mirror of
https://github.com/Ryujinx/Ryujinx.git
synced 2024-12-24 23:26:02 +00:00
152 lines
4.3 KiB
C#
152 lines
4.3 KiB
C#
using System;
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using System.Threading;
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namespace Ryujinx.Memory.Tracking
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{
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/// <summary>
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/// A bitmap that can be safely modified from multiple threads.
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/// </summary>
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internal class ConcurrentBitmap
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{
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public const int IntSize = 64;
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public const int IntShift = 6;
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public const int IntMask = IntSize - 1;
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/// <summary>
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/// Masks representing the bitmap. Least significant bit first, 64-bits per mask.
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/// </summary>
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public readonly long[] Masks;
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/// <summary>
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/// Create a new multithreaded bitmap.
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/// </summary>
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/// <param name="count">The number of bits to reserve</param>
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/// <param name="set">Whether the bits should be initially set or not</param>
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public ConcurrentBitmap(int count, bool set)
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{
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Masks = new long[(count + IntMask) / IntSize];
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if (set)
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{
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Array.Fill(Masks, -1L);
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}
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}
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/// <summary>
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/// Check if any bit in the bitmap is set.
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/// </summary>
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/// <returns>True if any bits are set, false otherwise</returns>
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public bool AnySet()
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{
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for (int i = 0; i < Masks.Length; i++)
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{
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if (Interlocked.Read(ref Masks[i]) != 0)
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{
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return true;
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}
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}
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return false;
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}
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/// <summary>
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/// Check if a bit in the bitmap is set.
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/// </summary>
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/// <param name="bit">The bit index to check</param>
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/// <returns>True if the bit is set, false otherwise</returns>
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public bool IsSet(int bit)
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{
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int wordIndex = bit >> IntShift;
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int wordBit = bit & IntMask;
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long wordMask = 1L << wordBit;
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return (Interlocked.Read(ref Masks[wordIndex]) & wordMask) != 0;
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}
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/// <summary>
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/// Check if any bit in a range of bits in the bitmap are set. (inclusive)
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/// </summary>
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/// <param name="start">The first bit index to check</param>
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/// <param name="end">The last bit index to check</param>
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/// <returns>True if a bit is set, false otherwise</returns>
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public bool IsSet(int start, int end)
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{
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if (start == end)
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{
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return IsSet(start);
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}
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int startIndex = start >> IntShift;
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int startBit = start & IntMask;
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long startMask = -1L << startBit;
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int endIndex = end >> IntShift;
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int endBit = end & IntMask;
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long endMask = (long)(ulong.MaxValue >> (IntMask - endBit));
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long startValue = Interlocked.Read(ref Masks[startIndex]);
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if (startIndex == endIndex)
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{
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return (startValue & startMask & endMask) != 0;
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}
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if ((startValue & startMask) != 0)
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{
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return true;
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}
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for (int i = startIndex + 1; i < endIndex; i++)
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{
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if (Interlocked.Read(ref Masks[i]) != 0)
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{
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return true;
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}
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}
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long endValue = Interlocked.Read(ref Masks[endIndex]);
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if ((endValue & endMask) != 0)
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{
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return true;
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}
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return false;
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}
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/// <summary>
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/// Set a bit at a specific index to either true or false.
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/// </summary>
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/// <param name="bit">The bit index to set</param>
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/// <param name="value">Whether the bit should be set or not</param>
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public void Set(int bit, bool value)
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{
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int wordIndex = bit >> IntShift;
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int wordBit = bit & IntMask;
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long wordMask = 1L << wordBit;
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if (value)
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{
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Interlocked.Or(ref Masks[wordIndex], wordMask);
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}
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else
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{
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Interlocked.And(ref Masks[wordIndex], ~wordMask);
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}
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}
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/// <summary>
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/// Clear the bitmap entirely, setting all bits to 0.
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/// </summary>
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public void Clear()
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{
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for (int i = 0; i < Masks.Length; i++)
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{
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Interlocked.Exchange(ref Masks[i], 0);
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}
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}
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}
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}
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