reduce duplication

1 files changed, 53 insertions, 21 deletions

diff --git a/catgy.c b/catgy.c
index 2a5025e..b917005 100644
--- a/catgy.c
+++ b/catgy.c
@@ -12,12 +12,15 @@ struct image {
 	uint8_t *data;
 };
 
-static int process(int argc, char **argv);
 static void bit3(struct image *img);
 static void chaos1(struct image *img);
 static void chaos3(struct image *img);
 static void blurge(struct image *img);
 static void gol(struct image *img);
+static int process(int argc, char **argv);
+static int duplicate(struct image *dest, struct image *img);
+static void move(struct image *dest, struct image *img);
+static uint8_t get(struct image *img, int x, int y, int o);
 
 int
 main(int argc, char **argv) {
@@ -80,42 +83,37 @@ blurge(struct image *img)
 static int
 neighbors(struct image *img, int x, int y, int o)
 {
-	const int stride = img->w * 3;
-	return (img->data[o + (x - 1) * 3 + (y    ) * stride] != 0) +
-	       (img->data[o + (x + 1) * 3 + (y    ) * stride] != 0) +
-	       (img->data[o + (x    ) * 3 + (y - 1) * stride] != 0) +
-	       (img->data[o + (x    ) * 3 + (y + 1) * stride] != 0) +
-	       (img->data[o + (x - 1) * 3 + (y - 1) * stride] != 0) +
-	       (img->data[o + (x - 1) * 3 + (y + 1) * stride] != 0) +
-	       (img->data[o + (x + 1) * 3 + (y - 1) * stride] != 0) +
-	       (img->data[o + (x + 1) * 3 + (y + 1) * stride] != 0);
+	return (get(img, x - 1, y    , o) != 0) +
+	       (get(img, x + 1, y    , o) != 0) + 
+	       (get(img, x    , y - 1, o) != 0) +
+	       (get(img, x    , y + 1, o) != 0) +
+	       (get(img, x - 1, y - 1, o) != 0) +
+	       (get(img, x - 1, y + 1, o) != 0) +
+	       (get(img, x + 1, y - 1, o) != 0) +
+	       (get(img, x + 1, y + 1, o) != 0);
 }
 
 static void
 gol(struct image *img)
 {
-	uint8_t *copy = malloc(img->w * img->h * img->chans);
-	if (copy == NULL) {
-		perror("malloc");
+	struct image copy;
+	if (duplicate(&copy, img))
 		return;
-	}
-	memcpy(copy, img->data, img->w * img->h * img->chans);
 
-	for (int y = 1; y < img->h - 1; y++) {
-		for (int x = 1; x < img->w - 1; x++) {
+	for (int y = 0; y < img->h; y++) {
+		for (int x = 0; x < img->w; x++) {
 			for (int o = 0; o < 3; o++) {
 				const int near = neighbors(img, x, y, o);
 				const int i = x * 3 + y * img->w * 3 + o;
 				if (near < 2 || near > 3)
-					copy[i] = 0;
+					copy.data[i] = 0;
 				else
-					copy[i] = 0xff;
+					copy.data[i] = 0xff;
 			}
 		}
 	}
 
-	memcpy(img->data, copy, img->w * img->h * img->chans);
-	free(copy);
+	move(img, &copy);
 }
 
 static int
@@ -181,3 +179,37 @@ process(int argc, char **argv)
 	stbi_image_free(img.data);
 	return 0;
 }
+
+static int
+duplicate(struct image *dest, struct image *src)
+{
+	memcpy(dest, src, sizeof(*dest));
+	dest->data = malloc(src->w * src->h * src->chans);
+	if (dest->data == NULL) {
+		perror("malloc");
+		return 1;
+	}
+	memcpy(dest->data, src->data, src->w * src->h * src->chans);
+	return 0;
+}
+
+static void
+move(struct image *dest, struct image *src)
+{
+	memcpy(dest->data, src->data, src->w * src->h * src->chans);
+	free(src->data);
+}
+
+static uint8_t
+get(struct image *img, int x, int y, int o)
+{
+	if (x < 0)
+		x = img->w + x;
+	if (x >= img->w)
+		x = x - img->w;
+	if (y < 0)
+		y = img->h + y;
+	if (y >= img->h)
+		y = y - img->h;
+	return img->data[o + x * 3 + y * img->w * 3];
+}