Doxygen Source Code Documentation
jdatasrc.c File Reference
#include "jinclude.h"#include "jpeglib.h"#include "jerror.h"Go to the source code of this file.
Data Structures | |
| struct | my_source_mgr |
Defines | |
| #define | INPUT_BUF_SIZE 4096 |
Typedefs | |
| typedef my_source_mgr * | my_src_ptr |
Functions | |
| init_source (j_decompress_ptr cinfo) | |
| fill_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) | |
Define Documentation
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Definition at line 35 of file jdatasrc.c. Referenced by fill_input_buffer(), and jpeg_stdio_src(). |
Typedef Documentation
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Definition at line 33 of file jdatasrc.c. |
Function Documentation
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Definition at line 90 of file jdatasrc.c. References my_source_mgr::buffer, jpeg_source_mgr::bytes_in_buffer, ERREXIT, my_source_mgr::infile, INPUT_BUF_SIZE, JFREAD, JPEG_EOI, jpeg_source_mgr::next_input_byte, my_source_mgr::pub, jpeg_decompress_struct::src, my_source_mgr::start_of_file, and WARNMS. Referenced by jpeg_stdio_src(), and skip_input_data().
00091 {
00092 my_src_ptr src = (my_src_ptr) cinfo->src;
00093 size_t nbytes;
00094
00095 nbytes = JFREAD(src->infile, src->buffer, INPUT_BUF_SIZE);
00096
00097 if (nbytes <= 0) {
00098 if (src->start_of_file) /* Treat empty input file as fatal error */
00099 ERREXIT(cinfo, JERR_INPUT_EMPTY);
00100 WARNMS(cinfo, JWRN_JPEG_EOF);
00101 /* Insert a fake EOI marker */
00102 src->buffer[0] = (JOCTET) 0xFF;
00103 src->buffer[1] = (JOCTET) JPEG_EOI;
00104 nbytes = 2;
00105 }
00106
00107 src->pub.next_input_byte = src->buffer;
00108 src->pub.bytes_in_buffer = nbytes;
00109 src->start_of_file = FALSE;
00110
00111 return TRUE;
00112 }
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Definition at line 44 of file jdatasrc.c. References jpeg_decompress_struct::src, and my_source_mgr::start_of_file. Referenced by jpeg_stdio_src().
00045 {
00046 my_src_ptr src = (my_src_ptr) cinfo->src;
00047
00048 /* We reset the empty-input-file flag for each image,
00049 * but we don't clear the input buffer.
00050 * This is correct behavior for reading a series of images from one source.
00051 */
00052 src->start_of_file = TRUE;
00053 }
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Definition at line 182 of file jdatasrc.c. References my_source_mgr::buffer, jpeg_source_mgr::bytes_in_buffer, fill_input_buffer(), my_source_mgr::infile, init_source(), INPUT_BUF_SIZE, JOCTET, jpeg_resync_to_restart(), jpeg_source_mgr::next_input_byte, my_source_mgr::pub, SIZEOF, skip_input_data(), jpeg_decompress_struct::src, and term_source(). Referenced by main(), and read_JPEG_file().
00183 {
00184 my_src_ptr src;
00185
00186 /* The source object and input buffer are made permanent so that a series
00187 * of JPEG images can be read from the same file by calling jpeg_stdio_src
00188 * only before the first one. (If we discarded the buffer at the end of
00189 * one image, we'd likely lose the start of the next one.)
00190 * This makes it unsafe to use this manager and a different source
00191 * manager serially with the same JPEG object. Caveat programmer.
00192 */
00193 if (cinfo->src == NULL) { /* first time for this JPEG object? */
00194 cinfo->src = (struct jpeg_source_mgr *)
00195 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00196 SIZEOF(my_source_mgr));
00197 src = (my_src_ptr) cinfo->src;
00198 src->buffer = (JOCTET *)
00199 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00200 INPUT_BUF_SIZE * SIZEOF(JOCTET));
00201 }
00202
00203 src = (my_src_ptr) cinfo->src;
00204 src->pub.init_source = init_source;
00205 src->pub.fill_input_buffer = fill_input_buffer;
00206 src->pub.skip_input_data = skip_input_data;
00207 src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
00208 src->pub.term_source = term_source;
00209 src->infile = infile;
00210 src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
00211 src->pub.next_input_byte = NULL; /* until buffer loaded */
00212 }
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Definition at line 128 of file jdatasrc.c. References jpeg_source_mgr::bytes_in_buffer, fill_input_buffer(), jpeg_source_mgr::next_input_byte, my_source_mgr::pub, and jpeg_decompress_struct::src. Referenced by jpeg_stdio_src().
00129 {
00130 my_src_ptr src = (my_src_ptr) cinfo->src;
00131
00132 /* Just a dumb implementation for now. Could use fseek() except
00133 * it doesn't work on pipes. Not clear that being smart is worth
00134 * any trouble anyway --- large skips are infrequent.
00135 */
00136 if (num_bytes > 0) {
00137 while (num_bytes > (long) src->pub.bytes_in_buffer) {
00138 num_bytes -= (long) src->pub.bytes_in_buffer;
00139 (void) fill_input_buffer(cinfo);
00140 /* note we assume that fill_input_buffer will never return FALSE,
00141 * so suspension need not be handled.
00142 */
00143 }
00144 src->pub.next_input_byte += (size_t) num_bytes;
00145 src->pub.bytes_in_buffer -= (size_t) num_bytes;
00146 }
00147 }
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Definition at line 169 of file jdatasrc.c. Referenced by jpeg_stdio_src().
00170 {
00171 /* no work necessary here */
00172 }
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