Line data Source code
1 : /*
2 : * jctrans.c
3 : *
4 : * This file was part of the Independent JPEG Group's software:
5 : * Copyright (C) 1995-1998, Thomas G. Lane.
6 : * Modified 2000-2009 by Guido Vollbeding.
7 : * It was modified by The libjpeg-turbo Project to include only code relevant
8 : * to libjpeg-turbo.
9 : * For conditions of distribution and use, see the accompanying README.ijg
10 : * 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 :
21 :
22 : /* Forward declarations */
23 : LOCAL(void) transencode_master_selection
24 : (j_compress_ptr cinfo, jvirt_barray_ptr *coef_arrays);
25 : LOCAL(void) transencode_coef_controller
26 : (j_compress_ptr cinfo, jvirt_barray_ptr *coef_arrays);
27 :
28 :
29 : /*
30 : * Compression initialization for writing raw-coefficient data.
31 : * Before calling this, all parameters and a data destination must be set up.
32 : * Call jpeg_finish_compress() to actually write the data.
33 : *
34 : * The number of passed virtual arrays must match cinfo->num_components.
35 : * Note that the virtual arrays need not be filled or even realized at
36 : * the time write_coefficients is called; indeed, if the virtual arrays
37 : * were requested from this compression object's memory manager, they
38 : * typically will be realized during this routine and filled afterwards.
39 : */
40 :
41 : GLOBAL(void)
42 0 : jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr *coef_arrays)
43 : {
44 0 : if (cinfo->global_state != CSTATE_START)
45 0 : ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
46 : /* Mark all tables to be written */
47 0 : jpeg_suppress_tables(cinfo, FALSE);
48 : /* (Re)initialize error mgr and destination modules */
49 0 : (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
50 0 : (*cinfo->dest->init_destination) (cinfo);
51 : /* Perform master selection of active modules */
52 0 : transencode_master_selection(cinfo, coef_arrays);
53 : /* Wait for jpeg_finish_compress() call */
54 0 : cinfo->next_scanline = 0; /* so jpeg_write_marker works */
55 0 : cinfo->global_state = CSTATE_WRCOEFS;
56 0 : }
57 :
58 :
59 : /*
60 : * Initialize the compression object with default parameters,
61 : * then copy from the source object all parameters needed for lossless
62 : * transcoding. Parameters that can be varied without loss (such as
63 : * scan script and Huffman optimization) are left in their default states.
64 : */
65 :
66 : GLOBAL(void)
67 0 : jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
68 : j_compress_ptr dstinfo)
69 : {
70 : JQUANT_TBL **qtblptr;
71 : jpeg_component_info *incomp, *outcomp;
72 : JQUANT_TBL *c_quant, *slot_quant;
73 : int tblno, ci, coefi;
74 :
75 : /* Safety check to ensure start_compress not called yet. */
76 0 : if (dstinfo->global_state != CSTATE_START)
77 0 : ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
78 : /* Copy fundamental image dimensions */
79 0 : dstinfo->image_width = srcinfo->image_width;
80 0 : dstinfo->image_height = srcinfo->image_height;
81 0 : dstinfo->input_components = srcinfo->num_components;
82 0 : dstinfo->in_color_space = srcinfo->jpeg_color_space;
83 : #if JPEG_LIB_VERSION >= 70
84 : dstinfo->jpeg_width = srcinfo->output_width;
85 : dstinfo->jpeg_height = srcinfo->output_height;
86 : dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size;
87 : dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size;
88 : #endif
89 : /* Initialize all parameters to default values */
90 0 : jpeg_set_defaults(dstinfo);
91 : /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
92 : * Fix it to get the right header markers for the image colorspace.
93 : */
94 0 : jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
95 0 : dstinfo->data_precision = srcinfo->data_precision;
96 0 : dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
97 : /* Copy the source's quantization tables. */
98 0 : for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
99 0 : if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
100 0 : qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
101 0 : if (*qtblptr == NULL)
102 0 : *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
103 0 : MEMCOPY((*qtblptr)->quantval,
104 : srcinfo->quant_tbl_ptrs[tblno]->quantval,
105 : sizeof((*qtblptr)->quantval));
106 0 : (*qtblptr)->sent_table = FALSE;
107 : }
108 : }
109 : /* Copy the source's per-component info.
110 : * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
111 : */
112 0 : dstinfo->num_components = srcinfo->num_components;
113 0 : if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
114 0 : ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
115 : MAX_COMPONENTS);
116 0 : for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
117 0 : ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
118 0 : outcomp->component_id = incomp->component_id;
119 0 : outcomp->h_samp_factor = incomp->h_samp_factor;
120 0 : outcomp->v_samp_factor = incomp->v_samp_factor;
121 0 : outcomp->quant_tbl_no = incomp->quant_tbl_no;
122 : /* Make sure saved quantization table for component matches the qtable
123 : * slot. If not, the input file re-used this qtable slot.
124 : * IJG encoder currently cannot duplicate this.
125 : */
126 0 : tblno = outcomp->quant_tbl_no;
127 0 : if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
128 0 : srcinfo->quant_tbl_ptrs[tblno] == NULL)
129 0 : ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
130 0 : slot_quant = srcinfo->quant_tbl_ptrs[tblno];
131 0 : c_quant = incomp->quant_table;
132 0 : if (c_quant != NULL) {
133 0 : for (coefi = 0; coefi < DCTSIZE2; coefi++) {
134 0 : if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
135 0 : ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
136 : }
137 : }
138 : /* Note: we do not copy the source's Huffman table assignments;
139 : * instead we rely on jpeg_set_colorspace to have made a suitable choice.
140 : */
141 : }
142 : /* Also copy JFIF version and resolution information, if available.
143 : * Strictly speaking this isn't "critical" info, but it's nearly
144 : * always appropriate to copy it if available. In particular,
145 : * if the application chooses to copy JFIF 1.02 extension markers from
146 : * the source file, we need to copy the version to make sure we don't
147 : * emit a file that has 1.02 extensions but a claimed version of 1.01.
148 : * We will *not*, however, copy version info from mislabeled "2.01" files.
149 : */
150 0 : if (srcinfo->saw_JFIF_marker) {
151 0 : if (srcinfo->JFIF_major_version == 1) {
152 0 : dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
153 0 : dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
154 : }
155 0 : dstinfo->density_unit = srcinfo->density_unit;
156 0 : dstinfo->X_density = srcinfo->X_density;
157 0 : dstinfo->Y_density = srcinfo->Y_density;
158 : }
159 0 : }
160 :
161 :
162 : /*
163 : * Master selection of compression modules for transcoding.
164 : * This substitutes for jcinit.c's initialization of the full compressor.
165 : */
166 :
167 : LOCAL(void)
168 0 : transencode_master_selection (j_compress_ptr cinfo,
169 : jvirt_barray_ptr *coef_arrays)
170 : {
171 : /* Although we don't actually use input_components for transcoding,
172 : * jcmaster.c's initial_setup will complain if input_components is 0.
173 : */
174 0 : cinfo->input_components = 1;
175 : /* Initialize master control (includes parameter checking/processing) */
176 0 : jinit_c_master_control(cinfo, TRUE /* transcode only */);
177 :
178 : /* Entropy encoding: either Huffman or arithmetic coding. */
179 0 : if (cinfo->arith_code) {
180 : #ifdef C_ARITH_CODING_SUPPORTED
181 : jinit_arith_encoder(cinfo);
182 : #else
183 0 : ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
184 : #endif
185 : } else {
186 0 : if (cinfo->progressive_mode) {
187 : #ifdef C_PROGRESSIVE_SUPPORTED
188 0 : jinit_phuff_encoder(cinfo);
189 : #else
190 : ERREXIT(cinfo, JERR_NOT_COMPILED);
191 : #endif
192 : } else
193 0 : jinit_huff_encoder(cinfo);
194 : }
195 :
196 : /* We need a special coefficient buffer controller. */
197 0 : transencode_coef_controller(cinfo, coef_arrays);
198 :
199 0 : jinit_marker_writer(cinfo);
200 :
201 : /* We can now tell the memory manager to allocate virtual arrays. */
202 0 : (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
203 :
204 : /* Write the datastream header (SOI, JFIF) immediately.
205 : * Frame and scan headers are postponed till later.
206 : * This lets application insert special markers after the SOI.
207 : */
208 0 : (*cinfo->marker->write_file_header) (cinfo);
209 0 : }
210 :
211 :
212 : /*
213 : * The rest of this file is a special implementation of the coefficient
214 : * buffer controller. This is similar to jccoefct.c, but it handles only
215 : * output from presupplied virtual arrays. Furthermore, we generate any
216 : * dummy padding blocks on-the-fly rather than expecting them to be present
217 : * in the arrays.
218 : */
219 :
220 : /* Private buffer controller object */
221 :
222 : typedef struct {
223 : struct jpeg_c_coef_controller pub; /* public fields */
224 :
225 : JDIMENSION iMCU_row_num; /* iMCU row # within image */
226 : JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
227 : int MCU_vert_offset; /* counts MCU rows within iMCU row */
228 : int MCU_rows_per_iMCU_row; /* number of such rows needed */
229 :
230 : /* Virtual block array for each component. */
231 : jvirt_barray_ptr *whole_image;
232 :
233 : /* Workspace for constructing dummy blocks at right/bottom edges. */
234 : JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
235 : } my_coef_controller;
236 :
237 : typedef my_coef_controller *my_coef_ptr;
238 :
239 :
240 : LOCAL(void)
241 0 : start_iMCU_row (j_compress_ptr cinfo)
242 : /* Reset within-iMCU-row counters for a new row */
243 : {
244 0 : my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
245 :
246 : /* In an interleaved scan, an MCU row is the same as an iMCU row.
247 : * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
248 : * But at the bottom of the image, process only what's left.
249 : */
250 0 : if (cinfo->comps_in_scan > 1) {
251 0 : coef->MCU_rows_per_iMCU_row = 1;
252 : } else {
253 0 : if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
254 0 : coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
255 : else
256 0 : coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
257 : }
258 :
259 0 : coef->mcu_ctr = 0;
260 0 : coef->MCU_vert_offset = 0;
261 0 : }
262 :
263 :
264 : /*
265 : * Initialize for a processing pass.
266 : */
267 :
268 : METHODDEF(void)
269 0 : start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
270 : {
271 0 : my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
272 :
273 0 : if (pass_mode != JBUF_CRANK_DEST)
274 0 : ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
275 :
276 0 : coef->iMCU_row_num = 0;
277 0 : start_iMCU_row(cinfo);
278 0 : }
279 :
280 :
281 : /*
282 : * Process some data.
283 : * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
284 : * per call, ie, v_samp_factor block rows for each component in the scan.
285 : * The data is obtained from the virtual arrays and fed to the entropy coder.
286 : * Returns TRUE if the iMCU row is completed, FALSE if suspended.
287 : *
288 : * NB: input_buf is ignored; it is likely to be a NULL pointer.
289 : */
290 :
291 : METHODDEF(boolean)
292 0 : compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
293 : {
294 0 : my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
295 : JDIMENSION MCU_col_num; /* index of current MCU within row */
296 0 : JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
297 0 : JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
298 : int blkn, ci, xindex, yindex, yoffset, blockcnt;
299 : JDIMENSION start_col;
300 : JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
301 : JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
302 : JBLOCKROW buffer_ptr;
303 : jpeg_component_info *compptr;
304 :
305 : /* Align the virtual buffers for the components used in this scan. */
306 0 : for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
307 0 : compptr = cinfo->cur_comp_info[ci];
308 0 : buffer[ci] = (*cinfo->mem->access_virt_barray)
309 0 : ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
310 0 : coef->iMCU_row_num * compptr->v_samp_factor,
311 0 : (JDIMENSION) compptr->v_samp_factor, FALSE);
312 : }
313 :
314 : /* Loop to process one whole iMCU row */
315 0 : for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
316 0 : yoffset++) {
317 0 : for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
318 0 : MCU_col_num++) {
319 : /* Construct list of pointers to DCT blocks belonging to this MCU */
320 0 : blkn = 0; /* index of current DCT block within MCU */
321 0 : for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
322 0 : compptr = cinfo->cur_comp_info[ci];
323 0 : start_col = MCU_col_num * compptr->MCU_width;
324 0 : blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
325 0 : : compptr->last_col_width;
326 0 : for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
327 0 : if (coef->iMCU_row_num < last_iMCU_row ||
328 0 : yindex+yoffset < compptr->last_row_height) {
329 : /* Fill in pointers to real blocks in this row */
330 0 : buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
331 0 : for (xindex = 0; xindex < blockcnt; xindex++)
332 0 : MCU_buffer[blkn++] = buffer_ptr++;
333 : } else {
334 : /* At bottom of image, need a whole row of dummy blocks */
335 0 : xindex = 0;
336 : }
337 : /* Fill in any dummy blocks needed in this row.
338 : * Dummy blocks are filled in the same way as in jccoefct.c:
339 : * all zeroes in the AC entries, DC entries equal to previous
340 : * block's DC value. The init routine has already zeroed the
341 : * AC entries, so we need only set the DC entries correctly.
342 : */
343 0 : for (; xindex < compptr->MCU_width; xindex++) {
344 0 : MCU_buffer[blkn] = coef->dummy_buffer[blkn];
345 0 : MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
346 0 : blkn++;
347 : }
348 : }
349 : }
350 : /* Try to write the MCU. */
351 0 : if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {
352 : /* Suspension forced; update state counters and exit */
353 0 : coef->MCU_vert_offset = yoffset;
354 0 : coef->mcu_ctr = MCU_col_num;
355 0 : return FALSE;
356 : }
357 : }
358 : /* Completed an MCU row, but perhaps not an iMCU row */
359 0 : coef->mcu_ctr = 0;
360 : }
361 : /* Completed the iMCU row, advance counters for next one */
362 0 : coef->iMCU_row_num++;
363 0 : start_iMCU_row(cinfo);
364 0 : return TRUE;
365 : }
366 :
367 :
368 : /*
369 : * Initialize coefficient buffer controller.
370 : *
371 : * Each passed coefficient array must be the right size for that
372 : * coefficient: width_in_blocks wide and height_in_blocks high,
373 : * with unitheight at least v_samp_factor.
374 : */
375 :
376 : LOCAL(void)
377 0 : transencode_coef_controller (j_compress_ptr cinfo,
378 : jvirt_barray_ptr *coef_arrays)
379 : {
380 : my_coef_ptr coef;
381 : JBLOCKROW buffer;
382 : int i;
383 :
384 0 : coef = (my_coef_ptr)
385 0 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
386 : sizeof(my_coef_controller));
387 0 : cinfo->coef = (struct jpeg_c_coef_controller *) coef;
388 0 : coef->pub.start_pass = start_pass_coef;
389 0 : coef->pub.compress_data = compress_output;
390 :
391 : /* Save pointer to virtual arrays */
392 0 : coef->whole_image = coef_arrays;
393 :
394 : /* Allocate and pre-zero space for dummy DCT blocks. */
395 0 : buffer = (JBLOCKROW)
396 0 : (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
397 : C_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK));
398 0 : jzero_far((void *) buffer, C_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK));
399 0 : for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
400 0 : coef->dummy_buffer[i] = buffer + i;
401 : }
402 0 : }
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