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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)
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 || 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 
144 LOCAL(void)
per_scan_setup(j_decompress_ptr cinfo)145 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   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 
243 LOCAL(void)
latch_quant_tables(j_decompress_ptr cinfo)244 latch_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 
277 METHODDEF(void)
start_input_pass(j_decompress_ptr cinfo)278 start_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 
294 METHODDEF(void)
finish_input_pass(j_decompress_ptr cinfo)295 finish_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 
311 METHODDEF(int)
consume_markers(j_decompress_ptr cinfo)312 consume_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 
362 METHODDEF(void)
reset_input_controller(j_decompress_ptr cinfo)363 reset_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 
384 GLOBAL(void)
jinit_input_controller(j_decompress_ptr cinfo)385 jinit_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