alexpete
100 lines
4.0 KiB
C++
100 lines
4.0 KiB
C++
/*
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* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
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* its licensors.
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*
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* For complete copyright and license terms please see the LICENSE at the root of this
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* distribution (the "License"). All use of this software is governed by the License,
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* or, if provided, by the license below or the license accompanying this file. Do not
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* remove or modify any license notices. This file 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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*
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*/
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#pragma once
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#include <AzCore/Math/MathUtils.h>
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#include <AzCore/std/containers/array.h>
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#include <AzCore/RTTI/TypeSafeIntegral.h>
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namespace AzNetworking
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{
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using BitsetChunk = uint32_t;
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//! @class RingBufferBitset
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//! @brief fixed size data structure optimized for storing and rotating large numbers of bits.
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template <uint32_t SIZE>
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class RingbufferBitset
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{
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public:
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static constexpr uint32_t NumBitsetChunkedBits = AZ::Log2(BitsetChunk(~0));
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static constexpr uint32_t RingbufferContainerSize = SIZE / NumBitsetChunkedBits;
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static_assert((SIZE % NumBitsetChunkedBits) == 0, "RingbufferBitset must be a multiple of NumBitsetChunkedBits");
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using RingbufferContainer = AZStd::array<BitsetChunk, RingbufferContainerSize>;
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RingbufferBitset();
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~RingbufferBitset() = default;
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//! Resets the bitset to all empty.
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void Reset();
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//! Gets the current value of the specified bit.
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//! @param index index of the bit to retrieve the value of
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//! @return boolean true if the bit is set, false otherwise
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bool GetBit(uint32_t index) const;
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//! Sets the specified bit to the provided value.
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//! @param index index of the bit to set
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//! @param value value to set the bit to
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void SetBit(uint32_t index, bool value);
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//! Returns the number of accessible bits in this ringbuffer bitset.
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//! @return the number of accessible bits in this ringbuffer bitset
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uint32_t GetValidBitCount() const;
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//! Pushes back the specified number of bits padding with zero bits.
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//! @param numBits the number of bits to push into the bitset
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void PushBackBits(uint32_t numBits);
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//! Retrieves a single element from the ringbuffer bitset.
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//! @param elementIndex the index of the ringbuffer element to retrieve
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//! @return the requested bitset element
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const BitsetChunk& GetBitsetElement(uint32_t elementIndex) const;
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//! Returns the number of bits that are unused in the head element.
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//! @return the number of bits that are unused in the head element
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uint32_t GetUnusedHeadBits() const;
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private:
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//! Converts the provided absolute index into a internal ring buffer element index.
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//! @param absoluteIndex the absolute index value to convert to a ring-buffer index
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//! @return the converted ring-buffer index
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uint32_t GetChunkIndexHelper(uint32_t absoluteIndex) const;
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//! Increments the internal head index.
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void IncrementHead();
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uint32_t m_headElementOffset = 0; //< What index is the first element in our ring buffer
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uint32_t m_unusedHeadBits = NumBitsetChunkedBits; //< How many bits are unused in the head RingbufferContainer element
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RingbufferContainer m_container;
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};
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//! Helper method for extracting a bit from a specific element.
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//! @param element the specific element to get the bit from
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//! @param bitIndex the index of the bit to retrieve
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//! @return boolean true if the bit is set, false otherwise
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template <typename TYPE>
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bool GetBitHelper(TYPE element, uint32_t bitIndex);
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//! A helper method for setting bits.
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//! @param element the specific element to set the bit within
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//! @param bitIndex the index of the bit to set
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//! @param value the value to set the bit to
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template <typename TYPE>
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void SetBitHelper(TYPE &element, uint32_t bitIndex, bool value);
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}
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#include <AzNetworking/DataStructures/RingBufferBitset.inl>
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