File: jdatadst.c

package info (click to toggle)
libjpeg-turbo 1:1.5.1-2
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 9,068 kB
  • ctags: 6,369
  • sloc: ansic: 43,407; asm: 25,683; sh: 5,436; java: 3,123; makefile: 797; xml: 24
file content (293 lines) | stat: -rw-r--r-- 9,760 bytes parent folder | download | duplicates (10)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
 * jdatadst.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * Modified 2009-2012 by Guido Vollbeding.
 * libjpeg-turbo Modifications:
 * Copyright (C) 2013, 2016, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README.ijg
 * file.
 *
 * This file contains compression data destination routines for the case of
 * emitting JPEG data to memory or to a file (or any stdio stream).
 * While these routines are sufficient for most applications,
 * some will want to use a different destination manager.
 * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
 * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
 * than 8 bits on your machine, you may need to do some tweaking.
 */

/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
#include "jinclude.h"
#include "jpeglib.h"
#include "jerror.h"

#ifndef HAVE_STDLIB_H           /* <stdlib.h> should declare malloc(),free() */
extern void *malloc (size_t size);
extern void free (void *ptr);
#endif


/* Expanded data destination object for stdio output */

typedef struct {
  struct jpeg_destination_mgr pub; /* public fields */

  FILE *outfile;                /* target stream */
  JOCTET *buffer;               /* start of buffer */
} my_destination_mgr;

typedef my_destination_mgr *my_dest_ptr;

#define OUTPUT_BUF_SIZE  4096   /* choose an efficiently fwrite'able size */


#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
/* Expanded data destination object for memory output */

typedef struct {
  struct jpeg_destination_mgr pub; /* public fields */

  unsigned char **outbuffer;    /* target buffer */
  unsigned long *outsize;
  unsigned char *newbuffer;     /* newly allocated buffer */
  JOCTET *buffer;               /* start of buffer */
  size_t bufsize;
} my_mem_destination_mgr;

typedef my_mem_destination_mgr *my_mem_dest_ptr;
#endif


/*
 * Initialize destination --- called by jpeg_start_compress
 * before any data is actually written.
 */

METHODDEF(void)
init_destination (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;

  /* Allocate the output buffer --- it will be released when done with image */
  dest->buffer = (JOCTET *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                                  OUTPUT_BUF_SIZE * sizeof(JOCTET));

  dest->pub.next_output_byte = dest->buffer;
  dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}

#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
METHODDEF(void)
init_mem_destination (j_compress_ptr cinfo)
{
  /* no work necessary here */
}
#endif


/*
 * Empty the output buffer --- called whenever buffer fills up.
 *
 * In typical applications, this should write the entire output buffer
 * (ignoring the current state of next_output_byte & free_in_buffer),
 * reset the pointer & count to the start of the buffer, and return TRUE
 * indicating that the buffer has been dumped.
 *
 * In applications that need to be able to suspend compression due to output
 * overrun, a FALSE return indicates that the buffer cannot be emptied now.
 * In this situation, the compressor will return to its caller (possibly with
 * an indication that it has not accepted all the supplied scanlines).  The
 * application should resume compression after it has made more room in the
 * output buffer.  Note that there are substantial restrictions on the use of
 * suspension --- see the documentation.
 *
 * When suspending, the compressor will back up to a convenient restart point
 * (typically the start of the current MCU). next_output_byte & free_in_buffer
 * indicate where the restart point will be if the current call returns FALSE.
 * Data beyond this point will be regenerated after resumption, so do not
 * write it out when emptying the buffer externally.
 */

METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;

  if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
      (size_t) OUTPUT_BUF_SIZE)
    ERREXIT(cinfo, JERR_FILE_WRITE);

  dest->pub.next_output_byte = dest->buffer;
  dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

  return TRUE;
}

#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
METHODDEF(boolean)
empty_mem_output_buffer (j_compress_ptr cinfo)
{
  size_t nextsize;
  JOCTET *nextbuffer;
  my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;

  /* Try to allocate new buffer with double size */
  nextsize = dest->bufsize * 2;
  nextbuffer = (JOCTET *) malloc(nextsize);

  if (nextbuffer == NULL)
    ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);

  MEMCOPY(nextbuffer, dest->buffer, dest->bufsize);

  if (dest->newbuffer != NULL)
    free(dest->newbuffer);

  dest->newbuffer = nextbuffer;

  dest->pub.next_output_byte = nextbuffer + dest->bufsize;
  dest->pub.free_in_buffer = dest->bufsize;

  dest->buffer = nextbuffer;
  dest->bufsize = nextsize;

  return TRUE;
}
#endif


/*
 * Terminate destination --- called by jpeg_finish_compress
 * after all data has been written.  Usually needs to flush buffer.
 *
 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
 * application must deal with any cleanup that should happen even
 * for error exit.
 */

METHODDEF(void)
term_destination (j_compress_ptr cinfo)
{
  my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
  size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;

  /* Write any data remaining in the buffer */
  if (datacount > 0) {
    if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
      ERREXIT(cinfo, JERR_FILE_WRITE);
  }
  fflush(dest->outfile);
  /* Make sure we wrote the output file OK */
  if (ferror(dest->outfile))
    ERREXIT(cinfo, JERR_FILE_WRITE);
}

#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
METHODDEF(void)
term_mem_destination (j_compress_ptr cinfo)
{
  my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;

  *dest->outbuffer = dest->buffer;
  *dest->outsize = (unsigned long)(dest->bufsize - dest->pub.free_in_buffer);
}
#endif


/*
 * Prepare for output to a stdio stream.
 * The caller must have already opened the stream, and is responsible
 * for closing it after finishing compression.
 */

GLOBAL(void)
jpeg_stdio_dest (j_compress_ptr cinfo, FILE *outfile)
{
  my_dest_ptr dest;

  /* The destination object is made permanent so that multiple JPEG images
   * can be written to the same file without re-executing jpeg_stdio_dest.
   */
  if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
    cinfo->dest = (struct jpeg_destination_mgr *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
                                  sizeof(my_destination_mgr));
  } else if (cinfo->dest->init_destination != init_destination) {
    /* It is unsafe to reuse the existing destination manager unless it was
     * created by this function.  Otherwise, there is no guarantee that the
     * opaque structure is the right size.  Note that we could just create a
     * new structure, but the old structure would not be freed until
     * jpeg_destroy_compress() was called.
     */
    ERREXIT(cinfo, JERR_BUFFER_SIZE);
  }

  dest = (my_dest_ptr) cinfo->dest;
  dest->pub.init_destination = init_destination;
  dest->pub.empty_output_buffer = empty_output_buffer;
  dest->pub.term_destination = term_destination;
  dest->outfile = outfile;
}


#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
/*
 * Prepare for output to a memory buffer.
 * The caller may supply an own initial buffer with appropriate size.
 * Otherwise, or when the actual data output exceeds the given size,
 * the library adapts the buffer size as necessary.
 * The standard library functions malloc/free are used for allocating
 * larger memory, so the buffer is available to the application after
 * finishing compression, and then the application is responsible for
 * freeing the requested memory.
 * Note:  An initial buffer supplied by the caller is expected to be
 * managed by the application.  The library does not free such buffer
 * when allocating a larger buffer.
 */

GLOBAL(void)
jpeg_mem_dest (j_compress_ptr cinfo,
               unsigned char **outbuffer, unsigned long *outsize)
{
  my_mem_dest_ptr dest;

  if (outbuffer == NULL || outsize == NULL)     /* sanity check */
    ERREXIT(cinfo, JERR_BUFFER_SIZE);

  /* The destination object is made permanent so that multiple JPEG images
   * can be written to the same buffer without re-executing jpeg_mem_dest.
   */
  if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
    cinfo->dest = (struct jpeg_destination_mgr *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
                                  sizeof(my_mem_destination_mgr));
  } else if (cinfo->dest->init_destination != init_mem_destination) {
    /* It is unsafe to reuse the existing destination manager unless it was
     * created by this function.
     */
    ERREXIT(cinfo, JERR_BUFFER_SIZE);
  }

  dest = (my_mem_dest_ptr) cinfo->dest;
  dest->pub.init_destination = init_mem_destination;
  dest->pub.empty_output_buffer = empty_mem_output_buffer;
  dest->pub.term_destination = term_mem_destination;
  dest->outbuffer = outbuffer;
  dest->outsize = outsize;
  dest->newbuffer = NULL;

  if (*outbuffer == NULL || *outsize == 0) {
    /* Allocate initial buffer */
    dest->newbuffer = *outbuffer = (unsigned char *) malloc(OUTPUT_BUF_SIZE);
    if (dest->newbuffer == NULL)
      ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
    *outsize = OUTPUT_BUF_SIZE;
  }

  dest->pub.next_output_byte = dest->buffer = *outbuffer;
  dest->pub.free_in_buffer = dest->bufsize = *outsize;
}
#endif