Rewrite vu-image-to-frame in C for performance and proper error handling

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

3 files changed, 116 insertions, 3 deletions

diff --git a/src/util.c b/src/util.c
index 2ae3a9f..215a961 100644
--- a/src/util.c
+++ b/src/util.c
@@ -96,7 +96,6 @@ tollu(const char *s, unsigned long long int min, unsigned long long int max, uns
 int
 tolli(const char *s, long long int min, long long int max, long long int *out)
 {
-	char *end;
 	int sign = 1;
 	unsigned long long int inter;
 	errno = 0;
diff --git a/src/vu-image-to-frame.c b/src/vu-image-to-frame.c
new file mode 100644
index 0000000..693ddf7
--- /dev/null
+++ b/src/vu-image-to-frame.c
@@ -0,0 +1,116 @@
+/* See LICENSE file for copyright and license details. */
+#include "arg.h"
+#include "util.h"
+
+#include <sys/wait.h>
+#include <string.h>
+#include <unistd.h>
+
+static char *
+xmemmem(char *h, const char *n, size_t hn, size_t nn)
+{
+	char *p, *end;
+	if (nn > hn)
+		return NULL;
+	end = h + (hn - nn + 1);
+	for (p = h; p != end; p++) {
+		p = memchr(p, *n, (size_t)(end - p));
+		if (!p)
+			return NULL;
+		if (!memcmp(p, n, nn))
+			return p;
+	}
+	return NULL;
+}
+
+static void
+usage(void)
+{
+	eprintf("usage: %s\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int pipe_rw[2];
+	int i, old_fd;
+	pid_t pid;
+	int status;
+	char buf[8096];
+	size_t ptr, n;
+	char *p;
+	ssize_t r;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+	if (argc)
+		usage();
+
+	if (pipe(pipe_rw))
+		eprintf("pipe:");
+
+	if (pipe_rw[0] == STDIN_FILENO || pipe_rw[1] == STDIN_FILENO)
+		eprintf("no stdin open\n");
+	if (pipe_rw[0] == STDOUT_FILENO || pipe_rw[1] == STDOUT_FILENO)
+		eprintf("no stdout open\n");
+	for (i = 0; i < 2; i++) {
+		if (pipe_rw[i] == STDERR_FILENO) {
+			pipe_rw[i] = dup(old_fd = pipe_rw[i]);
+			if (pipe_rw[i] < 0)
+				eprintf("dup:");
+			close(old_fd);
+		}
+	}
+
+	pid = fork();
+	if (pid < 0)
+		eprintf("fork:");
+
+	if (!pid) {
+		close(pipe_rw[0]);
+		if (dup2(pipe_rw[1], STDOUT_FILENO) < 0)
+			eprintf("dup2:");
+		close(pipe_rw[1]);
+		execlp("convert", "convert", "-", "-depth", "8", "-alpha", "activate", "pam:-", NULL);
+		eprintf("exec convert:");
+	}
+	
+	close(pipe_rw[1]);
+
+	for (ptr = 0;;) {
+		r = read(pipe_rw[0], buf + ptr, sizeof(buf) - ptr);
+		if (r < 0)
+			eprintf("read <subprocess>:");
+		if (r == 0)
+			break;
+		ptr += (size_t)r;
+		p = xmemmem(buf, "\nENDHDR\n", ptr, sizeof("\nENDHDR\n") - 1);
+		if (!p)
+			continue;
+		p += sizeof("\nENDHDR\n") - 1;
+		n = (size_t)(p - buf);
+		memmove(buf, buf + n, ptr - n);
+		n = ptr - n;
+		break;
+	}
+
+	for (;;) {
+		for (ptr = 0; ptr < n;) {
+			r = write(STDOUT_FILENO, buf + ptr, n - ptr);
+			if (r < 0)
+				eprintf("write <stdout>:");
+			ptr += (size_t)r;
+		}
+		r = read(pipe_rw[0], buf, sizeof(buf));
+		if (r < 0)
+			eprintf("read <subprocess>:");
+		if (r == 0)
+			break;
+		n = (size_t)r;
+	}
+
+	while (waitpid(pid, &status, 0) != pid);
+	return !!status;
+}
diff --git a/src/vu-image-to-frame.sh b/src/vu-image-to-frame.sh
deleted file mode 100755
index 42655d5..0000000
--- a/src/vu-image-to-frame.sh
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/bin/sh
-exec convert - -depth 8 -alpha activate pam:- | exec sed '1,/^ENDHDR$/d'