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/src/FreeImage/Source/LibJPEG/jcmainct.c

https://bitbucket.org/cabalistic/ogredeps/
C | 293 lines | 175 code | 39 blank | 79 comment | 31 complexity | 0fd86f703f29965f94dc8d0684e34bf0 MD5 | raw file
  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
 28typedef 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
 50typedef my_main_controller * my_main_ptr;
 51
 52
 53/* Forward declarations */
 54METHODDEF(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
 58METHODDEF(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
 68METHODDEF(void)
 69start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
 70{
 71  my_main_ptr main = (my_main_ptr) cinfo->main;
 72
 73  /* Do nothing in raw-data mode. */
 74  if (cinfo->raw_data_in)
 75    return;
 76
 77  main->cur_iMCU_row = 0;	/* initialize counters */
 78  main->rowgroup_ctr = 0;
 79  main->suspended = FALSE;
 80  main->pass_mode = pass_mode;	/* save mode for use by process_data */
 81
 82  switch (pass_mode) {
 83  case JBUF_PASS_THRU:
 84#ifdef FULL_MAIN_BUFFER_SUPPORTED
 85    if (main->whole_image[0] != NULL)
 86      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 87#endif
 88    main->pub.process_data = process_data_simple_main;
 89    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->whole_image[0] == NULL)
 95      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 96    main->pub.process_data = process_data_buffer_main;
 97    break;
 98#endif
 99  default:
100    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
101    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
112METHODDEF(void)
113process_data_simple_main (j_compress_ptr cinfo,
114			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
115			  JDIMENSION in_rows_avail)
116{
117  my_main_ptr main = (my_main_ptr) cinfo->main;
118
119  while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
120    /* Read input data if we haven't filled the main buffer yet */
121    if (main->rowgroup_ctr < (JDIMENSION) cinfo->min_DCT_v_scaled_size)
122      (*cinfo->prep->pre_process_data) (cinfo,
123					input_buf, in_row_ctr, in_rows_avail,
124					main->buffer, &main->rowgroup_ctr,
125					(JDIMENSION) cinfo->min_DCT_v_scaled_size);
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    if (main->rowgroup_ctr != (JDIMENSION) cinfo->min_DCT_v_scaled_size)
132      return;
133
134    /* Send the completed row to the compressor */
135    if (! (*cinfo->coef->compress_data) (cinfo, main->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      if (! main->suspended) {
143	(*in_row_ctr)--;
144	main->suspended = TRUE;
145      }
146      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    if (main->suspended) {
152      (*in_row_ctr)++;
153      main->suspended = FALSE;
154    }
155    main->rowgroup_ctr = 0;
156    main->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
168METHODDEF(void)
169process_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->pass_mode != JBUF_CRANK_DEST);
177
178  while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
179    /* Realign the virtual buffers if at the start of an iMCU row. */
180    if (main->rowgroup_ctr == 0) {
181      for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
182	   ci++, compptr++) {
183	main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
184	  ((j_common_ptr) cinfo, main->whole_image[ci],
185	   main->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->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->buffer, &main->rowgroup_ctr,
201					(JDIMENSION) DCTSIZE);
202      /* Return to application if we need more data to fill the iMCU row. */
203      if (main->rowgroup_ctr < DCTSIZE)
204	return;
205    }
206
207    /* Emit data, unless this is a sink-only pass. */
208    if (main->pass_mode != JBUF_SAVE_SOURCE) {
209      if (! (*cinfo->coef->compress_data) (cinfo, main->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->suspended) {
217	  (*in_row_ctr)--;
218	  main->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->suspended) {
226	(*in_row_ctr)++;
227	main->suspended = FALSE;
228      }
229    }
230
231    /* If get here, we are done with this iMCU row.  Mark buffer empty. */
232    main->rowgroup_ctr = 0;
233    main->cur_iMCU_row++;
234  }
235}
236
237#endif /* FULL_MAIN_BUFFER_SUPPORTED */
238
239
240/*
241 * Initialize main buffer controller.
242 */
243
244GLOBAL(void)
245jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
246{
247  my_main_ptr main;
248  int ci;
249  jpeg_component_info *compptr;
250
251  main = (my_main_ptr)
252    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
253				SIZEOF(my_main_controller));
254  cinfo->main = (struct jpeg_c_main_controller *) main;
255  main->pub.start_pass = start_pass_main;
256
257  /* We don't need to create a buffer in raw-data mode. */
258  if (cinfo->raw_data_in)
259    return;
260
261  /* Create the buffer.  It holds downsampled data, so each component
262   * may be of a different size.
263   */
264  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->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
271	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
272	 compptr->width_in_blocks * compptr->DCT_h_scaled_size,
273	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
274				(long) compptr->v_samp_factor) * DCTSIZE,
275	 (JDIMENSION) (compptr->v_samp_factor * compptr->DCT_v_scaled_size));
276    }
277#else
278    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
279#endif
280  } else {
281#ifdef FULL_MAIN_BUFFER_SUPPORTED
282    main->whole_image[0] = NULL; /* flag for no virtual arrays */
283#endif
284    /* Allocate a strip buffer for each component */
285    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
286	 ci++, compptr++) {
287      main->buffer[ci] = (*cinfo->mem->alloc_sarray)
288	((j_common_ptr) cinfo, JPOOL_IMAGE,
289	 compptr->width_in_blocks * compptr->DCT_h_scaled_size,
290	 (JDIMENSION) (compptr->v_samp_factor * compptr->DCT_v_scaled_size));
291    }
292  }
293}