 :       cinfo->inputctl->has_multiple_scans) {
     452                 :     int nscans;
     453                 :     /* Estimate number of scans to set pass_limit. */
     454               0 :     if (cinfo->progressive_mode) {
     455                 :       /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
     456               0 :       nscans = 2 + 3 * cinfo->num_components;
     457                 :     } else {
     458                 :       /* For a nonprogressive multiscan file, estimate 1 scan per component. */
     459               0 :       nscans = cinfo->num_components;
     460                 :     }
     461               0 :     cinfo->progress->pass_counter = 0L;
     462               0 :     cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
     463               0 :     cinfo->progress->completed_passes = 0;
     464               0 :     cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
     465                 :     /* Count the input pass as done */
     466               0 :     master->pass_number++;
     467                 :   }
     468                 : #endif /* D_MULTISCAN_FILES_SUPPORTED */
     469               5 : }
     470                 : 
     471                 : 
     472                 : /*
     473                 :  * Per-pass setup.
     474                 :  * This is called at the beginning of each output pass.  We determine which
     475                 :  * modules will be active during this pass and give them appropriate
     476                 :  * start_pass calls.  We also set is_dummy_pass to indicate whether this
     477                 :  * is a "real" output pass or a dummy pass for color quantization.
     478                 :  * (In the latter case, jdapistd.c will crank the pass to completion.)
     479                 :  */
     480                 : 
     481                 : METHODDEF(void)
     482               5 : prepare_for_output_pass (j_decompress_ptr cinfo)
     483                 : {
     484               5 :   my_master_ptr master = (my_master_ptr) cinfo->master;
     485                 : 
     486               5 :   if (master->pub.is_dummy_pass) {
     487                 : #ifdef QUANT_2PASS_SUPPORTED
     488                 :     /* Final pass of 2-pass quantization */
     489               0 :     master->pub.is_dummy_pass = FALSE;
     490               0 :     (*cinfo->cquantize->start_pass) (cinfo, FALSE);
     491               0 :     (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
     492               0 :     (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
     493                 : #else
     494                 :     ERREXIT(cinfo, JERR_NOT_COMPILED);
     495                 : #endif /* QUANT_2PASS_SUPPORTED */
     496                 :   } else {
     497               5 :     if (cinfo->quantize_colors && cinfo->colormap == NULL) {
     498                 :       /* Select new quantization method */
     499               0 :       if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
     500               0 :         cinfo->cquantize = master->quantizer_2pass;
     501               0 :         master->pub.is_dummy_pass = TRUE;
     502               0 :       } else if (cinfo->enable_1pass_quant) {
     503               0 :         cinfo->cquantize = master->quantizer_1pass;
     504                 :       } else {
     505               0 :         ERREXIT(cinfo, JERR_MODE_CHANGE);
     506                 :       }
     507                 :     }
     508               5 :     (*cinfo->idct->start_pass) (cinfo);
     509               5 :     (*cinfo->coef->start_output_pass) (cinfo);
     510               5 :     if (! cinfo->raw_data_out) {
     511               5 :       if (! master->using_merged_upsample)
     512               5 :         (*cinfo->cconvert->start_pass) (cinfo);
     513               5 :       (*cinfo->upsample->start_pass) (cinfo);
     514               5 :       if (cinfo->quantize_colors)
     515               0 :         (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
     516              10 :       (*cinfo->post->start_pass) (cinfo,
     517               5 :             (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
     518               5 :       (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
     519                 :     }
     520                 :   }
     521                 : 
     522                 :   /* Set up progress monitor's pass info if present */
     523               5 :   if (cinfo->progress != NULL) {
     524               0 :     cinfo->progress->completed_passes = master->pass_number;
     525               0 :     cinfo->progress->total_passes = master->pass_number +
     526               0 :                                     (master->pub.is_dummy_pass ? 2 : 1);
     527                 :     /* In buffered-image mode, we assume one more output pass if EOI not
     528                 :      * yet reached, but no more passes if EOI has been reached.
     529                 :      */
     530               0 :     if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
     531               0 :       cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
     532                 :     }
     533                 :   }
     534               5 : }
     535                 : 
     536                 : 
     537                 : /*
     538                 :  * Finish up at end of an output pass.
     539                 :  */
     540                 : 
     541                 : METHODDEF(void)
     542               5 : finish_output_pass (j_decompress_ptr cinfo)
     543                 : {
     544               5 :   my_master_ptr master = (my_master_ptr) cinfo->master;
     545                 : 
     546               5 :   if (cinfo->quantize_colors)
     547               0 :     (*cinfo->cquantize->finish_pass) (cinfo);
     548               5 :   master->pass_number++;
     549               5 : }
     550                 : 
     551                 : 
     552                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
     553                 : 
     554                 : /*
     555                 :  * Switch to a new external colormap between output passes.
     556                 :  */
     557                 : 
     558                 : GLOBAL(void)
     559               0 : jpeg_new_colormap (j_decompress_ptr cinfo)
     560                 : {
     561               0 :   my_master_ptr master = (my_master_ptr) cinfo->master;
     562                 : 
     563                 :   /* Prevent application from calling me at wrong times */
     564               0 :   if (cinfo->global_state != DSTATE_BUFIMAGE)
     565               0 :     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
     566                 : 
     567               0 :   if (cinfo->quantize_colors && cinfo->enable_external_quant &&
     568               0 :       cinfo->colormap != NULL) {
     569                 :     /* Select 2-pass quantizer for external colormap use */
     570               0 :     cinfo->cquantize = master->quantizer_2pass;
     571                 :     /* Notify quantizer of colormap change */
     572               0 :     (*cinfo->cquantize->new_color_map) (cinfo);
     573               0 :     master->pub.is_dummy_pass = FALSE; /* just in case */
     574                 :   } else
     575               0 :     ERREXIT(cinfo, JERR_MODE_CHANGE);
     576               0 : }
     577                 : 
     578                 : #endif /* D_MULTISCAN_FILES_SUPPORTED */
     579                 : 
     580                 : 
     581                 : /*
     582                 :  * Initialize master decompression control and select active modules.
     583                 :  * This is performed at the start of jpeg_start_decompress.
     584                 :  */
     585                 : 
     586                 : GLOBAL(void)
     587               5 : jinit_master_decompress (j_decompress_ptr cinfo)
     588                 : {
     589                 :   my_master_ptr master;
     590                 : 
     591               5 :   master = (my_master_ptr)
     592               5 :       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
     593                 :                                   SIZEOF(my_decomp_master));
     594               5 :   cinfo->master = (struct jpeg_decomp_master *) master;
     595               5 :   master->pub.prepare_for_output_pass = prepare_for_output_pass;
     596               5 :   master->pub.finish_output_pass = finish_output_pass;
     597                 : 
     598               5 :   master->pub.is_dummy_pass = FALSE;
     599                 : 
     600               5 :   master_selection(cinfo);
     601               5 : }

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