1 files changed, 138 insertions, 0 deletions
diff --git a/src/blind-multiply-matrices.c b/src/blind-multiply-matrices.c
new file mode 100644
index 0000000..9d37a04
--- /dev/null
+++ b/src/blind-multiply-matrices.c
@@ -0,0 +1,138 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+USAGE("[-en] leftmost-stream ... rightmost-stream")
+
+static int equal = 0;
+static size_t max_frame_size;
+
+#define PROCESS(TYPE)\
+	do {\
+		typedef TYPE pixel_t[4];\
+		pixel_t *res, *left, *right, *tmp;\
+		size_t i, j, w, h, h2, x, y, k, r;\
+		res = emalloc(max_frame_size);\
+		left = emalloc(max_frame_size);\
+		right = emalloc(max_frame_size);\
+		\
+		while (eread_frame(streams + (n_streams - 1), res)) {\
+			w = streams[n_streams - 1].width;\
+			h = streams[n_streams - 1].height;\
+			for (i = n_streams - 1; i--;) {\
+				tmp = res, res = right, right = tmp;\
+				if (!eread_frame(streams + i, left))\
+					goto done;\
+				h2 = streams[i].height;\
+				memset(res, 0, w * h2 * streams->pixel_size);\
+				\
+				/* XXX Is there any significant performance to be gained by transposing `right`? */\
+				if (equal) {\
+					for (y = r = 0; y < h2; y++) {\
+						for (x = 0; x < w; x++, r++) {\
+							for (k = 0; k < h; k++) \
+								res[r][1] += left[y * h + k][1] * right[k * w + x][1];\
+							res[r][3] = res[r][2] = res[r][0] = res[r][1];\
+						}\
+					}\
+				} else {\
+					for (y = r = 0; y < h2; y++)\
+						for (x = 0; x < w; x++, r++) \
+							for (k = 0; k < h; k++)\
+								for (j = 0; j < 4; j++)\
+									res[r][j] += left[y * h + k][j] * right[k * w + x][j];\
+				}\
+				\
+				h = h2;\
+			}\
+			ewriteall(STDOUT_FILENO, res, streams->frame_size, "<stdout>");\
+		}\
+		\
+	done:\
+		free(res);\
+		free(left);\
+		free(right);\
+	} while (0)
+
+static void process_lf(struct stream *streams, size_t n_streams) { PROCESS(double); }
+static void process_f (struct stream *streams, size_t n_streams) { PROCESS(float); }
+
+int
+main(int argc, char *argv[])
+{
+	struct stream *streams;
+	size_t n_streams, i, frames = 0;
+	int natural = 0, j;
+	char **rev_argv;
+	size_t max_width = 0, max_height = 0;
+	size_t width = 0, height = 0, w, h;
+	void (*process)(struct stream *streams, size_t n_streams);
+
+	ARGBEGIN {
+	case 'e':
+		equal = 1;
+		break;
+	case 'n':
+		natural = 1;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc < 2)
+		usage();
+
+	if (natural) {
+		rev_argv = alloca(argc * sizeof(*rev_argv));
+		for (j = 0; j < argc; j++)
+			rev_argv[j] = argv[argc - 1 - j];
+		argv = rev_argv;
+	}
+
+	n_streams = (size_t)argc;
+	streams = ecalloc(n_streams, sizeof(*streams));
+
+	for (i = 0; i < n_streams; i++) {
+		eopen_stream(streams + i, argv[i]);
+		if (streams[i].frames && streams[i].frames < frames)
+			frames = streams[i].frames;
+		if (streams->width > max_width)
+			max_width = streams->width;
+		if (streams->height > max_height)
+			max_height = streams->height;
+	}
+	for (i = 1; i < n_streams; i++)
+		if (strcmp(streams->pixfmt, streams[i].pixfmt))
+			eprintf("videos use incompatible pixel formats\n");
+
+	width  = streams[n_streams - 1].width;
+	height = streams[n_streams - 1].height;
+	for (i = n_streams - 1; i--;) {
+		if (streams[i].width != height)
+			eprintf("videos do not have the compatible geometry\n");
+		height = streams[i].height;
+	}
+
+	if (!strcmp(streams->pixfmt, "xyza"))
+		process = process_lf;
+	else if (!strcmp(streams->pixfmt, "xyza f"))
+		process = process_f;
+	else
+		eprintf("pixel format %s is not supported, try xyza\n", streams->pixfmt);
+
+	w = streams->width,  streams->width  = max_width;
+	h = streams->height, streams->height = max_height;
+	echeck_dimensions(streams, WIDTH | HEIGHT, NULL);
+	streams->width  = width;
+	streams->height = height;
+	streams->frames = frames;
+	fprint_stream_head(stdout, streams);
+	streams->width  = w;
+	streams->height = h;
+	efflush(stdout, "<stdout>");
+	max_frame_size = max_width * max_height * streams->pixel_size;
+
+	process(streams, n_streams);
+
+	free(streams);
+	return 0;
+}