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-rw-r--r--src/jpeg.c38
1 files changed, 27 insertions, 11 deletions
diff --git a/src/jpeg.c b/src/jpeg.c
index dde41ce..cf6e4fd 100644
--- a/src/jpeg.c
+++ b/src/jpeg.c
@@ -2,21 +2,33 @@
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
+#include <setjmp.h>
+#include <string.h>
#include "jpeglib.h"
#include "jpeg.h"
+struct error_mgr{
+ struct jpeg_error_mgr pub;
+ jmp_buf jmp_buffer;
+};
+
+static void error_exit(j_common_ptr cinfo){
+ printf("\nerror!\n");
+ exit(1);
+}
+
unsigned char *loadjpeg(char *filename, int *width, int *height){
struct jpeg_decompress_struct cinfo;
- struct jpeg_error_mgr jerr;
+ struct error_mgr jerr;
FILE *infile;
JSAMPARRAY buffer;
int row_stride;
int i = 0;
int j;
- int x, y;
+ int y;
unsigned char *retbuf;
if((infile = fopen(filename, "rb")) == NULL){
@@ -24,14 +36,23 @@ unsigned char *loadjpeg(char *filename, int *width, int *height){
exit(1);
}
- cinfo.err = jpeg_std_error(&jerr);
+ cinfo.err = jpeg_std_error(&jerr.pub);
+ jerr.pub.error_exit = error_exit;
+
jpeg_create_decompress(&cinfo);
jpeg_stdio_src(&cinfo, infile);
jpeg_read_header(&cinfo, TRUE);
+
+ /* parameters */
cinfo.do_fancy_upsampling = 0;
cinfo.do_block_smoothing = 0;
cinfo.quantize_colors = 0;
cinfo.dct_method = JDCT_IFAST;
+
+ jpeg_calc_output_dimensions(&cinfo);
+ row_stride = cinfo.output_width * cinfo.output_components;
+ buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo, JPOOL_IMAGE, row_stride, 4);
+
jpeg_start_decompress(&cinfo);
*width = cinfo.output_width;
*height = cinfo.output_height;
@@ -41,16 +62,11 @@ unsigned char *loadjpeg(char *filename, int *width, int *height){
fprintf(stderr, "TODO: greyscale images are not supported\n");
exit(1);
}
- row_stride = cinfo.output_width * cinfo.output_components;
- buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo, JPOOL_IMAGE, row_stride, 16);
for(y = 0; y < cinfo.output_height; ){
- int n = jpeg_read_scanlines(&cinfo, buffer, 16);
+ int n = jpeg_read_scanlines(&cinfo, buffer, 4);
for(j = 0; j < n; j++){
- for(x = 0; x < row_stride;){
- retbuf[i++] = buffer[j][x++];
- retbuf[i++] = buffer[j][x++];
- retbuf[i++] = buffer[j][x++];
- }
+ memcpy(&retbuf[i], buffer[j], row_stride);
+ i += row_stride;
}
y += n;
}