source: golgotha/src/i4/loaders/jpg/jcmainct.cc @ 80

Last change on this file since 80 was 80, checked in by Sam Hocevar, 12 years ago
  • Adding the Golgotha source code. Not sure what's going to be interesting in there, but since it's all public domain, there's certainly stuff to pick up.
File size: 9.7 KB
Line 
1/********************************************************************** <BR>
2  This file is part of Crack dot Com's free source code release of
3  Golgotha. <a href="http://www.crack.com/golgotha_release"> <BR> for
4  information about compiling & licensing issues visit this URL</a>
5  <PRE> If that doesn't help, contact Jonathan Clark at
6  golgotha_source@usa.net (Subject should have "GOLG" in it)
7***********************************************************************/
8
9/*
10 * jcmainct.c
11 *
12 * Copyright (C) 1994-1996, Thomas G. Lane.
13 * This file is part of the Independent JPEG Group's software.
14 * For conditions of distribution and use, see the accompanying README file.
15 *
16 * This file contains the main buffer controller for compression.
17 * The main buffer lies between the pre-processor and the JPEG
18 * compressor proper; it holds downsampled data in the JPEG colorspace.
19 */
20
21#define JPEG_INTERNALS
22#include "loaders/jpg/jinclude.h"
23#include "loaders/jpg/jpeglib.h"
24
25
26/* Note: currently, there is no operating mode in which a full-image buffer
27 * is needed at this step.  If there were, that mode could not be used with
28 * "raw data" input, since this module is bypassed in that case.  However,
29 * we've left the code here for possible use in special applications.
30 */
31#undef FULL_MAIN_BUFFER_SUPPORTED
32
33
34/* Private buffer controller object */
35
36typedef struct {
37  struct jpeg_c_main_controller pub; /* public fields */
38
39  JDIMENSION cur_iMCU_row;      /* number of current iMCU row */
40  JDIMENSION rowgroup_ctr;      /* counts row groups received in iMCU row */
41  boolean suspended;            /* remember if we suspended output */
42  J_BUF_MODE pass_mode;         /* current operating mode */
43
44  /* If using just a strip buffer, this points to the entire set of buffers
45   * (we allocate one for each component).  In the full-image case, this
46   * points to the currently accessible strips of the virtual arrays.
47   */
48  JSAMPARRAY buffer[MAX_COMPONENTS];
49
50#ifdef FULL_MAIN_BUFFER_SUPPORTED
51  /* If using full-image storage, this array holds pointers to virtual-array
52   * control blocks for each component.  Unused if not full-image storage.
53   */
54  jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
55#endif
56} my_main_controller;
57
58typedef my_main_controller * my_main_ptr;
59
60
61/* Forward declarations */
62METHODDEF(void) process_data_simple_main
63        JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
64             JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
65#ifdef FULL_MAIN_BUFFER_SUPPORTED
66METHODDEF(void) process_data_buffer_main
67        JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
68             JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
69#endif
70
71
72/*
73 * Initialize for a processing pass.
74 */
75
76METHODDEF(void)
77start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
78{
79  my_main_ptr main = (my_main_ptr) cinfo->main;
80
81  /* Do nothing in raw-data mode. */
82  if (cinfo->raw_data_in)
83    return;
84
85  main->cur_iMCU_row = 0;       /* initialize counters */
86  main->rowgroup_ctr = 0;
87  main->suspended = FALSE;
88  main->pass_mode = pass_mode;  /* save mode for use by process_data */
89
90  switch (pass_mode) {
91  case JBUF_PASS_THRU:
92#ifdef FULL_MAIN_BUFFER_SUPPORTED
93    if (main->whole_image[0] != NULL)
94      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
95#endif
96    main->pub.process_data = process_data_simple_main;
97    break;
98#ifdef FULL_MAIN_BUFFER_SUPPORTED
99  case JBUF_SAVE_SOURCE:
100  case JBUF_CRANK_DEST:
101  case JBUF_SAVE_AND_PASS:
102    if (main->whole_image[0] == NULL)
103      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
104    main->pub.process_data = process_data_buffer_main;
105    break;
106#endif
107  default:
108    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
109    break;
110  }
111}
112
113
114/*
115 * Process some data.
116 * This routine handles the simple pass-through mode,
117 * where we have only a strip buffer.
118 */
119
120METHODDEF(void)
121process_data_simple_main (j_compress_ptr cinfo,
122                          JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
123                          JDIMENSION in_rows_avail)
124{
125  my_main_ptr main = (my_main_ptr) cinfo->main;
126
127  while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
128    /* Read input data if we haven't filled the main buffer yet */
129    if (main->rowgroup_ctr < DCTSIZE)
130      (*cinfo->prep->pre_process_data) (cinfo,
131                                        input_buf, in_row_ctr, in_rows_avail,
132                                        main->buffer, &main->rowgroup_ctr,
133                                        (JDIMENSION) DCTSIZE);
134
135    /* If we don't have a full iMCU row buffered, return to application for
136     * more data.  Note that preprocessor will always pad to fill the iMCU row
137     * at the bottom of the image.
138     */
139    if (main->rowgroup_ctr != DCTSIZE)
140      return;
141
142    /* Send the completed row to the compressor */
143    if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
144      /* If compressor did not consume the whole row, then we must need to
145       * suspend processing and return to the application.  In this situation
146       * we pretend we didn't yet consume the last input row; otherwise, if
147       * it happened to be the last row of the image, the application would
148       * think we were done.
149       */
150      if (! main->suspended) {
151        (*in_row_ctr)--;
152        main->suspended = TRUE;
153      }
154      return;
155    }
156    /* We did finish the row.  Undo our little suspension hack if a previous
157     * call suspended; then mark the main buffer empty.
158     */
159    if (main->suspended) {
160      (*in_row_ctr)++;
161      main->suspended = FALSE;
162    }
163    main->rowgroup_ctr = 0;
164    main->cur_iMCU_row++;
165  }
166}
167
168
169#ifdef FULL_MAIN_BUFFER_SUPPORTED
170
171/*
172 * Process some data.
173 * This routine handles all of the modes that use a full-size buffer.
174 */
175
176METHODDEF(void)
177process_data_buffer_main (j_compress_ptr cinfo,
178                          JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
179                          JDIMENSION in_rows_avail)
180{
181  my_main_ptr main = (my_main_ptr) cinfo->main;
182  int ci;
183  jpeg_component_info *compptr;
184  boolean writing = (main->pass_mode != JBUF_CRANK_DEST);
185
186  while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
187    /* Realign the virtual buffers if at the start of an iMCU row. */
188    if (main->rowgroup_ctr == 0) {
189      for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
190           ci++, compptr++) {
191        main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
192          ((j_common_ptr) cinfo, main->whole_image[ci],
193           main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
194           (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
195      }
196      /* In a read pass, pretend we just read some source data. */
197      if (! writing) {
198        *in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
199        main->rowgroup_ctr = DCTSIZE;
200      }
201    }
202
203    /* If a write pass, read input data until the current iMCU row is full. */
204    /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
205    if (writing) {
206      (*cinfo->prep->pre_process_data) (cinfo,
207                                        input_buf, in_row_ctr, in_rows_avail,
208                                        main->buffer, &main->rowgroup_ctr,
209                                        (JDIMENSION) DCTSIZE);
210      /* Return to application if we need more data to fill the iMCU row. */
211      if (main->rowgroup_ctr < DCTSIZE)
212        return;
213    }
214
215    /* Emit data, unless this is a sink-only pass. */
216    if (main->pass_mode != JBUF_SAVE_SOURCE) {
217      if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
218        /* If compressor did not consume the whole row, then we must need to
219         * suspend processing and return to the application.  In this situation
220         * we pretend we didn't yet consume the last input row; otherwise, if
221         * it happened to be the last row of the image, the application would
222         * think we were done.
223         */
224        if (! main->suspended) {
225          (*in_row_ctr)--;
226          main->suspended = TRUE;
227        }
228        return;
229      }
230      /* We did finish the row.  Undo our little suspension hack if a previous
231       * call suspended; then mark the main buffer empty.
232       */
233      if (main->suspended) {
234        (*in_row_ctr)++;
235        main->suspended = FALSE;
236      }
237    }
238
239    /* If get here, we are done with this iMCU row.  Mark buffer empty. */
240    main->rowgroup_ctr = 0;
241    main->cur_iMCU_row++;
242  }
243}
244
245#endif /* FULL_MAIN_BUFFER_SUPPORTED */
246
247
248/*
249 * Initialize main buffer controller.
250 */
251
252GLOBAL(void)
253jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
254{
255  my_main_ptr main;
256  int ci;
257  jpeg_component_info *compptr;
258
259  main = (my_main_ptr)
260    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
261                                SIZEOF(my_main_controller));
262  cinfo->main = (struct jpeg_c_main_controller *) main;
263  main->pub.start_pass = start_pass_main;
264
265  /* We don't need to create a buffer in raw-data mode. */
266  if (cinfo->raw_data_in)
267    return;
268
269  /* Create the buffer.  It holds downsampled data, so each component
270   * may be of a different size.
271   */
272  if (need_full_buffer) {
273#ifdef FULL_MAIN_BUFFER_SUPPORTED
274    /* Allocate a full-image virtual array for each component */
275    /* Note we pad the bottom to a multiple of the iMCU height */
276    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
277         ci++, compptr++) {
278      main->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
279        ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
280         compptr->width_in_blocks * DCTSIZE,
281         (JDIMENSION) jround_up((long) compptr->height_in_blocks,
282                                (long) compptr->v_samp_factor) * DCTSIZE,
283         (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
284    }
285#else
286    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
287#endif
288  } else {
289#ifdef FULL_MAIN_BUFFER_SUPPORTED
290    main->whole_image[0] = NULL; /* flag for no virtual arrays */
291#endif
292    /* Allocate a strip buffer for each component */
293    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
294         ci++, compptr++) {
295      main->buffer[ci] = (*cinfo->mem->alloc_sarray)
296        ((j_common_ptr) cinfo, JPOOL_IMAGE,
297         compptr->width_in_blocks * DCTSIZE,
298         (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
299    }
300  }
301}
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