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annotate libs/libjpeg/jctrans.c @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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nuclear@0 1 /*
nuclear@0 2 * jctrans.c
nuclear@0 3 *
nuclear@0 4 * Copyright (C) 1995-1998, Thomas G. Lane.
nuclear@0 5 * This file is part of the Independent JPEG Group's software.
nuclear@0 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@0 7 *
nuclear@0 8 * This file contains library routines for transcoding compression,
nuclear@0 9 * that is, writing raw DCT coefficient arrays to an output JPEG file.
nuclear@0 10 * The routines in jcapimin.c will also be needed by a transcoder.
nuclear@0 11 */
nuclear@0 12
nuclear@0 13 #define JPEG_INTERNALS
nuclear@0 14 #include "jinclude.h"
nuclear@0 15 #include "jpeglib.h"
nuclear@0 16
nuclear@0 17
nuclear@0 18 /* Forward declarations */
nuclear@0 19 LOCAL(void) transencode_master_selection
nuclear@0 20 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
nuclear@0 21 LOCAL(void) transencode_coef_controller
nuclear@0 22 JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
nuclear@0 23
nuclear@0 24
nuclear@0 25 /*
nuclear@0 26 * Compression initialization for writing raw-coefficient data.
nuclear@0 27 * Before calling this, all parameters and a data destination must be set up.
nuclear@0 28 * Call jpeg_finish_compress() to actually write the data.
nuclear@0 29 *
nuclear@0 30 * The number of passed virtual arrays must match cinfo->num_components.
nuclear@0 31 * Note that the virtual arrays need not be filled or even realized at
nuclear@0 32 * the time write_coefficients is called; indeed, if the virtual arrays
nuclear@0 33 * were requested from this compression object's memory manager, they
nuclear@0 34 * typically will be realized during this routine and filled afterwards.
nuclear@0 35 */
nuclear@0 36
nuclear@0 37 GLOBAL(void)
nuclear@0 38 jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
nuclear@0 39 {
nuclear@0 40 if (cinfo->global_state != CSTATE_START)
nuclear@0 41 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@0 42 /* Mark all tables to be written */
nuclear@0 43 jpeg_suppress_tables(cinfo, FALSE);
nuclear@0 44 /* (Re)initialize error mgr and destination modules */
nuclear@0 45 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
nuclear@0 46 (*cinfo->dest->init_destination) (cinfo);
nuclear@0 47 /* Perform master selection of active modules */
nuclear@0 48 transencode_master_selection(cinfo, coef_arrays);
nuclear@0 49 /* Wait for jpeg_finish_compress() call */
nuclear@0 50 cinfo->next_scanline = 0; /* so jpeg_write_marker works */
nuclear@0 51 cinfo->global_state = CSTATE_WRCOEFS;
nuclear@0 52 }
nuclear@0 53
nuclear@0 54
nuclear@0 55 /*
nuclear@0 56 * Initialize the compression object with default parameters,
nuclear@0 57 * then copy from the source object all parameters needed for lossless
nuclear@0 58 * transcoding. Parameters that can be varied without loss (such as
nuclear@0 59 * scan script and Huffman optimization) are left in their default states.
nuclear@0 60 */
nuclear@0 61
nuclear@0 62 GLOBAL(void)
nuclear@0 63 jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
nuclear@0 64 j_compress_ptr dstinfo)
nuclear@0 65 {
nuclear@0 66 JQUANT_TBL ** qtblptr;
nuclear@0 67 jpeg_component_info *incomp, *outcomp;
nuclear@0 68 JQUANT_TBL *c_quant, *slot_quant;
nuclear@0 69 int tblno, ci, coefi;
nuclear@0 70
nuclear@0 71 /* Safety check to ensure start_compress not called yet. */
nuclear@0 72 if (dstinfo->global_state != CSTATE_START)
nuclear@0 73 ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
nuclear@0 74 /* Copy fundamental image dimensions */
nuclear@0 75 dstinfo->image_width = srcinfo->image_width;
nuclear@0 76 dstinfo->image_height = srcinfo->image_height;
nuclear@0 77 dstinfo->input_components = srcinfo->num_components;
nuclear@0 78 dstinfo->in_color_space = srcinfo->jpeg_color_space;
nuclear@0 79 /* Initialize all parameters to default values */
nuclear@0 80 jpeg_set_defaults(dstinfo);
nuclear@0 81 /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
nuclear@0 82 * Fix it to get the right header markers for the image colorspace.
nuclear@0 83 */
nuclear@0 84 jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
nuclear@0 85 dstinfo->data_precision = srcinfo->data_precision;
nuclear@0 86 dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
nuclear@0 87 /* Copy the source's quantization tables. */
nuclear@0 88 for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
nuclear@0 89 if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
nuclear@0 90 qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
nuclear@0 91 if (*qtblptr == NULL)
nuclear@0 92 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
nuclear@0 93 MEMCOPY((*qtblptr)->quantval,
nuclear@0 94 srcinfo->quant_tbl_ptrs[tblno]->quantval,
nuclear@0 95 SIZEOF((*qtblptr)->quantval));
nuclear@0 96 (*qtblptr)->sent_table = FALSE;
nuclear@0 97 }
nuclear@0 98 }
nuclear@0 99 /* Copy the source's per-component info.
nuclear@0 100 * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
nuclear@0 101 */
nuclear@0 102 dstinfo->num_components = srcinfo->num_components;
nuclear@0 103 if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
nuclear@0 104 ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
nuclear@0 105 MAX_COMPONENTS);
nuclear@0 106 for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
nuclear@0 107 ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
nuclear@0 108 outcomp->component_id = incomp->component_id;
nuclear@0 109 outcomp->h_samp_factor = incomp->h_samp_factor;
nuclear@0 110 outcomp->v_samp_factor = incomp->v_samp_factor;
nuclear@0 111 outcomp->quant_tbl_no = incomp->quant_tbl_no;
nuclear@0 112 /* Make sure saved quantization table for component matches the qtable
nuclear@0 113 * slot. If not, the input file re-used this qtable slot.
nuclear@0 114 * IJG encoder currently cannot duplicate this.
nuclear@0 115 */
nuclear@0 116 tblno = outcomp->quant_tbl_no;
nuclear@0 117 if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
nuclear@0 118 srcinfo->quant_tbl_ptrs[tblno] == NULL)
nuclear@0 119 ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
nuclear@0 120 slot_quant = srcinfo->quant_tbl_ptrs[tblno];
nuclear@0 121 c_quant = incomp->quant_table;
nuclear@0 122 if (c_quant != NULL) {
nuclear@0 123 for (coefi = 0; coefi < DCTSIZE2; coefi++) {
nuclear@0 124 if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
nuclear@0 125 ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
nuclear@0 126 }
nuclear@0 127 }
nuclear@0 128 /* Note: we do not copy the source's Huffman table assignments;
nuclear@0 129 * instead we rely on jpeg_set_colorspace to have made a suitable choice.
nuclear@0 130 */
nuclear@0 131 }
nuclear@0 132 /* Also copy JFIF version and resolution information, if available.
nuclear@0 133 * Strictly speaking this isn't "critical" info, but it's nearly
nuclear@0 134 * always appropriate to copy it if available. In particular,
nuclear@0 135 * if the application chooses to copy JFIF 1.02 extension markers from
nuclear@0 136 * the source file, we need to copy the version to make sure we don't
nuclear@0 137 * emit a file that has 1.02 extensions but a claimed version of 1.01.
nuclear@0 138 * We will *not*, however, copy version info from mislabeled "2.01" files.
nuclear@0 139 */
nuclear@0 140 if (srcinfo->saw_JFIF_marker) {
nuclear@0 141 if (srcinfo->JFIF_major_version == 1) {
nuclear@0 142 dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
nuclear@0 143 dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
nuclear@0 144 }
nuclear@0 145 dstinfo->density_unit = srcinfo->density_unit;
nuclear@0 146 dstinfo->X_density = srcinfo->X_density;
nuclear@0 147 dstinfo->Y_density = srcinfo->Y_density;
nuclear@0 148 }
nuclear@0 149 }
nuclear@0 150
nuclear@0 151
nuclear@0 152 /*
nuclear@0 153 * Master selection of compression modules for transcoding.
nuclear@0 154 * This substitutes for jcinit.c's initialization of the full compressor.
nuclear@0 155 */
nuclear@0 156
nuclear@0 157 LOCAL(void)
nuclear@0 158 transencode_master_selection (j_compress_ptr cinfo,
nuclear@0 159 jvirt_barray_ptr * coef_arrays)
nuclear@0 160 {
nuclear@0 161 /* Although we don't actually use input_components for transcoding,
nuclear@0 162 * jcmaster.c's initial_setup will complain if input_components is 0.
nuclear@0 163 */
nuclear@0 164 cinfo->input_components = 1;
nuclear@0 165 /* Initialize master control (includes parameter checking/processing) */
nuclear@0 166 jinit_c_master_control(cinfo, TRUE /* transcode only */);
nuclear@0 167
nuclear@0 168 /* Entropy encoding: either Huffman or arithmetic coding. */
nuclear@0 169 if (cinfo->arith_code) {
nuclear@0 170 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
nuclear@0 171 } else {
nuclear@0 172 if (cinfo->progressive_mode) {
nuclear@0 173 #ifdef C_PROGRESSIVE_SUPPORTED
nuclear@0 174 jinit_phuff_encoder(cinfo);
nuclear@0 175 #else
nuclear@0 176 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@0 177 #endif
nuclear@0 178 } else
nuclear@0 179 jinit_huff_encoder(cinfo);
nuclear@0 180 }
nuclear@0 181
nuclear@0 182 /* We need a special coefficient buffer controller. */
nuclear@0 183 transencode_coef_controller(cinfo, coef_arrays);
nuclear@0 184
nuclear@0 185 jinit_marker_writer(cinfo);
nuclear@0 186
nuclear@0 187 /* We can now tell the memory manager to allocate virtual arrays. */
nuclear@0 188 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
nuclear@0 189
nuclear@0 190 /* Write the datastream header (SOI, JFIF) immediately.
nuclear@0 191 * Frame and scan headers are postponed till later.
nuclear@0 192 * This lets application insert special markers after the SOI.
nuclear@0 193 */
nuclear@0 194 (*cinfo->marker->write_file_header) (cinfo);
nuclear@0 195 }
nuclear@0 196
nuclear@0 197
nuclear@0 198 /*
nuclear@0 199 * The rest of this file is a special implementation of the coefficient
nuclear@0 200 * buffer controller. This is similar to jccoefct.c, but it handles only
nuclear@0 201 * output from presupplied virtual arrays. Furthermore, we generate any
nuclear@0 202 * dummy padding blocks on-the-fly rather than expecting them to be present
nuclear@0 203 * in the arrays.
nuclear@0 204 */
nuclear@0 205
nuclear@0 206 /* Private buffer controller object */
nuclear@0 207
nuclear@0 208 typedef struct {
nuclear@0 209 struct jpeg_c_coef_controller pub; /* public fields */
nuclear@0 210
nuclear@0 211 JDIMENSION iMCU_row_num; /* iMCU row # within image */
nuclear@0 212 JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
nuclear@0 213 int MCU_vert_offset; /* counts MCU rows within iMCU row */
nuclear@0 214 int MCU_rows_per_iMCU_row; /* number of such rows needed */
nuclear@0 215
nuclear@0 216 /* Virtual block array for each component. */
nuclear@0 217 jvirt_barray_ptr * whole_image;
nuclear@0 218
nuclear@0 219 /* Workspace for constructing dummy blocks at right/bottom edges. */
nuclear@0 220 JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
nuclear@0 221 } my_coef_controller;
nuclear@0 222
nuclear@0 223 typedef my_coef_controller * my_coef_ptr;
nuclear@0 224
nuclear@0 225
nuclear@0 226 LOCAL(void)
nuclear@0 227 start_iMCU_row (j_compress_ptr cinfo)
nuclear@0 228 /* Reset within-iMCU-row counters for a new row */
nuclear@0 229 {
nuclear@0 230 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
nuclear@0 231
nuclear@0 232 /* In an interleaved scan, an MCU row is the same as an iMCU row.
nuclear@0 233 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
nuclear@0 234 * But at the bottom of the image, process only what's left.
nuclear@0 235 */
nuclear@0 236 if (cinfo->comps_in_scan > 1) {
nuclear@0 237 coef->MCU_rows_per_iMCU_row = 1;
nuclear@0 238 } else {
nuclear@0 239 if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
nuclear@0 240 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
nuclear@0 241 else
nuclear@0 242 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
nuclear@0 243 }
nuclear@0 244
nuclear@0 245 coef->mcu_ctr = 0;
nuclear@0 246 coef->MCU_vert_offset = 0;
nuclear@0 247 }
nuclear@0 248
nuclear@0 249
nuclear@0 250 /*
nuclear@0 251 * Initialize for a processing pass.
nuclear@0 252 */
nuclear@0 253
nuclear@0 254 METHODDEF(void)
nuclear@0 255 start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
nuclear@0 256 {
nuclear@0 257 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
nuclear@0 258
nuclear@0 259 if (pass_mode != JBUF_CRANK_DEST)
nuclear@0 260 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@0 261
nuclear@0 262 coef->iMCU_row_num = 0;
nuclear@0 263 start_iMCU_row(cinfo);
nuclear@0 264 }
nuclear@0 265
nuclear@0 266
nuclear@0 267 /*
nuclear@0 268 * Process some data.
nuclear@0 269 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
nuclear@0 270 * per call, ie, v_samp_factor block rows for each component in the scan.
nuclear@0 271 * The data is obtained from the virtual arrays and fed to the entropy coder.
nuclear@0 272 * Returns TRUE if the iMCU row is completed, FALSE if suspended.
nuclear@0 273 *
nuclear@0 274 * NB: input_buf is ignored; it is likely to be a NULL pointer.
nuclear@0 275 */
nuclear@0 276
nuclear@0 277 METHODDEF(boolean)
nuclear@0 278 compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
nuclear@0 279 {
nuclear@0 280 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
nuclear@0 281 JDIMENSION MCU_col_num; /* index of current MCU within row */
nuclear@0 282 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
nuclear@0 283 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
nuclear@0 284 int blkn, ci, xindex, yindex, yoffset, blockcnt;
nuclear@0 285 JDIMENSION start_col;
nuclear@0 286 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
nuclear@0 287 JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
nuclear@0 288 JBLOCKROW buffer_ptr;
nuclear@0 289 jpeg_component_info *compptr;
nuclear@0 290
nuclear@0 291 /* Align the virtual buffers for the components used in this scan. */
nuclear@0 292 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
nuclear@0 293 compptr = cinfo->cur_comp_info[ci];
nuclear@0 294 buffer[ci] = (*cinfo->mem->access_virt_barray)
nuclear@0 295 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
nuclear@0 296 coef->iMCU_row_num * compptr->v_samp_factor,
nuclear@0 297 (JDIMENSION) compptr->v_samp_factor, FALSE);
nuclear@0 298 }
nuclear@0 299
nuclear@0 300 /* Loop to process one whole iMCU row */
nuclear@0 301 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
nuclear@0 302 yoffset++) {
nuclear@0 303 for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
nuclear@0 304 MCU_col_num++) {
nuclear@0 305 /* Construct list of pointers to DCT blocks belonging to this MCU */
nuclear@0 306 blkn = 0; /* index of current DCT block within MCU */
nuclear@0 307 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
nuclear@0 308 compptr = cinfo->cur_comp_info[ci];
nuclear@0 309 start_col = MCU_col_num * compptr->MCU_width;
nuclear@0 310 blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
nuclear@0 311 : compptr->last_col_width;
nuclear@0 312 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
nuclear@0 313 if (coef->iMCU_row_num < last_iMCU_row ||
nuclear@0 314 yindex+yoffset < compptr->last_row_height) {
nuclear@0 315 /* Fill in pointers to real blocks in this row */
nuclear@0 316 buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
nuclear@0 317 for (xindex = 0; xindex < blockcnt; xindex++)
nuclear@0 318 MCU_buffer[blkn++] = buffer_ptr++;
nuclear@0 319 } else {
nuclear@0 320 /* At bottom of image, need a whole row of dummy blocks */
nuclear@0 321 xindex = 0;
nuclear@0 322 }
nuclear@0 323 /* Fill in any dummy blocks needed in this row.
nuclear@0 324 * Dummy blocks are filled in the same way as in jccoefct.c:
nuclear@0 325 * all zeroes in the AC entries, DC entries equal to previous
nuclear@0 326 * block's DC value. The init routine has already zeroed the
nuclear@0 327 * AC entries, so we need only set the DC entries correctly.
nuclear@0 328 */
nuclear@0 329 for (; xindex < compptr->MCU_width; xindex++) {
nuclear@0 330 MCU_buffer[blkn] = coef->dummy_buffer[blkn];
nuclear@0 331 MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
nuclear@0 332 blkn++;
nuclear@0 333 }
nuclear@0 334 }
nuclear@0 335 }
nuclear@0 336 /* Try to write the MCU. */
nuclear@0 337 if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
nuclear@0 338 /* Suspension forced; update state counters and exit */
nuclear@0 339 coef->MCU_vert_offset = yoffset;
nuclear@0 340 coef->mcu_ctr = MCU_col_num;
nuclear@0 341 return FALSE;
nuclear@0 342 }
nuclear@0 343 }
nuclear@0 344 /* Completed an MCU row, but perhaps not an iMCU row */
nuclear@0 345 coef->mcu_ctr = 0;
nuclear@0 346 }
nuclear@0 347 /* Completed the iMCU row, advance counters for next one */
nuclear@0 348 coef->iMCU_row_num++;
nuclear@0 349 start_iMCU_row(cinfo);
nuclear@0 350 return TRUE;
nuclear@0 351 }
nuclear@0 352
nuclear@0 353
nuclear@0 354 /*
nuclear@0 355 * Initialize coefficient buffer controller.
nuclear@0 356 *
nuclear@0 357 * Each passed coefficient array must be the right size for that
nuclear@0 358 * coefficient: width_in_blocks wide and height_in_blocks high,
nuclear@0 359 * with unitheight at least v_samp_factor.
nuclear@0 360 */
nuclear@0 361
nuclear@0 362 LOCAL(void)
nuclear@0 363 transencode_coef_controller (j_compress_ptr cinfo,
nuclear@0 364 jvirt_barray_ptr * coef_arrays)
nuclear@0 365 {
nuclear@0 366 my_coef_ptr coef;
nuclear@0 367 JBLOCKROW buffer;
nuclear@0 368 int i;
nuclear@0 369
nuclear@0 370 coef = (my_coef_ptr)
nuclear@0 371 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@0 372 SIZEOF(my_coef_controller));
nuclear@0 373 cinfo->coef = (struct jpeg_c_coef_controller *) coef;
nuclear@0 374 coef->pub.start_pass = start_pass_coef;
nuclear@0 375 coef->pub.compress_data = compress_output;
nuclear@0 376
nuclear@0 377 /* Save pointer to virtual arrays */
nuclear@0 378 coef->whole_image = coef_arrays;
nuclear@0 379
nuclear@0 380 /* Allocate and pre-zero space for dummy DCT blocks. */
nuclear@0 381 buffer = (JBLOCKROW)
nuclear@0 382 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@0 383 C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
nuclear@0 384 jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
nuclear@0 385 for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
nuclear@0 386 coef->dummy_buffer[i] = buffer + i;
nuclear@0 387 }
nuclear@0 388 }