1 /*
2 * jcmaster.c
3 *
4 * Copyright (C) 1991-1994, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains master control logic for the JPEG compressor.
9 * These routines are concerned with selecting the modules to be executed
10 * and with determining the number of passes and the work to be done in each
11 * pass.
12 */
13
14 #define JPEG_INTERNALS
15 #include "jinclude.h"
16 #include "jpeglib.h"
17
18
19 /* Private state */
20
21 typedef struct {
22 struct jpeg_comp_master pub; /* public fields */
23
24 int pass_number; /* eventually need more complex state... */
25 } my_comp_master;
26
27 typedef my_comp_master * my_master_ptr;
28
29
30 /*
31 * Support routines that do various essential calculations.
32 */
33
34 LOCAL void
initial_setup(j_compress_ptr cinfo)35 initial_setup (j_compress_ptr cinfo)
36 /* Do computations that are needed before master selection phase */
37 {
38 int ci;
39 jpeg_component_info *compptr;
40 long samplesperrow;
41 JDIMENSION jd_samplesperrow;
42
43 /* Sanity check on image dimensions */
44 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
45 || cinfo->num_components <= 0 || cinfo->input_components <= 0)
46 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
47
48 /* Make sure image isn't bigger than I can handle */
49 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
50 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
51 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
52
53 /* Width of an input scanline must be representable as JDIMENSION. */
54 samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
55 jd_samplesperrow = (JDIMENSION) samplesperrow;
56 if ((long) jd_samplesperrow != samplesperrow)
57 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
58
59 /* For now, precision must match compiled-in value... */
60 if (cinfo->data_precision != BITS_IN_JSAMPLE)
61 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
62
63 /* Check that number of components won't exceed internal array sizes */
64 if (cinfo->num_components > MAX_COMPONENTS)
65 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
66 MAX_COMPONENTS);
67
68 if (cinfo->num_components == 1) {
69 /* subsampling is a no-op, so it's safe to ignore it */
70 cinfo->comp_info[0].h_samp_factor = 1;
71 cinfo->comp_info[0].v_samp_factor = 1;
72 }
73
74 /* Compute maximum sampling factors; check factor validity */
75 cinfo->max_h_samp_factor = 1;
76 cinfo->max_v_samp_factor = 1;
77 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
78 ci++, compptr++) {
79 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
80 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
81 ERREXIT(cinfo, JERR_BAD_SAMPLING);
82 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
83 compptr->h_samp_factor);
84 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
85 compptr->v_samp_factor);
86 }
87
88 /* Compute dimensions of components */
89 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
90 ci++, compptr++) {
91 /* For compression, we never do DCT scaling. */
92 compptr->DCT_scaled_size = DCTSIZE;
93 /* Size in DCT blocks */
94 compptr->width_in_blocks = (JDIMENSION)
95 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
96 (long) (cinfo->max_h_samp_factor * DCTSIZE));
97 compptr->height_in_blocks = (JDIMENSION)
98 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
99 (long) (cinfo->max_v_samp_factor * DCTSIZE));
100 /* Size in samples */
101 compptr->downsampled_width = (JDIMENSION)
102 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
103 (long) cinfo->max_h_samp_factor);
104 compptr->downsampled_height = (JDIMENSION)
105 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
106 (long) cinfo->max_v_samp_factor);
107 /* Mark component needed (this flag isn't actually used for compression) */
108 compptr->component_needed = TRUE;
109 }
110
111 /* Compute number of fully interleaved MCU rows (number of times that
112 * main controller will call coefficient controller).
113 */
114 cinfo->total_iMCU_rows = (JDIMENSION)
115 jdiv_round_up((long) cinfo->image_height,
116 (long) (cinfo->max_v_samp_factor*DCTSIZE));
117 }
118
119
120 LOCAL void
per_scan_setup(j_compress_ptr cinfo)121 per_scan_setup (j_compress_ptr cinfo)
122 /* Do computations that are needed before processing a JPEG scan */
123 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
124 {
125 int ci, mcublks, tmp;
126 jpeg_component_info *compptr;
127
128 if (cinfo->comps_in_scan == 1) {
129
130 /* Noninterleaved (single-component) scan */
131 compptr = cinfo->cur_comp_info[0];
132
133 /* Overall image size in MCUs */
134 cinfo->MCUs_per_row = compptr->width_in_blocks;
135 cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
136
137 /* For noninterleaved scan, always one block per MCU */
138 compptr->MCU_width = 1;
139 compptr->MCU_height = 1;
140 compptr->MCU_blocks = 1;
141 compptr->MCU_sample_width = DCTSIZE;
142 compptr->last_col_width = 1;
143 compptr->last_row_height = 1;
144
145 /* Prepare array describing MCU composition */
146 cinfo->blocks_in_MCU = 1;
147 cinfo->MCU_membership[0] = 0;
148
149 } else {
150
151 /* Interleaved (multi-component) scan */
152 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
153 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
154 MAX_COMPS_IN_SCAN);
155
156 /* Overall image size in MCUs */
157 cinfo->MCUs_per_row = (JDIMENSION)
158 jdiv_round_up((long) cinfo->image_width,
159 (long) (cinfo->max_h_samp_factor*DCTSIZE));
160 cinfo->MCU_rows_in_scan = (JDIMENSION)
161 jdiv_round_up((long) cinfo->image_height,
162 (long) (cinfo->max_v_samp_factor*DCTSIZE));
163
164 cinfo->blocks_in_MCU = 0;
165
166 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
167 compptr = cinfo->cur_comp_info[ci];
168 /* Sampling factors give # of blocks of component in each MCU */
169 compptr->MCU_width = compptr->h_samp_factor;
170 compptr->MCU_height = compptr->v_samp_factor;
171 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
172 compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
173 /* Figure number of non-dummy blocks in last MCU column & row */
174 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
175 if (tmp == 0) tmp = compptr->MCU_width;
176 compptr->last_col_width = tmp;
177 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
178 if (tmp == 0) tmp = compptr->MCU_height;
179 compptr->last_row_height = tmp;
180 /* Prepare array describing MCU composition */
181 mcublks = compptr->MCU_blocks;
182 if (cinfo->blocks_in_MCU + mcublks > MAX_BLOCKS_IN_MCU)
183 ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
184 while (mcublks-- > 0) {
185 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
186 }
187 }
188
189 }
190
191 /* Convert restart specified in rows to actual MCU count. */
192 /* Note that count must fit in 16 bits, so we provide limiting. */
193 if (cinfo->restart_in_rows > 0) {
194 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
195 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
196 }
197 }
198
199
200 /*
201 * Master selection of compression modules.
202 * This is done once at the start of processing an image. We determine
203 * which modules will be used and give them appropriate initialization calls.
204 */
205
206 LOCAL void
master_selection(j_compress_ptr cinfo)207 master_selection (j_compress_ptr cinfo)
208 {
209 my_master_ptr master = (my_master_ptr) cinfo->master;
210
211 initial_setup(cinfo);
212 master->pass_number = 0;
213
214 /* There's not a lot of smarts here right now, but it'll get more
215 * complicated when we have multiple implementations available...
216 */
217
218 /* Preprocessing */
219 if (! cinfo->raw_data_in) {
220 jinit_color_converter(cinfo);
221 jinit_downsampler(cinfo);
222 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
223 }
224 /* Forward DCT */
225 jinit_forward_dct(cinfo);
226 /* Entropy encoding: either Huffman or arithmetic coding. */
227 if (cinfo->arith_code) {
228 #ifdef C_ARITH_CODING_SUPPORTED
229 jinit_arith_encoder(cinfo);
230 #else
231 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
232 #endif
233 } else
234 jinit_huff_encoder(cinfo);
235
236 /* For now, a full buffer is needed only for Huffman optimization. */
237 jinit_c_coef_controller(cinfo, cinfo->optimize_coding);
238 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
239
240 jinit_marker_writer(cinfo);
241
242 /* We can now tell the memory manager to allocate virtual arrays. */
243 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
244
245 /* Write the datastream header (SOI) immediately.
246 * Frame and scan headers are postponed till later.
247 * This lets application insert special markers after the SOI.
248 */
249 (*cinfo->marker->write_file_header) (cinfo);
250 }
251
252
253 /*
254 * Per-pass setup.
255 * This is called at the beginning of each pass. We determine which modules
256 * will be active during this pass and give them appropriate start_pass calls.
257 * We also set is_last_pass to indicate whether any more passes will be
258 * required.
259 */
260
261 METHODDEF void
prepare_for_pass(j_compress_ptr cinfo)262 prepare_for_pass (j_compress_ptr cinfo)
263 {
264 my_master_ptr master = (my_master_ptr) cinfo->master;
265 int ci;
266 int npasses;
267
268 /* ???? JUST A QUICK CROCK FOR NOW ??? */
269
270 /* For now, handle only single interleaved output scan; */
271 /* we support two passes for Huffman optimization. */
272
273 /* Prepare for single scan containing all components */
274 if (cinfo->num_components > MAX_COMPS_IN_SCAN)
275 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
276 MAX_COMPS_IN_SCAN);
277 cinfo->comps_in_scan = cinfo->num_components;
278 for (ci = 0; ci < cinfo->num_components; ci++) {
279 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
280 }
281
282 per_scan_setup(cinfo);
283
284 if (! cinfo->optimize_coding) {
285 /* Standard single-pass case */
286 npasses = 1;
287 master->pub.call_pass_startup = TRUE;
288 master->pub.is_last_pass = TRUE;
289 if (! cinfo->raw_data_in) {
290 (*cinfo->cconvert->start_pass) (cinfo);
291 (*cinfo->downsample->start_pass) (cinfo);
292 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
293 }
294 (*cinfo->fdct->start_pass) (cinfo);
295 (*cinfo->entropy->start_pass) (cinfo, FALSE);
296 (*cinfo->coef->start_pass) (cinfo, JBUF_PASS_THRU);
297 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
298 } else {
299 npasses = 2;
300 switch (master->pass_number) {
301 case 0:
302 /* Huffman optimization: run all modules, gather statistics */
303 master->pub.call_pass_startup = FALSE;
304 master->pub.is_last_pass = FALSE;
305 if (! cinfo->raw_data_in) {
306 (*cinfo->cconvert->start_pass) (cinfo);
307 (*cinfo->downsample->start_pass) (cinfo);
308 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
309 }
310 (*cinfo->fdct->start_pass) (cinfo);
311 (*cinfo->entropy->start_pass) (cinfo, TRUE);
312 (*cinfo->coef->start_pass) (cinfo, JBUF_SAVE_AND_PASS);
313 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
314 break;
315 case 1:
316 /* Second pass: reread data from coefficient buffer */
317 master->pub.is_last_pass = TRUE;
318 (*cinfo->entropy->start_pass) (cinfo, FALSE);
319 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
320 /* We emit frame/scan headers now */
321 (*cinfo->marker->write_frame_header) (cinfo);
322 (*cinfo->marker->write_scan_header) (cinfo);
323 break;
324 }
325 }
326
327 /* Set up progress monitor's pass info if present */
328 if (cinfo->progress != NULL) {
329 cinfo->progress->completed_passes = master->pass_number;
330 cinfo->progress->total_passes = npasses;
331 }
332
333 master->pass_number++;
334 }
335
336
337 /*
338 * Special start-of-pass hook.
339 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
340 * In single-pass processing, we need this hook because we don't want to
341 * write frame/scan headers during jpeg_start_compress; we want to let the
342 * application write COM markers etc. between jpeg_start_compress and the
343 * jpeg_write_scanlines loop.
344 * In multi-pass processing, this routine is not used.
345 */
346
347 METHODDEF void
pass_startup(j_compress_ptr cinfo)348 pass_startup (j_compress_ptr cinfo)
349 {
350 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
351
352 (*cinfo->marker->write_frame_header) (cinfo);
353 (*cinfo->marker->write_scan_header) (cinfo);
354 }
355
356
357 /*
358 * Finish up at end of pass.
359 */
360
361 METHODDEF void
finish_pass_master(j_compress_ptr cinfo)362 finish_pass_master (j_compress_ptr cinfo)
363 {
364 /* More complex logic later ??? */
365
366 /* The entropy coder needs an end-of-pass call, either to analyze
367 * statistics or to flush its output buffer.
368 */
369 (*cinfo->entropy->finish_pass) (cinfo);
370 }
371
372
373 /*
374 * Initialize master compression control.
375 * This creates my own subrecord and also performs the master selection phase,
376 * which causes other modules to create their subrecords.
377 */
378
379 GLOBAL void
jinit_master_compress(j_compress_ptr cinfo)380 jinit_master_compress (j_compress_ptr cinfo)
381 {
382 my_master_ptr master;
383
384 master = (my_master_ptr)
385 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
386 SIZEOF(my_comp_master));
387 cinfo->master = (struct jpeg_comp_master *) master;
388 master->pub.prepare_for_pass = prepare_for_pass;
389 master->pub.pass_startup = pass_startup;
390 master->pub.finish_pass = finish_pass_master;
391
392 master_selection(cinfo);
393 }
394