blind

commit 3273cb68f82adb0347e3ad1810fc891ad3dbe217
parent 70b03ed486e3fddcc9416a4a3e38576455ebfe98
Author: Mattias Andrée <maandree@kth.se>
Date:   Sun,  8 Jan 2017 05:16:25 +0100

Add vu-repeat

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

Diffstat:
A
src/vu-repeat.c
 | 
59
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 59 insertions(+), 0 deletions(-)
diff --git a/src/vu-repeat.c b/src/vu-repeat.c
@@ -0,0 +1,59 @@
+/* See LICENSE file for copyright and license details. */
+#include "arg.h"
+#include "util.h"
+
+#include <fcntl.h>
+#include <stdint.h>
+#include <unistd.h>
+
+static void
+usage(void)
+{
+	eprintf("usage: %s count file\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct stat st;
+	size_t count, ptr, n, ptw;
+	int fd;
+	ssize_t r;
+	char buf[BUFSIZ];
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc != 2)
+		usage();
+
+	if (tozu(argv[0], 0, SIZE_MAX, &count))
+		eprintf("the count must be an integer in [0, %zu]\n", SIZE_MAX);
+
+	fd = open(argv[1], O_RDONLY);
+	if (fd < 0)
+		eprintf("open %s:", argv[1]);
+
+	while (count--) {
+		posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
+		for (ptr = 0;;) {
+			r = pread(fd, buf, sizeof(buf), ptr);
+			if (r < 0)
+				eprintf("pread %s:", argv[1]);
+			else if (r == 0)
+				break;
+			ptr += n = (size_t)r;
+			for (ptw = 0; ptw < n;) {
+				r = write(STDOUT_FILENO, buf + ptw, n - ptw);
+				if (r < 0)
+					eprintf("write <stdout>:");
+				ptw += (size_t)r;
+			}
+		}
+	}
+
+	close(fd);
+	return 0;
+}