Line data Source code
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() */
27 : extern void *malloc (size_t size);
28 : extern void free (void *ptr);
29 : #endif
30 :
31 :
32 : /* Expanded data destination object for stdio output */
33 :
34 : typedef 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 :
41 : typedef 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 :
49 : typedef 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 :
59 : typedef 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 :
68 : METHODDEF(void)
69 0 : init_destination (j_compress_ptr cinfo)
70 : {
71 0 : my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
72 :
73 : /* Allocate the output buffer --- it will be released when done with image */
74 0 : dest->buffer = (JOCTET *)
75 0 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
76 : OUTPUT_BUF_SIZE * sizeof(JOCTET));
77 :
78 0 : dest->pub.next_output_byte = dest->buffer;
79 0 : dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
80 0 : }
81 :
82 : #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
83 : METHODDEF(void)
84 : init_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 :
114 : METHODDEF(boolean)
115 0 : empty_output_buffer (j_compress_ptr cinfo)
116 : {
117 0 : my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
118 :
119 0 : if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
120 : (size_t) OUTPUT_BUF_SIZE)
121 0 : ERREXIT(cinfo, JERR_FILE_WRITE);
122 :
123 0 : dest->pub.next_output_byte = dest->buffer;
124 0 : dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
125 :
126 0 : return TRUE;
127 : }
128 :
129 : #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
130 : METHODDEF(boolean)
131 : empty_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 :
171 : METHODDEF(void)
172 0 : term_destination (j_compress_ptr cinfo)
173 : {
174 0 : my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
175 0 : size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
176 :
177 : /* Write any data remaining in the buffer */
178 0 : if (datacount > 0) {
179 0 : if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
180 0 : ERREXIT(cinfo, JERR_FILE_WRITE);
181 : }
182 0 : fflush(dest->outfile);
183 : /* Make sure we wrote the output file OK */
184 0 : if (ferror(dest->outfile))
185 0 : ERREXIT(cinfo, JERR_FILE_WRITE);
186 0 : }
187 :
188 : #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
189 : METHODDEF(void)
190 : term_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 :
206 : GLOBAL(void)
207 0 : jpeg_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 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 0 : } 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 0 : ERREXIT(cinfo, JERR_BUFFER_SIZE);
226 : }
227 :
228 0 : dest = (my_dest_ptr) cinfo->dest;
229 0 : dest->pub.init_destination = init_destination;
230 0 : dest->pub.empty_output_buffer = empty_output_buffer;
231 0 : dest->pub.term_destination = term_destination;
232 0 : dest->outfile = outfile;
233 0 : }
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 :
251 : GLOBAL(void)
252 : jpeg_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
|
