1 : /*
2 : * jcmainct.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 the main buffer controller for compression.
9 : * The main buffer lies between the pre-processor and the JPEG
10 : * compressor proper; it holds downsampled data in the JPEG colorspace.
11 : */
12 :
13 : #define JPEG_INTERNALS
14 : #include "jinclude.h"
15 : #include "jpeglib.h"
16 :
17 :
18 : /* Note: currently, there is no operating mode in which a full-image buffer
19 : * is needed at this step. If there were, that mode could not be used with
20 : * "raw data" input, since this module is bypassed in that case. However,
21 : * we've left the code here for possible use in special applications.
22 : */
23 : #undef FULL_MAIN_BUFFER_SUPPORTED
24 :
25 :
26 : /* Private buffer controller object */
27 :
28 : typedef struct {
29 : struct jpeg_c_main_controller pub; /* public fields */
30 :
31 : JDIMENSION cur_iMCU_row; /* number of current iMCU row */
32 : JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */
33 : boolean suspended; /* remember if we suspended output */
34 : J_BUF_MODE pass_mode; /* current operating mode */
35 :
36 : /* If using just a strip buffer, this points to the entire set of buffers
37 : * (we allocate one for each component). In the full-image case, this
38 : * points to the currently accessible strips of the virtual arrays.
39 : */
40 : JSAMPARRAY buffer[MAX_COMPONENTS];
41 :
42 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
43 : /* If using full-image storage, this array holds pointers to virtual-array
44 : * control blocks for each component. Unused if not full-image storage.
45 : */
46 : jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
47 : #endif
48 : } my_main_controller;
49 :
50 : typedef my_main_controller * my_main_ptr;
51 :
52 :
53 : /* Forward declarations */
54 : METHODDEF(void) process_data_simple_main
55 : JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
56 : JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
57 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
58 : METHODDEF(void) process_data_buffer_main
59 : JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
60 : JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
61 : #endif
62 :
63 :
64 : /*
65 : * Initialize for a processing pass.
66 : */
67 :
68 : METHODDEF(void)
69 3 : start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
70 : {
71 3 : my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
72 :
73 : /* Do nothing in raw-data mode. */
74 3 : if (cinfo->raw_data_in)
75 0 : return;
76 :
77 3 : main_ptr->cur_iMCU_row = 0; /* initialize counters */
78 3 : main_ptr->rowgroup_ctr = 0;
79 3 : main_ptr->suspended = FALSE;
80 3 : main_ptr->pass_mode = pass_mode; /* save mode for use by process_data */
81 :
82 3 : switch (pass_mode) {
83 : case JBUF_PASS_THRU:
84 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
85 : if (main_ptr->whole_image[0] != NULL)
86 : ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
87 : #endif
88 3 : main_ptr->pub.process_data = process_data_simple_main;
89 3 : break;
90 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
91 : case JBUF_SAVE_SOURCE:
92 : case JBUF_CRANK_DEST:
93 : case JBUF_SAVE_AND_PASS:
94 : if (main_ptr->whole_image[0] == NULL)
95 : ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
96 : main_ptr->pub.process_data = process_data_buffer_main;
97 : break;
98 : #endif
99 : default:
100 0 : ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
101 0 : break;
102 : }
103 : }
104 :
105 :
106 : /*
107 : * Process some data.
108 : * This routine handles the simple pass-through mode,
109 : * where we have only a strip buffer.
110 : */
111 :
112 : METHODDEF(void)
113 144 : process_data_simple_main (j_compress_ptr cinfo,
114 : JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
115 : JDIMENSION in_rows_avail)
116 : {
117 144 : my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
118 :
119 306 : while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {
120 : /* Read input data if we haven't filled the main buffer yet */
121 159 : if (main_ptr->rowgroup_ctr < DCTSIZE)
122 159 : (*cinfo->prep->pre_process_data) (cinfo,
123 : input_buf, in_row_ctr, in_rows_avail,
124 : main_ptr->buffer, &main_ptr->rowgroup_ctr,
125 : (JDIMENSION) DCTSIZE);
126 :
127 : /* If we don't have a full iMCU row buffered, return to application for
128 : * more data. Note that preprocessor will always pad to fill the iMCU row
129 : * at the bottom of the image.
130 : */
131 159 : if (main_ptr->rowgroup_ctr != DCTSIZE)
132 141 : return;
133 :
134 : /* Send the completed row to the compressor */
135 18 : if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {
136 : /* If compressor did not consume the whole row, then we must need to
137 : * suspend processing and return to the application. In this situation
138 : * we pretend we didn't yet consume the last input row; otherwise, if
139 : * it happened to be the last row of the image, the application would
140 : * think we were done.
141 : */
142 0 : if (! main_ptr->suspended) {
143 0 : (*in_row_ctr)--;
144 0 : main_ptr->suspended = TRUE;
145 : }
146 0 : return;
147 : }
148 : /* We did finish the row. Undo our little suspension hack if a previous
149 : * call suspended; then mark the main buffer empty.
150 : */
151 18 : if (main_ptr->suspended) {
152 0 : (*in_row_ctr)++;
153 0 : main_ptr->suspended = FALSE;
154 : }
155 18 : main_ptr->rowgroup_ctr = 0;
156 18 : main_ptr->cur_iMCU_row++;
157 : }
158 : }
159 :
160 :
161 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
162 :
163 : /*
164 : * Process some data.
165 : * This routine handles all of the modes that use a full-size buffer.
166 : */
167 :
168 : METHODDEF(void)
169 : process_data_buffer_main (j_compress_ptr cinfo,
170 : JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
171 : JDIMENSION in_rows_avail)
172 : {
173 : my_main_ptr main = (my_main_ptr) cinfo->main;
174 : int ci;
175 : jpeg_component_info *compptr;
176 : boolean writing = (main_ptr->pass_mode != JBUF_CRANK_DEST);
177 :
178 : while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {
179 : /* Realign the virtual buffers if at the start of an iMCU row. */
180 : if (main_ptr->rowgroup_ctr == 0) {
181 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
182 : ci++, compptr++) {
183 : main_ptr->buffer[ci] = (*cinfo->mem->access_virt_sarray)
184 : ((j_common_ptr) cinfo, main_ptr->whole_image[ci],
185 : main_ptr->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
186 : (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
187 : }
188 : /* In a read pass, pretend we just read some source data. */
189 : if (! writing) {
190 : *in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
191 : main_ptr->rowgroup_ctr = DCTSIZE;
192 : }
193 : }
194 :
195 : /* If a write pass, read input data until the current iMCU row is full. */
196 : /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
197 : if (writing) {
198 : (*cinfo->prep->pre_process_data) (cinfo,
199 : input_buf, in_row_ctr, in_rows_avail,
200 : main_ptr->buffer, &main_ptr->rowgroup_ctr,
201 : (JDIMENSION) DCTSIZE);
202 : /* Return to application if we need more data to fill the iMCU row. */
203 : if (main_ptr->rowgroup_ctr < DCTSIZE)
204 : return;
205 : }
206 :
207 : /* Emit data, unless this is a sink-only pass. */
208 : if (main_ptr->pass_mode != JBUF_SAVE_SOURCE) {
209 : if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {
210 : /* If compressor did not consume the whole row, then we must need to
211 : * suspend processing and return to the application. In this situation
212 : * we pretend we didn't yet consume the last input row; otherwise, if
213 : * it happened to be the last row of the image, the application would
214 : * think we were done.
215 : */
216 : if (! main_ptr->suspended) {
217 : (*in_row_ctr)--;
218 : main_ptr->suspended = TRUE;
219 : }
220 : return;
221 : }
222 : /* We did finish the row. Undo our little suspension hack if a previous
223 : * call suspended; then mark the main buffer empty.
224 : */
225 : if (main_ptr->suspended) {
226 : (*in_row_ctr)++;
227 : main_ptr->suspended = FALSE;
228 : }
229 : }
230 :
231 : /* If get here, we are done with this iMCU row. Mark buffer empty. */
232 : main_ptr->rowgroup_ctr = 0;
233 : main_ptr->cur_iMCU_row++;
234 : }
235 : }
236 :
237 : #endif /* FULL_MAIN_BUFFER_SUPPORTED */
238 :
239 :
240 : /*
241 : * Initialize main buffer controller.
242 : */
243 :
244 : GLOBAL(void)
245 3 : jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
246 : {
247 : my_main_ptr main_ptr;
248 : int ci;
249 : jpeg_component_info *compptr;
250 :
251 3 : main_ptr = (my_main_ptr)
252 3 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
253 : SIZEOF(my_main_controller));
254 3 : cinfo->main = (struct jpeg_c_main_controller *) main_ptr;
255 3 : main_ptr->pub.start_pass = start_pass_main;
256 :
257 : /* We don't need to create a buffer in raw-data mode. */
258 3 : if (cinfo->raw_data_in)
259 0 : return;
260 :
261 : /* Create the buffer. It holds downsampled data, so each component
262 : * may be of a different size.
263 : */
264 3 : if (need_full_buffer) {
265 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
266 : /* Allocate a full-image virtual array for each component */
267 : /* Note we pad the bottom to a multiple of the iMCU height */
268 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
269 : ci++, compptr++) {
270 : main_ptr->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
271 : ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
272 : compptr->width_in_blocks * DCTSIZE,
273 : (JDIMENSION) jround_up((long) compptr->height_in_blocks,
274 : (long) compptr->v_samp_factor) * DCTSIZE,
275 : (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
276 : }
277 : #else
278 0 : ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
279 : #endif
280 : } else {
281 : #ifdef FULL_MAIN_BUFFER_SUPPORTED
282 : main_ptr->whole_image[0] = NULL; /* flag for no virtual arrays */
283 : #endif
284 : /* Allocate a strip buffer for each component */
285 15 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
286 9 : ci++, compptr++) {
287 18 : main_ptr->buffer[ci] = (*cinfo->mem->alloc_sarray)
288 27 : ((j_common_ptr) cinfo, JPOOL_IMAGE,
289 9 : compptr->width_in_blocks * DCTSIZE,
290 9 : (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
291 : }
292 : }
293 : }
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