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