source: trunk/libjpeg/jcapimin.c @ 283

Last change on this file since 283 was 283, checked in by rbri, 12 years ago

JPEG plugin: libjpeg updated to version 7

File size: 9.2 KB
Line 
1/*
2 * jcapimin.c
3 *
4 * Copyright (C) 1994-1998, 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 compression half
9 * of the JPEG library.  These are the "minimum" API routines that may be
10 * needed in either the normal full-compression case or the transcoding-only
11 * case.
12 *
13 * Most of the routines intended to be called directly by an application
14 * are in this file or in jcapistd.c.  But also see jcparam.c for
15 * parameter-setup helper routines, jcomapi.c for routines shared by
16 * compression and decompression, and jctrans.c for the transcoding case.
17 */
18
19#define JPEG_INTERNALS
20#include "jinclude.h"
21#include "jpeglib.h"
22
23
24/*
25 * Initialization of a JPEG compression object.
26 * The error manager must already be set up (in case memory manager fails).
27 */
28
29GLOBAL(void)
30jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)
31{
32  int i;
33
34  /* Guard against version mismatches between library and caller. */
35  cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
36  if (version != JPEG_LIB_VERSION)
37    ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
38  if (structsize != SIZEOF(struct jpeg_compress_struct))
39    ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 
40             (int) SIZEOF(struct jpeg_compress_struct), (int) structsize);
41
42  /* For debugging purposes, we zero the whole master structure.
43   * But the application has already set the err pointer, and may have set
44   * client_data, so we have to save and restore those fields.
45   * Note: if application hasn't set client_data, tools like Purify may
46   * complain here.
47   */
48  {
49    struct jpeg_error_mgr * err = cinfo->err;
50    void * client_data = cinfo->client_data; /* ignore Purify complaint here */
51    MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
52    cinfo->err = err;
53    cinfo->client_data = client_data;
54  }
55  cinfo->is_decompressor = FALSE;
56
57  /* Initialize a memory manager instance for this object */
58  jinit_memory_mgr((j_common_ptr) cinfo);
59
60  /* Zero out pointers to permanent structures. */
61  cinfo->progress = NULL;
62  cinfo->dest = NULL;
63
64  cinfo->comp_info = NULL;
65
66  for (i = 0; i < NUM_QUANT_TBLS; i++) {
67    cinfo->quant_tbl_ptrs[i] = NULL;
68    cinfo->q_scale_factor[i] = 100;
69  }
70
71  for (i = 0; i < NUM_HUFF_TBLS; i++) {
72    cinfo->dc_huff_tbl_ptrs[i] = NULL;
73    cinfo->ac_huff_tbl_ptrs[i] = NULL;
74  }
75
76  cinfo->script_space = NULL;
77
78  cinfo->input_gamma = 1.0;     /* in case application forgets */
79
80  /* OK, I'm ready */
81  cinfo->global_state = CSTATE_START;
82}
83
84
85/*
86 * Destruction of a JPEG compression object
87 */
88
89GLOBAL(void)
90jpeg_destroy_compress (j_compress_ptr cinfo)
91{
92  jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
93}
94
95
96/*
97 * Abort processing of a JPEG compression operation,
98 * but don't destroy the object itself.
99 */
100
101GLOBAL(void)
102jpeg_abort_compress (j_compress_ptr cinfo)
103{
104  jpeg_abort((j_common_ptr) cinfo); /* use common routine */
105}
106
107
108/*
109 * Forcibly suppress or un-suppress all quantization and Huffman tables.
110 * Marks all currently defined tables as already written (if suppress)
111 * or not written (if !suppress).  This will control whether they get emitted
112 * by a subsequent jpeg_start_compress call.
113 *
114 * This routine is exported for use by applications that want to produce
115 * abbreviated JPEG datastreams.  It logically belongs in jcparam.c, but
116 * since it is called by jpeg_start_compress, we put it here --- otherwise
117 * jcparam.o would be linked whether the application used it or not.
118 */
119
120GLOBAL(void)
121jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
122{
123  int i;
124  JQUANT_TBL * qtbl;
125  JHUFF_TBL * htbl;
126
127  for (i = 0; i < NUM_QUANT_TBLS; i++) {
128    if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
129      qtbl->sent_table = suppress;
130  }
131
132  for (i = 0; i < NUM_HUFF_TBLS; i++) {
133    if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
134      htbl->sent_table = suppress;
135    if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
136      htbl->sent_table = suppress;
137  }
138}
139
140
141/*
142 * Finish JPEG compression.
143 *
144 * If a multipass operating mode was selected, this may do a great deal of
145 * work including most of the actual output.
146 */
147
148GLOBAL(void)
149jpeg_finish_compress (j_compress_ptr cinfo)
150{
151  JDIMENSION iMCU_row;
152
153  if (cinfo->global_state == CSTATE_SCANNING ||
154      cinfo->global_state == CSTATE_RAW_OK) {
155    /* Terminate first pass */
156    if (cinfo->next_scanline < cinfo->image_height)
157      ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
158    (*cinfo->master->finish_pass) (cinfo);
159  } else if (cinfo->global_state != CSTATE_WRCOEFS)
160    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
161  /* Perform any remaining passes */
162  while (! cinfo->master->is_last_pass) {
163    (*cinfo->master->prepare_for_pass) (cinfo);
164    for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
165      if (cinfo->progress != NULL) {
166        cinfo->progress->pass_counter = (long) iMCU_row;
167        cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
168        (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
169      }
170      /* We bypass the main controller and invoke coef controller directly;
171       * all work is being done from the coefficient buffer.
172       */
173      if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
174        ERREXIT(cinfo, JERR_CANT_SUSPEND);
175    }
176    (*cinfo->master->finish_pass) (cinfo);
177  }
178  /* Write EOI, do final cleanup */
179  (*cinfo->marker->write_file_trailer) (cinfo);
180  (*cinfo->dest->term_destination) (cinfo);
181  /* We can use jpeg_abort to release memory and reset global_state */
182  jpeg_abort((j_common_ptr) cinfo);
183}
184
185
186/*
187 * Write a special marker.
188 * This is only recommended for writing COM or APPn markers.
189 * Must be called after jpeg_start_compress() and before
190 * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
191 */
192
193GLOBAL(void)
194jpeg_write_marker (j_compress_ptr cinfo, int marker,
195                   const JOCTET *dataptr, unsigned int datalen)
196{
197  JMETHOD(void, write_marker_byte, (j_compress_ptr info, int val));
198
199  if (cinfo->next_scanline != 0 ||
200      (cinfo->global_state != CSTATE_SCANNING &&
201       cinfo->global_state != CSTATE_RAW_OK &&
202       cinfo->global_state != CSTATE_WRCOEFS))
203    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
204
205  (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
206  write_marker_byte = cinfo->marker->write_marker_byte; /* copy for speed */
207  while (datalen--) {
208    (*write_marker_byte) (cinfo, *dataptr);
209    dataptr++;
210  }
211}
212
213/* Same, but piecemeal. */
214
215GLOBAL(void)
216jpeg_write_m_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
217{
218  if (cinfo->next_scanline != 0 ||
219      (cinfo->global_state != CSTATE_SCANNING &&
220       cinfo->global_state != CSTATE_RAW_OK &&
221       cinfo->global_state != CSTATE_WRCOEFS))
222    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
223
224  (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
225}
226
227GLOBAL(void)
228jpeg_write_m_byte (j_compress_ptr cinfo, int val)
229{
230  (*cinfo->marker->write_marker_byte) (cinfo, val);
231}
232
233
234/*
235 * Alternate compression function: just write an abbreviated table file.
236 * Before calling this, all parameters and a data destination must be set up.
237 *
238 * To produce a pair of files containing abbreviated tables and abbreviated
239 * image data, one would proceed as follows:
240 *
241 *              initialize JPEG object
242 *              set JPEG parameters
243 *              set destination to table file
244 *              jpeg_write_tables(cinfo);
245 *              set destination to image file
246 *              jpeg_start_compress(cinfo, FALSE);
247 *              write data...
248 *              jpeg_finish_compress(cinfo);
249 *
250 * jpeg_write_tables has the side effect of marking all tables written
251 * (same as jpeg_suppress_tables(..., TRUE)).  Thus a subsequent start_compress
252 * will not re-emit the tables unless it is passed write_all_tables=TRUE.
253 */
254
255GLOBAL(void)
256jpeg_write_tables (j_compress_ptr cinfo)
257{
258  if (cinfo->global_state != CSTATE_START)
259    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
260
261  /* (Re)initialize error mgr and destination modules */
262  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
263  (*cinfo->dest->init_destination) (cinfo);
264  /* Initialize the marker writer ... bit of a crock to do it here. */
265  jinit_marker_writer(cinfo);
266  /* Write them tables! */
267  (*cinfo->marker->write_tables_only) (cinfo);
268  /* And clean up. */
269  (*cinfo->dest->term_destination) (cinfo);
270  /*
271   * In library releases up through v6a, we called jpeg_abort() here to free
272   * any working memory allocated by the destination manager and marker
273   * writer.  Some applications had a problem with that: they allocated space
274   * of their own from the library memory manager, and didn't want it to go
275   * away during write_tables.  So now we do nothing.  This will cause a
276   * memory leak if an app calls write_tables repeatedly without doing a full
277   * compression cycle or otherwise resetting the JPEG object.  However, that
278   * seems less bad than unexpectedly freeing memory in the normal case.
279   * An app that prefers the old behavior can call jpeg_abort for itself after
280   * each call to jpeg_write_tables().
281   */
282}
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