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