initial

1 files changed, 54 insertions, 0 deletions

diff --git a/src/jpeg.c b/src/jpeg.c
new file mode 100644
index 0000000..6d3b40c
--- /dev/null
+++ b/src/jpeg.c
@@ -0,0 +1,54 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "jpeglib.h"
+
+#include "jpeg.h"
+
+unsigned char *loadjpeg(char *filename, int *width, int *height){
+	struct jpeg_decompress_struct cinfo;
+	struct jpeg_error_mgr jerr;
+
+	FILE *infile;
+	JSAMPARRAY buffer;
+	int row_stride;
+	int i = 0;
+	int x, y;
+	unsigned char *retbuf;
+
+	if((infile = fopen(filename, "rb")) == NULL){
+		fprintf(stderr, "can't open %s\n", filename);
+		exit(1);
+	}
+
+	cinfo.err = jpeg_std_error(&jerr);
+	jpeg_create_decompress(&cinfo);
+	jpeg_stdio_src(&cinfo, infile);
+	jpeg_read_header(&cinfo, TRUE);
+	jpeg_start_decompress(&cinfo);
+	*width = cinfo.output_width;
+	*height = cinfo.output_height;
+	retbuf = malloc(cinfo.output_components * (cinfo.output_width * cinfo.output_height));
+
+	if(cinfo.output_components != 3){
+		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, 1);
+	for(y = 0; y < cinfo.output_height; y++){
+		jpeg_read_scanlines(&cinfo, buffer, 1);
+		for(x = 0; x < row_stride; x++){
+			retbuf[i++] = buffer[0][x];
+		}
+		assert(i % *width == 0);
+	}
+	jpeg_finish_decompress(&cinfo);
+	jpeg_destroy_decompress(&cinfo);
+	fclose(infile);
+	return retbuf;
+}
+
+