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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)
init_destination(j_compress_ptr cinfo)69 init_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)
83 METHODDEF(void)
init_mem_destination(j_compress_ptr cinfo)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)
empty_output_buffer(j_compress_ptr cinfo)115 empty_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)
130 METHODDEF(boolean)
empty_mem_output_buffer(j_compress_ptr cinfo)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)
term_destination(j_compress_ptr cinfo)172 term_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)
189 METHODDEF(void)
term_mem_destination(j_compress_ptr cinfo)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)
jpeg_stdio_dest(j_compress_ptr cinfo,FILE * outfile)207 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   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 
251 GLOBAL(void)
jpeg_mem_dest(j_compress_ptr cinfo,unsigned char ** outbuffer,unsigned long * outsize)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
294