/[pcsx2_0.9.7]/trunk/3rdparty/libjpeg/jdinput.c
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Annotation of /trunk/3rdparty/libjpeg/jdinput.c

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Revision 31 - (hide annotations) (download)
Tue Sep 7 03:24:11 2010 UTC (10 years ago) by william
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File size: 13593 byte(s)
committing r3113 initial commit again...
1 william 31 /*
2     * jdinput.c
3     *
4     * Copyright (C) 1991-1997, Thomas G. Lane.
5     * Modified 2002-2009 by Guido Vollbeding.
6     * This file is part of the Independent JPEG Group's software.
7     * For conditions of distribution and use, see the accompanying README file.
8     *
9     * This file contains input control logic for the JPEG decompressor.
10     * These routines are concerned with controlling the decompressor's input
11     * processing (marker reading and coefficient decoding). The actual input
12     * reading is done in jdmarker.c, jdhuff.c, and jdarith.c.
13     */
14    
15     #define JPEG_INTERNALS
16     #include "jinclude.h"
17     #include "jpeglib.h"
18    
19    
20     /* Private state */
21    
22     typedef struct {
23     struct jpeg_input_controller pub; /* public fields */
24    
25     boolean inheaders; /* TRUE until first SOS is reached */
26     } my_input_controller;
27    
28     typedef my_input_controller * my_inputctl_ptr;
29    
30    
31     /* Forward declarations */
32     METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
33    
34    
35     /*
36     * Routines to calculate various quantities related to the size of the image.
37     */
38    
39     LOCAL(void)
40     initial_setup (j_decompress_ptr cinfo)
41     /* Called once, when first SOS marker is reached */
42     {
43     int ci;
44     jpeg_component_info *compptr;
45    
46     /* Make sure image isn't bigger than I can handle */
47     if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
48     (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
49     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
50    
51     /* For now, precision must match compiled-in value... */
52     if (cinfo->data_precision != BITS_IN_JSAMPLE)
53     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
54    
55     /* Check that number of components won't exceed internal array sizes */
56     if (cinfo->num_components > MAX_COMPONENTS)
57     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
58     MAX_COMPONENTS);
59    
60     /* Compute maximum sampling factors; check factor validity */
61     cinfo->max_h_samp_factor = 1;
62     cinfo->max_v_samp_factor = 1;
63     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
64     ci++, compptr++) {
65     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
66     compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
67     ERREXIT(cinfo, JERR_BAD_SAMPLING);
68     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
69     compptr->h_samp_factor);
70     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
71     compptr->v_samp_factor);
72     }
73    
74     /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
75     * In the full decompressor, this will be overridden by jdmaster.c;
76     * but in the transcoder, jdmaster.c is not used, so we must do it here.
77     */
78     cinfo->min_DCT_h_scaled_size = DCTSIZE;
79     cinfo->min_DCT_v_scaled_size = DCTSIZE;
80    
81     /* Compute dimensions of components */
82     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
83     ci++, compptr++) {
84     compptr->DCT_h_scaled_size = DCTSIZE;
85     compptr->DCT_v_scaled_size = DCTSIZE;
86     /* Size in DCT blocks */
87     compptr->width_in_blocks = (JDIMENSION)
88     jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
89     (long) (cinfo->max_h_samp_factor * DCTSIZE));
90     compptr->height_in_blocks = (JDIMENSION)
91     jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
92     (long) (cinfo->max_v_samp_factor * DCTSIZE));
93     /* downsampled_width and downsampled_height will also be overridden by
94     * jdmaster.c if we are doing full decompression. The transcoder library
95     * doesn't use these values, but the calling application might.
96     */
97     /* Size in samples */
98     compptr->downsampled_width = (JDIMENSION)
99     jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
100     (long) cinfo->max_h_samp_factor);
101     compptr->downsampled_height = (JDIMENSION)
102     jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
103     (long) cinfo->max_v_samp_factor);
104     /* Mark component needed, until color conversion says otherwise */
105     compptr->component_needed = TRUE;
106     /* Mark no quantization table yet saved for component */
107     compptr->quant_table = NULL;
108     }
109    
110     /* Compute number of fully interleaved MCU rows. */
111     cinfo->total_iMCU_rows = (JDIMENSION)
112     jdiv_round_up((long) cinfo->image_height,
113     (long) (cinfo->max_v_samp_factor*DCTSIZE));
114    
115     /* Decide whether file contains multiple scans */
116     if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
117     cinfo->inputctl->has_multiple_scans = TRUE;
118     else
119     cinfo->inputctl->has_multiple_scans = FALSE;
120     }
121    
122    
123     LOCAL(void)
124     per_scan_setup (j_decompress_ptr cinfo)
125     /* Do computations that are needed before processing a JPEG scan */
126     /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
127     {
128     int ci, mcublks, tmp;
129     jpeg_component_info *compptr;
130    
131     if (cinfo->comps_in_scan == 1) {
132    
133     /* Noninterleaved (single-component) scan */
134     compptr = cinfo->cur_comp_info[0];
135    
136     /* Overall image size in MCUs */
137     cinfo->MCUs_per_row = compptr->width_in_blocks;
138     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
139    
140     /* For noninterleaved scan, always one block per MCU */
141     compptr->MCU_width = 1;
142     compptr->MCU_height = 1;
143     compptr->MCU_blocks = 1;
144     compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
145     compptr->last_col_width = 1;
146     /* For noninterleaved scans, it is convenient to define last_row_height
147     * as the number of block rows present in the last iMCU row.
148     */
149     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
150     if (tmp == 0) tmp = compptr->v_samp_factor;
151     compptr->last_row_height = tmp;
152    
153     /* Prepare array describing MCU composition */
154     cinfo->blocks_in_MCU = 1;
155     cinfo->MCU_membership[0] = 0;
156    
157     } else {
158    
159     /* Interleaved (multi-component) scan */
160     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
161     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
162     MAX_COMPS_IN_SCAN);
163    
164     /* Overall image size in MCUs */
165     cinfo->MCUs_per_row = (JDIMENSION)
166     jdiv_round_up((long) cinfo->image_width,
167     (long) (cinfo->max_h_samp_factor*DCTSIZE));
168     cinfo->MCU_rows_in_scan = (JDIMENSION)
169     jdiv_round_up((long) cinfo->image_height,
170     (long) (cinfo->max_v_samp_factor*DCTSIZE));
171    
172     cinfo->blocks_in_MCU = 0;
173    
174     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
175     compptr = cinfo->cur_comp_info[ci];
176     /* Sampling factors give # of blocks of component in each MCU */
177     compptr->MCU_width = compptr->h_samp_factor;
178     compptr->MCU_height = compptr->v_samp_factor;
179     compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
180     compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
181     /* Figure number of non-dummy blocks in last MCU column & row */
182     tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
183     if (tmp == 0) tmp = compptr->MCU_width;
184     compptr->last_col_width = tmp;
185     tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
186     if (tmp == 0) tmp = compptr->MCU_height;
187     compptr->last_row_height = tmp;
188     /* Prepare array describing MCU composition */
189     mcublks = compptr->MCU_blocks;
190     if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
191     ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
192     while (mcublks-- > 0) {
193     cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
194     }
195     }
196    
197     }
198     }
199    
200    
201     /*
202     * Save away a copy of the Q-table referenced by each component present
203     * in the current scan, unless already saved during a prior scan.
204     *
205     * In a multiple-scan JPEG file, the encoder could assign different components
206     * the same Q-table slot number, but change table definitions between scans
207     * so that each component uses a different Q-table. (The IJG encoder is not
208     * currently capable of doing this, but other encoders might.) Since we want
209     * to be able to dequantize all the components at the end of the file, this
210     * means that we have to save away the table actually used for each component.
211     * We do this by copying the table at the start of the first scan containing
212     * the component.
213     * The JPEG spec prohibits the encoder from changing the contents of a Q-table
214     * slot between scans of a component using that slot. If the encoder does so
215     * anyway, this decoder will simply use the Q-table values that were current
216     * at the start of the first scan for the component.
217     *
218     * The decompressor output side looks only at the saved quant tables,
219     * not at the current Q-table slots.
220     */
221    
222     LOCAL(void)
223     latch_quant_tables (j_decompress_ptr cinfo)
224     {
225     int ci, qtblno;
226     jpeg_component_info *compptr;
227     JQUANT_TBL * qtbl;
228    
229     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
230     compptr = cinfo->cur_comp_info[ci];
231     /* No work if we already saved Q-table for this component */
232     if (compptr->quant_table != NULL)
233     continue;
234     /* Make sure specified quantization table is present */
235     qtblno = compptr->quant_tbl_no;
236     if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
237     cinfo->quant_tbl_ptrs[qtblno] == NULL)
238     ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
239     /* OK, save away the quantization table */
240     qtbl = (JQUANT_TBL *)
241     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
242     SIZEOF(JQUANT_TBL));
243     MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
244     compptr->quant_table = qtbl;
245     }
246     }
247    
248    
249     /*
250     * Initialize the input modules to read a scan of compressed data.
251     * The first call to this is done by jdmaster.c after initializing
252     * the entire decompressor (during jpeg_start_decompress).
253     * Subsequent calls come from consume_markers, below.
254     */
255    
256     METHODDEF(void)
257     start_input_pass (j_decompress_ptr cinfo)
258     {
259     per_scan_setup(cinfo);
260     latch_quant_tables(cinfo);
261     (*cinfo->entropy->start_pass) (cinfo);
262     (*cinfo->coef->start_input_pass) (cinfo);
263     cinfo->inputctl->consume_input = cinfo->coef->consume_data;
264     }
265    
266    
267     /*
268     * Finish up after inputting a compressed-data scan.
269     * This is called by the coefficient controller after it's read all
270     * the expected data of the scan.
271     */
272    
273     METHODDEF(void)
274     finish_input_pass (j_decompress_ptr cinfo)
275     {
276     cinfo->inputctl->consume_input = consume_markers;
277     }
278    
279    
280     /*
281     * Read JPEG markers before, between, or after compressed-data scans.
282     * Change state as necessary when a new scan is reached.
283     * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
284     *
285     * The consume_input method pointer points either here or to the
286     * coefficient controller's consume_data routine, depending on whether
287     * we are reading a compressed data segment or inter-segment markers.
288     */
289    
290     METHODDEF(int)
291     consume_markers (j_decompress_ptr cinfo)
292     {
293     my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
294     int val;
295    
296     if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
297     return JPEG_REACHED_EOI;
298    
299     val = (*cinfo->marker->read_markers) (cinfo);
300    
301     switch (val) {
302     case JPEG_REACHED_SOS: /* Found SOS */
303     if (inputctl->inheaders) { /* 1st SOS */
304     initial_setup(cinfo);
305     inputctl->inheaders = FALSE;
306     /* Note: start_input_pass must be called by jdmaster.c
307     * before any more input can be consumed. jdapimin.c is
308     * responsible for enforcing this sequencing.
309     */
310     } else { /* 2nd or later SOS marker */
311     if (! inputctl->pub.has_multiple_scans)
312     ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
313     start_input_pass(cinfo);
314     }
315     break;
316     case JPEG_REACHED_EOI: /* Found EOI */
317     inputctl->pub.eoi_reached = TRUE;
318     if (inputctl->inheaders) { /* Tables-only datastream, apparently */
319     if (cinfo->marker->saw_SOF)
320     ERREXIT(cinfo, JERR_SOF_NO_SOS);
321     } else {
322     /* Prevent infinite loop in coef ctlr's decompress_data routine
323     * if user set output_scan_number larger than number of scans.
324     */
325     if (cinfo->output_scan_number > cinfo->input_scan_number)
326     cinfo->output_scan_number = cinfo->input_scan_number;
327     }
328     break;
329     case JPEG_SUSPENDED:
330     break;
331     }
332    
333     return val;
334     }
335    
336    
337     /*
338     * Reset state to begin a fresh datastream.
339     */
340    
341     METHODDEF(void)
342     reset_input_controller (j_decompress_ptr cinfo)
343     {
344     my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
345    
346     inputctl->pub.consume_input = consume_markers;
347     inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
348     inputctl->pub.eoi_reached = FALSE;
349     inputctl->inheaders = TRUE;
350     /* Reset other modules */
351     (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
352     (*cinfo->marker->reset_marker_reader) (cinfo);
353     /* Reset progression state -- would be cleaner if entropy decoder did this */
354     cinfo->coef_bits = NULL;
355     }
356    
357    
358     /*
359     * Initialize the input controller module.
360     * This is called only once, when the decompression object is created.
361     */
362    
363     GLOBAL(void)
364     jinit_input_controller (j_decompress_ptr cinfo)
365     {
366     my_inputctl_ptr inputctl;
367    
368     /* Create subobject in permanent pool */
369     inputctl = (my_inputctl_ptr)
370     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
371     SIZEOF(my_input_controller));
372     cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
373     /* Initialize method pointers */
374     inputctl->pub.consume_input = consume_markers;
375     inputctl->pub.reset_input_controller = reset_input_controller;
376     inputctl->pub.start_input_pass = start_input_pass;
377     inputctl->pub.finish_input_pass = finish_input_pass;
378     /* Initialize state: can't use reset_input_controller since we don't
379     * want to try to reset other modules yet.
380     */
381     inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
382     inputctl->pub.eoi_reached = FALSE;
383     inputctl->inheaders = TRUE;
384     }

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