src/jpeg/jctrans.c

   1 /*
   2  * jctrans.c
   3  *
   4  * Copyright (C) 1995-1998, Thomas G. Lane.
   5  * This file is part of the Independent JPEG Group's software.
   6  * For conditions of distribution and use, see the accompanying README file.
   7  *
   8  * This file contains library routines for transcoding compression,
   9  * that is, writing raw DCT coefficient arrays to an output JPEG file.
  10  * The routines in jcapimin.c will also be needed by a transcoder.
  11  */
  12
  13 #define JPEG_INTERNALS
  14 #include "jinclude.h"
  15 #include "jpeglib.h"
  16
  17
  18 /* Forward declarations */
  19 LOCAL(void) transencode_master_selection
  20         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  21 LOCAL(void) transencode_coef_controller
  22         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  23
  24 #if defined(__VISAGECPP__)
  25 /* Visual Age fixups for multiple declarations */
  26 #  define start_pass_coef   start_pass_coef2 /* already in jccoeft.c */
  27 #  define compress_output   compress_output2 /* already in jccoeft.c */
  28 #endif
  29
  30
  31 /*
  32  * Compression initialization for writing raw-coefficient data.
  33  * Before calling this, all parameters and a data destination must be set up.
  34  * Call jpeg_finish_compress() to actually write the data.
  35  *
  36  * The number of passed virtual arrays must match cinfo->num_components.
  37  * Note that the virtual arrays need not be filled or even realized at
  38  * the time write_coefficients is called; indeed, if the virtual arrays
  39  * were requested from this compression object's memory manager, they
  40  * typically will be realized during this routine and filled afterwards.
  41  */
  42
  43 GLOBAL(void)
  44 jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
  45 {
  46   if (cinfo->global_state != CSTATE_START)
  47     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  48   /* Mark all tables to be written */
  49   jpeg_suppress_tables(cinfo, FALSE);
  50   /* (Re)initialize error mgr and destination modules */
  51   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
  52   (*cinfo->dest->init_destination) (cinfo);
  53   /* Perform master selection of active modules */
  54   transencode_master_selection(cinfo, coef_arrays);
  55   /* Wait for jpeg_finish_compress() call */
  56   cinfo->next_scanline = 0;     /* so jpeg_write_marker works */
  57   cinfo->global_state = CSTATE_WRCOEFS;
  58 }
  59
  60
  61 /*
  62  * Initialize the compression object with default parameters,
  63  * then copy from the source object all parameters needed for lossless
  64  * transcoding.  Parameters that can be varied without loss (such as
  65  * scan script and Huffman optimization) are left in their default states.
  66  */
  67
  68 GLOBAL(void)
  69 jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
  70                                j_compress_ptr dstinfo)
  71 {
  72   JQUANT_TBL ** qtblptr;
  73   jpeg_component_info *incomp, *outcomp;
  74   JQUANT_TBL *c_quant, *slot_quant;
  75   int tblno, ci, coefi;
  76
  77   /* Safety check to ensure start_compress not called yet. */
  78   if (dstinfo->global_state != CSTATE_START)
  79     ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
  80   /* Copy fundamental image dimensions */
  81   dstinfo->image_width = srcinfo->image_width;
  82   dstinfo->image_height = srcinfo->image_height;
  83   dstinfo->input_components = srcinfo->num_components;
  84   dstinfo->in_color_space = srcinfo->jpeg_color_space;
  85   /* Initialize all parameters to default values */
  86   jpeg_set_defaults(dstinfo);
  87   /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
  88    * Fix it to get the right header markers for the image colorspace.
  89    */
  90   jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
  91   dstinfo->data_precision = srcinfo->data_precision;
  92   dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
  93   /* Copy the source's quantization tables. */
  94   for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
  95     if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
  96       qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
  97       if (*qtblptr == NULL)
  98         *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
  99       MEMCOPY((*qtblptr)->quantval,
 100               srcinfo->quant_tbl_ptrs[tblno]->quantval,
 101               SIZEOF((*qtblptr)->quantval));
 102       (*qtblptr)->sent_table = FALSE;
 103     }
 104   }
 105   /* Copy the source's per-component info.
 106    * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
 107    */
 108   dstinfo->num_components = srcinfo->num_components;
 109   if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
 110     ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
 111              MAX_COMPONENTS);
 112   for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
 113        ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
 114     outcomp->component_id = incomp->component_id;
 115     outcomp->h_samp_factor = incomp->h_samp_factor;
 116     outcomp->v_samp_factor = incomp->v_samp_factor;
 117     outcomp->quant_tbl_no = incomp->quant_tbl_no;
 118     /* Make sure saved quantization table for component matches the qtable
 119      * slot.  If not, the input file re-used this qtable slot.
 120      * IJG encoder currently cannot duplicate this.
 121      */
 122     tblno = outcomp->quant_tbl_no;
 123     if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
 124         srcinfo->quant_tbl_ptrs[tblno] == NULL)
 125       ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
 126     slot_quant = srcinfo->quant_tbl_ptrs[tblno];
 127     c_quant = incomp->quant_table;
 128     if (c_quant != NULL) {
 129       for (coefi = 0; coefi < DCTSIZE2; coefi++) {
 130         if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
 131           ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
 132       }
 133     }
 134     /* Note: we do not copy the source's Huffman table assignments;
 135      * instead we rely on jpeg_set_colorspace to have made a suitable choice.
 136      */
 137   }
 138   /* Also copy JFIF version and resolution information, if available.
 139    * Strictly speaking this isn't "critical" info, but it's nearly
 140    * always appropriate to copy it if available.  In particular,
 141    * if the application chooses to copy JFIF 1.02 extension markers from
 142    * the source file, we need to copy the version to make sure we don't
 143    * emit a file that has 1.02 extensions but a claimed version of 1.01.
 144    * We will *not*, however, copy version info from mislabeled "2.01" files.
 145    */
 146   if (srcinfo->saw_JFIF_marker) {
 147     if (srcinfo->JFIF_major_version == 1) {
 148       dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
 149       dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
 150     }
 151     dstinfo->density_unit = srcinfo->density_unit;
 152     dstinfo->X_density = srcinfo->X_density;
 153     dstinfo->Y_density = srcinfo->Y_density;
 154   }
 155 }
 156
 157
 158 /*
 159  * Master selection of compression modules for transcoding.
 160  * This substitutes for jcinit.c's initialization of the full compressor.
 161  */
 162
 163 LOCAL(void)
 164 transencode_master_selection (j_compress_ptr cinfo,
 165                               jvirt_barray_ptr * coef_arrays)
 166 {
 167   /* Although we don't actually use input_components for transcoding,
 168    * jcmaster.c's initial_setup will complain if input_components is 0.
 169    */
 170   cinfo->input_components = 1;
 171   /* Initialize master control (includes parameter checking/processing) */
 172   jinit_c_master_control(cinfo, TRUE /* transcode only */);
 173
 174   /* Entropy encoding: either Huffman or arithmetic coding. */
 175   if (cinfo->arith_code) {
 176     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
 177   } else {
 178     if (cinfo->progressive_mode) {
 179 #ifdef C_PROGRESSIVE_SUPPORTED
 180       jinit_phuff_encoder(cinfo);
 181 #else
 182       ERREXIT(cinfo, JERR_NOT_COMPILED);
 183 #endif
 184     } else
 185       jinit_huff_encoder(cinfo);
 186   }
 187
 188   /* We need a special coefficient buffer controller. */
 189   transencode_coef_controller(cinfo, coef_arrays);
 190
 191   jinit_marker_writer(cinfo);
 192
 193   /* We can now tell the memory manager to allocate virtual arrays. */
 194   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
 195
 196   /* Write the datastream header (SOI, JFIF) immediately.
 197    * Frame and scan headers are postponed till later.
 198    * This lets application insert special markers after the SOI.
 199    */
 200   (*cinfo->marker->write_file_header) (cinfo);
 201 }
 202
 203
 204 /*
 205  * The rest of this file is a special implementation of the coefficient
 206  * buffer controller.  This is similar to jccoefct.c, but it handles only
 207  * output from presupplied virtual arrays.  Furthermore, we generate any
 208  * dummy padding blocks on-the-fly rather than expecting them to be present
 209  * in the arrays.
 210  */
 211
 212 /* Private buffer controller object */
 213
 214 typedef struct {
 215   struct jpeg_c_coef_controller pub; /* public fields */
 216
 217   JDIMENSION iMCU_row_num;      /* iMCU row # within image */
 218   JDIMENSION mcu_ctr;           /* counts MCUs processed in current row */
 219   int MCU_vert_offset;          /* counts MCU rows within iMCU row */
 220   int MCU_rows_per_iMCU_row;    /* number of such rows needed */
 221
 222   /* Virtual block array for each component. */
 223   jvirt_barray_ptr * whole_image;
 224
 225   /* Workspace for constructing dummy blocks at right/bottom edges. */
 226   JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
 227 } my_coef_controller;
 228
 229 typedef my_coef_controller * my_coef_ptr;
 230
 231
 232 LOCAL(void)
 233 start_iMCU_row (j_compress_ptr cinfo)
 234 /* Reset within-iMCU-row counters for a new row */
 235 {
 236   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 237
 238   /* In an interleaved scan, an MCU row is the same as an iMCU row.
 239    * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
 240    * But at the bottom of the image, process only what's left.
 241    */
 242   if (cinfo->comps_in_scan > 1) {
 243     coef->MCU_rows_per_iMCU_row = 1;
 244   } else {
 245     if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
 246       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
 247     else
 248       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
 249   }
 250
 251   coef->mcu_ctr = 0;
 252   coef->MCU_vert_offset = 0;
 253 }
 254
 255 /*
 256  * Initialize for a processing pass.
 257  */
 258
 259 METHODDEF(void)
 260 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
 261 {
 262   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 263
 264   if (pass_mode != JBUF_CRANK_DEST)
 265     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 266
 267   coef->iMCU_row_num = 0;
 268   start_iMCU_row(cinfo);
 269 }
 270
 271
 272 /*
 273  * Process some data.
 274  * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
 275  * per call, ie, v_samp_factor block rows for each component in the scan.
 276  * The data is obtained from the virtual arrays and fed to the entropy coder.
 277  * Returns TRUE if the iMCU row is completed, FALSE if suspended.
 278  *
 279  * NB: input_buf is ignored; it is likely to be a NULL pointer.
 280  */
 281
 282 METHODDEF(boolean)
 283 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
 284 {
 285   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
 286   JDIMENSION MCU_col_num;       /* index of current MCU within row */
 287   JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
 288   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
 289   int blkn, ci, xindex, yindex, yoffset, blockcnt;
 290   JDIMENSION start_col;
 291   JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
 292   JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
 293   JBLOCKROW buffer_ptr;
 294   jpeg_component_info *compptr;
 295
 296   /* Align the virtual buffers for the components used in this scan. */
 297   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 298     compptr = cinfo->cur_comp_info[ci];
 299     buffer[ci] = (*cinfo->mem->access_virt_barray)
 300       ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
 301        coef->iMCU_row_num * compptr->v_samp_factor,
 302        (JDIMENSION) compptr->v_samp_factor, FALSE);
 303   }
 304
 305   /* Loop to process one whole iMCU row */
 306   for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
 307        yoffset++) {
 308     for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
 309          MCU_col_num++) {
 310       /* Construct list of pointers to DCT blocks belonging to this MCU */
 311       blkn = 0;                 /* index of current DCT block within MCU */
 312       for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 313         compptr = cinfo->cur_comp_info[ci];
 314         start_col = MCU_col_num * compptr->MCU_width;
 315         blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
 316                                                 : compptr->last_col_width;
 317         for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
 318           if (coef->iMCU_row_num < last_iMCU_row ||
 319               yindex+yoffset < compptr->last_row_height) {
 320             /* Fill in pointers to real blocks in this row */
 321             buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
 322             for (xindex = 0; xindex < blockcnt; xindex++)
 323               MCU_buffer[blkn++] = buffer_ptr++;
 324           } else {
 325             /* At bottom of image, need a whole row of dummy blocks */
 326             xindex = 0;
 327           }
 328           /* Fill in any dummy blocks needed in this row.
 329            * Dummy blocks are filled in the same way as in jccoefct.c:
 330            * all zeroes in the AC entries, DC entries equal to previous
 331            * block's DC value.  The init routine has already zeroed the
 332            * AC entries, so we need only set the DC entries correctly.
 333            */
 334           for (; xindex < compptr->MCU_width; xindex++) {
 335             MCU_buffer[blkn] = coef->dummy_buffer[blkn];
 336             MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
 337             blkn++;
 338           }
 339         }
 340       }
 341       /* Try to write the MCU. */
 342       if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
 343         /* Suspension forced; update state counters and exit */
 344         coef->MCU_vert_offset = yoffset;
 345         coef->mcu_ctr = MCU_col_num;
 346         return FALSE;
 347       }
 348     }
 349     /* Completed an MCU row, but perhaps not an iMCU row */
 350     coef->mcu_ctr = 0;
 351   }
 352   /* Completed the iMCU row, advance counters for next one */
 353   coef->iMCU_row_num++;
 354   start_iMCU_row(cinfo);
 355   return TRUE;
 356 }
 357
 358
 359 /*
 360  * Initialize coefficient buffer controller.
 361  *
 362  * Each passed coefficient array must be the right size for that
 363  * coefficient: width_in_blocks wide and height_in_blocks high,
 364  * with unitheight at least v_samp_factor.
 365  */
 366
 367 LOCAL(void)
 368 transencode_coef_controller (j_compress_ptr cinfo,
 369                              jvirt_barray_ptr * coef_arrays)
 370 {
 371   my_coef_ptr coef;
 372   JBLOCKROW buffer;
 373   int i;
 374
 375   coef = (my_coef_ptr)
 376     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 377                                 SIZEOF(my_coef_controller));
 378   cinfo->coef = (struct jpeg_c_coef_controller *) coef;
 379   coef->pub.start_pass = start_pass_coef;
 380   coef->pub.compress_data = compress_output;
 381
 382   /* Save pointer to virtual arrays */
 383   coef->whole_image = coef_arrays;
 384
 385   /* Allocate and pre-zero space for dummy DCT blocks. */
 386   buffer = (JBLOCKROW)
 387     (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 388                                 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
 389   jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
 390   for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
 391     coef->dummy_buffer[i] = buffer + i;
 392   }
 393 }
 394
 395 #if defined(__VISAGECPP__)
 396 #  ifdef start_pass_coef2
 397 #   undef start_pass_coef2
 398 #  endif
 399 #  ifdef compress_output2
 400 #    undef compress_output2
 401 #  endif
 402 #endif