libtar: add support for xattr extensions

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/tar/urldecode.c b/lib/tar/urldecode.c
new file mode 100644
index 0000000..ac03f10
--- /dev/null
+++ b/lib/tar/urldecode.c
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "internal.h"
+
+static int xdigit(int x)
+{
+	if (isupper(x))
+		return x - 'A' + 0x0A;
+	if (islower(x))
+		return x - 'a' + 0x0A;
+	return x - '0';
+}
+
+void urldecode(char *str)
+{
+	unsigned char *out = (unsigned char *)str;
+	char *in = str;
+	int x;
+
+	while (*in != '\0') {
+		x = *(in++);
+
+		if (x == '%' && isxdigit(in[0]) && isxdigit(in[1])) {
+			x = xdigit(*(in++)) << 4;
+			x |= xdigit(*(in++));
+		}
+
+		*(out++) = x;
+	}
+
+	*out = '\0';
+}