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