Added a row_average member to struct quirc.

Prep to remove the VLA from threshold()

lib/quirc.c

@@ -37,9 +37,11 @@ struct quirc *quirc_new(void)
 void quirc_destroy(struct quirc *q)
 {
 	free(q->image);
+	/* q->pixels may alias q->image when their type representation is of the
+	   same size, so we need to be careful here */
 	if (sizeof(*q->image) != sizeof(*q->pixels))
 		free(q->pixels);
-
+	free(q->row_average);
 	free(q);
 }
 
@@ -47,6 +49,7 @@ int quirc_resize(struct quirc *q, int w, int h)
 {
 	uint8_t		*image  = NULL;
 	quirc_pixel_t	*pixels = NULL;
+	int		*row_average = NULL;
 
 	/*
 	 * XXX: w and h should be size_t (or at least unsigned) as negatives
@@ -85,6 +88,11 @@ int quirc_resize(struct quirc *q, int w, int h)
 			goto fail;
 	}
 
+	/* alloc a new buffer for q->row_average */
+	row_average = calloc(w, sizeof(int));
+	if (!row_average)
+		goto fail;
+
 	/* alloc succeeded, update `q` with the new size and buffers */
 	q->w = w;
 	q->h = h;
@@ -94,12 +102,15 @@ int quirc_resize(struct quirc *q, int w, int h)
 		free(q->pixels);
 		q->pixels = pixels;
 	}
+	free(q->row_average);
+	q->row_average = row_average;
 
 	return 0;
 	/* NOTREACHED */
 fail:
 	free(image);
 	free(pixels);
+	free(row_average);
 
 	return -1;
 }

lib/quirc_internal.h

@@ -77,6 +77,7 @@ struct quirc_grid {
 struct quirc {
 	uint8_t			*image;
 	quirc_pixel_t		*pixels;
+	int			*row_average; /* used by threshold() */
 	int			w;
 	int			h;