// Copyright 2020 The Pigweed Authors

//

// 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

//

//     https://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.

#include "pw_tokenizer/base64.h"

namespace pw::tokenizer {

extern "C" size_t pw_tokenizer_PrefixedBase64Encode(

    const void* binary_message,

    size_t binary_size_bytes,

    void* output_buffer,

    size_t output_buffer_size_bytes) {

  char* output = static_cast<char*>(output_buffer);

  const size_t encoded_size = Base64EncodedBufferSize(binary_size_bytes);

  if (output_buffer_size_bytes < encoded_size) {

    if (output_buffer_size_bytes > 0u) {

      output[0] = '\0';

    }

    return 0;

  }

  output[0] = PW_TOKENIZER_NESTED_PREFIX;

  base64::Encode(

      span(static_cast<const std::byte*>(binary_message), binary_size_bytes),

      &output[1]);

  output[encoded_size - 1] = '\0';

  return encoded_size - sizeof('\0');  // exclude the null terminator

}

void PrefixedBase64Encode(span<const std::byte> binary_message,

                          InlineString<>& output) {

  output.push_back(PW_TOKENIZER_NESTED_PREFIX);

  base64::Encode(binary_message, output);

}

extern "C" size_t pw_tokenizer_PrefixedBase64Decode(const void* base64_message,

                                                    size_t base64_size_bytes,

                                                    void* output_buffer,

                                                    size_t output_buffer_size) {

  const char* base64 = static_cast<const char*>(base64_message);

  if (base64_size_bytes == 0 || base64[0] != PW_TOKENIZER_NESTED_PREFIX) {

    return 0;

  }

  return base64::Decode(

      std::string_view(&base64[1], base64_size_bytes - 1),

      span(static_cast<std::byte*>(output_buffer), output_buffer_size));

}

}  // namespace pw::tokenizer