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() */
26extern void * malloc JPP((size_t size));
27extern void free JPP((void *ptr));
28#endif
29
30
31/* Expanded data destination object for stdio output */
32
33typedef 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
40typedef 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
48typedef 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
58typedef 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
67METHODDEF(void)
68init_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)
82METHODDEF(void)
83init_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
113METHODDEF(boolean)
114empty_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)
129METHODDEF(boolean)
130empty_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
170METHODDEF(void)
171term_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)
188METHODDEF(void)
189term_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
205GLOBAL(void)
206jpeg_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
242GLOBAL(void)
243jpeg_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