1/*
2 * jdatadst.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1994-1996, Thomas G. Lane.
6 * Modified 2009-2012 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2013, 2016, D. R. Commander.
9 * For conditions of distribution and use, see the accompanying README.ijg
10 * file.
11 *
12 * This file contains compression data destination routines for the case of
13 * emitting JPEG data to memory or to a file (or any stdio stream).
14 * While these routines are sufficient for most applications,
15 * some will want to use a different destination manager.
16 * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
17 * JOCTETs into 8-bit-wide elements on external storage. If char is wider
18 * than 8 bits on your machine, you may need to do some tweaking.
19 */
20
21/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
22#include "jinclude.h"
23#include "jpeglib.h"
24#include "jerror.h"
25
26#ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc(),free() */
27extern void *malloc (size_t size);
28extern void free (void *ptr);
29#endif
30
31
32/* Expanded data destination object for stdio output */
33
34typedef struct {
35 struct jpeg_destination_mgr pub; /* public fields */
36
37 FILE *outfile; /* target stream */
38 JOCTET *buffer; /* start of buffer */
39} my_destination_mgr;
40
41typedef my_destination_mgr *my_dest_ptr;
42
43#define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'able size */
44
45
46#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
47/* Expanded data destination object for memory output */
48
49typedef struct {
50 struct jpeg_destination_mgr pub; /* public fields */
51
52 unsigned char **outbuffer; /* target buffer */
53 unsigned long *outsize;
54 unsigned char *newbuffer; /* newly allocated buffer */
55 JOCTET *buffer; /* start of buffer */
56 size_t bufsize;
57} my_mem_destination_mgr;
58
59typedef my_mem_destination_mgr *my_mem_dest_ptr;
60#endif
61
62
63/*
64 * Initialize destination --- called by jpeg_start_compress
65 * before any data is actually written.
66 */
67
68METHODDEF(void)
69init_destination (j_compress_ptr cinfo)
70{
71 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
72
73 /* Allocate the output buffer --- it will be released when done with image */
74 dest->buffer = (JOCTET *)
75 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
76 OUTPUT_BUF_SIZE * sizeof(JOCTET));
77
78 dest->pub.next_output_byte = dest->buffer;
79 dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
80}
81
82#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
83METHODDEF(void)
84init_mem_destination (j_compress_ptr cinfo)
85{
86 /* no work necessary here */
87}
88#endif
89
90
91/*
92 * Empty the output buffer --- called whenever buffer fills up.
93 *
94 * In typical applications, this should write the entire output buffer
95 * (ignoring the current state of next_output_byte & free_in_buffer),
96 * reset the pointer & count to the start of the buffer, and return TRUE
97 * indicating that the buffer has been dumped.
98 *
99 * In applications that need to be able to suspend compression due to output
100 * overrun, a FALSE return indicates that the buffer cannot be emptied now.
101 * In this situation, the compressor will return to its caller (possibly with
102 * an indication that it has not accepted all the supplied scanlines). The
103 * application should resume compression after it has made more room in the
104 * output buffer. Note that there are substantial restrictions on the use of
105 * suspension --- see the documentation.
106 *
107 * When suspending, the compressor will back up to a convenient restart point
108 * (typically the start of the current MCU). next_output_byte & free_in_buffer
109 * indicate where the restart point will be if the current call returns FALSE.
110 * Data beyond this point will be regenerated after resumption, so do not
111 * write it out when emptying the buffer externally.
112 */
113
114METHODDEF(boolean)
115empty_output_buffer (j_compress_ptr cinfo)
116{
117 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
118
119 if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
120 (size_t) OUTPUT_BUF_SIZE)
121 ERREXIT(cinfo, JERR_FILE_WRITE);
122
123 dest->pub.next_output_byte = dest->buffer;
124 dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
125
126 return TRUE;
127}
128
129#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
130METHODDEF(boolean)
131empty_mem_output_buffer (j_compress_ptr cinfo)
132{
133 size_t nextsize;
134 JOCTET *nextbuffer;
135 my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
136
137 /* Try to allocate new buffer with double size */
138 nextsize = dest->bufsize * 2;
139 nextbuffer = (JOCTET *) malloc(nextsize);
140
141 if (nextbuffer == NULL)
142 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
143
144 MEMCOPY(nextbuffer, dest->buffer, dest->bufsize);
145
146 if (dest->newbuffer != NULL)
147 free(dest->newbuffer);
148
149 dest->newbuffer = nextbuffer;
150
151 dest->pub.next_output_byte = nextbuffer + dest->bufsize;
152 dest->pub.free_in_buffer = dest->bufsize;
153
154 dest->buffer = nextbuffer;
155 dest->bufsize = nextsize;
156
157 return TRUE;
158}
159#endif
160
161
162/*
163 * Terminate destination --- called by jpeg_finish_compress
164 * after all data has been written. Usually needs to flush buffer.
165 *
166 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
167 * application must deal with any cleanup that should happen even
168 * for error exit.
169 */
170
171METHODDEF(void)
172term_destination (j_compress_ptr cinfo)
173{
174 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
175 size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
176
177 /* Write any data remaining in the buffer */
178 if (datacount > 0) {
179 if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
180 ERREXIT(cinfo, JERR_FILE_WRITE);
181 }
182 fflush(dest->outfile);
183 /* Make sure we wrote the output file OK */
184 if (ferror(dest->outfile))
185 ERREXIT(cinfo, JERR_FILE_WRITE);
186}
187
188#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
189METHODDEF(void)
190term_mem_destination (j_compress_ptr cinfo)
191{
192 my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
193
194 *dest->outbuffer = dest->buffer;
195 *dest->outsize = (unsigned long)(dest->bufsize - dest->pub.free_in_buffer);
196}
197#endif
198
199
200/*
201 * Prepare for output to a stdio stream.
202 * The caller must have already opened the stream, and is responsible
203 * for closing it after finishing compression.
204 */
205
206GLOBAL(void)
207jpeg_stdio_dest (j_compress_ptr cinfo, FILE *outfile)
208{
209 my_dest_ptr dest;
210
211 /* The destination object is made permanent so that multiple JPEG images
212 * can be written to the same file without re-executing jpeg_stdio_dest.
213 */
214 if (cinfo->dest == NULL) { /* first time for this JPEG object? */
215 cinfo->dest = (struct jpeg_destination_mgr *)
216 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
217 sizeof(my_destination_mgr));
218 } else if (cinfo->dest->init_destination != init_destination) {
219 /* It is unsafe to reuse the existing destination manager unless it was
220 * created by this function. Otherwise, there is no guarantee that the
221 * opaque structure is the right size. Note that we could just create a
222 * new structure, but the old structure would not be freed until
223 * jpeg_destroy_compress() was called.
224 */
225 ERREXIT(cinfo, JERR_BUFFER_SIZE);
226 }
227
228 dest = (my_dest_ptr) cinfo->dest;
229 dest->pub.init_destination = init_destination;
230 dest->pub.empty_output_buffer = empty_output_buffer;
231 dest->pub.term_destination = term_destination;
232 dest->outfile = outfile;
233}
234
235
236#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
237/*
238 * Prepare for output to a memory buffer.
239 * The caller may supply an own initial buffer with appropriate size.
240 * Otherwise, or when the actual data output exceeds the given size,
241 * the library adapts the buffer size as necessary.
242 * The standard library functions malloc/free are used for allocating
243 * larger memory, so the buffer is available to the application after
244 * finishing compression, and then the application is responsible for
245 * freeing the requested memory.
246 * Note: An initial buffer supplied by the caller is expected to be
247 * managed by the application. The library does not free such buffer
248 * when allocating a larger buffer.
249 */
250
251GLOBAL(void)
252jpeg_mem_dest (j_compress_ptr cinfo,
253 unsigned char **outbuffer, unsigned long *outsize)
254{
255 my_mem_dest_ptr dest;
256
257 if (outbuffer == NULL || outsize == NULL) /* sanity check */
258 ERREXIT(cinfo, JERR_BUFFER_SIZE);
259
260 /* The destination object is made permanent so that multiple JPEG images
261 * can be written to the same buffer without re-executing jpeg_mem_dest.
262 */
263 if (cinfo->dest == NULL) { /* first time for this JPEG object? */
264 cinfo->dest = (struct jpeg_destination_mgr *)
265 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
266 sizeof(my_mem_destination_mgr));
267 } else if (cinfo->dest->init_destination != init_mem_destination) {
268 /* It is unsafe to reuse the existing destination manager unless it was
269 * created by this function.
270 */
271 ERREXIT(cinfo, JERR_BUFFER_SIZE);
272 }
273
274 dest = (my_mem_dest_ptr) cinfo->dest;
275 dest->pub.init_destination = init_mem_destination;
276 dest->pub.empty_output_buffer = empty_mem_output_buffer;
277 dest->pub.term_destination = term_mem_destination;
278 dest->outbuffer = outbuffer;
279 dest->outsize = outsize;
280 dest->newbuffer = NULL;
281
282 if (*outbuffer == NULL || *outsize == 0) {
283 /* Allocate initial buffer */
284 dest->newbuffer = *outbuffer = (unsigned char *) malloc(OUTPUT_BUF_SIZE);
285 if (dest->newbuffer == NULL)
286 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
287 *outsize = OUTPUT_BUF_SIZE;
288 }
289
290 dest->pub.next_output_byte = dest->buffer = *outbuffer;
291 dest->pub.free_in_buffer = dest->bufsize = *outsize;
292}
293#endif
294