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Checksum Support for ReadOnlySpan<byte> #841

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Checksum Support for ReadOnlySpan<byte> #841

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21 changes: 16 additions & 5 deletions src/ICSharpCode.SharpZipLib/Checksum/Adler32.cs
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Expand Up @@ -122,7 +122,7 @@ public void Update(byte[] buffer)
throw new ArgumentNullException(nameof(buffer));
}

Update(new ArraySegment<byte>(buffer, 0, buffer.Length));
Update((ReadOnlySpan<byte>)buffer);
}

/// <summary>
Expand All @@ -132,12 +132,23 @@ public void Update(byte[] buffer)
/// The chunk of data to add
/// </param>
public void Update(ArraySegment<byte> segment)
{
Update((ReadOnlySpan<byte>)segment);
}

/// <summary>
/// Update Adler32 data checksum based on a portion of a block of data
/// </summary>
/// <param name = "data">
/// The chunk of data to add
/// </param>
public void Update(ReadOnlySpan<byte> data)
{
//(By Per Bothner)
uint s1 = checkValue & 0xFFFF;
uint s2 = checkValue >> 16;
var count = segment.Count;
var offset = segment.Offset;
var count = data.Length;
var offset = 0;
while (count > 0)
{
// We can defer the modulo operation:
Expand All @@ -151,8 +162,8 @@ public void Update(ArraySegment<byte> segment)
count -= n;
while (--n >= 0)
{
s1 = s1 + (uint)(segment.Array[offset++] & 0xff);
s2 = s2 + s1;
s1 += (uint)(data[offset++] & 0xff);
s2 += s1;
}
s1 %= BASE;
s2 %= BASE;
Expand Down
23 changes: 12 additions & 11 deletions src/ICSharpCode.SharpZipLib/Checksum/BZip2Crc.cs
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Expand Up @@ -113,7 +113,7 @@ public void Update(byte[] buffer)
throw new ArgumentNullException(nameof(buffer));
}

Update(buffer, 0, buffer.Length);
Update((ReadOnlySpan<byte>)buffer);
}

/// <summary>
Expand All @@ -124,20 +124,21 @@ public void Update(byte[] buffer)
/// </param>
public void Update(ArraySegment<byte> segment)
{
Update(segment.Array, segment.Offset, segment.Count);
Update((ReadOnlySpan<byte>)segment);
}

/// <summary>
/// Internal helper function for updating a block of data using slicing.
/// Update CRC data checksum based on a portion of a block of data
/// </summary>
/// <param name="data">The array containing the data to add</param>
/// <param name="offset">Range start for <paramref name="data"/> (inclusive)</param>
/// <param name="count">The number of bytes to checksum starting from <paramref name="offset"/></param>
private void Update(byte[] data, int offset, int count)
/// <param name = "data">
/// The chunk of data to add
/// </param>
public void Update(ReadOnlySpan<byte> data)
{
int remainder = count % CrcUtilities.SlicingDegree;
int end = offset + count - remainder;
int remainder = data.Length % CrcUtilities.SlicingDegree;
int end = data.Length - remainder;

int offset = 0;
while (offset != end)
{
checkValue = CrcUtilities.UpdateDataForNormalPoly(data, offset, crcTable, checkValue);
Expand All @@ -156,11 +157,11 @@ private void Update(byte[] data, int offset, int count)
/// we do we're not here for long, so disabling inlining here improves
/// performance overall.
/// </summary>
/// <param name="data">The array containing the data to add</param>
/// <param name="data">The span containing the data to add</param>
/// <param name="offset">Range start for <paramref name="data"/> (inclusive)</param>
/// <param name="end">Range end for <paramref name="data"/> (exclusive)</param>
[MethodImpl(MethodImplOptions.NoInlining)]
private void SlowUpdateLoop(byte[] data, int offset, int end)
private void SlowUpdateLoop(ReadOnlySpan<byte> data, int offset, int end)
{
while (offset != end)
{
Expand Down
23 changes: 12 additions & 11 deletions src/ICSharpCode.SharpZipLib/Checksum/Crc32.cs
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Expand Up @@ -115,7 +115,7 @@ public void Update(byte[] buffer)
throw new ArgumentNullException(nameof(buffer));
}

Update(buffer, 0, buffer.Length);
Update((ReadOnlySpan<byte>)buffer);
}

/// <summary>
Expand All @@ -126,20 +126,21 @@ public void Update(byte[] buffer)
/// </param>
public void Update(ArraySegment<byte> segment)
{
Update(segment.Array, segment.Offset, segment.Count);
Update((ReadOnlySpan<byte>)segment);
}

/// <summary>
/// Internal helper function for updating a block of data using slicing.
/// Update CRC data checksum based on a portion of a block of data
/// </summary>
/// <param name="data">The array containing the data to add</param>
/// <param name="offset">Range start for <paramref name="data"/> (inclusive)</param>
/// <param name="count">The number of bytes to checksum starting from <paramref name="offset"/></param>
private void Update(byte[] data, int offset, int count)
/// <param name = "data">
/// The chunk of data to add
/// </param>
public void Update(ReadOnlySpan<byte> data)
{
int remainder = count % CrcUtilities.SlicingDegree;
int end = offset + count - remainder;
int remainder = data.Length % CrcUtilities.SlicingDegree;
int end = data.Length - remainder;

int offset = 0;
while (offset != end)
{
checkValue = CrcUtilities.UpdateDataForReversedPoly(data, offset, crcTable, checkValue);
Expand All @@ -158,11 +159,11 @@ private void Update(byte[] data, int offset, int count)
/// we do we're not here for long, so disabling inlining here improves
/// performance overall.
/// </summary>
/// <param name="data">The array containing the data to add</param>
/// <param name="data">The span containing the data to add</param>
/// <param name="offset">Range start for <paramref name="data"/> (inclusive)</param>
/// <param name="end">Range end for <paramref name="data"/> (exclusive)</param>
[MethodImpl(MethodImplOptions.NoInlining)]
private void SlowUpdateLoop(byte[] data, int offset, int end)
private void SlowUpdateLoop(ReadOnlySpan<byte> data, int offset, int end)
{
while (offset != end)
{
Expand Down
17 changes: 9 additions & 8 deletions src/ICSharpCode.SharpZipLib/Checksum/CrcUtilities.cs
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@@ -1,4 +1,5 @@
using System.Runtime.CompilerServices;
using System;
using System.Runtime.CompilerServices;

namespace ICSharpCode.SharpZipLib.Checksum
{
Expand Down Expand Up @@ -55,7 +56,7 @@ internal static uint[] GenerateSlicingLookupTable(uint polynomial, bool isRevers
/// Mixes the first four bytes of input with <paramref name="checkValue"/>
/// using normal ordering before calling <see cref="UpdateDataCommon"/>.
/// </summary>
/// <param name="input">Array of data to checksum</param>
/// <param name="input">Span of data to checksum</param>
/// <param name="offset">Offset to start reading <paramref name="input"/> from</param>
/// <param name="crcTable">The table to use for slicing-by-16 lookup</param>
/// <param name="checkValue">Checksum state before this update call</param>
Expand All @@ -66,7 +67,7 @@ internal static uint[] GenerateSlicingLookupTable(uint polynomial, bool isRevers
/// For performance reasons, this must be checked by the caller.
/// </remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static uint UpdateDataForNormalPoly(byte[] input, int offset, uint[] crcTable, uint checkValue)
internal static uint UpdateDataForNormalPoly(ReadOnlySpan<byte> input, int offset, uint[] crcTable, uint checkValue)
{
byte x1 = (byte)((byte)(checkValue >> 24) ^ input[offset]);
byte x2 = (byte)((byte)(checkValue >> 16) ^ input[offset + 1]);
Expand All @@ -80,7 +81,7 @@ internal static uint UpdateDataForNormalPoly(byte[] input, int offset, uint[] cr
/// Mixes the first four bytes of input with <paramref name="checkValue"/>
/// using reflected ordering before calling <see cref="UpdateDataCommon"/>.
/// </summary>
/// <param name="input">Array of data to checksum</param>
/// <param name="input">Span of data to checksum</param>
/// <param name="offset">Offset to start reading <paramref name="input"/> from</param>
/// <param name="crcTable">The table to use for slicing-by-16 lookup</param>
/// <param name="checkValue">Checksum state before this update call</param>
Expand All @@ -91,7 +92,7 @@ internal static uint UpdateDataForNormalPoly(byte[] input, int offset, uint[] cr
/// For performance reasons, this must be checked by the caller.
/// </remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static uint UpdateDataForReversedPoly(byte[] input, int offset, uint[] crcTable, uint checkValue)
internal static uint UpdateDataForReversedPoly(ReadOnlySpan<byte> input, int offset, uint[] crcTable, uint checkValue)
{
byte x1 = (byte)((byte)checkValue ^ input[offset]);
byte x2 = (byte)((byte)(checkValue >>= 8) ^ input[offset + 1]);
Expand All @@ -104,7 +105,7 @@ internal static uint UpdateDataForReversedPoly(byte[] input, int offset, uint[]
/// <summary>
/// A shared method for updating an unfinalized CRC checksum using slicing-by-16.
/// </summary>
/// <param name="input">Array of data to checksum</param>
/// <param name="input">Span of data to checksum</param>
/// <param name="offset">Offset to start reading <paramref name="input"/> from</param>
/// <param name="crcTable">The table to use for slicing-by-16 lookup</param>
/// <param name="x1">First byte of input after mixing with the old CRC</param>
Expand All @@ -124,14 +125,14 @@ internal static uint UpdateDataForReversedPoly(byte[] input, int offset, uint[]
/// Because most processors running C# have some kind of instruction-level
/// parallelism, the order of XOR operations can affect performance. This
/// ordering assumes that the assembly code generated by the just-in-time
/// compiler will emit a bunch of arithmetic operations for checking array
/// compiler will emit a bunch of arithmetic operations for checking span
/// bounds. Then it opportunistically XORs a1 and a2 to keep the processor
/// busy while those other parts of the pipeline handle the range check
/// calculations.
/// </para>
/// </remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static uint UpdateDataCommon(byte[] input, int offset, uint[] crcTable, byte x1, byte x2, byte x3, byte x4)
private static uint UpdateDataCommon(ReadOnlySpan<byte> input, int offset, uint[] crcTable, byte x1, byte x2, byte x3, byte x4)
{
uint result;
uint a1 = crcTable[x1 + 3840] ^ crcTable[x2 + 3584];
Expand Down
8 changes: 8 additions & 0 deletions src/ICSharpCode.SharpZipLib/Checksum/IChecksum.cs
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Expand Up @@ -47,5 +47,13 @@ long Value
/// The chunk of data to add
/// </param>
void Update(ArraySegment<byte> segment);

/// <summary>
/// Adds the byte array to the data checksum.
/// </summary>
/// <param name = "data">
/// The chunk of data to add
/// </param>
void Update(ReadOnlySpan<byte> data);
}
}