1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
|
/*
* jdapistd.c
*
* Copyright (C) 1994-1996, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file tqcontains application interface code for the decompression half
* of the JPEG library. These are the "standard" API routines that are
* used in the normal full-decompression case. They are not used by a
* transcoding-only application. Note that if an application links in
* jpeg_start_decompress, it will end up linking in the entire decompressor.
* We thus must separate this file from jdapimin.c to avoid linking the
* whole decompression library into a transcoder.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/* Forward declarations */
LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
/*
* Decompression initialization.
* jpeg_read_header must be completed before calling this.
*
* If a multipass operating mode was selected, this will do all but the
* last pass, and thus may take a great deal of time.
*
* Returns FALSE if suspended. The return value need be inspected only if
* a suspending data source is used.
*/
GLOBAL(boolean)
jpeg_start_decompress (j_decompress_ptr cinfo)
{
if (cinfo->global_state == DSTATE_READY) {
/* First call: initialize master control, select active modules */
jinit_master_decompress(cinfo);
if (cinfo->buffered_image) {
/* No more work here; expecting jpeg_start_output next */
cinfo->global_state = DSTATE_BUFIMAGE;
return TRUE;
}
cinfo->global_state = DSTATE_PRELOAD;
}
if (cinfo->global_state == DSTATE_PRELOAD) {
/* If file has multiple scans, absorb them all into the coef buffer */
if (cinfo->inputctl->has_multiple_scans) {
#ifdef D_MULTISCAN_FILES_SUPPORTED
for (;;) {
int retcode;
/* Call progress monitor hook if present */
if (cinfo->progress != NULL)
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
/* Absorb some more input */
retcode = (*cinfo->inputctl->consume_input) (cinfo);
if (retcode == JPEG_SUSPENDED)
return FALSE;
if (retcode == JPEG_REACHED_EOI)
break;
/* Advance progress counter if appropriate */
if (cinfo->progress != NULL &&
(retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
/* jdmaster underestimated number of scans; ratchet up one scan */
cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
}
}
}
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* D_MULTISCAN_FILES_SUPPORTED */
}
cinfo->output_scan_number = cinfo->input_scan_number;
} else if (cinfo->global_state != DSTATE_PRESCAN)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
/* Perform any dummy output passes, and set up for the final pass */
return output_pass_setup(cinfo);
}
/*
* Set up for an output pass, and perform any dummy pass(es) needed.
* Common subroutine for jpeg_start_decompress and jpeg_start_output.
* Entry: global_state = DSTATE_PRESCAN only if previously suspended.
* Exit: If done, returns TRUE and sets global_state for proper output mode.
* If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
*/
LOCAL(boolean)
output_pass_setup (j_decompress_ptr cinfo)
{
if (cinfo->global_state != DSTATE_PRESCAN) {
/* First call: do pass setup */
(*cinfo->master->prepare_for_output_pass) (cinfo);
cinfo->output_scanline = 0;
cinfo->global_state = DSTATE_PRESCAN;
}
/* Loop over any required dummy passes */
while (cinfo->master->is_dummy_pass) {
#ifdef TQUANT_2PASS_SUPPORTED
/* Crank through the dummy pass */
while (cinfo->output_scanline < cinfo->output_height) {
JDIMENSION last_scanline;
/* Call progress monitor hook if present */
if (cinfo->progress != NULL) {
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
cinfo->progress->pass_limit = (long) cinfo->output_height;
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
}
/* Process some data */
last_scanline = cinfo->output_scanline;
(*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
&cinfo->output_scanline, (JDIMENSION) 0);
if (cinfo->output_scanline == last_scanline)
return FALSE; /* No progress made, must suspend */
}
/* Finish up dummy pass, and set up for another one */
(*cinfo->master->finish_output_pass) (cinfo);
(*cinfo->master->prepare_for_output_pass) (cinfo);
cinfo->output_scanline = 0;
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* TQUANT_2PASS_SUPPORTED */
}
/* Ready for application to drive output pass through
* jpeg_read_scanlines or jpeg_read_raw_data.
*/
cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
return TRUE;
}
/*
* Read some scanlines of data from the JPEG decompressor.
*
* The return value will be the number of lines actually read.
* This may be less than the number requested in several cases,
* including bottom of image, data source suspension, and operating
* modes that emit multiple scanlines at a time.
*
* Note: we warn about excess calls to jpeg_read_scanlines() since
* this likely Q_SIGNALS an application programmer error. However,
* an oversize buffer (max_lines > scanlines remaining) is not an error.
*/
GLOBAL(JDIMENSION)
jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
JDIMENSION max_lines)
{
JDIMENSION row_ctr;
if (cinfo->global_state != DSTATE_SCANNING)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (cinfo->output_scanline >= cinfo->output_height) {
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
return 0;
}
/* Call progress monitor hook if present */
if (cinfo->progress != NULL) {
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
cinfo->progress->pass_limit = (long) cinfo->output_height;
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
}
/* Process some data */
row_ctr = 0;
(*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
cinfo->output_scanline += row_ctr;
return row_ctr;
}
/*
* Alternate entry point to read raw data.
* Processes exactly one iMCU row per call, unless suspended.
*/
GLOBAL(JDIMENSION)
jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
JDIMENSION max_lines)
{
JDIMENSION lines_per_iMCU_row;
if (cinfo->global_state != DSTATE_RAW_OK)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (cinfo->output_scanline >= cinfo->output_height) {
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
return 0;
}
/* Call progress monitor hook if present */
if (cinfo->progress != NULL) {
cinfo->progress->pass_counter = (long) cinfo->output_scanline;
cinfo->progress->pass_limit = (long) cinfo->output_height;
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
}
/* Verify that at least one iMCU row can be returned. */
lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
if (max_lines < lines_per_iMCU_row)
ERREXIT(cinfo, JERR_BUFFER_SIZE);
/* Decompress directly into user's buffer. */
if (! (*cinfo->coef->decompress_data) (cinfo, data))
return 0; /* suspension forced, can do nothing more */
/* OK, we processed one iMCU row. */
cinfo->output_scanline += lines_per_iMCU_row;
return lines_per_iMCU_row;
}
/* Additional entry points for buffered-image mode. */
#ifdef D_MULTISCAN_FILES_SUPPORTED
/*
* Initialize for an output pass in buffered-image mode.
*/
GLOBAL(boolean)
jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
{
if (cinfo->global_state != DSTATE_BUFIMAGE &&
cinfo->global_state != DSTATE_PRESCAN)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
/* Limit scan number to valid range */
if (scan_number <= 0)
scan_number = 1;
if (cinfo->inputctl->eoi_reached &&
scan_number > cinfo->input_scan_number)
scan_number = cinfo->input_scan_number;
cinfo->output_scan_number = scan_number;
/* Perform any dummy output passes, and set up for the real pass */
return output_pass_setup(cinfo);
}
/*
* Finish up after an output pass in buffered-image mode.
*
* Returns FALSE if suspended. The return value need be inspected only if
* a suspending data source is used.
*/
GLOBAL(boolean)
jpeg_finish_output (j_decompress_ptr cinfo)
{
if ((cinfo->global_state == DSTATE_SCANNING ||
cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
/* Terminate this pass. */
/* We do not require the whole pass to have been completed. */
(*cinfo->master->finish_output_pass) (cinfo);
cinfo->global_state = DSTATE_BUFPOST;
} else if (cinfo->global_state != DSTATE_BUFPOST) {
/* BUFPOST = repeat call after a suspension, anything else is error */
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
}
/* Read markers looking for SOS or EOI */
while (cinfo->input_scan_number <= cinfo->output_scan_number &&
! cinfo->inputctl->eoi_reached) {
if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
return FALSE; /* Suspend, come back later */
}
cinfo->global_state = DSTATE_BUFIMAGE;
return TRUE;
}
#endif /* D_MULTISCAN_FILES_SUPPORTED */
|
