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/*
* Copyright (C) 2020 The Android Open Source Project
*
* 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.
*/
#include "common/libs/utils/base64.h"
#include <cstddef>
#include <cstdint>
#include <optional>
#include <string>
#include <vector>
#include <openssl/evp.h>
namespace cuttlefish {
namespace {
// EVP_EncodedLength is boringssl specific so it can't be used outside of
// android.
std::optional<size_t> EncodedLength(size_t len) {
if (len + 2 < len) {
return std::nullopt;
}
len += 2;
len /= 3;
if (((len << 2) >> 2) != len) {
return std::nullopt;
}
len <<= 2;
if (len + 1 < len) {
return std::nullopt;
}
len++;
return {len};
}
// EVP_DecodedLength is boringssl specific so it can't be used outside of
// android.
std::optional<size_t> DecodedLength(size_t len) {
if (len % 4 != 0) {
return std::nullopt;
}
return {(len / 4) * 3};
}
} // namespace
bool EncodeBase64(const void *data, std::size_t size, std::string *out) {
auto len_res = EncodedLength(size);
if (!len_res) {
return false;
}
out->resize(*len_res);
auto enc_res =
EVP_EncodeBlock(reinterpret_cast<std::uint8_t *>(out->data()),
reinterpret_cast<const std::uint8_t *>(data), size);
if (enc_res < 0) {
return false;
}
out->resize(enc_res); // Don't count the terminating \0 character
return true;
}
bool DecodeBase64(const std::string &data, std::vector<std::uint8_t> *buffer) {
auto len_res = DecodedLength(data.size());
if (!len_res) {
return false;
}
auto out_len = *len_res;
buffer->resize(out_len);
auto actual_len = EVP_DecodeBlock(buffer->data(),
reinterpret_cast<const uint8_t *>(data.data()),
data.size());
if (actual_len < 0) {
return false;
}
// DecodeBlock leaves null characters at the end of the buffer when the
// decoded message is not a multiple of 3.
while (!buffer->empty() && buffer->back() == '\0') {
buffer->pop_back();
}
return true;
}
} // namespace cuttlefish
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