LCOV - app.info - media/libjpeg/jdcoefct.c

LCOV - code coverage report
| Current view: | directory - media/libjpeg - jdcoefct.c (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 320 | 75 | 23.4 %
| Date: | 2012-04-21 | Functions: | 10 | 5 | 50.0 %

           1                 : /*
           2                 :  * jdcoefct.c
           3                 :  *
           4                 :  * Copyright (C) 1994-1997, Thomas G. Lane.
           5                 :  * Copyright (C) 2010, 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 the coefficient buffer controller for decompression.
          10                 :  * This controller is the top level of the JPEG decompressor proper.
          11                 :  * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
          12                 :  *
          13                 :  * In buffered-image mode, this controller is the interface between
          14                 :  * input-oriented processing and output-oriented processing.
          15                 :  * Also, the input side (only) is used when reading a file for transcoding.
          16                 :  */
          17                 :
          18                 : #define JPEG_INTERNALS
          19                 : #include "jinclude.h"
          20                 : #include "jpeglib.h"
          21                 : #include "jpegcomp.h"
          22                 :
          23                 : /* Block smoothing is only applicable for progressive JPEG, so: */
          24                 : #ifndef D_PROGRESSIVE_SUPPORTED
          25                 : #undef BLOCK_SMOOTHING_SUPPORTED
          26                 : #endif
          27                 :
          28                 : /* Private buffer controller object */
          29                 :
          30                 : typedef struct {
          31                 :   struct jpeg_d_coef_controller pub; /* public fields */
          32                 :
          33                 :   /* These variables keep track of the current location of the input side. */
          34                 :   /* cinfo->input_iMCU_row is also used for this. */
          35                 :   JDIMENSION MCU_ctr;           /* counts MCUs processed in current row */
          36                 :   int MCU_vert_offset;          /* counts MCU rows within iMCU row */
          37                 :   int MCU_rows_per_iMCU_row;    /* number of such rows needed */
          38                 :
          39                 :   /* The output side's location is represented by cinfo->output_iMCU_row. */
          40                 :
          41                 :   /* In single-pass modes, it's sufficient to buffer just one MCU.
          42                 :    * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
          43                 :    * and let the entropy decoder write into that workspace each time.
          44                 :    * (On 80x86, the workspace is FAR even though it's not really very big;
          45                 :    * this is to keep the module interfaces unchanged when a large coefficient
          46                 :    * buffer is necessary.)
          47                 :    * In multi-pass modes, this array points to the current MCU's blocks
          48                 :    * within the virtual arrays; it is used only by the input side.
          49                 :    */
          50                 :   JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
          51                 :
          52                 :   /* Temporary workspace for one MCU */
          53                 :   JCOEF * workspace;
          54                 :
          55                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
          56                 :   /* In multi-pass modes, we need a virtual block array for each component. */
          57                 :   jvirt_barray_ptr whole_image[MAX_COMPONENTS];
          58                 : #endif
          59                 :
          60                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
          61                 :   /* When doing block smoothing, we latch coefficient Al values here */
          62                 :   int * coef_bits_latch;
          63                 : #define SAVED_COEFS  6          /* we save coef_bits[0..5] */
          64                 : #endif
          65                 : } my_coef_controller;
          66                 :
          67                 : typedef my_coef_controller * my_coef_ptr;
          68                 :
          69                 : /* Forward declarations */
          70                 : METHODDEF(int) decompress_onepass
          71                 :         JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
          72                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
          73                 : METHODDEF(int) decompress_data
          74                 :         JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
          75                 : #endif
          76                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
          77                 : LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo));
          78                 : METHODDEF(int) decompress_smooth_data
          79                 :         JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
          80                 : #endif
          81                 :
          82                 :
          83                 : LOCAL(void)
          84              16 : start_iMCU_row (j_decompress_ptr cinfo)
          85                 : /* Reset within-iMCU-row counters for a new row (input side) */
          86                 : {
          87              16 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
          88                 :
          89                 :   /* In an interleaved scan, an MCU row is the same as an iMCU row.
          90                 :    * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
          91                 :    * But at the bottom of the image, process only what's left.
          92                 :    */
          93              16 :   if (cinfo->comps_in_scan > 1) {
          94              16 :     coef->MCU_rows_per_iMCU_row = 1;
          95                 :   } else {
          96               0 :     if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
          97               0 :       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
          98                 :     else
          99               0 :       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
         100                 :   }
         101                 :
         102              16 :   coef->MCU_ctr = 0;
         103              16 :   coef->MCU_vert_offset = 0;
         104              16 : }
         105                 :
         106                 :
         107                 : /*
         108                 :  * Initialize for an input processing pass.
         109                 :  */
         110                 :
         111                 : METHODDEF(void)
         112               5 : start_input_pass (j_decompress_ptr cinfo)
         113                 : {
         114               5 :   cinfo->input_iMCU_row = 0;
         115               5 :   start_iMCU_row(cinfo);
         116               5 : }
         117                 :
         118                 :
         119                 : /*
         120                 :  * Initialize for an output processing pass.
         121                 :  */
         122                 :
         123                 : METHODDEF(void)
         124               5 : start_output_pass (j_decompress_ptr cinfo)
         125                 : {
         126                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
         127               5 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         128                 :
         129                 :   /* If multipass, check to see whether to use block smoothing on this pass */
         130               5 :   if (coef->pub.coef_arrays != NULL) {
         131               0 :     if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
         132               0 :       coef->pub.decompress_data = decompress_smooth_data;
         133                 :     else
         134               0 :       coef->pub.decompress_data = decompress_data;
         135                 :   }
         136                 : #endif
         137               5 :   cinfo->output_iMCU_row = 0;
         138               5 : }
         139                 :
         140                 :
         141                 : /*
         142                 :  * Decompress and return some data in the single-pass case.
         143                 :  * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
         144                 :  * Input and output must run in lockstep since we have only a one-MCU buffer.
         145                 :  * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
         146                 :  *
         147                 :  * NB: output_buf contains a plane for each component in image,
         148                 :  * which we index according to the component's SOF position.
         149                 :  */
         150                 :
         151                 : METHODDEF(int)
         152              18 : decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
         153                 : {
         154              18 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         155                 :   JDIMENSION MCU_col_num;       /* index of current MCU within row */
         156              18 :   JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
         157              18 :   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
         158                 :   int blkn, ci, xindex, yindex, yoffset, useful_width;
         159                 :   JSAMPARRAY output_ptr;
         160                 :   JDIMENSION start_col, output_col;
         161                 :   jpeg_component_info *compptr;
         162                 :   inverse_DCT_method_ptr inverse_DCT;
         163                 :
         164                 :   /* Loop to process as much as one whole iMCU row */
         165              52 :   for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
         166              16 :        yoffset++) {
         167              65 :     for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
         168              29 :          MCU_col_num++) {
         169                 :       /* Try to fetch an MCU.  Entropy decoder expects buffer to be zeroed. */
         170              31 :       jzero_far((void FAR *) coef->MCU_buffer[0],
         171              31 :                 (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
         172              31 :       if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
         173                 :         /* Suspension forced; update state counters and exit */
         174               2 :         coef->MCU_vert_offset = yoffset;
         175               2 :         coef->MCU_ctr = MCU_col_num;
         176               2 :         return JPEG_SUSPENDED;
         177                 :       }
         178                 :       /* Determine where data should go in output_buf and do the IDCT thing.
         179                 :        * We skip dummy blocks at the right and bottom edges (but blkn gets
         180                 :        * incremented past them!).  Note the inner loop relies on having
         181                 :        * allocated the MCU_buffer[] blocks sequentially.
         182                 :        */
         183              29 :       blkn = 0;                 /* index of current DCT block within MCU */
         184             116 :       for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
         185              87 :         compptr = cinfo->cur_comp_info[ci];
         186                 :         /* Don't bother to IDCT an uninteresting component. */
         187              87 :         if (! compptr->component_needed) {
         188               0 :           blkn += compptr->MCU_blocks;
         189               0 :           continue;
         190                 :         }
         191              87 :         inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
         192              87 :         useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
         193              87 :                                                     : compptr->last_col_width;
         194             174 :         output_ptr = output_buf[compptr->component_index] +
         195              87 :           yoffset * compptr->_DCT_scaled_size;
         196              87 :         start_col = MCU_col_num * compptr->MCU_sample_width;
         197             203 :         for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
         198             180 :           if (cinfo->input_iMCU_row < last_iMCU_row ||
         199              64 :               yoffset+yindex < compptr->last_row_height) {
         200             105 :             output_col = start_col;
         201             236 :             for (xindex = 0; xindex < useful_width; xindex++) {
         202             131 :               (*inverse_DCT) (cinfo, compptr,
         203             131 :                               (JCOEFPTR) coef->MCU_buffer[blkn+xindex],
         204                 :                               output_ptr, output_col);
         205             131 :               output_col += compptr->_DCT_scaled_size;
         206                 :             }
         207                 :           }
         208             116 :           blkn += compptr->MCU_width;
         209             116 :           output_ptr += compptr->_DCT_scaled_size;
         210                 :         }
         211                 :       }
         212                 :     }
         213                 :     /* Completed an MCU row, but perhaps not an iMCU row */
         214              16 :     coef->MCU_ctr = 0;
         215                 :   }
         216                 :   /* Completed the iMCU row, advance counters for next one */
         217              16 :   cinfo->output_iMCU_row++;
         218              16 :   if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
         219              11 :     start_iMCU_row(cinfo);
         220              11 :     return JPEG_ROW_COMPLETED;
         221                 :   }
         222                 :   /* Completed the scan */
         223               5 :   (*cinfo->inputctl->finish_input_pass) (cinfo);
         224               5 :   return JPEG_SCAN_COMPLETED;
         225                 : }
         226                 :
         227                 :
         228                 : /*
         229                 :  * Dummy consume-input routine for single-pass operation.
         230                 :  */
         231                 :
         232                 : METHODDEF(int)
         233               0 : dummy_consume_data (j_decompress_ptr cinfo)
         234                 : {
         235               0 :   return JPEG_SUSPENDED;        /* Always indicate nothing was done */
         236                 : }
         237                 :
         238                 :
         239                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
         240                 :
         241                 : /*
         242                 :  * Consume input data and store it in the full-image coefficient buffer.
         243                 :  * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
         244                 :  * ie, v_samp_factor block rows for each component in the scan.
         245                 :  * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
         246                 :  */
         247                 :
         248                 : METHODDEF(int)
         249               0 : consume_data (j_decompress_ptr cinfo)
         250                 : {
         251               0 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         252                 :   JDIMENSION MCU_col_num;       /* index of current MCU within row */
         253                 :   int blkn, ci, xindex, yindex, yoffset;
         254                 :   JDIMENSION start_col;
         255                 :   JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
         256                 :   JBLOCKROW buffer_ptr;
         257                 :   jpeg_component_info *compptr;
         258                 :
         259                 :   /* Align the virtual buffers for the components used in this scan. */
         260               0 :   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
         261               0 :     compptr = cinfo->cur_comp_info[ci];
         262               0 :     buffer[ci] = (*cinfo->mem->access_virt_barray)
         263               0 :       ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
         264               0 :        cinfo->input_iMCU_row * compptr->v_samp_factor,
         265               0 :        (JDIMENSION) compptr->v_samp_factor, TRUE);
         266                 :     /* Note: entropy decoder expects buffer to be zeroed,
         267                 :      * but this is handled automatically by the memory manager
         268                 :      * because we requested a pre-zeroed array.
         269                 :      */
         270                 :   }
         271                 :
         272                 :   /* Loop to process one whole iMCU row */
         273               0 :   for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
         274               0 :        yoffset++) {
         275               0 :     for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
         276               0 :          MCU_col_num++) {
         277                 :       /* Construct list of pointers to DCT blocks belonging to this MCU */
         278               0 :       blkn = 0;                 /* index of current DCT block within MCU */
         279               0 :       for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
         280               0 :         compptr = cinfo->cur_comp_info[ci];
         281               0 :         start_col = MCU_col_num * compptr->MCU_width;
         282               0 :         for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
         283               0 :           buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
         284               0 :           for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
         285               0 :             coef->MCU_buffer[blkn++] = buffer_ptr++;
         286                 :           }
         287                 :         }
         288                 :       }
         289                 :       /* Try to fetch the MCU. */
         290               0 :       if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
         291                 :         /* Suspension forced; update state counters and exit */
         292               0 :         coef->MCU_vert_offset = yoffset;
         293               0 :         coef->MCU_ctr = MCU_col_num;
         294               0 :         return JPEG_SUSPENDED;
         295                 :       }
         296                 :     }
         297                 :     /* Completed an MCU row, but perhaps not an iMCU row */
         298               0 :     coef->MCU_ctr = 0;
         299                 :   }
         300                 :   /* Completed the iMCU row, advance counters for next one */
         301               0 :   if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
         302               0 :     start_iMCU_row(cinfo);
         303               0 :     return JPEG_ROW_COMPLETED;
         304                 :   }
         305                 :   /* Completed the scan */
         306               0 :   (*cinfo->inputctl->finish_input_pass) (cinfo);
         307               0 :   return JPEG_SCAN_COMPLETED;
         308                 : }
         309                 :
         310                 :
         311                 : /*
         312                 :  * Decompress and return some data in the multi-pass case.
         313                 :  * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
         314                 :  * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
         315                 :  *
         316                 :  * NB: output_buf contains a plane for each component in image.
         317                 :  */
         318                 :
         319                 : METHODDEF(int)
         320               0 : decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
         321                 : {
         322               0 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         323               0 :   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
         324                 :   JDIMENSION block_num;
         325                 :   int ci, block_row, block_rows;
         326                 :   JBLOCKARRAY buffer;
         327                 :   JBLOCKROW buffer_ptr;
         328                 :   JSAMPARRAY output_ptr;
         329                 :   JDIMENSION output_col;
         330                 :   jpeg_component_info *compptr;
         331                 :   inverse_DCT_method_ptr inverse_DCT;
         332                 :
         333                 :   /* Force some input to be done if we are getting ahead of the input. */
         334               0 :   while (cinfo->input_scan_number < cinfo->output_scan_number ||
         335               0 :          (cinfo->input_scan_number == cinfo->output_scan_number &&
         336               0 :           cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
         337               0 :     if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
         338               0 :       return JPEG_SUSPENDED;
         339                 :   }
         340                 :
         341                 :   /* OK, output from the virtual arrays. */
         342               0 :   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         343               0 :        ci++, compptr++) {
         344                 :     /* Don't bother to IDCT an uninteresting component. */
         345               0 :     if (! compptr->component_needed)
         346               0 :       continue;
         347                 :     /* Align the virtual buffer for this component. */
         348               0 :     buffer = (*cinfo->mem->access_virt_barray)
         349               0 :       ((j_common_ptr) cinfo, coef->whole_image[ci],
         350               0 :        cinfo->output_iMCU_row * compptr->v_samp_factor,
         351               0 :        (JDIMENSION) compptr->v_samp_factor, FALSE);
         352                 :     /* Count non-dummy DCT block rows in this iMCU row. */
         353               0 :     if (cinfo->output_iMCU_row < last_iMCU_row)
         354               0 :       block_rows = compptr->v_samp_factor;
         355                 :     else {
         356                 :       /* NB: can't use last_row_height here; it is input-side-dependent! */
         357               0 :       block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
         358               0 :       if (block_rows == 0) block_rows = compptr->v_samp_factor;
         359                 :     }
         360               0 :     inverse_DCT = cinfo->idct->inverse_DCT[ci];
         361               0 :     output_ptr = output_buf[ci];
         362                 :     /* Loop over all DCT blocks to be processed. */
         363               0 :     for (block_row = 0; block_row < block_rows; block_row++) {
         364               0 :       buffer_ptr = buffer[block_row];
         365               0 :       output_col = 0;
         366               0 :       for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
         367               0 :         (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
         368                 :                         output_ptr, output_col);
         369               0 :         buffer_ptr++;
         370               0 :         output_col += compptr->_DCT_scaled_size;
         371                 :       }
         372               0 :       output_ptr += compptr->_DCT_scaled_size;
         373                 :     }
         374                 :   }
         375                 :
         376               0 :   if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
         377               0 :     return JPEG_ROW_COMPLETED;
         378               0 :   return JPEG_SCAN_COMPLETED;
         379                 : }
         380                 :
         381                 : #endif /* D_MULTISCAN_FILES_SUPPORTED */
         382                 :
         383                 :
         384                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
         385                 :
         386                 : /*
         387                 :  * This code applies interblock smoothing as described by section K.8
         388                 :  * of the JPEG standard: the first 5 AC coefficients are estimated from
         389                 :  * the DC values of a DCT block and its 8 neighboring blocks.
         390                 :  * We apply smoothing only for progressive JPEG decoding, and only if
         391                 :  * the coefficients it can estimate are not yet known to full precision.
         392                 :  */
         393                 :
         394                 : /* Natural-order array positions of the first 5 zigzag-order coefficients */
         395                 : #define Q01_POS  1
         396                 : #define Q10_POS  8
         397                 : #define Q20_POS  16
         398                 : #define Q11_POS  9
         399                 : #define Q02_POS  2
         400                 :
         401                 : /*
         402                 :  * Determine whether block smoothing is applicable and safe.
         403                 :  * We also latch the current states of the coef_bits[] entries for the
         404                 :  * AC coefficients; otherwise, if the input side of the decompressor
         405                 :  * advances into a new scan, we might think the coefficients are known
         406                 :  * more accurately than they really are.
         407                 :  */
         408                 :
         409                 : LOCAL(boolean)
         410               0 : smoothing_ok (j_decompress_ptr cinfo)
         411                 : {
         412               0 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         413               0 :   boolean smoothing_useful = FALSE;
         414                 :   int ci, coefi;
         415                 :   jpeg_component_info *compptr;
         416                 :   JQUANT_TBL * qtable;
         417                 :   int * coef_bits;
         418                 :   int * coef_bits_latch;
         419                 :
         420               0 :   if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
         421               0 :     return FALSE;
         422                 :
         423                 :   /* Allocate latch area if not already done */
         424               0 :   if (coef->coef_bits_latch == NULL)
         425               0 :     coef->coef_bits_latch = (int *)
         426               0 :       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
         427               0 :                                   cinfo->num_components *
         428                 :                                   (SAVED_COEFS * SIZEOF(int)));
         429               0 :   coef_bits_latch = coef->coef_bits_latch;
         430                 :
         431               0 :   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         432               0 :        ci++, compptr++) {
         433                 :     /* All components' quantization values must already be latched. */
         434               0 :     if ((qtable = compptr->quant_table) == NULL)
         435               0 :       return FALSE;
         436                 :     /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
         437               0 :     if (qtable->quantval[0] == 0 ||
         438               0 :         qtable->quantval[Q01_POS] == 0 ||
         439               0 :         qtable->quantval[Q10_POS] == 0 ||
         440               0 :         qtable->quantval[Q20_POS] == 0 ||
         441               0 :         qtable->quantval[Q11_POS] == 0 ||
         442               0 :         qtable->quantval[Q02_POS] == 0)
         443               0 :       return FALSE;
         444                 :     /* DC values must be at least partly known for all components. */
         445               0 :     coef_bits = cinfo->coef_bits[ci];
         446               0 :     if (coef_bits[0] < 0)
         447               0 :       return FALSE;
         448                 :     /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
         449               0 :     for (coefi = 1; coefi <= 5; coefi++) {
         450               0 :       coef_bits_latch[coefi] = coef_bits[coefi];
         451               0 :       if (coef_bits[coefi] != 0)
         452               0 :         smoothing_useful = TRUE;
         453                 :     }
         454               0 :     coef_bits_latch += SAVED_COEFS;
         455                 :   }
         456                 :
         457               0 :   return smoothing_useful;
         458                 : }
         459                 :
         460                 :
         461                 : /*
         462                 :  * Variant of decompress_data for use when doing block smoothing.
         463                 :  */
         464                 :
         465                 : METHODDEF(int)
         466               0 : decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
         467                 : {
         468               0 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
         469               0 :   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
         470                 :   JDIMENSION block_num, last_block_column;
         471                 :   int ci, block_row, block_rows, access_rows;
         472                 :   JBLOCKARRAY buffer;
         473                 :   JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
         474                 :   JSAMPARRAY output_ptr;
         475                 :   JDIMENSION output_col;
         476                 :   jpeg_component_info *compptr;
         477                 :   inverse_DCT_method_ptr inverse_DCT;
         478                 :   boolean first_row, last_row;
         479                 :   JCOEF * workspace;
         480                 :   int *coef_bits;
         481                 :   JQUANT_TBL *quanttbl;
         482                 :   INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
         483                 :   int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
         484                 :   int Al, pred;
         485                 :
         486                 :   /* Keep a local variable to avoid looking it up more than once */
         487               0 :   workspace = coef->workspace;
         488                 :
         489                 :   /* Force some input to be done if we are getting ahead of the input. */
         490               0 :   while (cinfo->input_scan_number <= cinfo->output_scan_number &&
         491               0 :          ! cinfo->inputctl->eoi_reached) {
         492               0 :     if (cinfo->input_scan_number == cinfo->output_scan_number) {
         493                 :       /* If input is working on current scan, we ordinarily want it to
         494                 :        * have completed the current row.  But if input scan is DC,
         495                 :        * we want it to keep one row ahead so that next block row's DC
         496                 :        * values are up to date.
         497                 :        */
         498               0 :       JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
         499               0 :       if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
         500               0 :         break;
         501                 :     }
         502               0 :     if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
         503               0 :       return JPEG_SUSPENDED;
         504                 :   }
         505                 :
         506                 :   /* OK, output from the virtual arrays. */
         507               0 :   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         508               0 :        ci++, compptr++) {
         509                 :     /* Don't bother to IDCT an uninteresting component. */
         510               0 :     if (! compptr->component_needed)
         511               0 :       continue;
         512                 :     /* Count non-dummy DCT block rows in this iMCU row. */
         513               0 :     if (cinfo->output_iMCU_row < last_iMCU_row) {
         514               0 :       block_rows = compptr->v_samp_factor;
         515               0 :       access_rows = block_rows * 2; /* this and next iMCU row */
         516               0 :       last_row = FALSE;
         517                 :     } else {
         518                 :       /* NB: can't use last_row_height here; it is input-side-dependent! */
         519               0 :       block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
         520               0 :       if (block_rows == 0) block_rows = compptr->v_samp_factor;
         521               0 :       access_rows = block_rows; /* this iMCU row only */
         522               0 :       last_row = TRUE;
         523                 :     }
         524                 :     /* Align the virtual buffer for this component. */
         525               0 :     if (cinfo->output_iMCU_row > 0) {
         526               0 :       access_rows += compptr->v_samp_factor; /* prior iMCU row too */
         527               0 :       buffer = (*cinfo->mem->access_virt_barray)
         528               0 :         ((j_common_ptr) cinfo, coef->whole_image[ci],
         529               0 :          (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
         530                 :          (JDIMENSION) access_rows, FALSE);
         531               0 :       buffer += compptr->v_samp_factor;      /* point to current iMCU row */
         532               0 :       first_row = FALSE;
         533                 :     } else {
         534               0 :       buffer = (*cinfo->mem->access_virt_barray)
         535               0 :         ((j_common_ptr) cinfo, coef->whole_image[ci],
         536                 :          (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
         537               0 :       first_row = TRUE;
         538                 :     }
         539                 :     /* Fetch component-dependent info */
         540               0 :     coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
         541               0 :     quanttbl = compptr->quant_table;
         542               0 :     Q00 = quanttbl->quantval[0];
         543               0 :     Q01 = quanttbl->quantval[Q01_POS];
         544               0 :     Q10 = quanttbl->quantval[Q10_POS];
         545               0 :     Q20 = quanttbl->quantval[Q20_POS];
         546               0 :     Q11 = quanttbl->quantval[Q11_POS];
         547               0 :     Q02 = quanttbl->quantval[Q02_POS];
         548               0 :     inverse_DCT = cinfo->idct->inverse_DCT[ci];
         549               0 :     output_ptr = output_buf[ci];
         550                 :     /* Loop over all DCT blocks to be processed. */
         551               0 :     for (block_row = 0; block_row < block_rows; block_row++) {
         552               0 :       buffer_ptr = buffer[block_row];
         553               0 :       if (first_row && block_row == 0)
         554               0 :         prev_block_row = buffer_ptr;
         555                 :       else
         556               0 :         prev_block_row = buffer[block_row-1];
         557               0 :       if (last_row && block_row == block_rows-1)
         558               0 :         next_block_row = buffer_ptr;
         559                 :       else
         560               0 :         next_block_row = buffer[block_row+1];
         561                 :       /* We fetch the surrounding DC values using a sliding-register approach.
         562                 :        * Initialize all nine here so as to do the right thing on narrow pics.
         563                 :        */
         564               0 :       DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
         565               0 :       DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
         566               0 :       DC7 = DC8 = DC9 = (int) next_block_row[0][0];
         567               0 :       output_col = 0;
         568               0 :       last_block_column = compptr->width_in_blocks - 1;
         569               0 :       for (block_num = 0; block_num <= last_block_column; block_num++) {
         570                 :         /* Fetch current DCT block into workspace so we can modify it. */
         571               0 :         jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
         572                 :         /* Update DC values */
         573               0 :         if (block_num < last_block_column) {
         574               0 :           DC3 = (int) prev_block_row[1][0];
         575               0 :           DC6 = (int) buffer_ptr[1][0];
         576               0 :           DC9 = (int) next_block_row[1][0];
         577                 :         }
         578                 :         /* Compute coefficient estimates per K.8.
         579                 :          * An estimate is applied only if coefficient is still zero,
         580                 :          * and is not known to be fully accurate.
         581                 :          */
         582                 :         /* AC01 */
         583               0 :         if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
         584               0 :           num = 36 * Q00 * (DC4 - DC6);
         585               0 :           if (num >= 0) {
         586               0 :             pred = (int) (((Q01<<7) + num) / (Q01<<8));
         587               0 :             if (Al > 0 && pred >= (1<<Al))
         588               0 :               pred = (1<<Al)-1;
         589                 :           } else {
         590               0 :             pred = (int) (((Q01<<7) - num) / (Q01<<8));
         591               0 :             if (Al > 0 && pred >= (1<<Al))
         592               0 :               pred = (1<<Al)-1;
         593               0 :             pred = -pred;
         594                 :           }
         595               0 :           workspace[1] = (JCOEF) pred;
         596                 :         }
         597                 :         /* AC10 */
         598               0 :         if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
         599               0 :           num = 36 * Q00 * (DC2 - DC8);
         600               0 :           if (num >= 0) {
         601               0 :             pred = (int) (((Q10<<7) + num) / (Q10<<8));
         602               0 :             if (Al > 0 && pred >= (1<<Al))
         603               0 :               pred = (1<<Al)-1;
         604                 :           } else {
         605               0 :             pred = (int) (((Q10<<7) - num) / (Q10<<8));
         606               0 :             if (Al > 0 && pred >= (1<<Al))
         607               0 :               pred = (1<<Al)-1;
         608               0 :             pred = -pred;
         609                 :           }
         610               0 :           workspace[8] = (JCOEF) pred;
         611                 :         }
         612                 :         /* AC20 */
         613               0 :         if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
         614               0 :           num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
         615               0 :           if (num >= 0) {
         616               0 :             pred = (int) (((Q20<<7) + num) / (Q20<<8));
         617               0 :             if (Al > 0 && pred >= (1<<Al))
         618               0 :               pred = (1<<Al)-1;
         619                 :           } else {
         620               0 :             pred = (int) (((Q20<<7) - num) / (Q20<<8));
         621               0 :             if (Al > 0 && pred >= (1<<Al))
         622               0 :               pred = (1<<Al)-1;
         623               0 :             pred = -pred;
         624                 :           }
         625               0 :           workspace[16] = (JCOEF) pred;
         626                 :         }
         627                 :         /* AC11 */
         628               0 :         if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
         629               0 :           num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
         630               0 :           if (num >= 0) {
         631               0 :             pred = (int) (((Q11<<7) + num) / (Q11<<8));
         632               0 :             if (Al > 0 && pred >= (1<<Al))
         633               0 :               pred = (1<<Al)-1;
         634                 :           } else {
         635               0 :             pred = (int) (((Q11<<7) - num) / (Q11<<8));
         636               0 :             if (Al > 0 && pred >= (1<<Al))
         637               0 :               pred = (1<<Al)-1;
         638               0 :             pred = -pred;
         639                 :           }
         640               0 :           workspace[9] = (JCOEF) pred;
         641                 :         }
         642                 :         /* AC02 */
         643               0 :         if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
         644               0 :           num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
         645               0 :           if (num >= 0) {
         646               0 :             pred = (int) (((Q02<<7) + num) / (Q02<<8));
         647               0 :             if (Al > 0 && pred >= (1<<Al))
         648               0 :               pred = (1<<Al)-1;
         649                 :           } else {
         650               0 :             pred = (int) (((Q02<<7) - num) / (Q02<<8));
         651               0 :             if (Al > 0 && pred >= (1<<Al))
         652               0 :               pred = (1<<Al)-1;
         653               0 :             pred = -pred;
         654                 :           }
         655               0 :           workspace[2] = (JCOEF) pred;
         656                 :         }
         657                 :         /* OK, do the IDCT */
         658               0 :         (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
         659                 :                         output_ptr, output_col);
         660                 :         /* Advance for next column */
         661               0 :         DC1 = DC2; DC2 = DC3;
         662               0 :         DC4 = DC5; DC5 = DC6;
         663               0 :         DC7 = DC8; DC8 = DC9;
         664               0 :         buffer_ptr++, prev_block_row++, next_block_row++;
         665               0 :         output_col += compptr->_DCT_scaled_size;
         666                 :       }
         667               0 :       output_ptr += compptr->_DCT_scaled_size;
         668                 :     }
         669                 :   }
         670                 :
         671               0 :   if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
         672               0 :     return JPEG_ROW_COMPLETED;
         673               0 :   return JPEG_SCAN_COMPLETED;
         674                 : }
         675                 :
         676                 : #endif /* BLOCK_SMOOTHING_SUPPORTED */
         677                 :
         678                 :
         679                 : /*
         680                 :  * Initialize coefficient buffer controller.
         681                 :  */
         682                 :
         683                 : GLOBAL(void)
         684               5 : jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
         685                 : {
         686                 :   my_coef_ptr coef;
         687                 :
         688               5 :   coef = (my_coef_ptr)
         689               5 :     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
         690                 :                                 SIZEOF(my_coef_controller));
         691               5 :   cinfo->coef = (struct jpeg_d_coef_controller *) coef;
         692               5 :   coef->pub.start_input_pass = start_input_pass;
         693               5 :   coef->pub.start_output_pass = start_output_pass;
         694                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
         695               5 :   coef->coef_bits_latch = NULL;
         696                 : #endif
         697                 :
         698                 :   /* Create the coefficient buffer. */
         699               5 :   if (need_full_buffer) {
         700                 : #ifdef D_MULTISCAN_FILES_SUPPORTED
         701                 :     /* Allocate a full-image virtual array for each component, */
         702                 :     /* padded to a multiple of samp_factor DCT blocks in each direction. */
         703                 :     /* Note we ask for a pre-zeroed array. */
         704                 :     int ci, access_rows;
         705                 :     jpeg_component_info *compptr;
         706                 :
         707               0 :     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
         708               0 :          ci++, compptr++) {
         709               0 :       access_rows = compptr->v_samp_factor;
         710                 : #ifdef BLOCK_SMOOTHING_SUPPORTED
         711                 :       /* If block smoothing could be used, need a bigger window */
         712               0 :       if (cinfo->progressive_mode)
         713               0 :         access_rows *= 3;
         714                 : #endif
         715               0 :       coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
         716               0 :         ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
         717               0 :          (JDIMENSION) jround_up((long) compptr->width_in_blocks,
         718               0 :                                 (long) compptr->h_samp_factor),
         719               0 :          (JDIMENSION) jround_up((long) compptr->height_in_blocks,
         720               0 :                                 (long) compptr->v_samp_factor),
         721                 :          (JDIMENSION) access_rows);
         722                 :     }
         723               0 :     coef->pub.consume_data = consume_data;
         724               0 :     coef->pub.decompress_data = decompress_data;
         725               0 :     coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
         726                 : #else
         727                 :     ERREXIT(cinfo, JERR_NOT_COMPILED);
         728                 : #endif
         729                 :   } else {
         730                 :     /* We only need a single-MCU buffer. */
         731                 :     JBLOCKROW buffer;
         732                 :     int i;
         733                 :
         734               5 :     buffer = (JBLOCKROW)
         735               5 :       (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
         736                 :                                   D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
         737              55 :     for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
         738              50 :       coef->MCU_buffer[i] = buffer + i;
         739                 :     }
         740               5 :     coef->pub.consume_data = dummy_consume_data;
         741               5 :     coef->pub.decompress_data = decompress_onepass;
         742               5 :     coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
         743                 :   }
         744                 :
         745                 :   /* Allocate the workspace buffer */
         746               5 :   coef->workspace = (JCOEF *)
         747               5 :     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
         748                 :                                 SIZEOF(JCOEF) * DCTSIZE2);
         749               5 : }

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