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Rewrite DbBuffer Read/Write methods with stackalloc #88395

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Rewrite DbBuffer Read/Write methods with stackalloc #88395

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df97c47
rewrite Read/Write with stackalloc
Poppyto Jul 4, 2023
ffcda84
rewrite of inherited CNativeBuffer:WriteODBCDateTime
Poppyto Jul 5, 2023
694218d
- rewrite ReadGuid
Poppyto Jul 6, 2023
dff8568
- span cannto be null
Poppyto Jul 6, 2023
32a230f
rewrite ReadGuid & WriteGuid
Poppyto Jul 6, 2023
0b1fd5c
update from suggestions
Poppyto Jul 6, 2023
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237 changes: 185 additions & 52 deletions src/libraries/System.Data.Odbc/src/Common/System/Data/ProviderBase/DbBuffer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,34 @@ internal byte[] ReadBytes(int offset, byte[] destination, int startIndex, int le
return destination;
}

internal Span<byte> ReadBytes(int offset, Span<byte> destination)
{
offset += BaseOffset;
Validate(offset, destination.Length);
Debug.Assert(0 == offset % ADP.PtrSize, "invalid alignment");

bool mustRelease = false;

try
{
DangerousAddRef(ref mustRelease);

IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
unsafe
{
new ReadOnlySpan<byte>(ptr.ToPointer(), destination.Length).CopyTo(destination);
}
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return destination;
}

internal char ReadChar(int offset)
{
short value = ReadInt16(offset);
Expand Down Expand Up @@ -257,6 +285,33 @@ internal void ReadInt16Array(int offset, short[] destination, int startIndex, in
}
}
}
internal void ReadInt16Array(int offset, Span<short> destination)
{
offset += BaseOffset;
Validate(offset, 2 * destination.Length);
Debug.Assert(0 == offset % ADP.PtrSize, "invalid alignment");
Debug.Assert(null != destination, "null destination");
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bool mustRelease = false;

try
{
DangerousAddRef(ref mustRelease);

IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
unsafe
{
new ReadOnlySpan<short>(ptr.ToPointer(), destination.Length).CopyTo(destination);
}
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}

internal int ReadInt32(int offset)
{
Expand Down Expand Up @@ -455,6 +510,34 @@ internal void WriteBytes(int offset, byte[] source, int startIndex, int length)
}
}

internal void WriteBytes(int offset, ReadOnlySpan<byte> source)
{
offset += BaseOffset;
Validate(offset, source.Length);
Debug.Assert(0 == offset % ADP.PtrSize, "invalid alignment");
Debug.Assert(null != source, "null source");
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bool mustRelease = false;

try
{
DangerousAddRef(ref mustRelease);

IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
unsafe
{
source.CopyTo(new Span<byte>(ptr.ToPointer(), source.Length));
}
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}

internal void WriteCharArray(int offset, char[] source, int startIndex, int length)
{
offset += BaseOffset;
Expand Down Expand Up @@ -536,6 +619,34 @@ internal void WriteInt16Array(int offset, short[] source, int startIndex, int le
}
}

internal void WriteInt16Array(int offset, ReadOnlySpan<short> source)
{
offset += BaseOffset;
Validate(offset, 2 * source.Length);
Debug.Assert(0 == offset % ADP.PtrSize, "invalid alignment");
Debug.Assert(null != source, "null source");
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bool mustRelease = false;

try
{
DangerousAddRef(ref mustRelease);

IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
unsafe
{
source.CopyTo(new Span<short>(ptr.ToPointer(), source.Length));
}
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}

internal void WriteInt32(int offset, int value)
{
offset += BaseOffset;
Expand Down Expand Up @@ -661,119 +772,141 @@ internal void ZeroMemory()

internal Guid ReadGuid(int offset)
{
// faster than Marshal.PtrToStructure(offset, typeof(Guid))
byte[] buffer = new byte[16];
ReadBytes(offset, buffer, 0, 16);
return new Guid(buffer);
offset += BaseOffset;
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Debug.Assert(0 == offset % ADP.PtrSize, "invalid alignment");
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bool mustRelease = false;
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
unsafe
{
return new Guid(new ReadOnlySpan<byte>(ptr.ToPointer(), sizeof(Guid)));
}
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}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteGuid(int offset, Guid value)
{
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// faster than Marshal.Copy(value.GetByteArray()
StructureToPtr(offset, value);
ReadOnlySpan<Guid> spanGuid = MemoryMarshal.CreateReadOnlySpan(ref Unsafe.AsRef(value), 1);
WriteBytes(offset, MemoryMarshal.AsBytes(spanGuid));
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}

internal DateTime ReadDate(int offset)
{
short[] buffer = new short[3];
ReadInt16Array(offset, buffer, 0, 3);
Span<short> spanBuffer = stackalloc short[3];
ReadInt16Array(offset, spanBuffer.Slice(0, 3));
return new DateTime(
unchecked((ushort)buffer[0]), // Year
unchecked((ushort)buffer[1]), // Month
unchecked((ushort)buffer[2])); // Day
unchecked((ushort)spanBuffer[0]), // Year
unchecked((ushort)spanBuffer[1]), // Month
unchecked((ushort)spanBuffer[2])); // Day
Comment on lines +819 to +824
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@xtqqczze xtqqczze Jul 7, 2023 •
edited
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This could also be rewritten as unsafe method:

[StructLayout(LayoutKind.Sequential)]
public unsafe readonly struct DateData
{
    public readonly ushort Year;
    public readonly ushort Month;
    public readonly ushort Day;
}
DateData data = *(DateData*)addr;
return new DateTime(data.Year, data.Month, data.Day);

}
internal void WriteDate(int offset, DateTime value)
{
short[] buffer = new short[3] {
Span<short> spanBuffer = stackalloc short[3] {
unchecked((short)value.Year),
unchecked((short)value.Month),
unchecked((short)value.Day),
};
WriteInt16Array(offset, buffer, 0, 3);
WriteInt16Array(offset, spanBuffer.Slice(0, 3));
}

internal TimeSpan ReadTime(int offset)
{
short[] buffer = new short[3];
ReadInt16Array(offset, buffer, 0, 3);
Span<short> spanBuffer = stackalloc short[3];
ReadInt16Array(offset, spanBuffer.Slice(0, 3));
return new TimeSpan(
unchecked((ushort)buffer[0]), // Hours
unchecked((ushort)buffer[1]), // Minutes
unchecked((ushort)buffer[2])); // Seconds
unchecked((ushort)spanBuffer[0]), // Hours
unchecked((ushort)spanBuffer[1]), // Minutes
unchecked((ushort)spanBuffer[2])); // Seconds
}
internal void WriteTime(int offset, TimeSpan value)
{
short[] buffer = new short[3] {
Span<short> spanBuffer = stackalloc short[3] {
unchecked((short)value.Hours),
unchecked((short)value.Minutes),
unchecked((short)value.Seconds),
};
WriteInt16Array(offset, buffer, 0, 3);
WriteInt16Array(offset, spanBuffer.Slice(0, 3));
}

internal DateTime ReadDateTime(int offset)
{
short[] buffer = new short[6];
ReadInt16Array(offset, buffer, 0, 6);
Span<short> spanBuffer = stackalloc short[6];
ReadInt16Array(offset, spanBuffer.Slice(0, 6));
int ticks = ReadInt32(offset + 12);
DateTime value = new DateTime(
unchecked((ushort)buffer[0]), // Year
unchecked((ushort)buffer[1]), // Month
unchecked((ushort)buffer[2]), // Day
unchecked((ushort)buffer[3]), // Hours
unchecked((ushort)buffer[4]), // Minutes
unchecked((ushort)buffer[5])); // Seconds
unchecked((ushort)spanBuffer[0]), // Year
unchecked((ushort)spanBuffer[1]), // Month
unchecked((ushort)spanBuffer[2]), // Day
unchecked((ushort)spanBuffer[3]), // Hours
unchecked((ushort)spanBuffer[4]), // Minutes
unchecked((ushort)spanBuffer[5])); // Seconds
return value.AddTicks(ticks / 100);
}
internal void WriteDateTime(int offset, DateTime value)
{
int ticks = (int)(value.Ticks % 10000000L) * 100;
short[] buffer = new short[6] {
Span<short> spanBuffer = stackalloc short[6] {
unchecked((short)value.Year),
unchecked((short)value.Month),
unchecked((short)value.Day),
unchecked((short)value.Hour),
unchecked((short)value.Minute),
unchecked((short)value.Second),
};
WriteInt16Array(offset, buffer, 0, 6);
WriteInt16Array(offset, spanBuffer.Slice(0, 6));
WriteInt32(offset + 12, ticks);
}

internal decimal ReadNumeric(int offset)
{
byte[] bits = new byte[20];
ReadBytes(offset, bits, 1, 19);
Span<byte> spanBits = stackalloc byte[20];
ReadBytes(offset, spanBits.Slice(1, 19));

int[] buffer = new int[4];
buffer[3] = ((int)bits[2]) << 16; // scale
if (0 == bits[3])
Span<int> spanBuffer = stackalloc int[4];
spanBuffer[3] = ((int)spanBits[2]) << 16; // scale
if (0 == spanBits[3])
{
buffer[3] |= unchecked((int)0x80000000); //sign
spanBuffer[3] |= unchecked((int)0x80000000); //sign
}
buffer[0] = BitConverter.ToInt32(bits, 4); // low
buffer[1] = BitConverter.ToInt32(bits, 8); // mid
buffer[2] = BitConverter.ToInt32(bits, 12); // high
if (0 != BitConverter.ToInt32(bits, 16))
spanBuffer[0] = BitConverter.ToInt32(spanBits.Slice(4)); // low
spanBuffer[1] = BitConverter.ToInt32(spanBits.Slice(8)); // mid
spanBuffer[2] = BitConverter.ToInt32(spanBits.Slice(12)); // high
if (0 != BitConverter.ToInt32(spanBits.Slice(16)))
{
throw ADP.NumericToDecimalOverflow();
}
return new decimal(buffer);
return new decimal(spanBuffer);
}

internal void WriteNumeric(int offset, decimal value, byte precision)
{
int[] tmp = decimal.GetBits(value);
byte[] buffer = new byte[20];

buffer[1] = precision;
Buffer.BlockCopy(tmp, 14, buffer, 2, 2); // copy sign and scale
buffer[3] = (byte)((0 == buffer[3]) ? 1 : 0); // flip sign for native
Buffer.BlockCopy(tmp, 0, buffer, 4, 12);
buffer[16] = 0;
buffer[17] = 0;
buffer[18] = 0;
buffer[19] = 0;
WriteBytes(offset, buffer, 1, 19);
Span<byte> spanBuffer = stackalloc byte[20];

Span<byte> spanByteTmp = MemoryMarshal.Cast<int, byte>(tmp.AsSpan());
Span<int> spanIntBuffer = MemoryMarshal.Cast<byte, int>(spanBuffer);

spanBuffer[1] = precision;
//Buffer.BlockCopy(tmp, 14, buffer, 2, 2); // copy sign and scale
spanByteTmp.Slice(14, 2).CopyTo(spanBuffer.Slice(2, 2));// copy sign and scale

spanBuffer[3] = (byte)((0 == spanBuffer[3]) ? 1 : 0); // flip sign for native
//Buffer.BlockCopy(tmp, 0, buffer, 4, 12);
spanByteTmp.Slice(0, 12).CopyTo(spanBuffer.Slice(4, 12));

spanBuffer[16] = 0;
spanBuffer[17] = 0;
spanBuffer[18] = 0;
spanBuffer[19] = 0;
WriteBytes(offset, spanBuffer.Slice(1, 19));
}

[ConditionalAttribute("DEBUG")]
Expand Down
4 changes: 2 additions & 2 deletions src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcUtils.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -332,15 +332,15 @@ internal HandleRef PtrOffset(int offset, int length)

internal void WriteODBCDateTime(int offset, DateTime value)
{
short[] buffer = new short[6] {
Span<short> spanBuffer = stackalloc short[6] {
unchecked((short)value.Year),
unchecked((short)value.Month),
unchecked((short)value.Day),
unchecked((short)value.Hour),
unchecked((short)value.Minute),
unchecked((short)value.Second),
};
WriteInt16Array(offset, buffer, 0, 6);
WriteInt16Array(offset, spanBuffer.Slice(0, 6));
WriteInt32(offset + 12, value.Millisecond * 1000000); //fraction
}
}
Expand Down
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