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Optimize the SqlGuid struct
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Optimizes the SqlGuid struct according to the idea
from dotnet#51836.
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@MichalPetryka
MichalPetryka committed Jul 20, 2022
1 parent 58efb7e commit e07c937
Showing 1 changed file with 59 additions and 49 deletions.
108 changes: 59 additions & 49 deletions src/libraries/System.Data.Common/src/System/Data/SQLTypes/SQLGuid.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Data.Common;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;
Expand All @@ -16,68 +19,65 @@ namespace System.Data.SqlTypes
[Serializable]
[XmlSchemaProvider("GetXsdType")]
[System.Runtime.CompilerServices.TypeForwardedFrom("System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
public struct SqlGuid : INullable, IComparable, IXmlSerializable, IEquatable<SqlGuid>
public struct SqlGuid : INullable, IComparable, ISerializable, IXmlSerializable, IEquatable<SqlGuid>
{
private const int SizeOfGuid = 16;
private const int SizeOfGuid = 16; // sizeof(Guid)

// NOTE: If any instance fields change, update SqlTypeWorkarounds type in System.Data.SqlClient.
private byte[]? m_value; // the SqlGuid is null if m_value is null
private Guid? _value; // the SqlGuid is null if _value is null

// constructor
// construct a SqlGuid.Null
private SqlGuid(bool fNull)
{
m_value = null;
_value = null;
}

public SqlGuid(byte[] value)
{
if (value == null || value.Length != SizeOfGuid)
throw new ArgumentException(SQLResource.InvalidArraySizeMessage);

m_value = new byte[SizeOfGuid];
value.CopyTo(m_value, 0);
}

internal SqlGuid(byte[] value, bool ignored)
{
if (value == null || value.Length != SizeOfGuid)
throw new ArgumentException(SQLResource.InvalidArraySizeMessage);

m_value = value;
_value = new Guid(value);
}

public SqlGuid(string s)
{
m_value = (new Guid(s)).ToByteArray();
_value = new Guid(s);
}

public SqlGuid(Guid g)
{
m_value = g.ToByteArray();
_value = g;
}

public SqlGuid(int a, short b, short c, byte d, byte e, byte f, byte g, byte h, byte i, byte j, byte k)
: this(new Guid(a, b, c, d, e, f, g, h, i, j, k))
{
}


// INullable
public bool IsNull
private SqlGuid(SerializationInfo si, StreamingContext sc)
{
get { return (m_value is null); }
ArgumentNullException.ThrowIfNull(si);
byte[]? value = (byte[]?)si.GetValue("m_value", typeof(byte[]));
if (value is null)
_value = null;
else
_value = new Guid(value);
}

// INullable
public bool IsNull => _value is null;

// property: Value
public Guid Value
{
get
{
if (m_value is null)
if (_value is null)
throw new SqlNullValueException();
else
return new Guid(m_value);
return _value.GetValueOrDefault();
}
}

Expand All @@ -95,18 +95,17 @@ public static explicit operator Guid(SqlGuid x)

public byte[]? ToByteArray()
{
byte[] ret = new byte[SizeOfGuid];
m_value!.CopyTo(ret, 0); // TODO: NRE
return ret;
if (_value is null)
return null;
return _value.GetValueOrDefault().ToByteArray();
}

public override string ToString()
{
if (m_value is null)
if (_value is null)
return SQLResource.NullString;

Guid g = new Guid(m_value);
return g.ToString();
return _value.GetValueOrDefault().ToString();
}

public static SqlGuid Parse(string s)
Expand All @@ -117,31 +116,37 @@ public static SqlGuid Parse(string s)
return new SqlGuid(s);
}


// Comparison operators
private static EComparison Compare(SqlGuid x, SqlGuid y)
{
// Comparison orders.
ReadOnlySpan<byte> rgiGuidOrder = new byte[16] { 10, 11, 12, 13, 14, 15, 8, 9, 6, 7, 4, 5, 0, 1, 2, 3 };

Debug.Assert(!x.IsNull);
Debug.Assert(!y.IsNull);

// Swap to the correct order to be compared
ReadOnlySpan<byte> xBytes = x.m_value;
ReadOnlySpan<byte> yBytes = y.m_value;
Span<byte> xBytes = stackalloc byte[sizeof(Guid)];
bool xWrote = x._value.GetValueOrDefault().TryWriteSpan(xBytes);
Debug.Assert(xWrote);

Span<byte> yBytes = stackalloc byte[sizeof(Guid)];
bool yWrote = y._value.GetValueOrDefault().TryWriteSpan(yBytes);
Debug.Assert(yWrote);

for (int i = 0; i < SizeOfGuid; i++)
{
byte b1 = xBytes[rgiGuidOrder[i]];
byte b2 = yBytes[rgiGuidOrder[i]];
if (b1 != b2)
{
return (b1 < b2) ? EComparison.LT : EComparison.GT;
return b1 < b2 ? EComparison.LT : EComparison.GT;
}
}

return EComparison.EQ;
}



// Implicit conversions

// Explicit conversions
Expand All @@ -161,7 +166,7 @@ public static explicit operator SqlGuid(SqlBinary x)
// Overloading comparison operators
public static SqlBoolean operator ==(SqlGuid x, SqlGuid y)
{
return (x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.EQ);
return x.IsNull || y.IsNull ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.EQ);
}

public static SqlBoolean operator !=(SqlGuid x, SqlGuid y)
Expand All @@ -171,12 +176,12 @@ public static explicit operator SqlGuid(SqlBinary x)

public static SqlBoolean operator <(SqlGuid x, SqlGuid y)
{
return (x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.LT);
return x.IsNull || y.IsNull ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.LT);
}

public static SqlBoolean operator >(SqlGuid x, SqlGuid y)
{
return (x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.GT);
return x.IsNull || y.IsNull ? SqlBoolean.Null : new SqlBoolean(Compare(x, y) == EComparison.GT);
}

public static SqlBoolean operator <=(SqlGuid x, SqlGuid y)
Expand Down Expand Up @@ -204,37 +209,37 @@ public static explicit operator SqlGuid(SqlBinary x)
// Alternative method for operator ==
public static SqlBoolean Equals(SqlGuid x, SqlGuid y)
{
return (x == y);
return x == y;
}

// Alternative method for operator !=
public static SqlBoolean NotEquals(SqlGuid x, SqlGuid y)
{
return (x != y);
return x != y;
}

// Alternative method for operator <
public static SqlBoolean LessThan(SqlGuid x, SqlGuid y)
{
return (x < y);
return x < y;
}

// Alternative method for operator >
public static SqlBoolean GreaterThan(SqlGuid x, SqlGuid y)
{
return (x > y);
return x > y;
}

// Alternative method for operator <=
public static SqlBoolean LessThanOrEqual(SqlGuid x, SqlGuid y)
{
return (x <= y);
return x <= y;
}

// Alternative method for operator >=
public static SqlBoolean GreaterThanOrEqual(SqlGuid x, SqlGuid y)
{
return (x >= y);
return x >= y;
}

// Alternative method for conversions.
Expand All @@ -249,7 +254,6 @@ public SqlBinary ToSqlBinary()
return (SqlBinary)this;
}


// IComparable
// Compares this object to another object, returning an integer that
// indicates the relationship.
Expand Down Expand Up @@ -292,7 +296,7 @@ public bool Equals(SqlGuid other) =>
(this == other).Value;

// For hashing purpose
public override int GetHashCode() => IsNull ? 0 : Value.GetHashCode();
public override int GetHashCode() => IsNull ? 0 : _value.GetValueOrDefault().GetHashCode();

XmlSchema? IXmlSerializable.GetSchema() { return null; }

Expand All @@ -303,23 +307,23 @@ void IXmlSerializable.ReadXml(XmlReader reader)
{
// Read the next value.
reader.ReadElementString();
m_value = null;
_value = null;
}
else
{
m_value = new Guid(reader.ReadElementString()).ToByteArray();
_value = new Guid(reader.ReadElementString());
}
}

void IXmlSerializable.WriteXml(XmlWriter writer)
{
if (m_value is null)
if (_value is null)
{
writer.WriteAttributeString("xsi", "nil", XmlSchema.InstanceNamespace, "true");
}
else
{
writer.WriteString(XmlConvert.ToString(new Guid(m_value)));
writer.WriteString(XmlConvert.ToString(_value.GetValueOrDefault()));
}
}

Expand All @@ -328,6 +332,12 @@ public static XmlQualifiedName GetXsdType(XmlSchemaSet schemaSet)
return new XmlQualifiedName("string", XmlSchema.Namespace);
}

void ISerializable.GetObjectData(SerializationInfo si, StreamingContext sc)
{
ArgumentNullException.ThrowIfNull(si);
si.AddValue("m_value", ToByteArray());
}

public static readonly SqlGuid Null = new SqlGuid(true);
} // SqlGuid
} // namespace System.Data.SqlTypes

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