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, 2018, 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)
initial_setup(j_decompress_ptr cinfo)44 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   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 ||
70         compptr->h_samp_factor > MAX_SAMP_FACTOR ||
71         compptr->v_samp_factor <= 0 ||
72         compptr->v_samp_factor > MAX_SAMP_FACTOR)
73       ERREXIT(cinfo, JERR_BAD_SAMPLING);
74     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
75                                    compptr->h_samp_factor);
76     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
77                                    compptr->v_samp_factor);
78   }
79 
80 #if JPEG_LIB_VERSION >= 80
81   cinfo->block_size = DCTSIZE;
82   cinfo->natural_order = jpeg_natural_order;
83   cinfo->lim_Se = DCTSIZE2 - 1;
84 #endif
85 
86   /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
87    * In the full decompressor, this will be overridden by jdmaster.c;
88    * but in the transcoder, jdmaster.c is not used, so we must do it here.
89    */
90 #if JPEG_LIB_VERSION >= 70
91   cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
92 #else
93   cinfo->min_DCT_scaled_size = DCTSIZE;
94 #endif
95 
96   /* Compute dimensions of components */
97   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
98        ci++, compptr++) {
99 #if JPEG_LIB_VERSION >= 70
100     compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
101 #else
102     compptr->DCT_scaled_size = DCTSIZE;
103 #endif
104     /* Size in DCT blocks */
105     compptr->width_in_blocks = (JDIMENSION)
106       jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor,
107                     (long)(cinfo->max_h_samp_factor * DCTSIZE));
108     compptr->height_in_blocks = (JDIMENSION)
109       jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor,
110                     (long)(cinfo->max_v_samp_factor * DCTSIZE));
111     /* Set the first and last MCU columns to decompress from multi-scan images.
112      * By default, decompress all of the MCU columns.
113      */
114     cinfo->master->first_MCU_col[ci] = 0;
115     cinfo->master->last_MCU_col[ci] = compptr->width_in_blocks - 1;
116     /* downsampled_width and downsampled_height will also be overridden by
117      * jdmaster.c if we are doing full decompression.  The transcoder library
118      * doesn't use these values, but the calling application might.
119      */
120     /* Size in samples */
121     compptr->downsampled_width = (JDIMENSION)
122       jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor,
123                     (long)cinfo->max_h_samp_factor);
124     compptr->downsampled_height = (JDIMENSION)
125       jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor,
126                     (long)cinfo->max_v_samp_factor);
127     /* Mark component needed, until color conversion says otherwise */
128     compptr->component_needed = TRUE;
129     /* Mark no quantization table yet saved for component */
130     compptr->quant_table = NULL;
131   }
132 
133   /* Compute number of fully interleaved MCU rows. */
134   cinfo->total_iMCU_rows = (JDIMENSION)
135     jdiv_round_up((long)cinfo->image_height,
136                   (long)(cinfo->max_v_samp_factor * DCTSIZE));
137 
138   /* Decide whether file contains multiple scans */
139   if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
140     cinfo->inputctl->has_multiple_scans = TRUE;
141   else
142     cinfo->inputctl->has_multiple_scans = FALSE;
143 }
144 
145 
146 LOCAL(void)
per_scan_setup(j_decompress_ptr cinfo)147 per_scan_setup(j_decompress_ptr cinfo)
148 /* Do computations that are needed before processing a JPEG scan */
149 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
150 {
151   int ci, mcublks, tmp;
152   jpeg_component_info *compptr;
153 
154   if (cinfo->comps_in_scan == 1) {
155 
156     /* Noninterleaved (single-component) scan */
157     compptr = cinfo->cur_comp_info[0];
158 
159     /* Overall image size in MCUs */
160     cinfo->MCUs_per_row = compptr->width_in_blocks;
161     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
162 
163     /* For noninterleaved scan, always one block per MCU */
164     compptr->MCU_width = 1;
165     compptr->MCU_height = 1;
166     compptr->MCU_blocks = 1;
167     compptr->MCU_sample_width = compptr->_DCT_scaled_size;
168     compptr->last_col_width = 1;
169     /* For noninterleaved scans, it is convenient to define last_row_height
170      * as the number of block rows present in the last iMCU row.
171      */
172     tmp = (int)(compptr->height_in_blocks % compptr->v_samp_factor);
173     if (tmp == 0) tmp = compptr->v_samp_factor;
174     compptr->last_row_height = tmp;
175 
176     /* Prepare array describing MCU composition */
177     cinfo->blocks_in_MCU = 1;
178     cinfo->MCU_membership[0] = 0;
179 
180   } else {
181 
182     /* Interleaved (multi-component) scan */
183     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
184       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
185                MAX_COMPS_IN_SCAN);
186 
187     /* Overall image size in MCUs */
188     cinfo->MCUs_per_row = (JDIMENSION)
189       jdiv_round_up((long)cinfo->image_width,
190                     (long)(cinfo->max_h_samp_factor * DCTSIZE));
191     cinfo->MCU_rows_in_scan = (JDIMENSION)
192       jdiv_round_up((long)cinfo->image_height,
193                     (long)(cinfo->max_v_samp_factor * DCTSIZE));
194 
195     cinfo->blocks_in_MCU = 0;
196 
197     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
198       compptr = cinfo->cur_comp_info[ci];
199       /* Sampling factors give # of blocks of component in each MCU */
200       compptr->MCU_width = compptr->h_samp_factor;
201       compptr->MCU_height = compptr->v_samp_factor;
202       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
203       compptr->MCU_sample_width = compptr->MCU_width *
204                                   compptr->_DCT_scaled_size;
205       /* Figure number of non-dummy blocks in last MCU column & row */
206       tmp = (int)(compptr->width_in_blocks % compptr->MCU_width);
207       if (tmp == 0) tmp = compptr->MCU_width;
208       compptr->last_col_width = tmp;
209       tmp = (int)(compptr->height_in_blocks % compptr->MCU_height);
210       if (tmp == 0) tmp = compptr->MCU_height;
211       compptr->last_row_height = tmp;
212       /* Prepare array describing MCU composition */
213       mcublks = compptr->MCU_blocks;
214       if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
215         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
216       while (mcublks-- > 0) {
217         cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
218       }
219     }
220 
221   }
222 }
223 
224 
225 /*
226  * Save away a copy of the Q-table referenced by each component present
227  * in the current scan, unless already saved during a prior scan.
228  *
229  * In a multiple-scan JPEG file, the encoder could assign different components
230  * the same Q-table slot number, but change table definitions between scans
231  * so that each component uses a different Q-table.  (The IJG encoder is not
232  * currently capable of doing this, but other encoders might.)  Since we want
233  * to be able to dequantize all the components at the end of the file, this
234  * means that we have to save away the table actually used for each component.
235  * We do this by copying the table at the start of the first scan containing
236  * the component.
237  * Rec. ITU-T T.81 | ISO/IEC 10918-1 prohibits the encoder from changing the
238  * contents of a Q-table slot between scans of a component using that slot.  If
239  * the encoder does so anyway, this decoder will simply use the Q-table values
240  * that were current at the start of the first scan for the component.
241  *
242  * The decompressor output side looks only at the saved quant tables,
243  * not at the current Q-table slots.
244  */
245 
246 LOCAL(void)
latch_quant_tables(j_decompress_ptr cinfo)247 latch_quant_tables(j_decompress_ptr cinfo)
248 {
249   int ci, qtblno;
250   jpeg_component_info *compptr;
251   JQUANT_TBL *qtbl;
252 
253   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
254     compptr = cinfo->cur_comp_info[ci];
255     /* No work if we already saved Q-table for this component */
256     if (compptr->quant_table != NULL)
257       continue;
258     /* Make sure specified quantization table is present */
259     qtblno = compptr->quant_tbl_no;
260     if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
261         cinfo->quant_tbl_ptrs[qtblno] == NULL)
262       ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
263     /* OK, save away the quantization table */
264     qtbl = (JQUANT_TBL *)
265       (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
266                                   sizeof(JQUANT_TBL));
267     MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], sizeof(JQUANT_TBL));
268     compptr->quant_table = qtbl;
269   }
270 }
271 
272 
273 /*
274  * Initialize the input modules to read a scan of compressed data.
275  * The first call to this is done by jdmaster.c after initializing
276  * the entire decompressor (during jpeg_start_decompress).
277  * Subsequent calls come from consume_markers, below.
278  */
279 
280 METHODDEF(void)
start_input_pass(j_decompress_ptr cinfo)281 start_input_pass(j_decompress_ptr cinfo)
282 {
283   per_scan_setup(cinfo);
284   latch_quant_tables(cinfo);
285   (*cinfo->entropy->start_pass) (cinfo);
286   (*cinfo->coef->start_input_pass) (cinfo);
287   cinfo->inputctl->consume_input = cinfo->coef->consume_data;
288 }
289 
290 
291 /*
292  * Finish up after inputting a compressed-data scan.
293  * This is called by the coefficient controller after it's read all
294  * the expected data of the scan.
295  */
296 
297 METHODDEF(void)
finish_input_pass(j_decompress_ptr cinfo)298 finish_input_pass(j_decompress_ptr cinfo)
299 {
300   cinfo->inputctl->consume_input = consume_markers;
301 }
302 
303 
304 /*
305  * Read JPEG markers before, between, or after compressed-data scans.
306  * Change state as necessary when a new scan is reached.
307  * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
308  *
309  * The consume_input method pointer points either here or to the
310  * coefficient controller's consume_data routine, depending on whether
311  * we are reading a compressed data segment or inter-segment markers.
312  */
313 
314 METHODDEF(int)
consume_markers(j_decompress_ptr cinfo)315 consume_markers(j_decompress_ptr cinfo)
316 {
317   my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl;
318   int val;
319 
320   if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
321     return JPEG_REACHED_EOI;
322 
323   val = (*cinfo->marker->read_markers) (cinfo);
324 
325   switch (val) {
326   case JPEG_REACHED_SOS:        /* Found SOS */
327     if (inputctl->inheaders) {  /* 1st SOS */
328       initial_setup(cinfo);
329       inputctl->inheaders = FALSE;
330       /* Note: start_input_pass must be called by jdmaster.c
331        * before any more input can be consumed.  jdapimin.c is
332        * responsible for enforcing this sequencing.
333        */
334     } else {                    /* 2nd or later SOS marker */
335       if (!inputctl->pub.has_multiple_scans)
336         ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
337       start_input_pass(cinfo);
338     }
339     break;
340   case JPEG_REACHED_EOI:        /* Found EOI */
341     inputctl->pub.eoi_reached = TRUE;
342     if (inputctl->inheaders) {  /* Tables-only datastream, apparently */
343       if (cinfo->marker->saw_SOF)
344         ERREXIT(cinfo, JERR_SOF_NO_SOS);
345     } else {
346       /* Prevent infinite loop in coef ctlr's decompress_data routine
347        * if user set output_scan_number larger than number of scans.
348        */
349       if (cinfo->output_scan_number > cinfo->input_scan_number)
350         cinfo->output_scan_number = cinfo->input_scan_number;
351     }
352     break;
353   case JPEG_SUSPENDED:
354     break;
355   }
356 
357   return val;
358 }
359 
360 
361 /*
362  * Reset state to begin a fresh datastream.
363  */
364 
365 METHODDEF(void)
reset_input_controller(j_decompress_ptr cinfo)366 reset_input_controller(j_decompress_ptr cinfo)
367 {
368   my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl;
369 
370   inputctl->pub.consume_input = consume_markers;
371   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
372   inputctl->pub.eoi_reached = FALSE;
373   inputctl->inheaders = TRUE;
374   /* Reset other modules */
375   (*cinfo->err->reset_error_mgr) ((j_common_ptr)cinfo);
376   (*cinfo->marker->reset_marker_reader) (cinfo);
377   /* Reset progression state -- would be cleaner if entropy decoder did this */
378   cinfo->coef_bits = NULL;
379 }
380 
381 
382 /*
383  * Initialize the input controller module.
384  * This is called only once, when the decompression object is created.
385  */
386 
387 GLOBAL(void)
jinit_input_controller(j_decompress_ptr cinfo)388 jinit_input_controller(j_decompress_ptr cinfo)
389 {
390   my_inputctl_ptr inputctl;
391 
392   /* Create subobject in permanent pool */
393   inputctl = (my_inputctl_ptr)
394     (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT,
395                                 sizeof(my_input_controller));
396   cinfo->inputctl = (struct jpeg_input_controller *)inputctl;
397   /* Initialize method pointers */
398   inputctl->pub.consume_input = consume_markers;
399   inputctl->pub.reset_input_controller = reset_input_controller;
400   inputctl->pub.start_input_pass = start_input_pass;
401   inputctl->pub.finish_input_pass = finish_input_pass;
402   /* Initialize state: can't use reset_input_controller since we don't
403    * want to try to reset other modules yet.
404    */
405   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
406   inputctl->pub.eoi_reached = FALSE;
407   inputctl->inheaders = TRUE;
408 }
409