Line data Source code
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 :
26 : typedef struct {
27 : struct jpeg_input_controller pub; /* public fields */
28 :
29 : boolean inheaders; /* TRUE until first SOS is reached */
30 : } my_input_controller;
31 :
32 : typedef my_input_controller *my_inputctl_ptr;
33 :
34 :
35 : /* Forward declarations */
36 : METHODDEF(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 :
43 : LOCAL(void)
44 0 : initial_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 0 : if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
52 0 : (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
53 0 : ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
54 :
55 : /* For now, precision must match compiled-in value... */
56 0 : if (cinfo->data_precision != BITS_IN_JSAMPLE)
57 0 : ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
58 :
59 : /* Check that number of components won't exceed internal array sizes */
60 0 : if (cinfo->num_components > MAX_COMPONENTS)
61 0 : ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
62 : MAX_COMPONENTS);
63 :
64 : /* Compute maximum sampling factors; check factor validity */
65 0 : cinfo->max_h_samp_factor = 1;
66 0 : cinfo->max_v_samp_factor = 1;
67 0 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
68 0 : ci++, compptr++) {
69 0 : if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
70 0 : compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
71 0 : ERREXIT(cinfo, JERR_BAD_SAMPLING);
72 0 : cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
73 : compptr->h_samp_factor);
74 0 : 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 0 : cinfo->min_DCT_scaled_size = DCTSIZE;
92 : #endif
93 :
94 : /* Compute dimensions of components */
95 0 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
96 0 : ci++, compptr++) {
97 : #if JPEG_LIB_VERSION >= 70
98 : compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
99 : #else
100 0 : compptr->DCT_scaled_size = DCTSIZE;
101 : #endif
102 : /* Size in DCT blocks */
103 0 : compptr->width_in_blocks = (JDIMENSION)
104 0 : jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
105 0 : (long) (cinfo->max_h_samp_factor * DCTSIZE));
106 0 : compptr->height_in_blocks = (JDIMENSION)
107 0 : jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
108 0 : (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 0 : cinfo->master->first_MCU_col[ci] = 0;
113 0 : 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 0 : compptr->downsampled_width = (JDIMENSION)
120 0 : jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
121 0 : (long) cinfo->max_h_samp_factor);
122 0 : compptr->downsampled_height = (JDIMENSION)
123 0 : jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
124 0 : (long) cinfo->max_v_samp_factor);
125 : /* Mark component needed, until color conversion says otherwise */
126 0 : compptr->component_needed = TRUE;
127 : /* Mark no quantization table yet saved for component */
128 0 : compptr->quant_table = NULL;
129 : }
130 :
131 : /* Compute number of fully interleaved MCU rows. */
132 0 : cinfo->total_iMCU_rows = (JDIMENSION)
133 0 : jdiv_round_up((long) cinfo->image_height,
134 0 : (long) (cinfo->max_v_samp_factor*DCTSIZE));
135 :
136 : /* Decide whether file contains multiple scans */
137 0 : if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
138 0 : cinfo->inputctl->has_multiple_scans = TRUE;
139 : else
140 0 : cinfo->inputctl->has_multiple_scans = FALSE;
141 0 : }
142 :
143 :
144 : LOCAL(void)
145 0 : per_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 0 : if (cinfo->comps_in_scan == 1) {
153 :
154 : /* Noninterleaved (single-component) scan */
155 0 : compptr = cinfo->cur_comp_info[0];
156 :
157 : /* Overall image size in MCUs */
158 0 : cinfo->MCUs_per_row = compptr->width_in_blocks;
159 0 : cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
160 :
161 : /* For noninterleaved scan, always one block per MCU */
162 0 : compptr->MCU_width = 1;
163 0 : compptr->MCU_height = 1;
164 0 : compptr->MCU_blocks = 1;
165 0 : compptr->MCU_sample_width = compptr->_DCT_scaled_size;
166 0 : 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 0 : tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
171 0 : if (tmp == 0) tmp = compptr->v_samp_factor;
172 0 : compptr->last_row_height = tmp;
173 :
174 : /* Prepare array describing MCU composition */
175 0 : cinfo->blocks_in_MCU = 1;
176 0 : cinfo->MCU_membership[0] = 0;
177 :
178 : } else {
179 :
180 : /* Interleaved (multi-component) scan */
181 0 : if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
182 0 : ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
183 : MAX_COMPS_IN_SCAN);
184 :
185 : /* Overall image size in MCUs */
186 0 : cinfo->MCUs_per_row = (JDIMENSION)
187 0 : jdiv_round_up((long) cinfo->image_width,
188 0 : (long) (cinfo->max_h_samp_factor*DCTSIZE));
189 0 : cinfo->MCU_rows_in_scan = (JDIMENSION)
190 0 : jdiv_round_up((long) cinfo->image_height,
191 0 : (long) (cinfo->max_v_samp_factor*DCTSIZE));
192 :
193 0 : cinfo->blocks_in_MCU = 0;
194 :
195 0 : for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
196 0 : compptr = cinfo->cur_comp_info[ci];
197 : /* Sampling factors give # of blocks of component in each MCU */
198 0 : compptr->MCU_width = compptr->h_samp_factor;
199 0 : compptr->MCU_height = compptr->v_samp_factor;
200 0 : compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
201 0 : compptr->MCU_sample_width = compptr->MCU_width * compptr->_DCT_scaled_size;
202 : /* Figure number of non-dummy blocks in last MCU column & row */
203 0 : tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
204 0 : if (tmp == 0) tmp = compptr->MCU_width;
205 0 : compptr->last_col_width = tmp;
206 0 : tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
207 0 : if (tmp == 0) tmp = compptr->MCU_height;
208 0 : compptr->last_row_height = tmp;
209 : /* Prepare array describing MCU composition */
210 0 : mcublks = compptr->MCU_blocks;
211 0 : if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
212 0 : ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
213 0 : while (mcublks-- > 0) {
214 0 : cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
215 : }
216 : }
217 :
218 : }
219 0 : }
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 :
243 : LOCAL(void)
244 0 : latch_quant_tables (j_decompress_ptr cinfo)
245 : {
246 : int ci, qtblno;
247 : jpeg_component_info *compptr;
248 : JQUANT_TBL *qtbl;
249 :
250 0 : for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
251 0 : compptr = cinfo->cur_comp_info[ci];
252 : /* No work if we already saved Q-table for this component */
253 0 : if (compptr->quant_table != NULL)
254 0 : continue;
255 : /* Make sure specified quantization table is present */
256 0 : qtblno = compptr->quant_tbl_no;
257 0 : if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
258 0 : cinfo->quant_tbl_ptrs[qtblno] == NULL)
259 0 : ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
260 : /* OK, save away the quantization table */
261 0 : qtbl = (JQUANT_TBL *)
262 0 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
263 : sizeof(JQUANT_TBL));
264 0 : MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], sizeof(JQUANT_TBL));
265 0 : compptr->quant_table = qtbl;
266 : }
267 0 : }
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 :
277 : METHODDEF(void)
278 0 : start_input_pass (j_decompress_ptr cinfo)
279 : {
280 0 : per_scan_setup(cinfo);
281 0 : latch_quant_tables(cinfo);
282 0 : (*cinfo->entropy->start_pass) (cinfo);
283 0 : (*cinfo->coef->start_input_pass) (cinfo);
284 0 : cinfo->inputctl->consume_input = cinfo->coef->consume_data;
285 0 : }
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 :
294 : METHODDEF(void)
295 0 : finish_input_pass (j_decompress_ptr cinfo)
296 : {
297 0 : cinfo->inputctl->consume_input = consume_markers;
298 0 : }
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 :
311 : METHODDEF(int)
312 0 : consume_markers (j_decompress_ptr cinfo)
313 : {
314 0 : my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
315 : int val;
316 :
317 0 : if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
318 0 : return JPEG_REACHED_EOI;
319 :
320 0 : val = (*cinfo->marker->read_markers) (cinfo);
321 :
322 0 : switch (val) {
323 : case JPEG_REACHED_SOS: /* Found SOS */
324 0 : if (inputctl->inheaders) { /* 1st SOS */
325 0 : initial_setup(cinfo);
326 0 : 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 0 : if (! inputctl->pub.has_multiple_scans)
333 0 : ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
334 0 : start_input_pass(cinfo);
335 : }
336 0 : break;
337 : case JPEG_REACHED_EOI: /* Found EOI */
338 0 : inputctl->pub.eoi_reached = TRUE;
339 0 : if (inputctl->inheaders) { /* Tables-only datastream, apparently */
340 0 : if (cinfo->marker->saw_SOF)
341 0 : 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 0 : if (cinfo->output_scan_number > cinfo->input_scan_number)
347 0 : cinfo->output_scan_number = cinfo->input_scan_number;
348 : }
349 0 : break;
350 : case JPEG_SUSPENDED:
351 0 : break;
352 : }
353 :
354 0 : return val;
355 : }
356 :
357 :
358 : /*
359 : * Reset state to begin a fresh datastream.
360 : */
361 :
362 : METHODDEF(void)
363 0 : reset_input_controller (j_decompress_ptr cinfo)
364 : {
365 0 : my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
366 :
367 0 : inputctl->pub.consume_input = consume_markers;
368 0 : inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
369 0 : inputctl->pub.eoi_reached = FALSE;
370 0 : inputctl->inheaders = TRUE;
371 : /* Reset other modules */
372 0 : (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
373 0 : (*cinfo->marker->reset_marker_reader) (cinfo);
374 : /* Reset progression state -- would be cleaner if entropy decoder did this */
375 0 : cinfo->coef_bits = NULL;
376 0 : }
377 :
378 :
379 : /*
380 : * Initialize the input controller module.
381 : * This is called only once, when the decompression object is created.
382 : */
383 :
384 : GLOBAL(void)
385 0 : jinit_input_controller (j_decompress_ptr cinfo)
386 : {
387 : my_inputctl_ptr inputctl;
388 :
389 : /* Create subobject in permanent pool */
390 0 : inputctl = (my_inputctl_ptr)
391 0 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
392 : sizeof(my_input_controller));
393 0 : cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
394 : /* Initialize method pointers */
395 0 : inputctl->pub.consume_input = consume_markers;
396 0 : inputctl->pub.reset_input_controller = reset_input_controller;
397 0 : inputctl->pub.start_input_pass = start_input_pass;
398 0 : 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 0 : inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
403 0 : inputctl->pub.eoi_reached = FALSE;
404 0 : inputctl->inheaders = TRUE;
405 0 : }
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