82 lines
2.3 KiB
C++
82 lines
2.3 KiB
C++
/*
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* SPDX-FileCopyrightText: Copyright (c) 2020, 2021, 2022 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
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* SPDX-FileCopyrightText: Copyright (c) Microsoft Corportaion. All rights reserved.
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <stdint.h>
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#include <algorithm>
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#include <atomic>
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#include <chrono>
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#include <cstring>
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#include <limits>
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namespace GDeflate
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{
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template<int N, typename T>
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static inline T _align(T a)
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{
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return (a + T(N) - 1) & ~(T(N) - 1);
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}
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template<typename T>
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static inline T _divRoundup(T a, T b)
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{
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return (a + b - 1) / b;
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}
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template<typename T>
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static inline uint32_t _lzCount(T a)
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{
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uint32_t n = 0;
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while (0 == (a & 1) && n < sizeof(T) * 8)
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{
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a >>= 1;
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++n;
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}
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return n;
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}
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template<typename T>
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static inline T GetBits(uint32_t*& in, uint32_t& offset, uint32_t numBitsToRead)
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{
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constexpr uint32_t kBitsPerBucket = sizeof(*in) * 8;
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T bits = 0;
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uint32_t numBitsConsumed = 0;
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while (numBitsConsumed < numBitsToRead)
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{
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const uint32_t numBits =
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std::min(numBitsToRead - numBitsConsumed, kBitsPerBucket - (offset % kBitsPerBucket));
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const T mask = std::numeric_limits<T>().max() >> (sizeof(T) * 8 - numBits);
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bits |= (T(*in >> (offset % kBitsPerBucket)) & mask) << numBitsConsumed;
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offset += numBits;
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numBitsConsumed += numBits;
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if (0 == offset % kBitsPerBucket)
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in++;
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}
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return bits;
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}
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} // namespace GDeflate
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