144 lines
4.1 KiB
C++
144 lines
4.1 KiB
C++
/*
|
|
* Base64Encode.cpp
|
|
*
|
|
* This source file is part of the FoundationDB open source project
|
|
*
|
|
* Copyright 2013-2024 Apple Inc. and the FoundationDB project 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
|
|
*
|
|
* 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 "fdbrpc/Base64Encode.h"
|
|
|
|
namespace {
|
|
|
|
// work around GCC bug 87476 (~9.0)
|
|
static const uint8_t urlEncodedTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
|
|
static const uint8_t regularBase64Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
|
|
template <bool UrlEncode>
|
|
uint8_t encodeValue(uint8_t valueIn) noexcept {
|
|
if constexpr (UrlEncode) {
|
|
return urlEncodedTable[valueIn];
|
|
} else {
|
|
return regularBase64Table[valueIn];
|
|
}
|
|
}
|
|
|
|
template <bool UrlEncode>
|
|
int doEncode(const uint8_t* __restrict plaintextIn, int lengthIn, uint8_t* __restrict codeOut) noexcept {
|
|
const uint8_t* plainchar = plaintextIn;
|
|
const uint8_t* const plaintextEnd = plaintextIn + lengthIn;
|
|
uint8_t* codechar = codeOut;
|
|
uint8_t result = 0;
|
|
uint8_t fragment = 0;
|
|
|
|
while (1) {
|
|
if (plainchar == plaintextEnd) {
|
|
return codechar - codeOut;
|
|
}
|
|
// byte 1 of 3
|
|
fragment = *plainchar++;
|
|
result = (fragment & 0x0fc) >> 2;
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
result = (fragment & 0x003) << 4;
|
|
if (plainchar == plaintextEnd) {
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
if constexpr (!UrlEncode) {
|
|
*codechar++ = '=';
|
|
*codechar++ = '=';
|
|
}
|
|
return codechar - codeOut;
|
|
}
|
|
// byte 2 of 3
|
|
fragment = *plainchar++;
|
|
result |= (fragment & 0x0f0) >> 4;
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
result = (fragment & 0x00f) << 2;
|
|
if (plainchar == plaintextEnd) {
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
if constexpr (!UrlEncode) {
|
|
*codechar++ = '=';
|
|
}
|
|
return codechar - codeOut;
|
|
}
|
|
// byte 3 of 3
|
|
fragment = *plainchar++;
|
|
result |= (fragment & 0x0c0) >> 6;
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
result = (fragment & 0x03f) >> 0;
|
|
*codechar++ = encodeValue<UrlEncode>(result);
|
|
}
|
|
/* control should not reach here */
|
|
return codechar - codeOut;
|
|
}
|
|
|
|
template <bool UrlEncode>
|
|
int getEncodedLength(int dataLength) noexcept {
|
|
if constexpr (UrlEncode) {
|
|
auto r = dataLength % 3;
|
|
if (r == 0)
|
|
return (dataLength / 3) * 4;
|
|
else
|
|
return (dataLength / 3) * 4 + r + 1;
|
|
} else {
|
|
// any non-zero remainder after dividing the input length by 3 results in 4 extra output chars due to padding
|
|
return ((dataLength + 2) / 3) * 4;
|
|
}
|
|
}
|
|
|
|
template <bool UrlEncode>
|
|
StringRef doEncodeWithArena(Arena& arena, StringRef plainText) {
|
|
auto encodedLen = getEncodedLength<UrlEncode>(plainText.size());
|
|
if (encodedLen <= 0)
|
|
return StringRef();
|
|
auto out = new (arena) uint8_t[encodedLen];
|
|
auto actualLen = doEncode<UrlEncode>(plainText.begin(), plainText.size(), out);
|
|
ASSERT_EQ(encodedLen, actualLen);
|
|
return StringRef(out, encodedLen);
|
|
}
|
|
|
|
} // anonymous namespace
|
|
|
|
namespace base64 {
|
|
|
|
int encode(const uint8_t* __restrict plaintextIn, int lengthIn, uint8_t* __restrict codeOut) noexcept {
|
|
return doEncode<false>(plaintextIn, lengthIn, codeOut);
|
|
}
|
|
|
|
int encodedLength(int dataLength) noexcept {
|
|
return getEncodedLength<false>(dataLength);
|
|
}
|
|
|
|
StringRef encode(Arena& arena, StringRef plainText) {
|
|
return doEncodeWithArena<false>(arena, plainText);
|
|
}
|
|
|
|
namespace url {
|
|
|
|
int encode(const uint8_t* __restrict plaintextIn, int lengthIn, uint8_t* __restrict codeOut) noexcept {
|
|
return doEncode<true>(plaintextIn, lengthIn, codeOut);
|
|
}
|
|
|
|
int encodedLength(int dataLength) noexcept {
|
|
return getEncodedLength<true>(dataLength);
|
|
}
|
|
|
|
StringRef encode(Arena& arena, StringRef plainText) {
|
|
return doEncodeWithArena<true>(arena, plainText);
|
|
}
|
|
|
|
} // namespace url
|
|
|
|
} // namespace base64
|