1 files changed, 63 insertions, 0 deletions
diff --git a/lib/base64.cc b/lib/base64.cc
new file mode 100644
index 0000000..2492526
--- /dev/null
+++ b/lib/base64.cc
@@ -0,0 +1,63 @@
+// nullmailer -- a simple relay-only MTA
+// Copyright (C) 2017  Bruce Guenter <bruce@untroubled.org>
+//
+// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+// You can contact me at <bruce@untroubled.org>.  There is also a mailing list
+// available to discuss this package.  To subscribe, send an email to
+// <nullmailer-subscribe@lists.untroubled.org>.
+
+#include "base64.h"
+
+static char basis[] =
+   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+void base64_encode(const mystring& in, mystring& out)
+{
+  size_t length;
+  const unsigned char* ptr;
+  char buf[4];
+  for (length = in.length(), ptr = (const unsigned char*)in.c_str();
+       length >= 3;
+       length -= 3, ptr += 3) {
+    base64_encode_chunk(ptr, 3, buf);
+    out.append(buf, 4);
+  }
+  if (length > 0) {
+    base64_encode_chunk(ptr, length, buf);
+    out.append(buf, 4);
+  }
+}
+
+void base64_encode_chunk(const unsigned char bin[3], unsigned len,
+			 char encoded[4])
+{
+  encoded[0] = basis[bin[0] >> 2];
+  switch(len) {
+  case 1:
+    encoded[1] = basis[(bin[0] << 4) & 0x3f];
+    encoded[2] = encoded[3] = '=';
+    break;
+  case 2:
+    encoded[1] = basis[(bin[0] << 4 | bin[1] >> 4) & 0x3f];
+    encoded[2] = basis[(bin[1] << 2) & 0x3f];
+    encoded[3] = '=';
+    break;
+  case 3:
+    encoded[1] = basis[(bin[0] << 4 | bin[1] >> 4) & 0x3f];
+    encoded[2] = basis[(bin[1] << 2 | bin[2] >> 6) & 0x3f];
+    encoded[3] = basis[bin[2] & 0x3f];
+  }
+}