1/*
2 * jdinput.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2010, 2016, D. R. Commander.
8 * Copyright (C) 2015, Google, Inc.
9 * For conditions of distribution and use, see the accompanying README.ijg
10 * file.
11 *
12 * This file contains input control logic for the JPEG decompressor.
13 * These routines are concerned with controlling the decompressor's input
14 * processing (marker reading and coefficient decoding). The actual input
15 * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c.
16 */
17
18#define JPEG_INTERNALS
19#include "jinclude.h"
20#include "jpeglib.h"
21#include "jpegcomp.h"
22
23
24/* Private state */
25
26typedef struct {
27 struct jpeg_input_controller pub; /* public fields */
28
29 boolean inheaders; /* TRUE until first SOS is reached */
30} my_input_controller;
31
32typedef my_input_controller *my_inputctl_ptr;
33
34
35/* Forward declarations */
36METHODDEF(int) consume_markers (j_decompress_ptr cinfo);
37
38
39/*
40 * Routines to calculate various quantities related to the size of the image.
41 */
42
43LOCAL(void)
44initial_setup (j_decompress_ptr cinfo)
45/* Called once, when first SOS marker is reached */
46{
47 int ci;
48 jpeg_component_info *compptr;
49
50 /* Make sure image isn't bigger than I can handle */
51 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
52 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
53 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
54
55 /* For now, precision must match compiled-in value... */
56 if (cinfo->data_precision != BITS_IN_JSAMPLE)
57 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
58
59 /* Check that number of components won't exceed internal array sizes */
60 if (cinfo->num_components > MAX_COMPONENTS)
61 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
62 MAX_COMPONENTS);
63
64 /* Compute maximum sampling factors; check factor validity */
65 cinfo->max_h_samp_factor = 1;
66 cinfo->max_v_samp_factor = 1;
67 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
68 ci++, compptr++) {
69 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
70 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
71 ERREXIT(cinfo, JERR_BAD_SAMPLING);
72 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
73 compptr->h_samp_factor);
74 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
75 compptr->v_samp_factor);
76 }
77
78#if JPEG_LIB_VERSION >=80
79 cinfo->block_size = DCTSIZE;
80 cinfo->natural_order = jpeg_natural_order;
81 cinfo->lim_Se = DCTSIZE2-1;
82#endif
83
84 /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
85 * In the full decompressor, this will be overridden by jdmaster.c;
86 * but in the transcoder, jdmaster.c is not used, so we must do it here.
87 */
88#if JPEG_LIB_VERSION >= 70
89 cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
90#else
91 cinfo->min_DCT_scaled_size = DCTSIZE;
92#endif
93
94 /* Compute dimensions of components */
95 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
96 ci++, compptr++) {
97#if JPEG_LIB_VERSION >= 70
98 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
99#else
100 compptr->DCT_scaled_size = DCTSIZE;
101#endif
102 /* Size in DCT blocks */
103 compptr->width_in_blocks = (JDIMENSION)
104 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
105 (long) (cinfo->max_h_samp_factor * DCTSIZE));
106 compptr->height_in_blocks = (JDIMENSION)
107 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
108 (long) (cinfo->max_v_samp_factor * DCTSIZE));
109 /* Set the first and last MCU columns to decompress from multi-scan images.
110 * By default, decompress all of the MCU columns.
111 */
112 cinfo->master->first_MCU_col[ci] = 0;
113 cinfo->master->last_MCU_col[ci] = compptr->width_in_blocks - 1;
114 /* downsampled_width and downsampled_height will also be overridden by
115 * jdmaster.c if we are doing full decompression. The transcoder library
116 * doesn't use these values, but the calling application might.
117 */
118 /* Size in samples */
119 compptr->downsampled_width = (JDIMENSION)
120 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
121 (long) cinfo->max_h_samp_factor);
122 compptr->downsampled_height = (JDIMENSION)
123 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
124 (long) cinfo->max_v_samp_factor);
125 /* Mark component needed, until color conversion says otherwise */
126 compptr->component_needed = TRUE;
127 /* Mark no quantization table yet saved for component */
128 compptr->quant_table = NULL;
129 }
130
131 /* Compute number of fully interleaved MCU rows. */
132 cinfo->total_iMCU_rows = (JDIMENSION)
133 jdiv_round_up((long) cinfo->image_height,
134 (long) (cinfo->max_v_samp_factor*DCTSIZE));
135
136 /* Decide whether file contains multiple scans */
137 if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
138 cinfo->inputctl->has_multiple_scans = TRUE;
139 else
140 cinfo->inputctl->has_multiple_scans = FALSE;
141}
142
143
144LOCAL(void)
145per_scan_setup (j_decompress_ptr cinfo)
146/* Do computations that are needed before processing a JPEG scan */
147/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
148{
149 int ci, mcublks, tmp;
150 jpeg_component_info *compptr;
151
152 if (cinfo->comps_in_scan == 1) {
153
154 /* Noninterleaved (single-component) scan */
155 compptr = cinfo->cur_comp_info[0];
156
157 /* Overall image size in MCUs */
158 cinfo->MCUs_per_row = compptr->width_in_blocks;
159 cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
160
161 /* For noninterleaved scan, always one block per MCU */
162 compptr->MCU_width = 1;
163 compptr->MCU_height = 1;
164 compptr->MCU_blocks = 1;
165 compptr->MCU_sample_width = compptr->_DCT_scaled_size;
166 compptr->last_col_width = 1;
167 /* For noninterleaved scans, it is convenient to define last_row_height
168 * as the number of block rows present in the last iMCU row.
169 */
170 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
171 if (tmp == 0) tmp = compptr->v_samp_factor;
172 compptr->last_row_height = tmp;
173
174 /* Prepare array describing MCU composition */
175 cinfo->blocks_in_MCU = 1;
176 cinfo->MCU_membership[0] = 0;
177
178 } else {
179
180 /* Interleaved (multi-component) scan */
181 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
182 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
183 MAX_COMPS_IN_SCAN);
184
185 /* Overall image size in MCUs */
186 cinfo->MCUs_per_row = (JDIMENSION)
187 jdiv_round_up((long) cinfo->image_width,
188 (long) (cinfo->max_h_samp_factor*DCTSIZE));
189 cinfo->MCU_rows_in_scan = (JDIMENSION)
190 jdiv_round_up((long) cinfo->image_height,
191 (long) (cinfo->max_v_samp_factor*DCTSIZE));
192
193 cinfo->blocks_in_MCU = 0;
194
195 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
196 compptr = cinfo->cur_comp_info[ci];
197 /* Sampling factors give # of blocks of component in each MCU */
198 compptr->MCU_width = compptr->h_samp_factor;
199 compptr->MCU_height = compptr->v_samp_factor;
200 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
201 compptr->MCU_sample_width = compptr->MCU_width * compptr->_DCT_scaled_size;
202 /* Figure number of non-dummy blocks in last MCU column & row */
203 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
204 if (tmp == 0) tmp = compptr->MCU_width;
205 compptr->last_col_width = tmp;
206 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
207 if (tmp == 0) tmp = compptr->MCU_height;
208 compptr->last_row_height = tmp;
209 /* Prepare array describing MCU composition */
210 mcublks = compptr->MCU_blocks;
211 if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
212 ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
213 while (mcublks-- > 0) {
214 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
215 }
216 }
217
218 }
219}
220
221
222/*
223 * Save away a copy of the Q-table referenced by each component present
224 * in the current scan, unless already saved during a prior scan.
225 *
226 * In a multiple-scan JPEG file, the encoder could assign different components
227 * the same Q-table slot number, but change table definitions between scans
228 * so that each component uses a different Q-table. (The IJG encoder is not
229 * currently capable of doing this, but other encoders might.) Since we want
230 * to be able to dequantize all the components at the end of the file, this
231 * means that we have to save away the table actually used for each component.
232 * We do this by copying the table at the start of the first scan containing
233 * the component.
234 * The JPEG spec prohibits the encoder from changing the contents of a Q-table
235 * slot between scans of a component using that slot. If the encoder does so
236 * anyway, this decoder will simply use the Q-table values that were current
237 * at the start of the first scan for the component.
238 *
239 * The decompressor output side looks only at the saved quant tables,
240 * not at the current Q-table slots.
241 */
242
243LOCAL(void)
244latch_quant_tables (j_decompress_ptr cinfo)
245{
246 int ci, qtblno;
247 jpeg_component_info *compptr;
248 JQUANT_TBL *qtbl;
249
250 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
251 compptr = cinfo->cur_comp_info[ci];
252 /* No work if we already saved Q-table for this component */
253 if (compptr->quant_table != NULL)
254 continue;
255 /* Make sure specified quantization table is present */
256 qtblno = compptr->quant_tbl_no;
257 if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
258 cinfo->quant_tbl_ptrs[qtblno] == NULL)
259 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
260 /* OK, save away the quantization table */
261 qtbl = (JQUANT_TBL *)
262 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
263 sizeof(JQUANT_TBL));
264 MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], sizeof(JQUANT_TBL));
265 compptr->quant_table = qtbl;
266 }
267}
268
269
270/*
271 * Initialize the input modules to read a scan of compressed data.
272 * The first call to this is done by jdmaster.c after initializing
273 * the entire decompressor (during jpeg_start_decompress).
274 * Subsequent calls come from consume_markers, below.
275 */
276
277METHODDEF(void)
278start_input_pass (j_decompress_ptr cinfo)
279{
280 per_scan_setup(cinfo);
281 latch_quant_tables(cinfo);
282 (*cinfo->entropy->start_pass) (cinfo);
283 (*cinfo->coef->start_input_pass) (cinfo);
284 cinfo->inputctl->consume_input = cinfo->coef->consume_data;
285}
286
287
288/*
289 * Finish up after inputting a compressed-data scan.
290 * This is called by the coefficient controller after it's read all
291 * the expected data of the scan.
292 */
293
294METHODDEF(void)
295finish_input_pass (j_decompress_ptr cinfo)
296{
297 cinfo->inputctl->consume_input = consume_markers;
298}
299
300
301/*
302 * Read JPEG markers before, between, or after compressed-data scans.
303 * Change state as necessary when a new scan is reached.
304 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
305 *
306 * The consume_input method pointer points either here or to the
307 * coefficient controller's consume_data routine, depending on whether
308 * we are reading a compressed data segment or inter-segment markers.
309 */
310
311METHODDEF(int)
312consume_markers (j_decompress_ptr cinfo)
313{
314 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
315 int val;
316
317 if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
318 return JPEG_REACHED_EOI;
319
320 val = (*cinfo->marker->read_markers) (cinfo);
321
322 switch (val) {
323 case JPEG_REACHED_SOS: /* Found SOS */
324 if (inputctl->inheaders) { /* 1st SOS */
325 initial_setup(cinfo);
326 inputctl->inheaders = FALSE;
327 /* Note: start_input_pass must be called by jdmaster.c
328 * before any more input can be consumed. jdapimin.c is
329 * responsible for enforcing this sequencing.
330 */
331 } else { /* 2nd or later SOS marker */
332 if (! inputctl->pub.has_multiple_scans)
333 ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
334 start_input_pass(cinfo);
335 }
336 break;
337 case JPEG_REACHED_EOI: /* Found EOI */
338 inputctl->pub.eoi_reached = TRUE;
339 if (inputctl->inheaders) { /* Tables-only datastream, apparently */
340 if (cinfo->marker->saw_SOF)
341 ERREXIT(cinfo, JERR_SOF_NO_SOS);
342 } else {
343 /* Prevent infinite loop in coef ctlr's decompress_data routine
344 * if user set output_scan_number larger than number of scans.
345 */
346 if (cinfo->output_scan_number > cinfo->input_scan_number)
347 cinfo->output_scan_number = cinfo->input_scan_number;
348 }
349 break;
350 case JPEG_SUSPENDED:
351 break;
352 }
353
354 return val;
355}
356
357
358/*
359 * Reset state to begin a fresh datastream.
360 */
361
362METHODDEF(void)
363reset_input_controller (j_decompress_ptr cinfo)
364{
365 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
366
367 inputctl->pub.consume_input = consume_markers;
368 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
369 inputctl->pub.eoi_reached = FALSE;
370 inputctl->inheaders = TRUE;
371 /* Reset other modules */
372 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
373 (*cinfo->marker->reset_marker_reader) (cinfo);
374 /* Reset progression state -- would be cleaner if entropy decoder did this */
375 cinfo->coef_bits = NULL;
376}
377
378
379/*
380 * Initialize the input controller module.
381 * This is called only once, when the decompression object is created.
382 */
383
384GLOBAL(void)
385jinit_input_controller (j_decompress_ptr cinfo)
386{
387 my_inputctl_ptr inputctl;
388
389 /* Create subobject in permanent pool */
390 inputctl = (my_inputctl_ptr)
391 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
392 sizeof(my_input_controller));
393 cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
394 /* Initialize method pointers */
395 inputctl->pub.consume_input = consume_markers;
396 inputctl->pub.reset_input_controller = reset_input_controller;
397 inputctl->pub.start_input_pass = start_input_pass;
398 inputctl->pub.finish_input_pass = finish_input_pass;
399 /* Initialize state: can't use reset_input_controller since we don't
400 * want to try to reset other modules yet.
401 */
402 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
403 inputctl->pub.eoi_reached = FALSE;
404 inputctl->inheaders = TRUE;
405}
406