1 files changed, 68 insertions, 0 deletions
diff --git a/libar2_decode_base64.c b/libar2_decode_base64.c
new file mode 100644
index 0000000..df35a60
--- /dev/null
+++ b/libar2_decode_base64.c
@@ -0,0 +1,68 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+#define FF 0xFF
+static const unsigned char lut[256] = {
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, 62, FF, FF, FF, 63,
+	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, FF, FF, FF, FF, FF, FF,
+	FF,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, FF, FF, FF, FF, FF,
+	FF, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF,
+	FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF, FF
+};
+
+
+size_t
+libar2_decode_base64(const char *str_, void *data_, size_t *lenp)
+{
+	const unsigned char *str = (const unsigned char *)str_;
+	unsigned char *data = data_;
+	unsigned char a, b, c, d;
+	size_t ret = 0;
+
+	*lenp = 0;
+
+	for(;; str += 4) {
+		if (lut[str[0]] == FF || lut[str[1]] == FF)
+			break;
+		a = lut[str[0]];
+		b = lut[str[1]];
+		ret += 2;
+		if (data)
+			*data++ = (unsigned char)((a << 2) | (b >> 4));
+		++*lenp;
+
+		if (lut[str[2]] == FF) {
+			ret += (str[2] == '=');
+			ret += (str[2] == '=' && str[3] == '=');
+			break;
+		}
+		c = lut[str[2]];
+		ret += 1;
+		if (data)
+			*data++ = (unsigned char)((b << 4) | (c >> 2));
+		++*lenp;
+
+		if (lut[str[3]] == FF) {
+			ret += (str[3] == '=');
+			break;
+		}
+		d = lut[str[3]];
+		ret += 1;
+		if (data)
+			*data++ = (unsigned char)((c << 6) | (d >> 0));
+		++*lenp;
+	}
+
+	return ret;
+}