C bindings for base64 functions

include/olm/base64.h

+/* Copyright 2015, 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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.
+ */
+
+/* C bindings for base64 functions */
+
+
+#ifndef OLM_BASE64_H_
+#define OLM_BASE64_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/**
+ * The number of bytes of unpadded base64 needed to encode a length of input.
+ */
+size_t olm_encode_base64_length(
+    size_t input_length
+);
+
+/**
+ * Encode the raw input as unpadded base64.
+ * Writes encode_base64_length(input_length) bytes to the output buffer.
+ * The input can overlap with the last three quarters of the output buffer.
+ * That is, the input pointer may be output + output_length - input_length.
+ *
+ * Returns number of bytes encoded
+ */
+size_t olm_encode_base64(
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+);
+
+/**
+ * The number of bytes of raw data a length of unpadded base64 will encode to.
+ * Returns size_t(-1) if the length is not a valid length for base64.
+ */
+size_t olm_decode_base64_length(
+    size_t input_length
+);
+
+/**
+ * Decodes the unpadded base64 input to raw bytes.
+ * Writes decode_base64_length(input_length) bytes to the output buffer.
+ * The output can overlap with the first three quarters of the input buffer.
+ * That is, the input pointers and output pointer may be the same.
+ *
+ * Returns number of bytes decoded
+ */
+size_t olm_decode_base64(
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+);
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif /* OLM_BASE64_H_ */

src/base64.cpp

@@ -12,9 +12,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#include "olm/base64.h"
 #include "olm/base64.hh"
 
-
 namespace {
 
 static const std::uint8_t ENCODE_BASE64[64] = {
@@ -134,3 +134,34 @@ std::uint8_t const * olm::decode_base64(
     }
     return input + input_length;
 }
+
+
+// implementations of base64.h
+
+size_t olm_encode_base64_length(
+    size_t input_length
+) {
+    return olm::encode_base64_length(input_length);
+}
+
+size_t olm_encode_base64(
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+) {
+    uint8_t * r = olm::encode_base64(input, input_length, output);
+    return r - output;
+}
+
+size_t olm_decode_base64_length(
+    size_t input_length
+) {
+    return olm::decode_base64_length(input_length);
+}
+
+size_t olm_decode_base64(
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+) {
+    olm::decode_base64(input, input_length, output);
+    return olm::decode_base64_length(input_length);
+}

tests/test_base64.cpp

 #include "olm/base64.hh"
+#include "olm/base64.h"
 #include "unittest.hh"
 
 int main() {
 
 { /* Base64 encode test */
-TestCase test_case("Base64 encode test");
+TestCase test_case("Base64 C++ binding encode test");
 
 std::uint8_t input[] = "Hello World";
 std::uint8_t expected_output[] = "SGVsbG8gV29ybGQ";
@@ -18,8 +19,24 @@ olm::encode_base64(input, input_length, output);
 assert_equals(expected_output, output, output_length);
 }
 
+{
+TestCase test_case("Base64 C binding encode test");
+
+std::uint8_t input[] = "Hello World";
+std::uint8_t expected_output[] = "SGVsbG8gV29ybGQ";
+std::size_t input_length = sizeof(input) - 1;
+
+std::size_t output_length = ::olm_encode_base64_length(input_length);
+assert_equals(std::size_t(15), output_length);
+
+std::uint8_t output[output_length];
+output_length = ::olm_encode_base64(input, input_length, output);
+assert_equals(std::size_t(15), output_length);
+assert_equals(expected_output, output, output_length);
+}
+
 { /* Base64 decode test */
-TestCase test_case("Base64 decode test");
+TestCase test_case("Base64 C++ binding decode test");
 
 std::uint8_t input[] = "SGVsbG8gV29ybGQ";
 std::uint8_t expected_output[] = "Hello World";
@@ -33,4 +50,21 @@ olm::decode_base64(input, input_length, output);
 assert_equals(expected_output, output, output_length);
 }
 
+{
+TestCase test_case("Base64 C binding decode test");
+
+std::uint8_t input[] = "SGVsbG8gV29ybGQ";
+std::uint8_t expected_output[] = "Hello World";
+std::size_t input_length = sizeof(input) - 1;
+
+std::size_t output_length = ::olm_decode_base64_length(input_length);
+assert_equals(std::size_t(11), output_length);
+
+std::uint8_t output[output_length];
+output_length = ::olm_decode_base64(input, input_length, output);
+assert_equals(std::size_t(11), output_length);
+assert_equals(expected_output, output, output_length);
+}
+
+
 }