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jdatasrc.c File Reference
#include "jinclude.h"
#include "jpeglib.h"
#include "jerror.h"
Include dependency graph for jdatasrc.c:

Go to the source code of this file.

Classes

struct  my_source_mgr
 

Macros

#define INPUT_BUF_SIZE   4096 /* choose an efficiently fread'able size */
 

Typedefs

typedef my_source_mgrmy_src_ptr
 

Functions

 init_source (j_decompress_ptr cinfo)
 
 init_mem_source (j_decompress_ptr cinfo)
 
 fill_input_buffer (j_decompress_ptr cinfo)
 
 fill_mem_input_buffer (j_decompress_ptr cinfo)
 
 skip_input_data (j_decompress_ptr cinfo, long num_bytes)
 
 term_source (j_decompress_ptr cinfo)
 
 jpeg_stdio_src (j_decompress_ptr cinfo, FILE *infile)
 
 jpeg_mem_src (j_decompress_ptr cinfo, const unsigned char *inbuffer, unsigned long insize)
 

Macro Definition Documentation

◆ INPUT_BUF_SIZE

#define INPUT_BUF_SIZE   4096 /* choose an efficiently fread'able size */

Definition at line 36 of file jdatasrc.c.

Typedef Documentation

◆ my_src_ptr

Definition at line 34 of file jdatasrc.c.

Function Documentation

◆ fill_input_buffer()

fill_input_buffer ( j_decompress_ptr  cinfo)

Definition at line 97 of file jdatasrc.c.

98 {
99  my_src_ptr src = (my_src_ptr) cinfo->src;
100  size_t nbytes;
101 
102  nbytes = JFREAD(src->infile, src->buffer, INPUT_BUF_SIZE);
103 
104  if (nbytes <= 0) {
105  if (src->start_of_file) /* Treat empty input file as fatal error */
106  ERREXIT(cinfo, JERR_INPUT_EMPTY);
107  WARNMS(cinfo, JWRN_JPEG_EOF);
108  /* Insert a fake EOI marker */
109  src->buffer[0] = (JOCTET) 0xFF;
110  src->buffer[1] = (JOCTET) JPEG_EOI;
111  nbytes = 2;
112  }
113 
114  src->pub.next_input_byte = src->buffer;
115  src->pub.bytes_in_buffer = nbytes;
116  src->start_of_file = FALSE;
117 
118  return TRUE;
119 }
#define TRUE
Definition: types.h:120
#define ERREXIT(msg)
Definition: rdjpgcom.c:72
#define JFREAD(file, buf, sizeofbuf)
Definition: jinclude.h:92
#define INPUT_BUF_SIZE
Definition: jdatasrc.c:36
#define WARNMS(cinfo, code)
Definition: jerror.h:251
GLenum src
Definition: glext.h:6340
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
#define JPEG_EOI
Definition: jpeglib.h:1124
my_source_mgr * my_src_ptr
Definition: jdatasrc.c:34
char JOCTET
Definition: jmorecfg.h:167

Referenced by jpeg_stdio_src().

◆ fill_mem_input_buffer()

fill_mem_input_buffer ( j_decompress_ptr  cinfo)

Definition at line 122 of file jdatasrc.c.

123 {
124  static const JOCTET mybuffer[4] = {
125  (JOCTET) 0xFF, (JOCTET) JPEG_EOI, 0, 0
126  };
127 
128  /* The whole JPEG data is expected to reside in the supplied memory
129  * buffer, so any request for more data beyond the given buffer size
130  * is treated as an error.
131  */
132  WARNMS(cinfo, JWRN_JPEG_EOF);
133 
134  /* Insert a fake EOI marker */
135 
136  cinfo->src->next_input_byte = mybuffer;
137  cinfo->src->bytes_in_buffer = 2;
138 
139  return TRUE;
140 }
#define TRUE
Definition: types.h:120
#define WARNMS(cinfo, code)
Definition: jerror.h:251
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
#define JPEG_EOI
Definition: jpeglib.h:1124
char JOCTET
Definition: jmorecfg.h:167

Referenced by jpeg_mem_src().

◆ init_mem_source()

init_mem_source ( j_decompress_ptr  cinfo)

Definition at line 57 of file jdatasrc.c.

58 {
59  /* no work necessary here */
60 }

Referenced by jpeg_mem_src().

◆ init_source()

init_source ( j_decompress_ptr  cinfo)

Definition at line 45 of file jdatasrc.c.

46 {
47  my_src_ptr src = (my_src_ptr) cinfo->src;
48 
49  /* We reset the empty-input-file flag for each image,
50  * but we don't clear the input buffer.
51  * This is correct behavior for reading a series of images from one source.
52  */
53  src->start_of_file = TRUE;
54 }
#define TRUE
Definition: types.h:120
GLenum src
Definition: glext.h:6340
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
my_source_mgr * my_src_ptr
Definition: jdatasrc.c:34

Referenced by jpeg_stdio_src().

◆ jpeg_mem_src()

jpeg_mem_src ( j_decompress_ptr  cinfo,
const unsigned char inbuffer,
unsigned long  insize 
)

Definition at line 249 of file jdatasrc.c.

251 {
252  struct jpeg_source_mgr * src;
253 
254  if (inbuffer == NULL || insize == 0) /* Treat empty input as fatal error */
255  ERREXIT(cinfo, JERR_INPUT_EMPTY);
256 
257  /* The source object is made permanent so that a series of JPEG images
258  * can be read from the same buffer by calling jpeg_mem_src only before
259  * the first one.
260  */
261  if (cinfo->src == NULL) { /* first time for this JPEG object? */
262  cinfo->src = (struct jpeg_source_mgr *)
263  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
264  SIZEOF(struct jpeg_source_mgr));
265  }
266 
267  src = cinfo->src;
268  src->init_source = init_mem_source;
269  src->fill_input_buffer = fill_mem_input_buffer;
270  src->skip_input_data = skip_input_data;
271  src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
272  src->term_source = term_source;
273  src->bytes_in_buffer = (size_t) insize;
274  src->next_input_byte = (const JOCTET *) inbuffer;
275 }
const unsigned char * inbuffer
Definition: jpeglib.h:982
#define ERREXIT(msg)
Definition: rdjpgcom.c:72
term_source(j_decompress_ptr cinfo)
Definition: jdatasrc.c:197
struct jpeg_common_struct * j_common_ptr
Definition: jpeglib.h:284
fill_mem_input_buffer(j_decompress_ptr cinfo)
Definition: jdatasrc.c:122
#define SIZEOF(_ar)
Definition: calc.h:97
smooth NULL
Definition: ftsmooth.c:416
__kernel_size_t size_t
Definition: linux.h:237
init_mem_source(j_decompress_ptr cinfo)
Definition: jdatasrc.c:57
skip_input_data(j_decompress_ptr cinfo, long num_bytes)
Definition: jdatasrc.c:156
jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired)
Definition: jdmarker.c:1343
const unsigned char unsigned long insize
Definition: jpeglib.h:982
GLenum src
Definition: glext.h:6340
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
#define JPOOL_PERMANENT
Definition: jpeglib.h:807
char JOCTET
Definition: jmorecfg.h:167

◆ jpeg_stdio_src()

jpeg_stdio_src ( j_decompress_ptr  cinfo,
FILE infile 
)

Definition at line 210 of file jdatasrc.c.

211 {
212  my_src_ptr src;
213 
214  /* The source object and input buffer are made permanent so that a series
215  * of JPEG images can be read from the same file by calling jpeg_stdio_src
216  * only before the first one. (If we discarded the buffer at the end of
217  * one image, we'd likely lose the start of the next one.)
218  * This makes it unsafe to use this manager and a different source
219  * manager serially with the same JPEG object. Caveat programmer.
220  */
221  if (cinfo->src == NULL) { /* first time for this JPEG object? */
222  cinfo->src = (struct jpeg_source_mgr *)
223  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
225  src = (my_src_ptr) cinfo->src;
226  src->buffer = (JOCTET *)
227  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
229  }
230 
231  src = (my_src_ptr) cinfo->src;
232  src->pub.init_source = init_source;
233  src->pub.fill_input_buffer = fill_input_buffer;
234  src->pub.skip_input_data = skip_input_data;
235  src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
236  src->pub.term_source = term_source;
237  src->infile = infile;
238  src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
239  src->pub.next_input_byte = NULL; /* until buffer loaded */
240 }
term_source(j_decompress_ptr cinfo)
Definition: jdatasrc.c:197
struct jpeg_common_struct * j_common_ptr
Definition: jpeglib.h:284
static FILE * infile
Definition: rdjpgcom.c:65
#define SIZEOF(_ar)
Definition: calc.h:97
init_source(j_decompress_ptr cinfo)
Definition: jdatasrc.c:45
smooth NULL
Definition: ftsmooth.c:416
#define INPUT_BUF_SIZE
Definition: jdatasrc.c:36
skip_input_data(j_decompress_ptr cinfo, long num_bytes)
Definition: jdatasrc.c:156
jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired)
Definition: jdmarker.c:1343
GLenum src
Definition: glext.h:6340
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
my_source_mgr * my_src_ptr
Definition: jdatasrc.c:34
#define JPOOL_PERMANENT
Definition: jpeglib.h:807
char JOCTET
Definition: jmorecfg.h:167
fill_input_buffer(j_decompress_ptr cinfo)
Definition: jdatasrc.c:97

Referenced by main(), and read_JPEG_file().

◆ skip_input_data()

skip_input_data ( j_decompress_ptr  cinfo,
long  num_bytes 
)

Definition at line 156 of file jdatasrc.c.

157 {
158  struct jpeg_source_mgr * src = cinfo->src;
159 
160  /* Just a dumb implementation for now. Could use fseek() except
161  * it doesn't work on pipes. Not clear that being smart is worth
162  * any trouble anyway --- large skips are infrequent.
163  */
164  if (num_bytes > 0) {
165  while (num_bytes > (long) src->bytes_in_buffer) {
166  num_bytes -= (long) src->bytes_in_buffer;
167  (void) (*src->fill_input_buffer) (cinfo);
168  /* note we assume that fill_input_buffer will never return FALSE,
169  * so suspension need not be handled.
170  */
171  }
172  src->next_input_byte += (size_t) num_bytes;
173  src->bytes_in_buffer -= (size_t) num_bytes;
174  }
175 }
__kernel_size_t size_t
Definition: linux.h:237
ed2 num_bytes
Definition: write.c:2846
GLenum src
Definition: glext.h:6340
struct jpeg_source_mgr * src
Definition: jpeglib.h:463
#define long
Definition: qsort.c:33

Referenced by jpeg_mem_src(), and jpeg_stdio_src().

◆ term_source()

term_source ( j_decompress_ptr  cinfo)

Definition at line 197 of file jdatasrc.c.

198 {
199  /* no work necessary here */
200 }

Referenced by jpeg_mem_src(), and jpeg_stdio_src().