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Dees_Troy51a0e822012-09-05 15:24:24 -04001/*
2 * jdapistd.c
3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains application interface code for the decompression half
9 * of the JPEG library. These are the "standard" API routines that are
10 * used in the normal full-decompression case. They are not used by a
11 * transcoding-only application. Note that if an application links in
12 * jpeg_start_decompress, it will end up linking in the entire decompressor.
13 * We thus must separate this file from jdapimin.c to avoid linking the
14 * whole decompression library into a transcoder.
15 */
16
17#define JPEG_INTERNALS
18#include "jinclude.h"
19#include "jpeglib.h"
20
21
22/* Forward declarations */
23LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
24
25
26/*
27 * Decompression initialization.
28 * jpeg_read_header must be completed before calling this.
29 *
30 * If a multipass operating mode was selected, this will do all but the
31 * last pass, and thus may take a great deal of time.
32 *
33 * Returns FALSE if suspended. The return value need be inspected only if
34 * a suspending data source is used.
35 */
36
37GLOBAL(boolean)
38jpeg_start_decompress (j_decompress_ptr cinfo)
39{
40 if (cinfo->global_state == DSTATE_READY) {
41 /* First call: initialize master control, select active modules */
42 jinit_master_decompress(cinfo);
43 if (cinfo->buffered_image) {
44 /* No more work here; expecting jpeg_start_output next */
45 cinfo->global_state = DSTATE_BUFIMAGE;
46 return TRUE;
47 }
48 cinfo->global_state = DSTATE_PRELOAD;
49 }
50 if (cinfo->global_state == DSTATE_PRELOAD) {
51 /* If file has multiple scans, absorb them all into the coef buffer */
52 if (cinfo->inputctl->has_multiple_scans) {
53#ifdef D_MULTISCAN_FILES_SUPPORTED
54 for (;;) {
55 int retcode;
56 /* Call progress monitor hook if present */
57 if (cinfo->progress != NULL)
58 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
59 /* Absorb some more input */
60 retcode = (*cinfo->inputctl->consume_input) (cinfo);
61 if (retcode == JPEG_SUSPENDED)
62 return FALSE;
63 if (retcode == JPEG_REACHED_EOI)
64 break;
65 /* Advance progress counter if appropriate */
66 if (cinfo->progress != NULL &&
67 (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
68 if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
69 /* jdmaster underestimated number of scans; ratchet up one scan */
70 cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
71 }
72 }
73 }
74#else
75 ERREXIT(cinfo, JERR_NOT_COMPILED);
76#endif /* D_MULTISCAN_FILES_SUPPORTED */
77 }
78 cinfo->output_scan_number = cinfo->input_scan_number;
79 } else if (cinfo->global_state != DSTATE_PRESCAN)
80 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
81 /* Perform any dummy output passes, and set up for the final pass */
82 return output_pass_setup(cinfo);
83}
84
85/*
86 * Tile decompression initialization.
87 * jpeg_read_header must be completed before calling this.
88 */
89
90GLOBAL(boolean)
91jpeg_start_tile_decompress (j_decompress_ptr cinfo)
92{
93 if (cinfo->global_state == DSTATE_READY) {
94 /* First call: initialize master control, select active modules */
95 cinfo->tile_decode = TRUE;
96 jinit_master_decompress(cinfo);
97 if (cinfo->buffered_image) {
98 cinfo->global_state = DSTATE_BUFIMAGE;
99 return TRUE;
100 }
101 cinfo->global_state = DSTATE_PRELOAD;
102 }
103 if (cinfo->global_state == DSTATE_PRELOAD) {
104 cinfo->output_scan_number = cinfo->input_scan_number;
105 } else if (cinfo->global_state != DSTATE_PRESCAN)
106 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
107 /* Perform any dummy output passes, and set up for the final pass */
108 return output_pass_setup(cinfo);
109}
110
111
112/*
113 * Set up for an output pass, and perform any dummy pass(es) needed.
114 * Common subroutine for jpeg_start_decompress and jpeg_start_output.
115 * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
116 * Exit: If done, returns TRUE and sets global_state for proper output mode.
117 * If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
118 */
119
120LOCAL(boolean)
121output_pass_setup (j_decompress_ptr cinfo)
122{
123 if (cinfo->global_state != DSTATE_PRESCAN) {
124 /* First call: do pass setup */
125 (*cinfo->master->prepare_for_output_pass) (cinfo);
126 cinfo->output_scanline = 0;
127 cinfo->global_state = DSTATE_PRESCAN;
128 }
129 /* Loop over any required dummy passes */
130 while (cinfo->master->is_dummy_pass) {
131#ifdef QUANT_2PASS_SUPPORTED
132 /* Crank through the dummy pass */
133 while (cinfo->output_scanline < cinfo->output_height) {
134 JDIMENSION last_scanline;
135 /* Call progress monitor hook if present */
136 if (cinfo->progress != NULL) {
137 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
138 cinfo->progress->pass_limit = (long) cinfo->output_height;
139 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
140 }
141 /* Process some data */
142 last_scanline = cinfo->output_scanline;
143 (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
144 &cinfo->output_scanline, (JDIMENSION) 0);
145 if (cinfo->output_scanline == last_scanline)
146 return FALSE; /* No progress made, must suspend */
147 }
148 /* Finish up dummy pass, and set up for another one */
149 (*cinfo->master->finish_output_pass) (cinfo);
150 (*cinfo->master->prepare_for_output_pass) (cinfo);
151 cinfo->output_scanline = 0;
152#else
153 ERREXIT(cinfo, JERR_NOT_COMPILED);
154#endif /* QUANT_2PASS_SUPPORTED */
155 }
156 /* Ready for application to drive output pass through
157 * jpeg_read_scanlines or jpeg_read_raw_data.
158 */
159 cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
160 return TRUE;
161}
162
163
164/*
165 * Read some scanlines of data from the JPEG decompressor.
166 *
167 * The return value will be the number of lines actually read.
168 * This may be less than the number requested in several cases,
169 * including bottom of image, data source suspension, and operating
170 * modes that emit multiple scanlines at a time.
171 *
172 * Note: we warn about excess calls to jpeg_read_scanlines() since
173 * this likely signals an application programmer error. However,
174 * an oversize buffer (max_lines > scanlines remaining) is not an error.
175 */
176
177GLOBAL(JDIMENSION)
178jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
179 JDIMENSION max_lines)
180{
181 JDIMENSION row_ctr;
182
183 if (cinfo->global_state != DSTATE_SCANNING)
184 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
185 if (cinfo->output_scanline >= cinfo->output_height) {
186 WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
187 return 0;
188 }
189
190 /* Call progress monitor hook if present */
191 if (cinfo->progress != NULL) {
192 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
193 cinfo->progress->pass_limit = (long) cinfo->output_height;
194 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
195 }
196
197 /* Process some data */
198 row_ctr = 0;
199 (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
200 cinfo->output_scanline += row_ctr;
201 return row_ctr;
202}
203/*
204 * Initialize the jpeg decoder to decompressing a rectangle with size of (width, height)
205 * and its upper-left corner located at (start_x, start_y).
206 * Align start_x and start_y to multiplies of iMCU width and height, respectively.
207 * Also, the new reader position and sampled image size will be returned in
208 * (start_x, start_y) and (width, height), respectively.
209 */
210
211GLOBAL(void)
212jpeg_init_read_tile_scanline(j_decompress_ptr cinfo, huffman_index *index,
213 int *start_x, int *start_y, int *width, int *height)
214{
215 // Calculates the boundary of iMCU
216 int lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
217 int lines_per_iMCU_col = cinfo->max_h_samp_factor * DCTSIZE;
218 int row_offset = *start_y / lines_per_iMCU_row;
219 int col_left_boundary = ((*start_x / lines_per_iMCU_col)
220 / index->MCU_sample_size) * index->MCU_sample_size;
221 int col_right_boundary =
222 jdiv_round_up(*start_x + *width, lines_per_iMCU_col);
223
224 cinfo->coef->MCU_columns_to_skip =
225 *start_x / lines_per_iMCU_col - col_left_boundary;
226
227 *height = (*start_y - row_offset * lines_per_iMCU_row) + *height;
228 *start_x = col_left_boundary * lines_per_iMCU_col;
229 *start_y = row_offset * lines_per_iMCU_row;
230 cinfo->image_width = jmin(cinfo->original_image_width,
231 col_right_boundary * lines_per_iMCU_col) -
232 col_left_boundary * lines_per_iMCU_col;
233 cinfo->input_iMCU_row = row_offset;
234 cinfo->output_iMCU_row = row_offset;
235
236 // Updates JPEG decoder parameter
237 jinit_color_deconverter(cinfo);
238 jpeg_calc_output_dimensions(cinfo);
239 jinit_upsampler(cinfo);
240 (*cinfo->master->prepare_for_output_pass) (cinfo);
241 if (cinfo->progressive_mode)
242 (*cinfo->entropy->start_pass) (cinfo);
243 else
244 jpeg_decompress_per_scan_setup(cinfo);
245
246 int sample_size = DCTSIZE / cinfo->min_DCT_scaled_size;
247
248 *height = jdiv_round_up(*height, sample_size);
249 *width = cinfo->output_width;
250 cinfo->output_scanline = lines_per_iMCU_row * row_offset / sample_size;
251 cinfo->inputctl->consume_input = cinfo->coef->consume_data;
252 cinfo->inputctl->consume_input_build_huffman_index =
253 cinfo->coef->consume_data_build_huffman_index;
254 cinfo->entropy->index = index;
255 cinfo->input_iMCU_row = row_offset;
256 cinfo->output_iMCU_row = row_offset;
257 cinfo->coef->MCU_column_left_boundary = col_left_boundary;
258 cinfo->coef->MCU_column_right_boundary = col_right_boundary;
259 cinfo->coef->column_left_boundary =
260 col_left_boundary / index->MCU_sample_size;
261 cinfo->coef->column_right_boundary =
262 jdiv_round_up(col_right_boundary, index->MCU_sample_size);
263}
264
265/*
266 * Read a scanline from the current position.
267 *
268 * Return the number of lines actually read.
269 */
270
271GLOBAL(JDIMENSION)
272jpeg_read_tile_scanline (j_decompress_ptr cinfo, huffman_index *index,
273 JSAMPARRAY scanlines)
274{
275 // Calculates the boundary of iMCU
276 int lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
277 int lines_per_iMCU_col = cinfo->max_h_samp_factor * DCTSIZE;
278 int sample_size = DCTSIZE / cinfo->min_DCT_scaled_size;
279 JDIMENSION row_ctr = 0;
280
281 if (cinfo->progressive_mode) {
282 (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, 1);
283 } else {
284 if (cinfo->output_scanline % (lines_per_iMCU_row / sample_size) == 0) {
285 // Set the read head to the next iMCU row
286 int iMCU_row_offset = cinfo->output_scanline /
287 (lines_per_iMCU_row / sample_size);
288 int offset_data_col_position = cinfo->coef->MCU_column_left_boundary /
289 index->MCU_sample_size;
290 huffman_offset_data offset_data =
291 index->scan[0].offset[iMCU_row_offset][offset_data_col_position];
292 (*cinfo->entropy->configure_huffman_decoder) (cinfo, offset_data);
293 }
294 (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, 1);
295 }
296
297 cinfo->output_scanline += row_ctr;
298 return row_ctr;
299}
300
301/*
302 * Alternate entry point to read raw data.
303 * Processes exactly one iMCU row per call, unless suspended.
304 */
305
306GLOBAL(JDIMENSION)
307jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
308 JDIMENSION max_lines)
309{
310 JDIMENSION lines_per_iMCU_row;
311
312 if (cinfo->global_state != DSTATE_RAW_OK)
313 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
314 if (cinfo->output_scanline >= cinfo->output_height) {
315 WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
316 return 0;
317 }
318
319 /* Call progress monitor hook if present */
320 if (cinfo->progress != NULL) {
321 cinfo->progress->pass_counter = (long) cinfo->output_scanline;
322 cinfo->progress->pass_limit = (long) cinfo->output_height;
323 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
324 }
325
326 /* Verify that at least one iMCU row can be returned. */
327 lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
328 if (max_lines < lines_per_iMCU_row)
329 ERREXIT(cinfo, JERR_BUFFER_SIZE);
330
331 /* Decompress directly into user's buffer. */
332 if (! (*cinfo->coef->decompress_data) (cinfo, data))
333 return 0; /* suspension forced, can do nothing more */
334
335 /* OK, we processed one iMCU row. */
336 cinfo->output_scanline += lines_per_iMCU_row;
337 return lines_per_iMCU_row;
338}
339
340
341/* Additional entry points for buffered-image mode. */
342
343#ifdef D_MULTISCAN_FILES_SUPPORTED
344
345/*
346 * Initialize for an output pass in buffered-image mode.
347 */
348
349GLOBAL(boolean)
350jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
351{
352 if (cinfo->global_state != DSTATE_BUFIMAGE &&
353 cinfo->global_state != DSTATE_PRESCAN)
354 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
355 /* Limit scan number to valid range */
356 if (scan_number <= 0)
357 scan_number = 1;
358 if (cinfo->inputctl->eoi_reached &&
359 scan_number > cinfo->input_scan_number)
360 scan_number = cinfo->input_scan_number;
361 cinfo->output_scan_number = scan_number;
362 /* Perform any dummy output passes, and set up for the real pass */
363 return output_pass_setup(cinfo);
364}
365
366
367/*
368 * Finish up after an output pass in buffered-image mode.
369 *
370 * Returns FALSE if suspended. The return value need be inspected only if
371 * a suspending data source is used.
372 */
373
374GLOBAL(boolean)
375jpeg_finish_output (j_decompress_ptr cinfo)
376{
377 if ((cinfo->global_state == DSTATE_SCANNING ||
378 cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
379 /* Terminate this pass. */
380 /* We do not require the whole pass to have been completed. */
381 (*cinfo->master->finish_output_pass) (cinfo);
382 cinfo->global_state = DSTATE_BUFPOST;
383 } else if (cinfo->global_state != DSTATE_BUFPOST) {
384 /* BUFPOST = repeat call after a suspension, anything else is error */
385 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
386 }
387 /* Read markers looking for SOS or EOI */
388 while (cinfo->input_scan_number <= cinfo->output_scan_number &&
389 ! cinfo->inputctl->eoi_reached) {
390 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
391 return FALSE; /* Suspend, come back later */
392 }
393 cinfo->global_state = DSTATE_BUFIMAGE;
394 return TRUE;
395}
396
397#endif /* D_MULTISCAN_FILES_SUPPORTED */