1 files changed, 70 insertions, 0 deletions
diff --git a/src/blind-cut.c b/src/blind-cut.c
new file mode 100644
index 0000000..e229cf1
--- /dev/null
+++ b/src/blind-cut.c
@@ -0,0 +1,70 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <fcntl.h>
+#include <limits.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+USAGE("start-point (end-point | 'end') file")
+
+int
+main(int argc, char *argv[])
+{
+	struct stream stream;
+	size_t frame_size, start = 0, end = 0, ptr, max;
+	ssize_t r;
+	char buf[BUFSIZ];
+	int to_end = 0;
+
+	ENOFLAGS(argc != 3);
+
+	if (!strcmp(argv[0], "end"))
+		eprintf("refusing to create video with zero frames\n");
+	else
+		start = etozu_arg("the start point", argv[1], 0, SIZE_MAX);
+
+	if (!strcmp(argv[1], "end"))
+		to_end = 1;
+	else
+		end = etozu_arg("the end point", argv[1], 0, SIZE_MAX);
+
+	stream.file = argv[2];
+	stream.fd = eopen(stream.file, O_RDONLY);
+	einit_stream(&stream);
+	if (to_end)
+		end = stream.frames;
+	else if (end > stream.frames)
+		eprintf("end point is after end of video\n");
+	stream.frames = end - start;
+	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);
+
+	if (start >= end)
+		eprintf("%s\n", start > end ?
+			"start point is after end point" :
+			"refusing to create video with zero frames");
+	end   = end   * frame_size + stream.headlen;
+	start = start * frame_size + stream.headlen;
+
+	posix_fadvise(stream.fd, start, end - start, POSIX_FADV_SEQUENTIAL);
+	for (ptr = start; ptr < end; ptr += (size_t)r) {
+		max = end - ptr;
+		max = max < sizeof(buf) ? max : sizeof(buf);
+		r = pread(stream.fd, buf, max, ptr);
+		if (r < 0)
+			eprintf("pread %s:", stream.file);
+		if (r == 0)
+			eprintf("%s: file is shorter than expected\n", stream.file);
+		ewriteall(STDOUT_FILENO, buf, (size_t)r, "<stdout>");
+	}
+
+	close(stream.fd);
+	return 0;
+}