2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
6 * These libraries and programs are free software; you can
7 * redistribute them and/or modify them under the terms of the GNU
8 * Lesser General Public License as published by the Free Software
9 * Foundation; either version 2 of the License, or (at your option)
12 * These libraries and programs are distributed in the hope that
13 * they will be useful, but WITHOUT ANY WARRANTY; without even the
14 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
15 * PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with these libraries and programs; if not, write
20 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
21 * Floor, Boston, MA 02110-1301 USA
23 /* $XConsortium: jdapistd.c /main/2 1996/05/09 03:46:26 drk $ */
27 * Copyright (C) 1994-1996, Thomas G. Lane.
28 * This file is part of the Independent JPEG Group's software.
29 * For conditions of distribution and use, see the accompanying README file.
31 * This file contains application interface code for the decompression half
32 * of the JPEG library. These are the "standard" API routines that are
33 * used in the normal full-decompression case. They are not used by a
34 * transcoding-only application. Note that if an application links in
35 * jpeg_start_decompress, it will end up linking in the entire decompressor.
36 * We thus must separate this file from jdapimin.c to avoid linking the
37 * whole decompression library into a transcoder.
40 #define JPEG_INTERNALS
45 /* Forward declarations */
46 LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
50 * Decompression initialization.
51 * jpeg_read_header must be completed before calling this.
53 * If a multipass operating mode was selected, this will do all but the
54 * last pass, and thus may take a great deal of time.
56 * Returns FALSE if suspended. The return value need be inspected only if
57 * a suspending data source is used.
61 jpeg_start_decompress (j_decompress_ptr cinfo)
63 if (cinfo->global_state == DSTATE_READY) {
64 /* First call: initialize master control, select active modules */
65 jinit_master_decompress(cinfo);
66 if (cinfo->buffered_image) {
67 /* No more work here; expecting jpeg_start_output next */
68 cinfo->global_state = DSTATE_BUFIMAGE;
71 cinfo->global_state = DSTATE_PRELOAD;
73 if (cinfo->global_state == DSTATE_PRELOAD) {
74 /* If file has multiple scans, absorb them all into the coef buffer */
75 if (cinfo->inputctl->has_multiple_scans) {
76 #ifdef D_MULTISCAN_FILES_SUPPORTED
79 /* Call progress monitor hook if present */
80 if (cinfo->progress != NULL)
81 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
82 /* Absorb some more input */
83 retcode = (*cinfo->inputctl->consume_input) (cinfo);
84 if (retcode == JPEG_SUSPENDED)
86 if (retcode == JPEG_REACHED_EOI)
88 /* Advance progress counter if appropriate */
89 if (cinfo->progress != NULL &&
90 (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
91 if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
92 /* jdmaster underestimated number of scans; ratchet up one scan */
93 cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
98 ERREXIT(cinfo, JERR_NOT_COMPILED);
99 #endif /* D_MULTISCAN_FILES_SUPPORTED */
101 cinfo->output_scan_number = cinfo->input_scan_number;
102 } else if (cinfo->global_state != DSTATE_PRESCAN)
103 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
104 /* Perform any dummy output passes, and set up for the final pass */
105 return output_pass_setup(cinfo);
110 * Set up for an output pass, and perform any dummy pass(es) needed.
111 * Common subroutine for jpeg_start_decompress and jpeg_start_output.
112 * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
113 * Exit: If done, returns TRUE and sets global_state for proper output mode.
114 * If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
118 output_pass_setup (j_decompress_ptr cinfo)
120 if (cinfo->global_state != DSTATE_PRESCAN) {
121 /* First call: do pass setup */
122 (*cinfo->master->prepare_for_output_pass) (cinfo);
123 cinfo->output_scanline = 0;
124 cinfo->global_state = DSTATE_PRESCAN;
126 /* Loop over any required dummy passes */
127 while (cinfo->master->is_dummy_pass) {
128 #ifdef QUANT_2PASS_SUPPORTED
129 /* Crank through the dummy pass */
130 while (cinfo->output_scanline < cinfo->output_height) {
131 JDIMENSION last_scanline;
132 /* Call progress monitor hook if present */
133 if (cinfo->progress != NULL) {
134 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
135 cinfo->progress->pass_limit = (long) cinfo->output_height;
136 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
138 /* Process some data */
139 last_scanline = cinfo->output_scanline;
140 (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
141 &cinfo->output_scanline, (JDIMENSION) 0);
142 if (cinfo->output_scanline == last_scanline)
143 return FALSE; /* No progress made, must suspend */
145 /* Finish up dummy pass, and set up for another one */
146 (*cinfo->master->finish_output_pass) (cinfo);
147 (*cinfo->master->prepare_for_output_pass) (cinfo);
148 cinfo->output_scanline = 0;
150 ERREXIT(cinfo, JERR_NOT_COMPILED);
151 #endif /* QUANT_2PASS_SUPPORTED */
153 /* Ready for application to drive output pass through
154 * jpeg_read_scanlines or jpeg_read_raw_data.
156 cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
162 * Read some scanlines of data from the JPEG decompressor.
164 * The return value will be the number of lines actually read.
165 * This may be less than the number requested in several cases,
166 * including bottom of image, data source suspension, and operating
167 * modes that emit multiple scanlines at a time.
169 * Note: we warn about excess calls to jpeg_read_scanlines() since
170 * this likely signals an application programmer error. However,
171 * an oversize buffer (max_lines > scanlines remaining) is not an error.
175 jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
176 JDIMENSION max_lines)
180 if (cinfo->global_state != DSTATE_SCANNING)
181 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
182 if (cinfo->output_scanline >= cinfo->output_height) {
183 WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
187 /* Call progress monitor hook if present */
188 if (cinfo->progress != NULL) {
189 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
190 cinfo->progress->pass_limit = (long) cinfo->output_height;
191 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
194 /* Process some data */
196 (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
197 cinfo->output_scanline += row_ctr;
203 * Alternate entry point to read raw data.
204 * Processes exactly one iMCU row per call, unless suspended.
208 jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
209 JDIMENSION max_lines)
211 JDIMENSION lines_per_iMCU_row;
213 if (cinfo->global_state != DSTATE_RAW_OK)
214 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
215 if (cinfo->output_scanline >= cinfo->output_height) {
216 WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
220 /* Call progress monitor hook if present */
221 if (cinfo->progress != NULL) {
222 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
223 cinfo->progress->pass_limit = (long) cinfo->output_height;
224 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
227 /* Verify that at least one iMCU row can be returned. */
228 lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
229 if (max_lines < lines_per_iMCU_row)
230 ERREXIT(cinfo, JERR_BUFFER_SIZE);
232 /* Decompress directly into user's buffer. */
233 if (! (*cinfo->coef->decompress_data) (cinfo, data))
234 return 0; /* suspension forced, can do nothing more */
236 /* OK, we processed one iMCU row. */
237 cinfo->output_scanline += lines_per_iMCU_row;
238 return lines_per_iMCU_row;
242 /* Additional entry points for buffered-image mode. */
244 #ifdef D_MULTISCAN_FILES_SUPPORTED
247 * Initialize for an output pass in buffered-image mode.
251 jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
253 if (cinfo->global_state != DSTATE_BUFIMAGE &&
254 cinfo->global_state != DSTATE_PRESCAN)
255 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
256 /* Limit scan number to valid range */
257 if (scan_number <= 0)
259 if (cinfo->inputctl->eoi_reached &&
260 scan_number > cinfo->input_scan_number)
261 scan_number = cinfo->input_scan_number;
262 cinfo->output_scan_number = scan_number;
263 /* Perform any dummy output passes, and set up for the real pass */
264 return output_pass_setup(cinfo);
269 * Finish up after an output pass in buffered-image mode.
271 * Returns FALSE if suspended. The return value need be inspected only if
272 * a suspending data source is used.
276 jpeg_finish_output (j_decompress_ptr cinfo)
278 if ((cinfo->global_state == DSTATE_SCANNING ||
279 cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
280 /* Terminate this pass. */
281 /* We do not require the whole pass to have been completed. */
282 (*cinfo->master->finish_output_pass) (cinfo);
283 cinfo->global_state = DSTATE_BUFPOST;
284 } else if (cinfo->global_state != DSTATE_BUFPOST) {
285 /* BUFPOST = repeat call after a suspension, anything else is error */
286 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
288 /* Read markers looking for SOS or EOI */
289 while (cinfo->input_scan_number <= cinfo->output_scan_number &&
290 ! cinfo->inputctl->eoi_reached) {
291 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
292 return FALSE; /* Suspend, come back later */
294 cinfo->global_state = DSTATE_BUFIMAGE;
298 #endif /* D_MULTISCAN_FILES_SUPPORTED */