1 files changed, 105 insertions, 0 deletions
diff --git a/util/base64.c b/util/base64.c
new file mode 100644
index 0000000..e386c11
--- /dev/null
+++ b/util/base64.c
@@ -0,0 +1,105 @@
+/*
+ * base64.c - RFC4648-compliant base64 encoding
+ *
+ * Copyright (c) 2020 Hannes Reinecke, SUSE
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA  02110-1301, USA.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+static const char base64_table[65] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+/**
+ * base64_encode() - base64-encode some bytes
+ * @src: the bytes to encode
+ * @srclen: number of bytes to encode
+ * @dst: (output) the base64-encoded string.  Not NUL-terminated.
+ *
+ * Encodes the input string using characters from the set [A-Za-z0-9+,].
+ * The encoded string is roughly 4/3 times the size of the input string.
+ *
+ * Return: length of the encoded string
+ */
+int base64_encode(const unsigned char *src, int srclen, char *dst)
+{
+	int i, bits = 0;
+	u_int32_t ac = 0;
+	char *cp = dst;
+
+	for (i = 0; i < srclen; i++) {
+		ac = (ac << 8) | src[i];
+		bits += 8;
+		do {
+			bits -= 6;
+			*cp++ = base64_table[(ac >> bits) & 0x3f];
+		} while (bits >= 6);
+	}
+	if (bits) {
+		*cp++ = base64_table[(ac << (6 - bits)) & 0x3f];
+		bits -= 6;
+	}
+	while (bits < 0) {
+		*cp++ = '=';
+		bits += 2;
+	}
+
+	return cp - dst;
+}
+
+/**
+ * base64_decode() - base64-decode some bytes
+ * @src: the base64-encoded string to decode
+ * @len: number of bytes to decode
+ * @dst: (output) the decoded bytes.
+ *
+ * Decodes the base64-encoded bytes @src according to RFC 4648.
+ *
+ * Return: number of decoded bytes
+ */
+int base64_decode(const char *src, int srclen, unsigned char *dst)
+{
+	u_int32_t ac = 0;
+	int i, bits = 0;
+	unsigned char *bp = dst;
+
+        for (i = 0; i < srclen; i++) {
+                const char *p = strchr(base64_table, src[i]);
+
+                if (src[i] == '=') {
+                        ac = (ac << 6);
+			bits += 6;
+			if (bits >= 8)
+				bits -= 8;
+                        continue;
+                }
+                if (p == NULL || src[i] == 0)
+                        return -EINVAL;
+                ac = (ac << 6) | (p - base64_table);
+                bits += 6;
+                if (bits >= 8) {
+                        bits -= 8;
+                        *bp++ = (unsigned char)(ac >> bits);
+                }
+	}
+	if (ac && ((1 << bits) - 1))
+		return -EAGAIN;
+
+	return bp - dst;
+}