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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/base64.h"
#include <stddef.h>
#include "base/check.h"
#include "base/numerics/checked_math.h"
#include "third_party/modp_b64/modp_b64.h"
namespace base {
std::string Base64Encode(span<const uint8_t> input) {
std::string output;
Base64EncodeAppend(input, &output);
return output;
}
void Base64EncodeAppend(span<const uint8_t> input, std::string* output) {
// Ensure `modp_b64_encode_len` will not overflow. Note this length and
// `modp_b64_encode`'s output includes a trailing NUL byte.
CHECK_LE(input.size(), MODP_B64_MAX_INPUT_LEN);
size_t encode_len = modp_b64_encode_len(input.size());
size_t prefix_len = output->size();
output->resize(base::CheckAdd(encode_len, prefix_len).ValueOrDie());
const size_t output_size = modp_b64_encode(
output->data() + prefix_len, reinterpret_cast<const char*>(input.data()),
input.size());
// `output_size` does not include the trailing NUL byte, so this removes it.
output->resize(prefix_len + output_size);
}
void Base64Encode(StringPiece input, std::string* output) {
*output = Base64Encode(base::as_bytes(base::make_span(input)));
}
bool Base64Decode(StringPiece input, std::string* output) {
std::string temp;
temp.resize(modp_b64_decode_len(input.size()));
// does not null terminate result since result is binary data!
size_t input_size = input.size();
size_t output_size = modp_b64_decode(&(temp[0]), input.data(), input_size);
if (output_size == MODP_B64_ERROR)
return false;
temp.resize(output_size);
output->swap(temp);
return true;
}
absl::optional<std::vector<uint8_t>> Base64Decode(StringPiece input) {
std::vector<uint8_t> ret(modp_b64_decode_len(input.size()));
size_t input_size = input.size();
size_t output_size = modp_b64_decode(reinterpret_cast<char*>(ret.data()),
input.data(), input_size);
if (output_size == MODP_B64_ERROR)
return absl::nullopt;
ret.resize(output_size);
return ret;
}
} // namespace base
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