m + Add vu-cut

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 92 insertions, 0 deletions

diff --git a/src/vu-cut.c b/src/vu-cut.c
new file mode 100644
index 0000000..011e31c
--- /dev/null
+++ b/src/vu-cut.c
@@ -0,0 +1,92 @@
+/* See LICENSE file for copyright and license details. */
+#include "arg.h"
+#include "stream.h"
+#include "util.h"
+
+#include <fcntl.h>
+#include <limits.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+static void
+usage(void)
+{
+	eprintf("usage: %s start-point (end-point | 'end') file\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct stream stream;
+	size_t frame_size, start = 0, end = 0, ptr, max, n, ptw;
+	ssize_t r;
+	char buf[BUFSIZ];
+	int to_end = 0;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc != 3)
+		usage();
+
+	if (!strcmp(argv[0], "end")) {
+		eprintf("refusing to create video with zero frames\n");
+	} else if (tozu(argv[0], 0, SIZE_MAX, &start)) {
+		eprintf("the start point must be an integer in [0, %zu]\n", SIZE_MAX);
+	}
+
+	if (!strcmp(argv[1], "end")) {
+		to_end = 1;
+	} else if (tozu(argv[1], 0, SIZE_MAX, &end)) {
+		eprintf("the end point must be an integer in [0, %zu]\n", SIZE_MAX);
+	}
+
+	stream.file = argv[2];
+	stream.fd = open(stream.file, O_RDONLY);
+	if (stream.fd < 0)
+		eprintf("open %s:", stream.file);
+	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);
+	fflush(stdout);
+	if (ferror(stdout))
+		eprintf("<stdout>:");
+	if (stream.width > SIZE_MAX / stream.height)
+		eprintf("%s: video is too large\n", stream.file);
+	frame_size = stream.width * stream.height;
+	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 *= frame_size;
+	start *= frame_size;
+
+	for (ptr = start; ptr < end;) {
+		max = end - ptr;
+		max = sizeof(buf) < max ? sizeof(buf) : max;
+		r = read(stream.fd, buf + ptr, max);
+		if (r < 0)
+			eprintf("read %s:", stream.file);
+		if (r == 0)
+			eprintf("%s: file is shorter than expected\n", stream.file);
+		ptr += n = (size_t)r;
+		for (ptw = 0; ptw < n; ptw += (size_t)r) {
+			r = write(STDOUT_FILENO, buf + ptw, n - ptw);
+			if (r < 0)
+				eprintf("write <stdout>:");
+		}
+	}
+
+	close(stream.fd);
+	return 0;
+}