static int
scan_JPEG_header (int verbose)
{
int marker;
/* Expect SOI at start of file */
if (first_marker() != M_SOI)
ERREXIT("Expected SOI marker first");
/* Scan miscellaneous markers until we reach SOS. */
for (;;) {
marker = next_marker();
switch (marker) {
case M_SOF0: /* Baseline */
case M_SOF1: /* Extended sequential, Huffman */
case M_SOF2: /* Progressive, Huffman */
case M_SOF3: /* Lossless, Huffman */
case M_SOF5: /* Differential sequential, Huffman */
case M_SOF6: /* Differential progressive, Huffman */
case M_SOF7: /* Differential lossless, Huffman */
case M_SOF9: /* Extended sequential, arithmetic */
case M_SOF10: /* Progressive, arithmetic */
case M_SOF11: /* Lossless, arithmetic */
case M_SOF13: /* Differential sequential, arithmetic */
case M_SOF14: /* Differential progressive, arithmetic */
case M_SOF15: /* Differential lossless, arithmetic */
if (verbose)
process_SOFn(marker);
else
skip_variable();
break;
case M_SOS: /* stop before hitting compressed data */
return marker;
case M_EOI: /* in case it's a tables-only JPEG stream */
return marker;
case M_COM:
process_COM();
break;
default: /* Anything else just gets skipped */
skip_variable(); /* we assume it has a parameter count... */
break;
}
} /* end loop */
}
static int get_jpeg_image_dimensions(ImageSize *is, int *width, int *height)
{
int marker = -1, jpeg_ok = 0;
*width = *height = -1;
if (is->infile || !is->file) {
/* Expect SOI at start of file */
if (first_marker(is) == M_SOI) {
jpeg_ok = 1;
/* Scan miscellaneous markers until we reach SOS. */
for (; marker != M_SOS && marker != M_EOI; ) {
marker = next_marker(is);
switch (marker) {
/* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be,
* treated as SOFn. C4 in particular is actually DHT.
*/
case M_SOF0: /* Baseline */
case M_SOF1: /* Extended sequential, Huffman */
case M_SOF2: /* Progressive, Huffman */
case M_SOF3: /* Lossless, Huffman */
case M_SOF5: /* Differential sequential, Huffman */
case M_SOF6: /* Differential progressive, Huffman */
case M_SOF7: /* Differential lossless, Huffman */
case M_SOF9: /* Extended sequential, arithmetic */
case M_SOF10: /* Progressive, arithmetic */
case M_SOF11: /* Lossless, arithmetic */
case M_SOF13: /* Differential sequential, arithmetic */
case M_SOF14: /* Differential progressive, arithmetic */
case M_SOF15: /* Differential lossless, arithmetic */
get_image_dimensions(is, width, height);
break;
default: /* Anything else just gets skipped */
if (skip_variable(is) < 0)
return -1;
break;
}
}
}
}
return jpeg_ok;
}
static int
scan_JPEG_header (int verbose)
{
int marker;
/* Expect SOI at start of file */
if (first_marker() != M_SOI)
ERREXIT("Expected SOI marker first");
/* Scan miscellaneous markers until we reach SOS. */
for (;;) {
marker = next_marker();
switch (marker) {
/* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be,
* treated as SOFn. C4 in particular is actually DHT.
*/
case M_SOF0: /* Baseline */
case M_SOF1: /* Extended sequential, Huffman */
case M_SOF2: /* Progressive, Huffman */
case M_SOF3: /* Lossless, Huffman */
case M_SOF5: /* Differential sequential, Huffman */
case M_SOF6: /* Differential progressive, Huffman */
case M_SOF7: /* Differential lossless, Huffman */
case M_SOF9: /* Extended sequential, arithmetic */
case M_SOF10: /* Progressive, arithmetic */
case M_SOF11: /* Lossless, arithmetic */
case M_SOF13: /* Differential sequential, arithmetic */
case M_SOF14: /* Differential progressive, arithmetic */
case M_SOF15: /* Differential lossless, arithmetic */
if (verbose)
process_SOFn(marker);
else
skip_variable();
break;
case M_SOS: /* stop before hitting compressed data */
return marker;
case M_EOI: /* in case it's a tables-only JPEG stream */
return marker;
case M_COM:
process_COM();
break;
case M_APP12:
/* Some digital camera makers put useful textual information into
* APP12 markers, so we print those out too when in -verbose mode.
*/
if (verbose) {
printf("APP12 contains:\n");
process_COM();
} else
skip_variable();
break;
default: /* Anything else just gets skipped */
skip_variable(); /* we assume it has a parameter count... */
break;
}
} /* end loop */
}
