Fixed inverted logic in base64 encode/decode (aws#126)

* Fixed inverted logic in base64 encode/decode

* Added base64 unit test, fixed Base64Encode

Author: Justin Boswell

source/Types.cpp

@@ -65,7 +65,7 @@ namespace Aws
                 ByteBuf tempBuf = aws_byte_buf_from_array(output.data(), output.size());
                 tempBuf.len = 0;
 
-                if (aws_base64_decode(&toDecode, &tempBuf))
+                if (aws_base64_decode(&toDecode, &tempBuf) == AWS_OP_SUCCESS)
                 {
                     return output;
                 }
@@ -86,8 +86,14 @@ namespace Aws
                 ByteBuf tempBuf = aws_byte_buf_from_array(output.data(), output.size());
                 tempBuf.len = 0;
 
-                if (aws_base64_encode(&toEncode, &tempBuf))
+                if (aws_base64_encode(&toEncode, &tempBuf) == AWS_OP_SUCCESS)
                 {
+                    // encoding appends a null terminator, and accounts for it in the encoded length,
+                    // which makes the string 1 character too long
+                    if (output.back() == 0)
+                    {
+                        output.pop_back();
+                    }
                     return output;
                 }
             }

tests/CMakeLists.txt

@@ -12,6 +12,7 @@ add_test_case(EventLoopResourceSafety)
 add_net_test_case(MqttClientResourceSafety)
 add_test_case(ClientBootstrapResourceSafety)
 add_net_test_case(TLSContextResourceSafety)
+add_test_case(Base64RoundTrip)
 add_test_case(DateTimeBinding)
 add_test_case(BasicJsonParsing)
 add_test_case(JsonNullParsing)

tests/TypesTest.cpp

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+#include <aws/crt/Api.h>
+#include <aws/crt/Types.h>
+#include <aws/testing/aws_test_harness.h>
+
+static int s_base64_round_trip(struct aws_allocator *allocator, void *ctx)
+{
+    (void)ctx;
+    Aws::Crt::ApiHandle apiHandle(allocator);
+
+    {
+        Aws::Crt::String test_data = "foobar";
+        Aws::Crt::String expected = "Zm9vYmFy";
+
+        const Aws::Crt::Vector<uint8_t> test_vector(test_data.begin(), test_data.end());
+        const Aws::Crt::Vector<uint8_t> expected_vector(expected.begin(), expected.end());
+
+        Aws::Crt::String encoded = Aws::Crt::Base64Encode(test_vector);
+        ASSERT_BIN_ARRAYS_EQUALS(expected.data(), expected.size(), encoded.data(), encoded.size());
+
+        Aws::Crt::Vector<uint8_t> decoded = Aws::Crt::Base64Decode(encoded);
+        ASSERT_BIN_ARRAYS_EQUALS(test_vector.data(), test_vector.size(), decoded.data(), decoded.size());
+    }
+
+    return 0;
+}
+
+AWS_TEST_CASE(Base64RoundTrip, s_base64_round_trip)