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comparison mupdf-source/thirdparty/libjpeg/jdatadst.c @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * jdatadst.c
3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * Modified 2009-2022 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 #define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'able size */
32
33 typedef struct {
34 struct jpeg_destination_mgr pub; /* public fields */
35
36 FILE * outfile; /* target stream */
37 JOCTET buffer[OUTPUT_BUF_SIZE]; /* output buffer */
38 } my_destination_mgr;
39
40 typedef my_destination_mgr * my_dest_ptr;
41
42
43 /* Expanded data destination object for memory output */
44
45 typedef struct {
46 struct jpeg_destination_mgr pub; /* public fields */
47
48 unsigned char ** outbuffer; /* target buffer */
49 size_t * outsize;
50 unsigned char * newbuffer; /* newly allocated buffer */
51 JOCTET * buffer; /* start of buffer */
52 size_t bufsize;
53 } my_mem_destination_mgr;
54
55 typedef my_mem_destination_mgr * my_mem_dest_ptr;
56
57
58 /*
59 * Initialize destination --- called by jpeg_start_compress
60 * before any data is actually written.
61 */
62
63 METHODDEF(void)
64 init_destination (j_compress_ptr cinfo)
65 {
66 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
67
68 dest->pub.next_output_byte = dest->buffer;
69 dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
70 }
71
72 METHODDEF(void)
73 init_mem_destination (j_compress_ptr cinfo)
74 {
75 /* no work necessary here */
76 }
77
78
79 /*
80 * Empty the output buffer --- called whenever buffer fills up.
81 *
82 * In typical applications, this should write the entire output buffer
83 * (ignoring the current state of next_output_byte & free_in_buffer),
84 * reset the pointer & count to the start of the buffer, and return TRUE
85 * indicating that the buffer has been dumped.
86 *
87 * In applications that need to be able to suspend compression due to output
88 * overrun, a FALSE return indicates that the buffer cannot be emptied now.
89 * In this situation, the compressor will return to its caller (possibly with
90 * an indication that it has not accepted all the supplied scanlines). The
91 * application should resume compression after it has made more room in the
92 * output buffer. Note that there are substantial restrictions on the use of
93 * suspension --- see the documentation.
94 *
95 * When suspending, the compressor will back up to a convenient restart point
96 * (typically the start of the current MCU). next_output_byte & free_in_buffer
97 * indicate where the restart point will be if the current call returns FALSE.
98 * Data beyond this point will be regenerated after resumption, so do not
99 * write it out when emptying the buffer externally.
100 */
101
102 METHODDEF(boolean)
103 empty_output_buffer (j_compress_ptr cinfo)
104 {
105 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
106
107 if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
108 (size_t) OUTPUT_BUF_SIZE)
109 ERREXIT(cinfo, JERR_FILE_WRITE);
110
111 dest->pub.next_output_byte = dest->buffer;
112 dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
113
114 return TRUE;
115 }
116
117 METHODDEF(boolean)
118 empty_mem_output_buffer (j_compress_ptr cinfo)
119 {
120 size_t nextsize;
121 JOCTET * nextbuffer;
122 my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
123
124 /* Try to allocate new buffer with double size */
125 nextsize = dest->bufsize * 2;
126 nextbuffer = (JOCTET *) malloc(nextsize);
127
128 if (nextbuffer == NULL)
129 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 11);
130
131 MEMCOPY(nextbuffer, dest->buffer, dest->bufsize);
132
133 if (dest->newbuffer != NULL)
134 free(dest->newbuffer);
135
136 dest->newbuffer = nextbuffer;
137
138 dest->pub.next_output_byte = nextbuffer + dest->bufsize;
139 dest->pub.free_in_buffer = dest->bufsize;
140
141 dest->buffer = nextbuffer;
142 dest->bufsize = nextsize;
143
144 return TRUE;
145 }
146
147
148 /*
149 * Terminate destination --- called by jpeg_finish_compress
150 * after all data has been written. Usually needs to flush buffer.
151 *
152 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
153 * application must deal with any cleanup that should happen even
154 * for error exit.
155 */
156
157 METHODDEF(void)
158 term_destination (j_compress_ptr cinfo)
159 {
160 my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
161 size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
162
163 /* Write any data remaining in the buffer */
164 if (datacount > 0) {
165 if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
166 ERREXIT(cinfo, JERR_FILE_WRITE);
167 }
168 JFFLUSH(dest->outfile);
169 /* Make sure we wrote the output file OK */
170 if (JFERROR(dest->outfile))
171 ERREXIT(cinfo, JERR_FILE_WRITE);
172 }
173
174 METHODDEF(void)
175 term_mem_destination (j_compress_ptr cinfo)
176 {
177 my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
178
179 *dest->outbuffer = dest->buffer;
180 *dest->outsize = dest->bufsize - dest->pub.free_in_buffer;
181 }
182
183
184 /*
185 * Prepare for output to a stdio stream.
186 * The caller must have already opened the stream,
187 * and is responsible for closing it after finishing compression.
188 */
189
190 GLOBAL(void)
191 jpeg_stdio_dest (j_compress_ptr cinfo, FILE * outfile)
192 {
193 my_dest_ptr dest;
194
195 /* The destination object is made permanent so that multiple JPEG images
196 * can be written to the same file without re-executing jpeg_stdio_dest.
197 * This makes it dangerous to use this manager and a different destination
198 * manager serially with the same JPEG object, because their private object
199 * sizes may be different. Caveat programmer.
200 */
201 if (cinfo->dest == NULL) { /* first time for this JPEG object? */
202 cinfo->dest = (struct jpeg_destination_mgr *) (*cinfo->mem->alloc_small)
203 ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(my_destination_mgr));
204 }
205
206 dest = (my_dest_ptr) cinfo->dest;
207 dest->pub.init_destination = init_destination;
208 dest->pub.empty_output_buffer = empty_output_buffer;
209 dest->pub.term_destination = term_destination;
210 dest->outfile = outfile;
211 }
212
213
214 /*
215 * Prepare for output to a memory buffer.
216 * The caller may supply an own initial buffer with appropriate size.
217 * Otherwise, or when the actual data output exceeds the given size,
218 * the library adapts the buffer size as necessary.
219 * The standard library functions malloc/free are used for allocating
220 * larger memory, so the buffer is available to the application after
221 * finishing compression, and then the application is responsible for
222 * freeing the requested memory.
223 * Note: An initial buffer supplied by the caller is expected to be
224 * managed by the application. The library does not free such buffer
225 * when allocating a larger buffer.
226 */
227
228 GLOBAL(void)
229 jpeg_mem_dest (j_compress_ptr cinfo,
230 unsigned char ** outbuffer, size_t * outsize)
231 {
232 my_mem_dest_ptr dest;
233
234 if (outbuffer == NULL || outsize == NULL) /* sanity check */
235 ERREXIT(cinfo, JERR_BUFFER_SIZE);
236
237 /* The destination object is made permanent so that multiple JPEG images
238 * can be written to the same buffer without re-executing jpeg_mem_dest.
239 */
240 if (cinfo->dest == NULL) { /* first time for this JPEG object? */
241 cinfo->dest = (struct jpeg_destination_mgr *) (*cinfo->mem->alloc_small)
242 ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(my_mem_destination_mgr));
243 }
244
245 dest = (my_mem_dest_ptr) cinfo->dest;
246 dest->pub.init_destination = init_mem_destination;
247 dest->pub.empty_output_buffer = empty_mem_output_buffer;
248 dest->pub.term_destination = term_mem_destination;
249 dest->outbuffer = outbuffer;
250 dest->outsize = outsize;
251 dest->newbuffer = NULL;
252
253 if (*outbuffer == NULL || *outsize == 0) {
254 /* Allocate initial buffer */
255 dest->newbuffer = *outbuffer = (unsigned char *) malloc(OUTPUT_BUF_SIZE);
256 if (dest->newbuffer == NULL)
257 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
258 *outsize = OUTPUT_BUF_SIZE;
259 }
260
261 dest->pub.next_output_byte = dest->buffer = *outbuffer;
262 dest->pub.free_in_buffer = dest->bufsize = *outsize;
263 }