Adds base64 support via mbedtls

This is inspered in the work done at: #1123

src/utils/base64.cc

@@ -0,0 +1,80 @@
+/*
+ * ModSecurity, http://www.modsecurity.org/
+ * Copyright (c) 2015 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+ *
+ * You may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * If any of the files related to licensing are missing or if you have any
+ * other questions related to licensing please contact Trustwave Holdings, Inc.
+ * directly using the email address security@modsecurity.org.
+ *
+ */
+
+#include <string>
+#include <fstream>
+#include <iostream>
+
+#include "utils/base64.h"
+#include "mbedtls/base64.h"
+#include <string.h>
+
+namespace modsecurity {
+namespace Utils {
+
+
+std::string Base64::encode(std::string& data) {
+    size_t encoded_len = 0;
+    unsigned char *d = NULL;
+    std::string ret;
+
+    mbedtls_base64_encode(NULL, 0, &encoded_len,
+        reinterpret_cast<const unsigned char*>(data.c_str()), data.size());
+
+    d = reinterpret_cast<unsigned char*>(malloc(sizeof(char) * encoded_len));
+    if (d == NULL) {
+        return data;
+    }
+
+    memset(d, '\0', encoded_len);
+
+    mbedtls_base64_encode(d, encoded_len, &encoded_len,
+        (unsigned char*) data.c_str(), data.size());
+
+    ret.assign(reinterpret_cast<const char*>(d));
+    free(d);
+
+
+    return std::string(reinterpret_cast<const char*>(d));
+}
+
+
+std::string Base64::decode(std::string& data) {
+    size_t decoded_len = 0;
+    unsigned char *d = NULL;
+    std::string ret;
+
+    mbedtls_base64_decode(NULL, 0, &decoded_len,
+        reinterpret_cast<const unsigned char*>(data.c_str()), data.length());
+
+    d = reinterpret_cast<unsigned char*>(malloc(sizeof(char) * decoded_len));
+    if (d == NULL) {
+        return data;
+    }
+
+    memset(d, '\0', decoded_len);
+
+    mbedtls_base64_decode(d, decoded_len, &decoded_len,
+       reinterpret_cast<const unsigned char*>(data.c_str()), data.length());
+
+    ret.assign(reinterpret_cast<const char*>(d));
+    free(d);
+
+    return ret;
+}
+
+
+}  // namespace Utils
+}  // namespace modsecurity