Refactor jpg-conversion-utilities

First of all, there was lots of libjpeg-specific cruft that just didn't
have any right to exist (METHODDEF(), strange typedefs, use of the
internal memory pool for no reason). This is gone now.

Additionally, we make use of the save and proven utility functions and
in general the code should be more well-separated now.

What is left to do is clear up the part where we mix the colors with the
mask.

1 files changed, 46 insertions, 48 deletions

diff --git a/jpg2ff.c b/jpg2ff.c
index 85c935d..8d51fb6 100644
--- a/jpg2ff.c
+++ b/jpg2ff.c
@@ -5,12 +5,13 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include <jpeglib.h>
 
 #include "util.h"
 
-METHODDEF(void)
+static void
 jpeg_error(j_common_ptr js)
 {
 	fprintf(stderr, "%s: libjpeg: ", argv0);
@@ -18,6 +19,31 @@ jpeg_error(j_common_ptr js)
 	exit(1);
 }
 
+static void
+jpeg_setup_reader(struct jpeg_decompress_struct *s, struct jpeg_error_mgr *e,
+                  uint32_t *w, uint32_t *h)
+{
+	jpeg_create_decompress(s);
+	e->error_exit = jpeg_error;
+	s->err = jpeg_std_error(e);
+
+	jpeg_stdio_src(s, stdin);
+	jpeg_read_header(s, 1);
+	*w = s->image_width;
+	*h = s->image_height;
+	s->output_components = 3;     /* color components per pixel */
+	s->out_color_space = JCS_RGB; /* input color space */
+
+	jpeg_start_decompress(s);
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s\n", argv0);
+	exit(1);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -25,72 +51,44 @@ main(int argc, char *argv[])
 	struct jpeg_error_mgr jerr;
 	uint32_t width, height;
 	uint16_t *row;
+	uint8_t *rowin;
 	size_t rowlen, i;
-	JSAMPARRAY jpgrow;
 
+	/* arguments */
 	argv0 = argv[0], argc--, argv++;
 
 	if (argc) {
-		fprintf(stderr, "usage: %s\n", argv0);
-		return 1;
+		usage();
 	}
 
-	/* load jpg */
-	js.err = jpeg_std_error(&jerr);
-	jerr.error_exit = jpeg_error;
-
-	jpeg_create_decompress(&js);
-
-	jpeg_stdio_src(&js, stdin);
-
-	jpeg_read_header(&js, 1);
-	width = js.image_width;
-	height = js.image_height;
-
-	/* set output format */
-	js.output_components = 3;     /* color components per pixel */
-	js.out_color_space = JCS_RGB; /* input color space */
-
-	jpeg_start_decompress(&js);
-
-	/* create output buffers */
-	jpgrow = (*js.mem->alloc_sarray)((j_common_ptr)&js,
-	                                 JPOOL_IMAGE, width *
-	                                 js.output_components, 1);
+	/* prepare */
+	jpeg_setup_reader(&js, &jerr, &width, &height);
+	row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(uint16_t));
 	rowlen = width * (sizeof("RGBA") - 1);
-	if(!(row = malloc(rowlen * sizeof(uint16_t)))) {
-		fprintf(stderr, "%s: malloc: out of memory\n", argv0);
-		return 1;
-	}
+	rowin = ereallocarray(NULL, width, (sizeof("RGB") - 1) * sizeof(uint8_t));
 
 	/* write data */
-	write_ff_header(width, height);
+	ff_write_header(width, height);
 
 	while (js.output_scanline < js.output_height) {
-		/* jpeg_read_scanlines expects an array of pointers to
-		 * scanlines.
-		 * Here the array is only one element long, but you could
-		 * ask for more than one scanline at a time if that's more
-		 * convenient. */
-		jpeg_read_scanlines(&js, jpgrow, 1);
+		jpeg_read_scanlines(&js, &rowin, 1);
 
 		for (i = 0; i < width; ++i) {
-			row[4*i + 0] = htons(jpgrow[0][3*i + 0] * 257);
-			row[4*i + 1] = htons(jpgrow[0][3*i + 1] * 257);
-			row[4*i + 2] = htons(jpgrow[0][3*i + 2] * 257);
-			row[4*i + 3] = htons(65535);
+			row[4 * i + 0] = htons(rowin[3 * i + 0] * 257);
+			row[4 * i + 1] = htons(rowin[3 * i + 1] * 257);
+			row[4 * i + 2] = htons(rowin[3 * i + 2] * 257);
+			row[4 * i + 3] = htons(65535);
 		}
 
-		if (fwrite(row, sizeof(uint16_t), rowlen, stdout) != rowlen)
-			goto writerr;
+		if (fwrite(row, sizeof(uint16_t), rowlen, stdout) != rowlen) {
+			fprintf(stderr, "%s: fwrite: %s\n", argv0, strerror(errno));
+			return 1;
+		}
 	}
+
+	/* clean up */
 	jpeg_finish_decompress(&js);
 	jpeg_destroy_decompress(&js);
 
 	return 0;
-writerr:
-	fprintf(stderr, "%s: fwrite: ", argv0);
-	perror(NULL);
-
-	return 1;
 }