Implement URL safe base64 coding, as specified by RFC 4648.

1 files changed, 48 insertions, 0 deletions

diff --git a/base64url-encode.c b/base64url-encode.c
new file mode 100644
index 00000000..6af33fb8
--- /dev/null
+++ b/base64url-encode.c
@@ -0,0 +1,48 @@
+/* base64url-encode.c
+
+   Copyright (C) 2015 Amos Jeffries, Niels Möller
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * 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.
+
+   or both in parallel, as here.
+
+   GNU Nettle 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "base64.h"
+
+void
+base64url_encode_init(struct base64_encode_ctx *ctx)
+{
+  static const uint8_t base64url_encode_table[64] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "abcdefghijklmnopqrstuvwxyz"
+    "0123456789-_";
+
+  ctx->word = ctx->bits = 0;
+  ctx->alphabet = base64url_encode_table;
+}