workbench/libs/jpeg/jctrans.c

   1 /*
   2  * jctrans.c
   3  *
   4  * Copyright (C) 1995-1998, Thomas G. Lane.
   5  * Modified 2000-2012 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 library routines for transcoding compression,
  10  * that is, writing raw DCT coefficient arrays to an output JPEG file.
  11  * The routines in jcapimin.c will also be needed by a transcoder.
  12  */
  13
  14 #define JPEG_INTERNALS
  15 #include "jinclude.h"
  16 #include "jpeglib.h"
  17
  18
  19 /* Forward declarations */
  20 LOCAL(void) transencode_master_selection
  21         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  22 LOCAL(void) transencode_coef_controller
  23         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  24
  25
  26 /*
  27  * Compression initialization for writing raw-coefficient data.
  28  * Before calling this, all parameters and a data destination must be set up.
  29  * Call jpeg_finish_compress() to actually write the data.
  30  *
  31  * The number of passed virtual arrays must match cinfo->num_components.
  32  * Note that the virtual arrays need not be filled or even realized at
  33  * the time write_coefficients is called; indeed, if the virtual arrays
  34  * were requested from this compression object's memory manager, they
  35  * typically will be realized during this routine and filled afterwards.
  36  */
  37
  38 GLOBAL(void)
  39 jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
  40 {
  41   if (cinfo->global_state != CSTATE_START)
  42     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  43   /* Mark all tables to be written */
  44   jpeg_suppress_tables(cinfo, FALSE);
  45   /* (Re)initialize error mgr and destination modules */
  46   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
  47   (*cinfo->dest->init_destination) (cinfo);
  48   /* Perform master selection of active modules */
  49   transencode_master_selection(cinfo, coef_arrays);
  50   /* Wait for jpeg_finish_compress() call */
  51   cinfo->next_scanline = 0;     /* so jpeg_write_marker works */
  52   cinfo->global_state = CSTATE_WRCOEFS;
  53 }
  54
  55
  56 /*
  57  * Initialize the compression object with default parameters,
  58  * then copy from the source object all parameters needed for lossless
  59  * transcoding.  Parameters that can be varied without loss (such as
  60  * scan script and Huffman optimization) are left in their default states.
  61  */
  62
  63 GLOBAL(void)
  64 jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
  65                                j_compress_ptr dstinfo)
  66 {
  67   JQUANT_TBL ** qtblptr;
  68   jpeg_component_info *incomp, *outcomp;
  69   JQUANT_TBL *c_quant, *slot_quant;
  70   int tblno, ci, coefi;
  71
  72   /* Safety check to ensure start_compress not called yet. */
  73   if (dstinfo->global_state != CSTATE_START)
  74     ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
  75   /* Copy fundamental image dimensions */
  76   dstinfo->image_width = srcinfo->image_width;
  77   dstinfo->image_height = srcinfo->image_height;
  78   dstinfo->input_components = srcinfo->num_components;
  79   dstinfo->in_color_space = srcinfo->jpeg_color_space;
  80   dstinfo->jpeg_width = srcinfo->output_width;
  81   dstinfo->jpeg_height = srcinfo->output_height;
  82   dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size;
  83   dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size;
  84   /* Initialize all parameters to default values */
  85   jpeg_set_defaults(dstinfo);
  86   /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
  87    * Fix it to get the right header markers for the image colorspace.
  88    * Note: Entropy table assignment in jpeg_set_colorspace depends
  89    * on color_transform.
  90    */
  91   dstinfo->color_transform = srcinfo->color_transform;
  92   jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
  93   dstinfo->data_precision = srcinfo->data_precision;
  94   dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
  95   /* Copy the source's quantization tables. */
  96   for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
  97     if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
  98       qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
  99       if (*qtblptr == NULL)
 100         *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
 101       MEMCOPY((*qtblptr)->quantval,
 102               srcinfo->quant_tbl_ptrs[tblno]->quantval,
 103               SIZEOF((*qtblptr)->quantval));
 104       (*qtblptr)->sent_table = FALSE;
 105     }
 106   }
 107   /* Copy the source's per-component info.
 108    * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
 109    */
 110   dstinfo->num_components = srcinfo->num_components;
 111   if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
 112     ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
 113              MAX_COMPONENTS);
 114   for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
 115        ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
 116     outcomp->component_id = incomp->component_id;
 117     outcomp->h_samp_factor = incomp->h_samp_factor;
 118     outcomp->v_samp_factor = incomp->v_samp_factor;
 119     outcomp->quant_tbl_no = incomp->quant_tbl_no;
 120     /* Make sure saved quantization table for component matches the qtable
 121      * slot.  If not, the input file re-used this qtable slot.
 122      * IJG encoder currently cannot duplicate this.
 123      */
 124     tblno = outcomp->quant_tbl_no;
 125     if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
 126         srcinfo->quant_tbl_ptrs[tblno] == NULL)
 127       ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
 128     slot_quant = srcinfo->quant_tbl_ptrs[tblno];
 129     c_quant = incomp->quant_table;
 130     if (c_quant != NULL) {
 131       for (coefi = 0; coefi < DCTSIZE2; coefi++) {
 132         if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
 133           ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
 134       }
 135     }
 136     /* Note: we do not copy the source's entropy table assignments;
 137      * instead we rely on jpeg_set_colorspace to have made a suitable choice.
 138      */
 139   }
 140   /* Also copy JFIF version and resolution information, if available.
 141    * Strictly speaking this isn't "critical" info, but it's nearly
 142    * always appropriate to copy it if available.  In particular,
 143    * if the application chooses to copy JFIF 1.02 extension markers from
 144    * the source file, we need to copy the version to make sure we don't
 145    * emit a file that has 1.02 extensions but a claimed version of 1.01.
 146    * We will *not*, however, copy version info from mislabeled "2.01" files.
 147    */
 148   if (srcinfo->saw_JFIF_marker) {
 149     if (srcinfo->JFIF_major_version == 1) {
 150       dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
 151       dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
 152     }
 153     dstinfo->density_unit = srcinfo->density_unit;
 154     dstinfo->X_density = srcinfo->X_density;
 155     dstinfo->Y_density = srcinfo->Y_density;
 156   }
 157 }
 158
 159
 160 /*
 161  * Master selection of compression modules for transcoding.
 162  * This substitutes for jcinit.c's initialization of the full compressor.
 163  */
 164
 165 LOCAL(void)
 166 transencode_master_selection (j_compress_ptr cinfo,
 167                               jvirt_barray_ptr * coef_arrays)
 168 {
 169   /* Initialize master control (includes parameter checking/processing) */
 170   jinit_c_master_control(cinfo, TRUE /* transcode only */);
 171
 172   /* Entropy encoding: either Huffman or arithmetic coding. */
 173   if (cinfo->arith_code)
 174     jinit_arith_encoder(cinfo);
 175   else {
 176     jinit_huff_encoder(cinfo);
 177   }
 178
 179   /* We need a special coefficient buffer controller. */
 180   transencode_coef_controller(cinfo, coef_arrays);
 181
 182   jinit_marker_writer(cinfo);
 183
 184   /* We can now tell the memory manager to allocate virtual arrays. */
 185   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
 186
 187   /* Write the datastream header (SOI, JFIF) immediately.
 188    * Frame and scan headers are postponed till later.
 189    * This lets application insert special markers after the SOI.
 190    */
 191   (*cinfo->marker->write_file_header) (cinfo);
 192 }
 193
 194
 195 /*
 196  * The rest of this file is a special implementation of the coefficient
 197  * buffer controller.  This is similar to jccoefct.c, but it handles only
 198  * output from presupplied virtual arrays.  Furthermore, we generate any
 199  * dummy padding blocks on-the-fly rather than expecting them to be present
 200  * in the arrays.
 201  */
 202
 203 /* Private buffer controller object */
 204
 205 typedef struct {
 206   struct jpeg_c_coef_controller pub; /* public fields */
 207
 208   JDIMENSION iMCU_row_num;      /* iMCU row # within image */
 209   JDIMENSION mcu_ctr;           /* counts MCUs processed in current row */
 210   int MCU_vert_offset;          /* counts MCU rows within iMCU row */
 211   int MCU_rows_per_iMCU_row;    /* number of such rows needed */
 212
 213   /* Virtual block array for each component. */
 214   jvirt_barray_ptr * whole_image;
 215
 216   /* Workspace for constructing dummy blocks at right/bottom edges. */
 217   JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
 218 } my_coef_controller;
 219
 220 typedef my_coef_controller * my_coef_ptr;
 221
 222
 223 LOCAL(void)
 224 start_iMCU_row (j_compress_ptr cinfo)
 225 /* Reset within-iMCU-row counters for a new row */
 226 {
 227   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 228
 229   /* In an interleaved scan, an MCU row is the same as an iMCU row.
 230    * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
 231    * But at the bottom of the image, process only what's left.
 232    */
 233   if (cinfo->comps_in_scan > 1) {
 234     coef->MCU_rows_per_iMCU_row = 1;
 235   } else {
 236     if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
 237       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
 238     else
 239       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
 240   }
 241
 242   coef->mcu_ctr = 0;
 243   coef->MCU_vert_offset = 0;
 244 }
 245
 246
 247 /*
 248  * Initialize for a processing pass.
 249  */
 250
 251 METHODDEF(void)
 252 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
 253 {
 254   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 255
 256   if (pass_mode != JBUF_CRANK_DEST)
 257     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 258
 259   coef->iMCU_row_num = 0;
 260   start_iMCU_row(cinfo);
 261 }
 262
 263
 264 /*
 265  * Process some data.
 266  * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
 267  * per call, ie, v_samp_factor block rows for each component in the scan.
 268  * The data is obtained from the virtual arrays and fed to the entropy coder.
 269  * Returns TRUE if the iMCU row is completed, FALSE if suspended.
 270  *
 271  * NB: input_buf is ignored; it is likely to be a NULL pointer.
 272  */
 273
 274 METHODDEF(boolean)
 275 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
 276 {
 277   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 278   JDIMENSION MCU_col_num;       /* index of current MCU within row */
 279   JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
 280   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
 281   int blkn, ci, xindex, yindex, yoffset, blockcnt;
 282   JDIMENSION start_col;
 283   JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
 284   JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
 285   JBLOCKROW buffer_ptr;
 286   jpeg_component_info *compptr;
 287
 288   /* Align the virtual buffers for the components used in this scan. */
 289   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 290     compptr = cinfo->cur_comp_info[ci];
 291     buffer[ci] = (*cinfo->mem->access_virt_barray)
 292       ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
 293        coef->iMCU_row_num * compptr->v_samp_factor,
 294        (JDIMENSION) compptr->v_samp_factor, FALSE);
 295   }
 296
 297   /* Loop to process one whole iMCU row */
 298   for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
 299        yoffset++) {
 300     for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
 301          MCU_col_num++) {
 302       /* Construct list of pointers to DCT blocks belonging to this MCU */
 303       blkn = 0;                 /* index of current DCT block within MCU */
 304       for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 305         compptr = cinfo->cur_comp_info[ci];
 306         start_col = MCU_col_num * compptr->MCU_width;
 307         blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
 308                                                 : compptr->last_col_width;
 309         for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
 310           if (coef->iMCU_row_num < last_iMCU_row ||
 311               yindex+yoffset < compptr->last_row_height) {
 312             /* Fill in pointers to real blocks in this row */
 313             buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
 314             for (xindex = 0; xindex < blockcnt; xindex++)
 315               MCU_buffer[blkn++] = buffer_ptr++;
 316           } else {
 317             /* At bottom of image, need a whole row of dummy blocks */
 318             xindex = 0;
 319           }
 320           /* Fill in any dummy blocks needed in this row.
 321            * Dummy blocks are filled in the same way as in jccoefct.c:
 322            * all zeroes in the AC entries, DC entries equal to previous
 323            * block's DC value.  The init routine has already zeroed the
 324            * AC entries, so we need only set the DC entries correctly.
 325            */
 326           for (; xindex < compptr->MCU_width; xindex++) {
 327             MCU_buffer[blkn] = coef->dummy_buffer[blkn];
 328             MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
 329             blkn++;
 330           }
 331         }
 332       }
 333       /* Try to write the MCU. */
 334       if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
 335         /* Suspension forced; update state counters and exit */
 336         coef->MCU_vert_offset = yoffset;
 337         coef->mcu_ctr = MCU_col_num;
 338         return FALSE;
 339       }
 340     }
 341     /* Completed an MCU row, but perhaps not an iMCU row */
 342     coef->mcu_ctr = 0;
 343   }
 344   /* Completed the iMCU row, advance counters for next one */
 345   coef->iMCU_row_num++;
 346   start_iMCU_row(cinfo);
 347   return TRUE;
 348 }
 349
 350
 351 /*
 352  * Initialize coefficient buffer controller.
 353  *
 354  * Each passed coefficient array must be the right size for that
 355  * coefficient: width_in_blocks wide and height_in_blocks high,
 356  * with unitheight at least v_samp_factor.
 357  */
 358
 359 LOCAL(void)
 360 transencode_coef_controller (j_compress_ptr cinfo,
 361                              jvirt_barray_ptr * coef_arrays)
 362 {
 363   my_coef_ptr coef;
 364   JBLOCKROW buffer;
 365   int i;
 366
 367   coef = (my_coef_ptr)
 368     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 369                                 SIZEOF(my_coef_controller));
 370   cinfo->coef = &coef->pub;
 371   coef->pub.start_pass = start_pass_coef;
 372   coef->pub.compress_data = compress_output;
 373
 374   /* Save pointer to virtual arrays */
 375   coef->whole_image = coef_arrays;
 376
 377   /* Allocate and pre-zero space for dummy DCT blocks. */
 378   buffer = (JBLOCKROW)
 379     (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 380                                 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
 381   FMEMZERO((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
 382   for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
 383     coef->dummy_buffer[i] = buffer + i;
 384   }
 385 }