Files
doris/be/src/util/coding.cpp
2019-06-09 15:55:46 +08:00

94 lines
3.0 KiB
C++

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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.
//
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/coding.h"
namespace doris {
uint8_t* encode_varint32(uint8_t* dst, uint32_t v) {
// Operate on characters as unsigneds
static const int B = 128;
if (v < (1 << 7)) {
*(dst++) = v;
} else if (v < (1 << 14)) {
*(dst++) = v | B;
*(dst++) = v >> 7;
} else if (v < (1 << 21)) {
*(dst++) = v | B;
*(dst++) = (v >> 7) | B;
*(dst++) = v >> 14;
} else if (v < (1 << 28)) {
*(dst++) = v | B;
*(dst++) = (v >> 7) | B;
*(dst++) = (v >> 14) | B;
*(dst++) = v >> 21;
} else {
*(dst++) = v | B;
*(dst++) = (v >> 7) | B;
*(dst++) = (v >> 14) | B;
*(dst++) = (v >> 21) | B;
*(dst++) = v >> 28;
}
return dst;
}
const uint8_t* decode_varint32_ptr_fallback(const uint8_t* p, const uint8_t* limit,
uint32_t* value) {
uint32_t result = 0;
for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
uint32_t byte = *p;
p++;
if (byte & 128) {
// More bytes are present
result |= ((byte & 127) << shift);
} else {
result |= (byte << shift);
*value = result;
return p;
}
}
return nullptr;
}
const uint8_t* decode_varint64_ptr(const uint8_t* p, const uint8_t* limit, uint64_t* value) {
uint64_t result = 0;
for (uint32_t shift = 0; shift <= 63 && p < limit; shift += 7) {
uint64_t byte = *p;
p++;
if (byte & 128) {
// More bytes are present
result |= ((byte & 127) << shift);
} else {
result |= (byte << shift);
*value = result;
return p;
}
}
return nullptr;
}
}