1 files changed, 47 insertions, 0 deletions
diff --git a/src/blind-reverse.c b/src/blind-reverse.c
new file mode 100644
index 0000000..5c978f2
--- /dev/null
+++ b/src/blind-reverse.c
@@ -0,0 +1,47 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <limits.h>
+#include <unistd.h>
+
+USAGE("file")
+
+int
+main(int argc, char *argv[])
+{
+	struct stream stream;
+	size_t frame_size, ptr, end, n;
+	ssize_t r;
+	char buf[BUFSIZ];
+
+	ENOFLAGS(argc != 1);
+
+	stream.file = argv[0];
+	stream.fd = eopen(stream.file, O_RDONLY);
+	einit_stream(&stream);
+	fprint_stream_head(stdout, &stream);
+	efflush(stdout, "<stdout>");
+	echeck_frame_size(stream.width, stream.height, stream.pixel_size, 0, stream.file);
+	frame_size = stream.width * stream.height * stream.pixel_size;
+	if (stream.frames > SSIZE_MAX / frame_size)
+		eprintf("%s: video is too large\n", stream.file);
+
+	posix_fadvise(stream.fd, 0, 0, POSIX_FADV_RANDOM);
+	while (stream.frames--) {
+		ptr = stream.frames * frame_size;
+		end = ptr + frame_size;
+		while (ptr < end) {
+			r = pread(stream.fd, buf, sizeof(buf), ptr);
+			if (r < 0)
+				eprintf("pread %s:", stream.file);
+			else if (r == 0)
+				eprintf("%s: file is shorter than expected\n", stream.file);
+			ptr += n = (size_t)r;
+			ewriteall(STDOUT_FILENO, buf, n, "<stdout>");
+		}
+	}
+
+	close(stream.fd);
+	return 0;
+}