Firstborn/Library/PackageCache/com.unity.collections@1.4.0/Unity.Collections/UnsafeBitArray.cs

680 lines
26 KiB
C#
Raw Normal View History

2023-03-28 13:24:16 -04:00
using System;
using System.Diagnostics;
using Unity.Jobs;
using Unity.Mathematics;
namespace Unity.Collections.LowLevel.Unsafe
{
/// <summary>
/// An arbitrarily-sized array of bits.
/// </summary>
/// <remarks>
/// The number of allocated bytes is always a multiple of 8. For example, a 65-bit array could fit in 9 bytes, but its allocation is actually 16 bytes.
/// </remarks>
[DebuggerDisplay("Length = {Length}, IsCreated = {IsCreated}")]
[DebuggerTypeProxy(typeof(UnsafeBitArrayDebugView))]
[BurstCompatible]
public unsafe struct UnsafeBitArray
: INativeDisposable
{
/// <summary>
/// Pointer to the data.
/// </summary>
/// <value>Pointer to the data.</value>
[NativeDisableUnsafePtrRestriction]
public ulong* Ptr;
/// <summary>
/// The number of bits.
/// </summary>
/// <value>The number of bits.</value>
public int Length;
/// <summary>
/// The allocator to use.
/// </summary>
/// <value>The allocator to use.</value>
public AllocatorManager.AllocatorHandle Allocator;
/// <summary>
/// Initializes and returns an instance of UnsafeBitArray which aliases an existing buffer.
/// </summary>
/// <param name="ptr">An existing buffer.</param>
/// <param name="allocator">The allocator that was used to allocate the bytes. Needed to dispose this array.</param>
/// <param name="sizeInBytes">The number of bytes. The length will be `sizeInBytes * 8`.</param>
public unsafe UnsafeBitArray(void* ptr, int sizeInBytes, AllocatorManager.AllocatorHandle allocator = new AllocatorManager.AllocatorHandle())
{
CheckSizeMultipleOf8(sizeInBytes);
Ptr = (ulong*)ptr;
Length = sizeInBytes * 8;
Allocator = allocator;
}
/// <summary>
/// Initializes and returns an instance of UnsafeBitArray.
/// </summary>
/// <param name="numBits">Number of bits.</param>
/// <param name="allocator">The allocator to use.</param>
/// <param name="options">Whether newly allocated bytes should be zeroed out.</param>
public UnsafeBitArray(int numBits, AllocatorManager.AllocatorHandle allocator, NativeArrayOptions options = NativeArrayOptions.ClearMemory)
{
CollectionHelper.CheckAllocator(allocator);
Allocator = allocator;
var sizeInBytes = Bitwise.AlignUp(numBits, 64) / 8;
Ptr = (ulong*)Memory.Unmanaged.Allocate(sizeInBytes, 16, allocator);
Length = numBits;
if (options == NativeArrayOptions.ClearMemory)
{
UnsafeUtility.MemClear(Ptr, sizeInBytes);
}
}
/// <summary>
/// Whether this array has been allocated (and not yet deallocated).
/// </summary>
/// <value>True if this array has been allocated (and not yet deallocated).</value>
public bool IsCreated => Ptr != null;
/// <summary>
/// Releases all resources (memory and safety handles).
/// </summary>
public void Dispose()
{
if (CollectionHelper.ShouldDeallocate(Allocator))
{
Memory.Unmanaged.Free(Ptr, Allocator);
Allocator = AllocatorManager.Invalid;
}
Ptr = null;
Length = 0;
}
/// <summary>
/// Creates and schedules a job that will dispose this array.
/// </summary>
/// <param name="inputDeps">The handle of a job which the new job will depend upon.</param>
/// <returns>The handle of a new job that will dispose this array. The new job depends upon inputDeps.</returns>
[NotBurstCompatible /* This is not burst compatible because of IJob's use of a static IntPtr. Should switch to IJobBurstSchedulable in the future */]
public JobHandle Dispose(JobHandle inputDeps)
{
if (CollectionHelper.ShouldDeallocate(Allocator))
{
var jobHandle = new UnsafeDisposeJob { Ptr = Ptr, Allocator = Allocator }.Schedule(inputDeps);
Ptr = null;
Allocator = AllocatorManager.Invalid;
return jobHandle;
}
Ptr = null;
return inputDeps;
}
/// <summary>
/// Sets all the bits to 0.
/// </summary>
public void Clear()
{
var sizeInBytes = Bitwise.AlignUp(Length, 64) / 8;
UnsafeUtility.MemClear(Ptr, sizeInBytes);
}
/// <summary>
/// Sets the bit at an index to 0 or 1.
/// </summary>
/// <param name="pos">Index of the bit to set.</param>
/// <param name="value">True for 1, false for 0.</param>
public void Set(int pos, bool value)
{
CheckArgs(pos, 1);
var idx = pos >> 6;
var shift = pos & 0x3f;
var mask = 1ul << shift;
var bits = (Ptr[idx] & ~mask) | ((ulong)-Bitwise.FromBool(value) & mask);
Ptr[idx] = bits;
}
/// <summary>
/// Sets a range of bits to 0 or 1.
/// </summary>
/// <remarks>
/// The range runs from index `pos` up to (but not including) `pos + numBits`.
/// No exception is thrown if `pos + numBits` exceeds the length.
/// </remarks>
/// <param name="pos">Index of the first bit to set.</param>
/// <param name="value">True for 1, false for 0.</param>
/// <param name="numBits">Number of bits to set.</param>
/// <exception cref="ArgumentException">Thrown if pos is out of bounds or if numBits is less than 1.</exception>
public void SetBits(int pos, bool value, int numBits)
{
CheckArgs(pos, numBits);
var end = math.min(pos + numBits, Length);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful << shiftB;
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
var orBits = (ulong)-Bitwise.FromBool(value);
var orBitsB = maskB & orBits;
var orBitsE = maskE & orBits;
var cmaskB = ~maskB;
var cmaskE = ~maskE;
if (idxB == idxE)
{
var maskBE = maskB & maskE;
var cmaskBE = ~maskBE;
var orBitsBE = orBitsB & orBitsE;
Ptr[idxB] = (Ptr[idxB] & cmaskBE) | orBitsBE;
return;
}
Ptr[idxB] = (Ptr[idxB] & cmaskB) | orBitsB;
for (var idx = idxB + 1; idx < idxE; ++idx)
{
Ptr[idx] = orBits;
}
Ptr[idxE] = (Ptr[idxE] & cmaskE) | orBitsE;
}
/// <summary>
/// Copies bits of a ulong to bits in this array.
/// </summary>
/// <remarks>
/// The destination bits in this array run from index `pos` up to (but not including) `pos + numBits`.
/// No exception is thrown if `pos + numBits` exceeds the length.
///
/// The lowest bit of the ulong is copied to the first destination bit; the second-lowest bit of the ulong is
/// copied to the second destination bit; and so forth.
/// </remarks>
/// <param name="pos">Index of the first bit to set.</param>
/// <param name="value">Unsigned long from which to copy bits.</param>
/// <param name="numBits">Number of bits to set (must be between 1 and 64).</param>
/// <exception cref="ArgumentException">Thrown if pos is out of bounds or if numBits is not between 1 and 64.</exception>
public void SetBits(int pos, ulong value, int numBits = 1)
{
CheckArgsUlong(pos, numBits);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
if (shiftB + numBits <= 64)
{
var mask = 0xfffffffffffffffful >> (64 - numBits);
Ptr[idxB] = Bitwise.ReplaceBits(Ptr[idxB], shiftB, mask, value);
return;
}
var end = math.min(pos + numBits, Length);
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful >> shiftB;
Ptr[idxB] = Bitwise.ReplaceBits(Ptr[idxB], shiftB, maskB, value);
var valueE = value >> (64 - shiftB);
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
Ptr[idxE] = Bitwise.ReplaceBits(Ptr[idxE], 0, maskE, valueE);
}
/// <summary>
/// Returns a ulong which has bits copied from this array.
/// </summary>
/// <remarks>
/// The source bits in this array run from index `pos` up to (but not including) `pos + numBits`.
/// No exception is thrown if `pos + numBits` exceeds the length.
///
/// The first source bit is copied to the lowest bit of the ulong; the second source bit is copied to the second-lowest bit of the ulong; and so forth. Any remaining bits in the ulong will be 0.
/// </remarks>
/// <param name="pos">Index of the first bit to get.</param>
/// <param name="numBits">Number of bits to get (must be between 1 and 64).</param>
/// <exception cref="ArgumentException">Thrown if pos is out of bounds or if numBits is not between 1 and 64.</exception>
/// <returns>A ulong which has bits copied from this array.</returns>
public ulong GetBits(int pos, int numBits = 1)
{
CheckArgsUlong(pos, numBits);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
if (shiftB + numBits <= 64)
{
var mask = 0xfffffffffffffffful >> (64 - numBits);
return Bitwise.ExtractBits(Ptr[idxB], shiftB, mask);
}
var end = math.min(pos + numBits, Length);
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful >> shiftB;
ulong valueB = Bitwise.ExtractBits(Ptr[idxB], shiftB, maskB);
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
ulong valueE = Bitwise.ExtractBits(Ptr[idxE], 0, maskE);
return (valueE << (64 - shiftB)) | valueB;
}
/// <summary>
/// Returns true if the bit at an index is 1.
/// </summary>
/// <param name="pos">Index of the bit to test.</param>
/// <returns>True if the bit at the index is 1.</returns>
/// <exception cref="ArgumentException">Thrown if `pos` is out of bounds.</exception>
public bool IsSet(int pos)
{
CheckArgs(pos, 1);
var idx = pos >> 6;
var shift = pos & 0x3f;
var mask = 1ul << shift;
return 0ul != (Ptr[idx] & mask);
}
internal void CopyUlong(int dstPos, ref UnsafeBitArray srcBitArray, int srcPos, int numBits) => SetBits(dstPos, srcBitArray.GetBits(srcPos, numBits), numBits);
/// <summary>
/// Copies a range of bits from this array to another range in this array.
/// </summary>
/// <remarks>
/// The bits to copy run from index `srcPos` up to (but not including) `srcPos + numBits`.
/// The bits to set run from index `dstPos` up to (but not including) `dstPos + numBits`.
///
/// The ranges may overlap, but the result in the overlapping region is undefined.
/// </remarks>
/// <param name="dstPos">Index of the first bit to set.</param>
/// <param name="srcPos">Index of the first bit to copy.</param>
/// <param name="numBits">Number of bits to copy.</param>
/// <exception cref="ArgumentException">Thrown if either `dstPos + numBits` or `srcPos + numBits` exceed the length of this array.</exception>
public void Copy(int dstPos, int srcPos, int numBits)
{
if (dstPos == srcPos)
{
return;
}
Copy(dstPos, ref this, srcPos, numBits);
}
/// <summary>
/// Copies a range of bits from an array to a range of bits in this array.
/// </summary>
/// <remarks>
/// The bits to copy in the source array run from index srcPos up to (but not including) `srcPos + numBits`.
/// The bits to set in the destination array run from index dstPos up to (but not including) `dstPos + numBits`.
///
/// It's fine if source and destination array are one and the same, even if the ranges overlap, but the result in the overlapping region is undefined.
/// </remarks>
/// <param name="dstPos">Index of the first bit to set.</param>
/// <param name="srcBitArray">The source array.</param>
/// <param name="srcPos">Index of the first bit to copy.</param>
/// <param name="numBits">The number of bits to copy.</param>
/// <exception cref="ArgumentException">Thrown if either `dstPos + numBits` or `srcBitArray + numBits` exceed the length of this array.</exception>
public void Copy(int dstPos, ref UnsafeBitArray srcBitArray, int srcPos, int numBits)
{
if (numBits == 0)
{
return;
}
CheckArgsCopy(ref this, dstPos, ref srcBitArray, srcPos, numBits);
if (numBits <= 64) // 1x CopyUlong
{
CopyUlong(dstPos, ref srcBitArray, srcPos, numBits);
}
else if (numBits <= 128) // 2x CopyUlong
{
CopyUlong(dstPos, ref srcBitArray, srcPos, 64);
numBits -= 64;
if (numBits > 0)
{
CopyUlong(dstPos + 64, ref srcBitArray, srcPos + 64, numBits);
}
}
else if ((dstPos & 7) == (srcPos & 7)) // aligned copy
{
var dstPosInBytes = CollectionHelper.Align(dstPos, 8) >> 3;
var srcPosInBytes = CollectionHelper.Align(srcPos, 8) >> 3;
var numPreBits = dstPosInBytes * 8 - dstPos;
if (numPreBits > 0)
{
CopyUlong(dstPos, ref srcBitArray, srcPos, numPreBits);
}
var numBitsLeft = numBits - numPreBits;
var numBytes = numBitsLeft / 8;
if (numBytes > 0)
{
unsafe
{
UnsafeUtility.MemMove((byte*)Ptr + dstPosInBytes, (byte*)srcBitArray.Ptr + srcPosInBytes, numBytes);
}
}
var numPostBits = numBitsLeft & 7;
if (numPostBits > 0)
{
CopyUlong((dstPosInBytes + numBytes) * 8, ref srcBitArray, (srcPosInBytes + numBytes) * 8, numPostBits);
}
}
else // unaligned copy
{
var dstPosAligned = CollectionHelper.Align(dstPos, 64);
var numPreBits = dstPosAligned - dstPos;
if (numPreBits > 0)
{
CopyUlong(dstPos, ref srcBitArray, srcPos, numPreBits);
numBits -= numPreBits;
dstPos += numPreBits;
srcPos += numPreBits;
}
for (; numBits >= 64; numBits -= 64, dstPos += 64, srcPos += 64)
{
Ptr[dstPos >> 6] = srcBitArray.GetBits(srcPos, 64);
}
if (numBits > 0)
{
CopyUlong(dstPos, ref srcBitArray, srcPos, numBits);
}
}
}
/// <summary>
/// Returns the index of the first occurrence in this array of *N* contiguous 0 bits.
/// </summary>
/// <remarks>The search is linear.</remarks>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of contiguous 0 bits to look for.</param>
/// <returns>The index of the first occurrence in this array of `numBits` contiguous 0 bits. Range is pos up to (but not including) the length of this array. Returns -1 if no occurrence is found.</returns>
public int Find(int pos, int numBits)
{
var count = Length - pos;
CheckArgsPosCount(pos, count, numBits);
return Bitwise.Find(Ptr, pos, count, numBits);
}
/// <summary>
/// Returns the index of the first occurrence in this array of a given number of contiguous 0 bits.
/// </summary>
/// <remarks>The search is linear.</remarks>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of contiguous 0 bits to look for.</param>
/// <param name="count">Number of indexes to consider as the return value.</param>
/// <returns>The index of the first occurrence in this array of `numBits` contiguous 0 bits. Range is pos up to (but not including) `pos + count`. Returns -1 if no occurrence is found.</returns>
public int Find(int pos, int count, int numBits)
{
CheckArgsPosCount(pos, count, numBits);
return Bitwise.Find(Ptr, pos, count, numBits);
}
/// <summary>
/// Returns true if none of the bits in a range are 1 (*i.e.* all bits in the range are 0).
/// </summary>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of bits to test. Defaults to 1.</param>
/// <returns>Returns true if none of the bits in range `pos` up to (but not including) `pos + numBits` are 1.</returns>
/// <exception cref="ArgumentException">Thrown if `pos` is out of bounds or `numBits` is less than 1.</exception>
public bool TestNone(int pos, int numBits = 1)
{
CheckArgs(pos, numBits);
var end = math.min(pos + numBits, Length);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful << shiftB;
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
if (idxB == idxE)
{
var mask = maskB & maskE;
return 0ul == (Ptr[idxB] & mask);
}
if (0ul != (Ptr[idxB] & maskB))
{
return false;
}
for (var idx = idxB + 1; idx < idxE; ++idx)
{
if (0ul != Ptr[idx])
{
return false;
}
}
return 0ul == (Ptr[idxE] & maskE);
}
/// <summary>
/// Returns true if at least one of the bits in a range is 1.
/// </summary>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of bits to test. Defaults to 1.</param>
/// <returns>True if one or more of the bits in range `pos` up to (but not including) `pos + numBits` are 1.</returns>
/// <exception cref="ArgumentException">Thrown if `pos` is out of bounds or `numBits` is less than 1.</exception>
public bool TestAny(int pos, int numBits = 1)
{
CheckArgs(pos, numBits);
var end = math.min(pos + numBits, Length);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful << shiftB;
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
if (idxB == idxE)
{
var mask = maskB & maskE;
return 0ul != (Ptr[idxB] & mask);
}
if (0ul != (Ptr[idxB] & maskB))
{
return true;
}
for (var idx = idxB + 1; idx < idxE; ++idx)
{
if (0ul != Ptr[idx])
{
return true;
}
}
return 0ul != (Ptr[idxE] & maskE);
}
/// <summary>
/// Returns true if all of the bits in a range are 1.
/// </summary>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of bits to test. Defaults to 1.</param>
/// <returns>True if all of the bits in range `pos` up to (but not including) `pos + numBits` are 1.</returns>
/// <exception cref="ArgumentException">Thrown if `pos` is out of bounds or `numBits` is less than 1.</exception>
public bool TestAll(int pos, int numBits = 1)
{
CheckArgs(pos, numBits);
var end = math.min(pos + numBits, Length);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful << shiftB;
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
if (idxB == idxE)
{
var mask = maskB & maskE;
return mask == (Ptr[idxB] & mask);
}
if (maskB != (Ptr[idxB] & maskB))
{
return false;
}
for (var idx = idxB + 1; idx < idxE; ++idx)
{
if (0xfffffffffffffffful != Ptr[idx])
{
return false;
}
}
return maskE == (Ptr[idxE] & maskE);
}
/// <summary>
/// Returns the number of bits in a range that are 1.
/// </summary>
/// <param name="pos">Index of the bit at which to start searching.</param>
/// <param name="numBits">Number of bits to test. Defaults to 1.</param>
/// <returns>The number of bits in a range of bits that are 1.</returns>
/// <exception cref="ArgumentException">Thrown if `pos` is out of bounds or `numBits` is less than 1.</exception>
public int CountBits(int pos, int numBits = 1)
{
CheckArgs(pos, numBits);
var end = math.min(pos + numBits, Length);
var idxB = pos >> 6;
var shiftB = pos & 0x3f;
var idxE = (end - 1) >> 6;
var shiftE = end & 0x3f;
var maskB = 0xfffffffffffffffful << shiftB;
var maskE = 0xfffffffffffffffful >> (64 - shiftE);
if (idxB == idxE)
{
var mask = maskB & maskE;
return math.countbits(Ptr[idxB] & mask);
}
var count = math.countbits(Ptr[idxB] & maskB);
for (var idx = idxB + 1; idx < idxE; ++idx)
{
count += math.countbits(Ptr[idx]);
}
count += math.countbits(Ptr[idxE] & maskE);
return count;
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
static void CheckSizeMultipleOf8(int sizeInBytes)
{
if ((sizeInBytes & 7) != 0)
throw new ArgumentException($"BitArray invalid arguments: sizeInBytes {sizeInBytes} (must be multiple of 8-bytes, sizeInBytes: {sizeInBytes}).");
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
void CheckArgs(int pos, int numBits)
{
if (pos < 0
|| pos >= Length
|| numBits < 1)
{
throw new ArgumentException($"BitArray invalid arguments: pos {pos} (must be 0-{Length - 1}), numBits {numBits} (must be greater than 0).");
}
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
void CheckArgsPosCount(int begin, int count, int numBits)
{
if (begin < 0 || begin >= Length)
{
throw new ArgumentException($"BitArray invalid argument: begin {begin} (must be 0-{Length - 1}).");
}
if (count < 0 || count > Length)
{
throw new ArgumentException($"BitArray invalid argument: count {count} (must be 0-{Length}).");
}
if (numBits < 1 || count < numBits)
{
throw new ArgumentException($"BitArray invalid argument: numBits {numBits} (must be greater than 0).");
}
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
void CheckArgsUlong(int pos, int numBits)
{
CheckArgs(pos, numBits);
if (numBits < 1 || numBits > 64)
{
throw new ArgumentException($"BitArray invalid arguments: numBits {numBits} (must be 1-64).");
}
if (pos + numBits > Length)
{
throw new ArgumentException($"BitArray invalid arguments: Out of bounds pos {pos}, numBits {numBits}, Length {Length}.");
}
}
[Conditional("ENABLE_UNITY_COLLECTIONS_CHECKS")]
static void CheckArgsCopy(ref UnsafeBitArray dstBitArray, int dstPos, ref UnsafeBitArray srcBitArray, int srcPos, int numBits)
{
if (srcPos + numBits > srcBitArray.Length)
{
throw new ArgumentException($"BitArray invalid arguments: Out of bounds - source position {srcPos}, numBits {numBits}, source bit array Length {srcBitArray.Length}.");
}
if (dstPos + numBits > dstBitArray.Length)
{
throw new ArgumentException($"BitArray invalid arguments: Out of bounds - destination position {dstPos}, numBits {numBits}, destination bit array Length {dstBitArray.Length}.");
}
}
}
sealed class UnsafeBitArrayDebugView
{
UnsafeBitArray Data;
public UnsafeBitArrayDebugView(UnsafeBitArray data)
{
Data = data;
}
public bool[] Bits
{
get
{
var array = new bool[Data.Length];
for (int i = 0; i < Data.Length; ++i)
{
array[i] = Data.IsSet(i);
}
return array;
}
}
}
}