compiler/libjpeg/main/jctrans.c

   1 /*
   2     $Id$
   3 */
   4
   5 /*
   6  * jctrans.c
   7  *
   8  * Copyright (C) 1995-1998, Thomas G. Lane.
   9  * This file is part of the Independent JPEG Group's software.
  10  * For conditions of distribution and use, see the accompanying README file.
  11  *
  12  * This file contains library routines for transcoding compression,
  13  * that is, writing raw DCT coefficient arrays to an output JPEG file.
  14  * The routines in jcapimin.c will also be needed by a transcoder.
  15  */
  16
  17 #define JPEG_INTERNALS
  18 #include "jinclude.h"
  19 #include "jpeglib.h"
  20 #include "jlossy.h"             /* Private declarations for lossy codec */
  21
  22
  23 /* Forward declarations */
  24 LOCAL(void) transencode_master_selection
  25         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  26 LOCAL(void) transencode_codec
  27         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  28 LOCAL(void) transencode_coef_controller
  29         JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  30
  31
  32 /*
  33  * Compression initialization for writing raw-coefficient data.
  34  * Before calling this, all parameters and a data destination must be set up.
  35  * Call jpeg_finish_compress() to actually write the data.
  36  *
  37  * The number of passed virtual arrays must match cinfo->num_components.
  38  * Note that the virtual arrays need not be filled or even realized at
  39  * the time write_coefficients is called; indeed, if the virtual arrays
  40  * were requested from this compression object's memory manager, they
  41  * typically will be realized during this routine and filled afterwards.
  42  */
  43
  44 JGLOBAL(void)
  45 jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
  46 {
  47   if (cinfo->global_state != CSTATE_START)
  48     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  49   /* Mark all tables to be written */
  50   jpeg_suppress_tables(cinfo, FALSE);
  51   /* (Re)initialize error mgr and destination modules */
  52   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
  53   (*cinfo->dest->init_destination) (cinfo);
  54   /* Perform master selection of active modules */
  55   transencode_master_selection(cinfo, coef_arrays);
  56   /* Wait for jpeg_finish_compress() call */
  57   cinfo->next_scanline = 0;     /* so jpeg_write_marker works */
  58   cinfo->global_state = CSTATE_WRCOEFS;
  59 }
  60
  61
  62 /*
  63  * Initialize the compression object with default parameters,
  64  * then copy from the source object all parameters needed for lossless
  65  * transcoding.  Parameters that can be varied without loss (such as
  66  * scan script and Huffman optimization) are left in their default states.
  67  */
  68
  69 JGLOBAL(void)
  70 jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
  71                                j_compress_ptr dstinfo)
  72 {
  73   JQUANT_TBL ** qtblptr;
  74   jpeg_component_info *incomp, *outcomp;
  75   JQUANT_TBL *c_quant, *slot_quant;
  76   int tblno, ci, coefi;
  77
  78   /* Safety check to ensure start_compress not called yet. */
  79   if (dstinfo->global_state != CSTATE_START)
  80     ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
  81   /* Copy fundamental image dimensions */
  82   dstinfo->image_width = srcinfo->image_width;
  83   dstinfo->image_height = srcinfo->image_height;
  84   dstinfo->input_components = srcinfo->num_components;
  85   dstinfo->in_color_space = srcinfo->jpeg_color_space;
  86   /* Initialize all parameters to default values */
  87   jpeg_set_defaults(dstinfo);
  88   /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
  89    * Fix it to get the right header markers for the image colorspace.
  90    */
  91   jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
  92   dstinfo->data_precision = srcinfo->data_precision;
  93   dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
  94   /* Copy the source's quantization tables. */
  95   for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
  96     if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
  97       qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
  98       if (*qtblptr == NULL)
  99         *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
 100       MEMCOPY((*qtblptr)->quantval,
 101               srcinfo->quant_tbl_ptrs[tblno]->quantval,
 102               SIZEOF((*qtblptr)->quantval));
 103       (*qtblptr)->sent_table = FALSE;
 104     }
 105   }
 106   /* Copy the source's per-component info.
 107    * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
 108    */
 109   dstinfo->num_components = srcinfo->num_components;
 110   if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
 111     ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
 112              MAX_COMPONENTS);
 113   for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
 114        ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
 115     outcomp->component_id = incomp->component_id;
 116     outcomp->h_samp_factor = incomp->h_samp_factor;
 117     outcomp->v_samp_factor = incomp->v_samp_factor;
 118     outcomp->quant_tbl_no = incomp->quant_tbl_no;
 119     /* Make sure saved quantization table for component matches the qtable
 120      * slot.  If not, the input file re-used this qtable slot.
 121      * IJG encoder currently cannot duplicate this.
 122      */
 123     tblno = outcomp->quant_tbl_no;
 124     if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
 125         srcinfo->quant_tbl_ptrs[tblno] == NULL)
 126       ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
 127     slot_quant = srcinfo->quant_tbl_ptrs[tblno];
 128     c_quant = incomp->quant_table;
 129     if (c_quant != NULL) {
 130       for (coefi = 0; coefi < DCTSIZE2; coefi++) {
 131         if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
 132           ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
 133       }
 134     }
 135     /* Note: we do not copy the source's Huffman table assignments;
 136      * instead we rely on jpeg_set_colorspace to have made a suitable choice.
 137      */
 138   }
 139   /* Also copy JFIF version and resolution information, if available.
 140    * Strictly speaking this isn't "critical" info, but it's nearly
 141    * always appropriate to copy it if available.  In particular,
 142    * if the application chooses to copy JFIF 1.02 extension markers from
 143    * the source file, we need to copy the version to make sure we don't
 144    * emit a file that has 1.02 extensions but a claimed version of 1.01.
 145    * We will *not*, however, copy version info from mislabeled "2.01" files.
 146    */
 147   if (srcinfo->saw_JFIF_marker) {
 148     if (srcinfo->JFIF_major_version == 1) {
 149       dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
 150       dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
 151     }
 152     dstinfo->density_unit = srcinfo->density_unit;
 153     dstinfo->X_density = srcinfo->X_density;
 154     dstinfo->Y_density = srcinfo->Y_density;
 155   }
 156 }
 157
 158
 159 /*
 160  * Master selection of compression modules for transcoding.
 161  * This substitutes for jcinit.c's initialization of the full compressor.
 162  */
 163
 164 LOCAL(void)
 165 transencode_master_selection (j_compress_ptr cinfo,
 166                               jvirt_barray_ptr * coef_arrays)
 167 {
 168   cinfo->data_unit = DCTSIZE;
 169   /* Although we don't actually use input_components for transcoding,
 170    * jcmaster.c's initial_setup will complain if input_components is 0.
 171    */
 172   cinfo->input_components = 1;
 173   /* Initialize master control (includes parameter checking/processing) */
 174   jinit_c_master_control(cinfo, TRUE /* transcode only */);
 175
 176   /* We need a special compression codec. */
 177   transencode_codec(cinfo, coef_arrays);
 178
 179   jinit_marker_writer(cinfo);
 180
 181   /* We can now tell the memory manager to allocate virtual arrays. */
 182   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
 183
 184   /* Write the datastream header (SOI, JFIF) immediately.
 185    * Frame and scan headers are postponed till later.
 186    * This lets application insert special markers after the SOI.
 187    */
 188   (*cinfo->marker->write_file_header) (cinfo);
 189 }
 190
 191
 192 /*
 193  * The rest of this file is a special implementation of the coefficient
 194  * buffer controller.  This is similar to jccoefct.c, but it handles only
 195  * output from presupplied virtual arrays.  Furthermore, we generate any
 196  * dummy padding blocks on-the-fly rather than expecting them to be present
 197  * in the arrays.
 198  */
 199
 200 /* Private buffer controller object */
 201
 202 typedef struct {
 203   JDIMENSION iMCU_row_num;      /* iMCU row # within image */
 204   JDIMENSION mcu_ctr;           /* counts MCUs processed in current row */
 205   int MCU_vert_offset;          /* counts MCU rows within iMCU row */
 206   int MCU_rows_per_iMCU_row;    /* number of such rows needed */
 207
 208   /* Virtual block array for each component. */
 209   jvirt_barray_ptr * whole_image;
 210
 211   /* Workspace for constructing dummy blocks at right/bottom edges. */
 212   JBLOCKROW dummy_buffer[C_MAX_DATA_UNITS_IN_MCU];
 213 } c_coef_controller;
 214
 215 typedef c_coef_controller * c_coef_ptr;
 216
 217
 218 LOCAL(void)
 219 start_iMCU_row (j_compress_ptr cinfo)
 220 /* Reset within-iMCU-row counters for a new row */
 221 {
 222   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 223   c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
 224
 225   /* In an interleaved scan, an MCU row is the same as an iMCU row.
 226    * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
 227    * But at the bottom of the image, process only what's left.
 228    */
 229   if (cinfo->comps_in_scan > 1) {
 230     coef->MCU_rows_per_iMCU_row = 1;
 231   } else {
 232     if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
 233       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
 234     else
 235       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
 236   }
 237
 238   coef->mcu_ctr = 0;
 239   coef->MCU_vert_offset = 0;
 240 }
 241
 242
 243 /*
 244  * Initialize for a processing pass.
 245  */
 246
 247 METHODDEF(void)
 248 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
 249 {
 250   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 251   c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
 252
 253   if (pass_mode != JBUF_CRANK_DEST)
 254     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 255
 256   coef->iMCU_row_num = 0;
 257   start_iMCU_row(cinfo);
 258 }
 259
 260
 261 /*
 262  * Process some data.
 263  * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
 264  * per call, ie, v_samp_factor block rows for each component in the scan.
 265  * The data is obtained from the virtual arrays and fed to the entropy coder.
 266  * Returns TRUE if the iMCU row is completed, FALSE if suspended.
 267  *
 268  * NB: input_buf is ignored; it is likely to be a NULL pointer.
 269  */
 270
 271 METHODDEF(boolean)
 272 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
 273 {
 274   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 275   c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
 276   JDIMENSION MCU_col_num;       /* index of current MCU within row */
 277   JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
 278   JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
 279   int blkn, ci, xindex, yindex, yoffset, blockcnt;
 280   JDIMENSION start_col;
 281   JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
 282   JBLOCKROW MCU_buffer[C_MAX_DATA_UNITS_IN_MCU];
 283   JBLOCKROW buffer_ptr;
 284   jpeg_component_info *compptr;
 285
 286   /* Align the virtual buffers for the components used in this scan. */
 287   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 288     compptr = cinfo->cur_comp_info[ci];
 289     buffer[ci] = (*cinfo->mem->access_virt_barray)
 290       ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
 291        coef->iMCU_row_num * compptr->v_samp_factor,
 292        (JDIMENSION) compptr->v_samp_factor, FALSE);
 293   }
 294
 295   /* Loop to process one whole iMCU row */
 296   for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
 297        yoffset++) {
 298     for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
 299          MCU_col_num++) {
 300       /* Construct list of pointers to DCT blocks belonging to this MCU */
 301       blkn = 0;                 /* index of current DCT block within MCU */
 302       for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 303         compptr = cinfo->cur_comp_info[ci];
 304         start_col = MCU_col_num * compptr->MCU_width;
 305         blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
 306                                                 : compptr->last_col_width;
 307         for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
 308           if (coef->iMCU_row_num < last_iMCU_row ||
 309               yindex+yoffset < compptr->last_row_height) {
 310             /* Fill in pointers to real blocks in this row */
 311             buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
 312             for (xindex = 0; xindex < blockcnt; xindex++)
 313               MCU_buffer[blkn++] = buffer_ptr++;
 314           } else {
 315             /* At bottom of image, need a whole row of dummy blocks */
 316             xindex = 0;
 317           }
 318           /* Fill in any dummy blocks needed in this row.
 319            * Dummy blocks are filled in the same way as in jccoefct.c:
 320            * all zeroes in the AC entries, DC entries equal to previous
 321            * block's DC value.  The init routine has already zeroed the
 322            * AC entries, so we need only set the DC entries correctly.
 323            */
 324           for (; xindex < compptr->MCU_width; xindex++) {
 325             MCU_buffer[blkn] = coef->dummy_buffer[blkn];
 326             MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
 327             blkn++;
 328           }
 329         }
 330       }
 331       /* Try to write the MCU. */
 332       if (! (*lossyc->entropy_encode_mcu) (cinfo, MCU_buffer)) {
 333         /* Suspension forced; update state counters and exit */
 334         coef->MCU_vert_offset = yoffset;
 335         coef->mcu_ctr = MCU_col_num;
 336         return FALSE;
 337       }
 338     }
 339     /* Completed an MCU row, but perhaps not an iMCU row */
 340     coef->mcu_ctr = 0;
 341   }
 342   /* Completed the iMCU row, advance counters for next one */
 343   coef->iMCU_row_num++;
 344   start_iMCU_row(cinfo);
 345   return TRUE;
 346 }
 347
 348
 349 /*
 350  * Initialize coefficient buffer controller.
 351  *
 352  * Each passed coefficient array must be the right size for that
 353  * coefficient: width_in_data_units wide and height_in_data_units high,
 354  * with unitheight at least v_samp_factor.
 355  */
 356
 357 LOCAL(void)
 358 transencode_coef_controller (j_compress_ptr cinfo,
 359                              jvirt_barray_ptr * coef_arrays)
 360 {
 361   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
 362   c_coef_ptr coef;
 363   JBLOCKROW buffer;
 364   int i;
 365
 366   coef = (c_coef_ptr)
 367     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 368                                 SIZEOF(c_coef_controller));
 369   lossyc->coef_private = (struct jpeg_c_coef_controller *) coef;
 370
 371   /* Save pointer to virtual arrays */
 372   coef->whole_image = coef_arrays;
 373
 374   /* Allocate and pre-zero space for dummy DCT blocks. */
 375   buffer = (JBLOCKROW)
 376     (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 377                                 C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
 378   jzero_far((void FAR *) buffer, C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
 379   for (i = 0; i < C_MAX_DATA_UNITS_IN_MCU; i++) {
 380     coef->dummy_buffer[i] = buffer + i;
 381   }
 382 }
 383
 384
 385 /*
 386  * Initialize the transencoer codec.
 387  * This is called only once, during master selection.
 388  */
 389
 390 LOCAL(void)
 391 transencode_codec (j_compress_ptr cinfo,
 392                    jvirt_barray_ptr * coef_arrays)
 393 {
 394   j_lossy_c_ptr lossyc;
 395
 396   /* Create subobject in permanent pool */
 397   lossyc = (j_lossy_c_ptr)
 398     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
 399                                 SIZEOF(jpeg_lossy_c_codec));
 400   cinfo->codec = (struct jpeg_c_codec *) lossyc;
 401
 402   /* Initialize sub-modules */
 403
 404   /* Entropy encoding: either Huffman or arithmetic coding. */
 405   if (cinfo->arith_code) {
 406     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
 407   } else {
 408     if (cinfo->process == JPROC_PROGRESSIVE) {
 409 #ifdef C_PROGRESSIVE_SUPPORTED
 410       jinit_phuff_encoder(cinfo);
 411 #else
 412       ERREXIT(cinfo, JERR_NOT_COMPILED);
 413 #endif
 414     } else
 415       jinit_shuff_encoder(cinfo);
 416   }
 417
 418   /* We need a special coefficient buffer controller. */
 419   transencode_coef_controller(cinfo, coef_arrays);
 420
 421   /* Initialize method pointers */
 422   lossyc->pub.start_pass = start_pass_coef;
 423   lossyc->pub.compress_data = compress_output;
 424 }