7 * Copyright (C) 1994-1995, Thomas G. Lane.
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9 * This file is part of the Independent JPEG Group's software.
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11 * For conditions of distribution and use, see the accompanying README file.
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15 * This file contains the coefficient buffer controller for decompression.
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17 * This controller is the top level of the JPEG decompressor proper.
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19 * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
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23 * In buffered-image mode, this controller is the interface between
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25 * input-oriented processing and output-oriented processing.
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27 * Also, the input side (only) is used when reading a file for transcoding.
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33 #define JPEG_INTERNALS
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35 #include "jinclude.h"
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37 #include "radiant_jpeglib.h"
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41 /* Block smoothing is only applicable for progressive JPEG, so: */
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43 #ifndef D_PROGRESSIVE_SUPPORTED
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45 #undef BLOCK_SMOOTHING_SUPPORTED
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51 /* Private buffer controller object */
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57 struct jpeg_d_coef_controller pub; /* public fields */
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61 /* These variables keep track of the current location of the input side. */
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63 /* cinfo->input_iMCU_row is also used for this. */
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65 JDIMENSION MCU_ctr; /* counts MCUs processed in current row */
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67 int MCU_vert_offset; /* counts MCU rows within iMCU row */
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69 int MCU_rows_per_iMCU_row; /* number of such rows needed */
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73 /* The output side's location is represented by cinfo->output_iMCU_row. */
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77 /* In single-pass modes, it's sufficient to buffer just one MCU.
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79 * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
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81 * and let the entropy decoder write into that workspace each time.
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83 * (On 80x86, the workspace is FAR even though it's not really very big;
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85 * this is to keep the module interfaces unchanged when a large coefficient
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87 * buffer is necessary.)
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89 * In multi-pass modes, this array points to the current MCU's blocks
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91 * within the virtual arrays; it is used only by the input side.
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95 JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
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99 #ifdef D_MULTISCAN_FILES_SUPPORTED
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101 /* In multi-pass modes, we need a virtual block array for each component. */
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103 jvirt_barray_ptr whole_image[MAX_COMPONENTS];
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109 #ifdef BLOCK_SMOOTHING_SUPPORTED
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111 /* When doing block smoothing, we latch coefficient Al values here */
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113 int * coef_bits_latch;
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115 #define SAVED_COEFS 6 /* we save coef_bits[0..5] */
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119 } my_coef_controller;
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123 typedef my_coef_controller * my_coef_ptr;
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127 /* Forward declarations */
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129 METHODDEF int decompress_onepass
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131 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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133 #ifdef D_MULTISCAN_FILES_SUPPORTED
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135 METHODDEF int decompress_data
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137 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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141 #ifdef BLOCK_SMOOTHING_SUPPORTED
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143 LOCAL boolean smoothing_ok JPP((j_decompress_ptr cinfo));
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145 METHODDEF int decompress_smooth_data
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147 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
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157 start_iMCU_row (j_decompress_ptr cinfo)
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159 /* Reset within-iMCU-row counters for a new row (input side) */
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163 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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167 /* In an interleaved scan, an MCU row is the same as an iMCU row.
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169 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
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171 * But at the bottom of the image, process only what's left.
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175 if (cinfo->comps_in_scan > 1) {
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177 coef->MCU_rows_per_iMCU_row = 1;
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181 if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
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183 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
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187 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
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195 coef->MCU_vert_offset = 0;
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205 * Initialize for an input processing pass.
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213 start_input_pass (j_decompress_ptr cinfo)
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217 cinfo->input_iMCU_row = 0;
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219 start_iMCU_row(cinfo);
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229 * Initialize for an output processing pass.
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237 start_output_pass (j_decompress_ptr cinfo)
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241 #ifdef BLOCK_SMOOTHING_SUPPORTED
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243 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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247 /* If multipass, check to see whether to use block smoothing on this pass */
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249 if (coef->pub.coef_arrays != NULL) {
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251 if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
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253 coef->pub.decompress_data = decompress_smooth_data;
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257 coef->pub.decompress_data = decompress_data;
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263 cinfo->output_iMCU_row = 0;
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273 * Decompress and return some data in the single-pass case.
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275 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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277 * Input and output must run in lockstep since we have only a one-MCU buffer.
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279 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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283 * NB: output_buf contains a plane for each component in image.
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285 * For single pass, this is the same as the components in the scan.
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293 decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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297 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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299 JDIMENSION MCU_col_num; /* index of current MCU within row */
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301 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
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303 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
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305 int blkn, ci, xindex, yindex, yoffset, useful_width;
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307 JSAMPARRAY output_ptr;
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309 JDIMENSION start_col, output_col;
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311 jpeg_component_info *compptr;
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313 inverse_DCT_method_ptr inverse_DCT;
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317 /* Loop to process as much as one whole iMCU row */
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319 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
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323 for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
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327 /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
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329 jzero_far((void FAR *) coef->MCU_buffer[0],
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331 (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
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333 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
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335 /* Suspension forced; update state counters and exit */
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337 coef->MCU_vert_offset = yoffset;
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339 coef->MCU_ctr = MCU_col_num;
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341 return JPEG_SUSPENDED;
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345 /* Determine where data should go in output_buf and do the IDCT thing.
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347 * We skip dummy blocks at the right and bottom edges (but blkn gets
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349 * incremented past them!). Note the inner loop relies on having
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351 * allocated the MCU_buffer[] blocks sequentially.
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355 blkn = 0; /* index of current DCT block within MCU */
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357 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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359 compptr = cinfo->cur_comp_info[ci];
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361 /* Don't bother to IDCT an uninteresting component. */
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363 if (! compptr->component_needed) {
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365 blkn += compptr->MCU_blocks;
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371 inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
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373 useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
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375 : compptr->last_col_width;
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377 output_ptr = output_buf[ci] + yoffset * compptr->DCT_scaled_size;
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379 start_col = MCU_col_num * compptr->MCU_sample_width;
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381 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
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383 if (cinfo->input_iMCU_row < last_iMCU_row ||
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385 yoffset+yindex < compptr->last_row_height) {
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387 output_col = start_col;
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389 for (xindex = 0; xindex < useful_width; xindex++) {
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391 (*inverse_DCT) (cinfo, compptr,
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393 (JCOEFPTR) coef->MCU_buffer[blkn+xindex],
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395 output_ptr, output_col);
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397 output_col += compptr->DCT_scaled_size;
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403 blkn += compptr->MCU_width;
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405 output_ptr += compptr->DCT_scaled_size;
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413 /* Completed an MCU row, but perhaps not an iMCU row */
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419 /* Completed the iMCU row, advance counters for next one */
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421 cinfo->output_iMCU_row++;
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423 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
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425 start_iMCU_row(cinfo);
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427 return JPEG_ROW_COMPLETED;
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431 /* Completed the scan */
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433 (*cinfo->inputctl->finish_input_pass) (cinfo);
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435 return JPEG_SCAN_COMPLETED;
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445 * Dummy consume-input routine for single-pass operation.
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453 dummy_consume_data (j_decompress_ptr cinfo)
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457 return JPEG_SUSPENDED; /* Always indicate nothing was done */
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465 #ifdef D_MULTISCAN_FILES_SUPPORTED
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471 * Consume input data and store it in the full-image coefficient buffer.
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473 * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
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475 * ie, v_samp_factor block rows for each component in the scan.
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477 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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485 consume_data (j_decompress_ptr cinfo)
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489 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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491 JDIMENSION MCU_col_num; /* index of current MCU within row */
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493 int blkn, ci, xindex, yindex, yoffset;
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495 JDIMENSION start_col;
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497 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
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499 JBLOCKROW buffer_ptr;
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501 jpeg_component_info *compptr;
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505 /* Align the virtual buffers for the components used in this scan. */
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507 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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509 compptr = cinfo->cur_comp_info[ci];
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511 buffer[ci] = (*cinfo->mem->access_virt_barray)
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513 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
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515 cinfo->input_iMCU_row * compptr->v_samp_factor,
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517 (JDIMENSION) compptr->v_samp_factor, TRUE);
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519 /* Note: entropy decoder expects buffer to be zeroed,
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521 * but this is handled automatically by the memory manager
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523 * because we requested a pre-zeroed array.
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531 /* Loop to process one whole iMCU row */
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533 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
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537 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
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541 /* Construct list of pointers to DCT blocks belonging to this MCU */
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543 blkn = 0; /* index of current DCT block within MCU */
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545 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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547 compptr = cinfo->cur_comp_info[ci];
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549 start_col = MCU_col_num * compptr->MCU_width;
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551 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
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553 buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
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555 for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
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557 coef->MCU_buffer[blkn++] = buffer_ptr++;
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565 /* Try to fetch the MCU. */
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567 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
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569 /* Suspension forced; update state counters and exit */
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571 coef->MCU_vert_offset = yoffset;
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573 coef->MCU_ctr = MCU_col_num;
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575 return JPEG_SUSPENDED;
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581 /* Completed an MCU row, but perhaps not an iMCU row */
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587 /* Completed the iMCU row, advance counters for next one */
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589 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
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591 start_iMCU_row(cinfo);
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593 return JPEG_ROW_COMPLETED;
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597 /* Completed the scan */
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599 (*cinfo->inputctl->finish_input_pass) (cinfo);
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601 return JPEG_SCAN_COMPLETED;
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611 * Decompress and return some data in the multi-pass case.
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613 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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615 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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619 * NB: output_buf contains a plane for each component in image.
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627 decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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631 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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633 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
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635 JDIMENSION block_num;
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637 int ci, block_row, block_rows;
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639 JBLOCKARRAY buffer;
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641 JBLOCKROW buffer_ptr;
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643 JSAMPARRAY output_ptr;
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645 JDIMENSION output_col;
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647 jpeg_component_info *compptr;
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649 inverse_DCT_method_ptr inverse_DCT;
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653 /* Force some input to be done if we are getting ahead of the input. */
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655 while (cinfo->input_scan_number < cinfo->output_scan_number ||
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657 (cinfo->input_scan_number == cinfo->output_scan_number &&
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659 cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
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661 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
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663 return JPEG_SUSPENDED;
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669 /* OK, output from the virtual arrays. */
\r
671 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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675 /* Don't bother to IDCT an uninteresting component. */
\r
677 if (! compptr->component_needed)
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681 /* Align the virtual buffer for this component. */
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683 buffer = (*cinfo->mem->access_virt_barray)
\r
685 ((j_common_ptr) cinfo, coef->whole_image[ci],
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687 cinfo->output_iMCU_row * compptr->v_samp_factor,
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689 (JDIMENSION) compptr->v_samp_factor, FALSE);
\r
691 /* Count non-dummy DCT block rows in this iMCU row. */
\r
693 if (cinfo->output_iMCU_row < last_iMCU_row)
\r
695 block_rows = compptr->v_samp_factor;
\r
699 /* NB: can't use last_row_height here; it is input-side-dependent! */
\r
701 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
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703 if (block_rows == 0) block_rows = compptr->v_samp_factor;
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707 inverse_DCT = cinfo->idct->inverse_DCT[ci];
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709 output_ptr = output_buf[ci];
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711 /* Loop over all DCT blocks to be processed. */
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713 for (block_row = 0; block_row < block_rows; block_row++) {
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715 buffer_ptr = buffer[block_row];
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719 for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
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721 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
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723 output_ptr, output_col);
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727 output_col += compptr->DCT_scaled_size;
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731 output_ptr += compptr->DCT_scaled_size;
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739 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
\r
741 return JPEG_ROW_COMPLETED;
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743 return JPEG_SCAN_COMPLETED;
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749 #endif /* D_MULTISCAN_FILES_SUPPORTED */
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755 #ifdef BLOCK_SMOOTHING_SUPPORTED
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761 * This code applies interblock smoothing as described by section K.8
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763 * of the JPEG standard: the first 5 AC coefficients are estimated from
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765 * the DC values of a DCT block and its 8 neighboring blocks.
\r
767 * We apply smoothing only for progressive JPEG decoding, and only if
\r
769 * the coefficients it can estimate are not yet known to full precision.
\r
777 * Determine whether block smoothing is applicable and safe.
\r
779 * We also latch the current states of the coef_bits[] entries for the
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781 * AC coefficients; otherwise, if the input side of the decompressor
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783 * advances into a new scan, we might think the coefficients are known
\r
785 * more accurately than they really are.
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793 smoothing_ok (j_decompress_ptr cinfo)
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797 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
\r
799 boolean smoothing_useful = FALSE;
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803 jpeg_component_info *compptr;
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805 JQUANT_TBL * qtable;
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809 int * coef_bits_latch;
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813 if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
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819 /* Allocate latch area if not already done */
\r
821 if (coef->coef_bits_latch == NULL)
\r
823 coef->coef_bits_latch = (int *)
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825 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
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827 cinfo->num_components *
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829 (SAVED_COEFS * SIZEOF(int)));
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831 coef_bits_latch = coef->coef_bits_latch;
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835 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
\r
839 /* All components' quantization values must already be latched. */
\r
841 if ((qtable = compptr->quant_table) == NULL)
\r
845 /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
\r
847 for (coefi = 0; coefi <= 5; coefi++) {
\r
849 if (qtable->quantval[coefi] == 0)
\r
855 /* DC values must be at least partly known for all components. */
\r
857 coef_bits = cinfo->coef_bits[ci];
\r
859 if (coef_bits[0] < 0)
\r
863 /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
\r
865 for (coefi = 1; coefi <= 5; coefi++) {
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867 coef_bits_latch[coefi] = coef_bits[coefi];
\r
869 if (coef_bits[coefi] != 0)
\r
871 smoothing_useful = TRUE;
\r
875 coef_bits_latch += SAVED_COEFS;
\r
881 return smoothing_useful;
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891 * Variant of decompress_data for use when doing block smoothing.
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899 decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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903 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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905 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
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907 JDIMENSION block_num, last_block_column;
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909 int ci, block_row, block_rows, access_rows;
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911 JBLOCKARRAY buffer;
\r
913 JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
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915 JSAMPARRAY output_ptr;
\r
917 JDIMENSION output_col;
\r
919 jpeg_component_info *compptr;
\r
921 inverse_DCT_method_ptr inverse_DCT;
\r
923 boolean first_row, last_row;
\r
929 JQUANT_TBL *quanttbl;
\r
931 INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
\r
933 int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
\r
939 /* Force some input to be done if we are getting ahead of the input. */
\r
941 while (cinfo->input_scan_number <= cinfo->output_scan_number &&
\r
943 ! cinfo->inputctl->eoi_reached) {
\r
945 if (cinfo->input_scan_number == cinfo->output_scan_number) {
\r
947 /* If input is working on current scan, we ordinarily want it to
\r
949 * have completed the current row. But if input scan is DC,
\r
951 * we want it to keep one row ahead so that next block row's DC
\r
953 * values are up to date.
\r
957 JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
\r
959 if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
\r
965 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
\r
967 return JPEG_SUSPENDED;
\r
973 /* OK, output from the virtual arrays. */
\r
975 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
\r
979 /* Don't bother to IDCT an uninteresting component. */
\r
981 if (! compptr->component_needed)
\r
985 /* Count non-dummy DCT block rows in this iMCU row. */
\r
987 if (cinfo->output_iMCU_row < last_iMCU_row) {
\r
989 block_rows = compptr->v_samp_factor;
\r
991 access_rows = block_rows * 2; /* this and next iMCU row */
\r
997 /* NB: can't use last_row_height here; it is input-side-dependent! */
\r
999 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
\r
1001 if (block_rows == 0) block_rows = compptr->v_samp_factor;
\r
1003 access_rows = block_rows; /* this iMCU row only */
\r
1009 /* Align the virtual buffer for this component. */
\r
1011 if (cinfo->output_iMCU_row > 0) {
\r
1013 access_rows += compptr->v_samp_factor; /* prior iMCU row too */
\r
1015 buffer = (*cinfo->mem->access_virt_barray)
\r
1017 ((j_common_ptr) cinfo, coef->whole_image[ci],
\r
1019 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
\r
1021 (JDIMENSION) access_rows, FALSE);
\r
1023 buffer += compptr->v_samp_factor; /* point to current iMCU row */
\r
1025 first_row = FALSE;
\r
1029 buffer = (*cinfo->mem->access_virt_barray)
\r
1031 ((j_common_ptr) cinfo, coef->whole_image[ci],
\r
1033 (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
\r
1039 /* Fetch component-dependent info */
\r
1041 coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
\r
1043 quanttbl = compptr->quant_table;
\r
1045 Q00 = quanttbl->quantval[0];
\r
1047 Q01 = quanttbl->quantval[1];
\r
1049 Q10 = quanttbl->quantval[2];
\r
1051 Q20 = quanttbl->quantval[3];
\r
1053 Q11 = quanttbl->quantval[4];
\r
1055 Q02 = quanttbl->quantval[5];
\r
1057 inverse_DCT = cinfo->idct->inverse_DCT[ci];
\r
1059 output_ptr = output_buf[ci];
\r
1061 /* Loop over all DCT blocks to be processed. */
\r
1063 for (block_row = 0; block_row < block_rows; block_row++) {
\r
1065 buffer_ptr = buffer[block_row];
\r
1067 if (first_row && block_row == 0)
\r
1069 prev_block_row = buffer_ptr;
\r
1073 prev_block_row = buffer[block_row-1];
\r
1075 if (last_row && block_row == block_rows-1)
\r
1077 next_block_row = buffer_ptr;
\r
1081 next_block_row = buffer[block_row+1];
\r
1083 /* We fetch the surrounding DC values using a sliding-register approach.
\r
1085 * Initialize all nine here so as to do the right thing on narrow pics.
\r
1089 DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
\r
1091 DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
\r
1093 DC7 = DC8 = DC9 = (int) next_block_row[0][0];
\r
1097 last_block_column = compptr->width_in_blocks - 1;
\r
1099 for (block_num = 0; block_num <= last_block_column; block_num++) {
\r
1101 /* Fetch current DCT block into workspace so we can modify it. */
\r
1103 jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
\r
1105 /* Update DC values */
\r
1107 if (block_num < last_block_column) {
\r
1109 DC3 = (int) prev_block_row[1][0];
\r
1111 DC6 = (int) buffer_ptr[1][0];
\r
1113 DC9 = (int) next_block_row[1][0];
\r
1117 /* Compute coefficient estimates per K.8.
\r
1119 * An estimate is applied only if coefficient is still zero,
\r
1121 * and is not known to be fully accurate.
\r
1127 if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
\r
1129 num = 36 * Q00 * (DC4 - DC6);
\r
1133 pred = (int) (((Q01<<7) + num) / (Q01<<8));
\r
1135 if (Al > 0 && pred >= (1<<Al))
\r
1141 pred = (int) (((Q01<<7) - num) / (Q01<<8));
\r
1143 if (Al > 0 && pred >= (1<<Al))
\r
1151 workspace[1] = (JCOEF) pred;
\r
1157 if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
\r
1159 num = 36 * Q00 * (DC2 - DC8);
\r
1163 pred = (int) (((Q10<<7) + num) / (Q10<<8));
\r
1165 if (Al > 0 && pred >= (1<<Al))
\r
1171 pred = (int) (((Q10<<7) - num) / (Q10<<8));
\r
1173 if (Al > 0 && pred >= (1<<Al))
\r
1181 workspace[8] = (JCOEF) pred;
\r
1187 if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
\r
1189 num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
\r
1193 pred = (int) (((Q20<<7) + num) / (Q20<<8));
\r
1195 if (Al > 0 && pred >= (1<<Al))
\r
1201 pred = (int) (((Q20<<7) - num) / (Q20<<8));
\r
1203 if (Al > 0 && pred >= (1<<Al))
\r
1211 workspace[16] = (JCOEF) pred;
\r
1217 if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
\r
1219 num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
\r
1223 pred = (int) (((Q11<<7) + num) / (Q11<<8));
\r
1225 if (Al > 0 && pred >= (1<<Al))
\r
1231 pred = (int) (((Q11<<7) - num) / (Q11<<8));
\r
1233 if (Al > 0 && pred >= (1<<Al))
\r
1241 workspace[9] = (JCOEF) pred;
\r
1247 if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
\r
1249 num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
\r
1253 pred = (int) (((Q02<<7) + num) / (Q02<<8));
\r
1255 if (Al > 0 && pred >= (1<<Al))
\r
1261 pred = (int) (((Q02<<7) - num) / (Q02<<8));
\r
1263 if (Al > 0 && pred >= (1<<Al))
\r
1271 workspace[2] = (JCOEF) pred;
\r
1275 /* OK, do the IDCT */
\r
1277 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
\r
1279 output_ptr, output_col);
\r
1281 /* Advance for next column */
\r
1283 DC1 = DC2; DC2 = DC3;
\r
1285 DC4 = DC5; DC5 = DC6;
\r
1287 DC7 = DC8; DC8 = DC9;
\r
1289 buffer_ptr++, prev_block_row++, next_block_row++;
\r
1291 output_col += compptr->DCT_scaled_size;
\r
1295 output_ptr += compptr->DCT_scaled_size;
\r
1303 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
\r
1305 return JPEG_ROW_COMPLETED;
\r
1307 return JPEG_SCAN_COMPLETED;
\r
1313 #endif /* BLOCK_SMOOTHING_SUPPORTED */
\r
1321 * Initialize coefficient buffer controller.
\r
1329 jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
\r
1337 coef = (my_coef_ptr)
\r
1339 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
\r
1341 SIZEOF(my_coef_controller));
\r
1343 cinfo->coef = (struct jpeg_d_coef_controller *) coef;
\r
1345 coef->pub.start_input_pass = start_input_pass;
\r
1347 coef->pub.start_output_pass = start_output_pass;
\r
1349 #ifdef BLOCK_SMOOTHING_SUPPORTED
\r
1351 coef->coef_bits_latch = NULL;
\r
1357 /* Create the coefficient buffer. */
\r
1359 if (need_full_buffer) {
\r
1361 #ifdef D_MULTISCAN_FILES_SUPPORTED
\r
1363 /* Allocate a full-image virtual array for each component, */
\r
1365 /* padded to a multiple of samp_factor DCT blocks in each direction. */
\r
1367 /* Note we ask for a pre-zeroed array. */
\r
1369 int ci, access_rows;
\r
1371 jpeg_component_info *compptr;
\r
1375 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
\r
1377 ci++, compptr++) {
\r
1379 access_rows = compptr->v_samp_factor;
\r
1381 #ifdef BLOCK_SMOOTHING_SUPPORTED
\r
1383 /* If block smoothing could be used, need a bigger window */
\r
1385 if (cinfo->progressive_mode)
\r
1391 coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
\r
1393 ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
\r
1395 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
\r
1397 (long) compptr->h_samp_factor),
\r
1399 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
\r
1401 (long) compptr->v_samp_factor),
\r
1403 (JDIMENSION) access_rows);
\r
1407 coef->pub.consume_data = consume_data;
\r
1409 coef->pub.decompress_data = decompress_data;
\r
1411 coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
\r
1415 ERREXIT(cinfo, JERR_NOT_COMPILED);
\r
1421 /* We only need a single-MCU buffer. */
\r
1429 buffer = (JBLOCKROW)
\r
1431 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
\r
1433 D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
\r
1435 for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
\r
1437 coef->MCU_buffer[i] = buffer + i;
\r
1441 coef->pub.consume_data = dummy_consume_data;
\r
1443 coef->pub.decompress_data = decompress_onepass;
\r
1445 coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
\r