1 files changed, 63 insertions, 0 deletions
diff --git a/lib/extras/hex.c b/lib/extras/hex.c
new file mode 100644
index 0000000..b88777f
--- /dev/null
+++ b/lib/extras/hex.c
@@ -0,0 +1,63 @@
+/* CC0 license (public domain) - see LICENSE file for details */
+#include <config.h>
+#include <hex.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static bool char_to_hex(unsigned char *val, char c)
+{
+	if (c >= '0' && c <= '9') {
+		*val = c - '0';
+		return true;
+	}
+	if (c >= 'a' && c <= 'f') {
+		*val = c - 'a' + 10;
+		return true;
+	}
+	if (c >= 'A' && c <= 'F') {
+		*val = c - 'A' + 10;
+		return true;
+	}
+	return false;
+}
+
+bool hex_decode(const char *str, size_t slen, void *buf, size_t bufsize)
+{
+	unsigned char v1, v2;
+	unsigned char *p = buf;
+
+	while (slen > 1) {
+		if (!char_to_hex(&v1, str[0]) || !char_to_hex(&v2, str[1]))
+			return false;
+		if (!bufsize)
+			return false;
+		*(p++) = (v1 << 4) | v2;
+		str += 2;
+		slen -= 2;
+		bufsize--;
+	}
+	return slen == 0 && bufsize == 0;
+}
+
+static const char HEX_CHARS[] = "0123456789abcdef";
+
+bool hex_encode(const void *buf, size_t bufsize, char *dest, size_t destsize)
+{
+	size_t used = 0;
+
+	if (destsize < 1)
+		return false;
+
+	while (used < bufsize) {
+		unsigned int c = ((const unsigned char *)buf)[used];
+		if (destsize < 3)
+			return false;
+		*(dest++) = HEX_CHARS[(c >> 4) & 0xF];
+		*(dest++) = HEX_CHARS[c & 0xF];
+		used++;
+		destsize -= 2;
+	}
+	*dest = '\0';
+
+	return used + 1;
+}