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/thirdparty/jpeg/jctrans.c

http://crashrpt.googlecode.com/
C | 382 lines | 214 code | 46 blank | 122 comment | 41 complexity | acf6bb1b07e0cebfdc08ab0354db12a1 MD5 | raw file
  1/*
  2 * jctrans.c
  3 *
  4 * Copyright (C) 1995-1998, Thomas G. Lane.
  5 * Modified 2000-2009 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 */
 20LOCAL(void) transencode_master_selection
 21	JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
 22LOCAL(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
 38GLOBAL(void)
 39jpeg_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
 63GLOBAL(void)
 64jpeg_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   */
 89  jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
 90  dstinfo->data_precision = srcinfo->data_precision;
 91  dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
 92  /* Copy the source's quantization tables. */
 93  for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
 94    if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
 95      qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
 96      if (*qtblptr == NULL)
 97	*qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
 98      MEMCOPY((*qtblptr)->quantval,
 99	      srcinfo->quant_tbl_ptrs[tblno]->quantval,
100	      SIZEOF((*qtblptr)->quantval));
101      (*qtblptr)->sent_table = FALSE;
102    }
103  }
104  /* Copy the source's per-component info.
105   * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
106   */
107  dstinfo->num_components = srcinfo->num_components;
108  if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
109    ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
110	     MAX_COMPONENTS);
111  for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
112       ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
113    outcomp->component_id = incomp->component_id;
114    outcomp->h_samp_factor = incomp->h_samp_factor;
115    outcomp->v_samp_factor = incomp->v_samp_factor;
116    outcomp->quant_tbl_no = incomp->quant_tbl_no;
117    /* Make sure saved quantization table for component matches the qtable
118     * slot.  If not, the input file re-used this qtable slot.
119     * IJG encoder currently cannot duplicate this.
120     */
121    tblno = outcomp->quant_tbl_no;
122    if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
123	srcinfo->quant_tbl_ptrs[tblno] == NULL)
124      ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
125    slot_quant = srcinfo->quant_tbl_ptrs[tblno];
126    c_quant = incomp->quant_table;
127    if (c_quant != NULL) {
128      for (coefi = 0; coefi < DCTSIZE2; coefi++) {
129	if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
130	  ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
131      }
132    }
133    /* Note: we do not copy the source's Huffman table assignments;
134     * instead we rely on jpeg_set_colorspace to have made a suitable choice.
135     */
136  }
137  /* Also copy JFIF version and resolution information, if available.
138   * Strictly speaking this isn't "critical" info, but it's nearly
139   * always appropriate to copy it if available.  In particular,
140   * if the application chooses to copy JFIF 1.02 extension markers from
141   * the source file, we need to copy the version to make sure we don't
142   * emit a file that has 1.02 extensions but a claimed version of 1.01.
143   * We will *not*, however, copy version info from mislabeled "2.01" files.
144   */
145  if (srcinfo->saw_JFIF_marker) {
146    if (srcinfo->JFIF_major_version == 1) {
147      dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
148      dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
149    }
150    dstinfo->density_unit = srcinfo->density_unit;
151    dstinfo->X_density = srcinfo->X_density;
152    dstinfo->Y_density = srcinfo->Y_density;
153  }
154}
155
156
157/*
158 * Master selection of compression modules for transcoding.
159 * This substitutes for jcinit.c's initialization of the full compressor.
160 */
161
162LOCAL(void)
163transencode_master_selection (j_compress_ptr cinfo,
164			      jvirt_barray_ptr * coef_arrays)
165{
166  /* Initialize master control (includes parameter checking/processing) */
167  jinit_c_master_control(cinfo, TRUE /* transcode only */);
168
169  /* Entropy encoding: either Huffman or arithmetic coding. */
170  if (cinfo->arith_code)
171    jinit_arith_encoder(cinfo);
172  else {
173    jinit_huff_encoder(cinfo);
174  }
175
176  /* We need a special coefficient buffer controller. */
177  transencode_coef_controller(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
202typedef struct {
203  struct jpeg_c_coef_controller pub; /* public fields */
204
205  JDIMENSION iMCU_row_num;	/* iMCU row # within image */
206  JDIMENSION mcu_ctr;		/* counts MCUs processed in current row */
207  int MCU_vert_offset;		/* counts MCU rows within iMCU row */
208  int MCU_rows_per_iMCU_row;	/* number of such rows needed */
209
210  /* Virtual block array for each component. */
211  jvirt_barray_ptr * whole_image;
212
213  /* Workspace for constructing dummy blocks at right/bottom edges. */
214  JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
215} my_coef_controller;
216
217typedef my_coef_controller * my_coef_ptr;
218
219
220LOCAL(void)
221start_iMCU_row (j_compress_ptr cinfo)
222/* Reset within-iMCU-row counters for a new row */
223{
224  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
225
226  /* In an interleaved scan, an MCU row is the same as an iMCU row.
227   * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
228   * But at the bottom of the image, process only what's left.
229   */
230  if (cinfo->comps_in_scan > 1) {
231    coef->MCU_rows_per_iMCU_row = 1;
232  } else {
233    if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
234      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
235    else
236      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
237  }
238
239  coef->mcu_ctr = 0;
240  coef->MCU_vert_offset = 0;
241}
242
243
244/*
245 * Initialize for a processing pass.
246 */
247
248METHODDEF(void)
249start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
250{
251  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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
271METHODDEF(boolean)
272compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
273{
274  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
275  JDIMENSION MCU_col_num;	/* index of current MCU within row */
276  JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
277  JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
278  int blkn, ci, xindex, yindex, yoffset, blockcnt;
279  JDIMENSION start_col;
280  JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
281  JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
282  JBLOCKROW buffer_ptr;
283  jpeg_component_info *compptr;
284
285  /* Align the virtual buffers for the components used in this scan. */
286  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
287    compptr = cinfo->cur_comp_info[ci];
288    buffer[ci] = (*cinfo->mem->access_virt_barray)
289      ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
290       coef->iMCU_row_num * compptr->v_samp_factor,
291       (JDIMENSION) compptr->v_samp_factor, FALSE);
292  }
293
294  /* Loop to process one whole iMCU row */
295  for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
296       yoffset++) {
297    for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
298	 MCU_col_num++) {
299      /* Construct list of pointers to DCT blocks belonging to this MCU */
300      blkn = 0;			/* index of current DCT block within MCU */
301      for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
302	compptr = cinfo->cur_comp_info[ci];
303	start_col = MCU_col_num * compptr->MCU_width;
304	blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
305						: compptr->last_col_width;
306	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
307	  if (coef->iMCU_row_num < last_iMCU_row ||
308	      yindex+yoffset < compptr->last_row_height) {
309	    /* Fill in pointers to real blocks in this row */
310	    buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
311	    for (xindex = 0; xindex < blockcnt; xindex++)
312	      MCU_buffer[blkn++] = buffer_ptr++;
313	  } else {
314	    /* At bottom of image, need a whole row of dummy blocks */
315	    xindex = 0;
316	  }
317	  /* Fill in any dummy blocks needed in this row.
318	   * Dummy blocks are filled in the same way as in jccoefct.c:
319	   * all zeroes in the AC entries, DC entries equal to previous
320	   * block's DC value.  The init routine has already zeroed the
321	   * AC entries, so we need only set the DC entries correctly.
322	   */
323	  for (; xindex < compptr->MCU_width; xindex++) {
324	    MCU_buffer[blkn] = coef->dummy_buffer[blkn];
325	    MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
326	    blkn++;
327	  }
328	}
329      }
330      /* Try to write the MCU. */
331      if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
332	/* Suspension forced; update state counters and exit */
333	coef->MCU_vert_offset = yoffset;
334	coef->mcu_ctr = MCU_col_num;
335	return FALSE;
336      }
337    }
338    /* Completed an MCU row, but perhaps not an iMCU row */
339    coef->mcu_ctr = 0;
340  }
341  /* Completed the iMCU row, advance counters for next one */
342  coef->iMCU_row_num++;
343  start_iMCU_row(cinfo);
344  return TRUE;
345}
346
347
348/*
349 * Initialize coefficient buffer controller.
350 *
351 * Each passed coefficient array must be the right size for that
352 * coefficient: width_in_blocks wide and height_in_blocks high,
353 * with unitheight at least v_samp_factor.
354 */
355
356LOCAL(void)
357transencode_coef_controller (j_compress_ptr cinfo,
358			     jvirt_barray_ptr * coef_arrays)
359{
360  my_coef_ptr coef;
361  JBLOCKROW buffer;
362  int i;
363
364  coef = (my_coef_ptr)
365    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
366				SIZEOF(my_coef_controller));
367  cinfo->coef = (struct jpeg_c_coef_controller *) coef;
368  coef->pub.start_pass = start_pass_coef;
369  coef->pub.compress_data = compress_output;
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_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
378  jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
379  for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
380    coef->dummy_buffer[i] = buffer + i;
381  }
382}