1 files changed, 63 insertions, 0 deletions
diff --git a/src/blind-read-head.c b/src/blind-read-head.c
new file mode 100644
index 0000000..afb2fbc
--- /dev/null
+++ b/src/blind-read-head.c
@@ -0,0 +1,63 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <ctype.h>
+#include <unistd.h>
+
+USAGE("")
+
+int
+main(int argc, char *argv[])
+{
+	char buf[STREAM_HEAD_MAX];
+	char magic[] = {'\0', 'u', 'i', 'v', 'f'};
+	char b, *p;
+	size_t i, ptr;
+	ssize_t r;
+
+	ENOFLAGS(argc);
+
+	for (ptr = 0; ptr < sizeof(buf);) {
+		r = read(STDIN_FILENO, buf + ptr, 1);
+		if (r < 0)
+			eprintf("read <stdin>:");
+		if (r == 0)
+			goto bad_format;
+		if (buf[ptr++] == '\n')
+			break;
+	}
+	if (ptr == sizeof(buf))
+		goto bad_format;
+
+	p = buf;
+	for (i = 0; i < 5; i++) {
+		r = read(STDIN_FILENO, &b, 1);
+		if (r < 0)
+			eprintf("read <stdin>:");
+		if (r == 0 || b != magic[i])
+			goto bad_format;
+	}
+
+	for (i = 0; i < 3; i++) {
+		if (!isdigit(*p))
+			goto bad_format;
+		while (isdigit(*p)) p++;
+		if (*p++ != ' ')
+			goto bad_format;
+	}
+	while (isalnum(*p) || *p == ' ') {
+		if (p[0] == ' ' && p[-1] == ' ')
+			goto bad_format;
+		p++;
+	}
+	if (p[-1] == ' ' || p[0] != '\n')
+		goto bad_format;
+
+	ewriteall(STDOUT_FILENO, buf, ptr, "<stdout>");
+
+	return 0;
+bad_format:
+	eprintf("<stdin>: file format not supported\n");
+	return 0;
+}