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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Data.Common;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace System.Data.ProviderBase
{
// DbBuffer is abstract to require derived class to exist
// so that when debugging, we can tell the difference between one DbBuffer and another
internal abstract class DbBuffer : SafeHandle
{
private readonly int _bufferLength;
protected unsafe DbBuffer(int initialSize) : base(IntPtr.Zero, true)
{
if (0 < initialSize)
{
_bufferLength = initialSize;
RuntimeHelpers.PrepareConstrainedRegions();
try
{ }
finally
{
base.handle = (IntPtr)Interop.Kernel32.LocalAllocZeroed((uint)initialSize);
}
if (IntPtr.Zero == base.handle)
{
throw new OutOfMemoryException();
}
}
}
protected DbBuffer(IntPtr invalidHandleValue, bool ownsHandle) : base(invalidHandleValue, ownsHandle)
{
}
private const int BaseOffset = 0;
public override bool IsInvalid
{
get
{
return (IntPtr.Zero == base.handle);
}
}
internal int Length
{
get
{
return _bufferLength;
}
}
internal string PtrToStringUni(int offset, int length)
{
offset += BaseOffset;
Validate(offset, 2 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
string? value = null;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
value = Marshal.PtrToStringUni(ptr, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal byte ReadByte(int offset)
{
offset += BaseOffset;
ValidateCheck(offset, 1);
Debug.Assert(0 == offset % 4, "invalid alignment");
byte value;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
value = Marshal.ReadByte(ptr, offset);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal byte[] ReadBytes(int offset, int length)
{
byte[] value = new byte[length];
return ReadBytes(offset, value, 0, length);
}
internal byte[] ReadBytes(int offset, byte[] destination, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != destination, "null destination");
Debug.Assert(startIndex + length <= destination.Length, "destination too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(ptr, destination, startIndex, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return destination;
}
internal char ReadChar(int offset)
{
short value = ReadInt16(offset);
return unchecked((char)value);
}
internal char[] ReadChars(int offset, char[] destination, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 2 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != destination, "null destination");
Debug.Assert(startIndex + length <= destination.Length, "destination too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(ptr, destination, startIndex, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return destination;
}
internal double ReadDouble(int offset)
{
long value = ReadInt64(offset);
return BitConverter.Int64BitsToDouble(value);
}
internal short ReadInt16(int offset)
{
offset += BaseOffset;
ValidateCheck(offset, 2);
Debug.Assert(0 == offset % 2, "invalid alignment");
short value;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
value = Marshal.ReadInt16(ptr, offset);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal void ReadInt16Array(int offset, short[] destination, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 2 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != destination, "null destination");
Debug.Assert(startIndex + length <= destination.Length, "destination too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(ptr, destination, startIndex, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal int ReadInt32(int offset)
{
offset += BaseOffset;
ValidateCheck(offset, 4);
Debug.Assert(0 == offset % 4, "invalid alignment");
int value;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
value = Marshal.ReadInt32(ptr, offset);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal void ReadInt32Array(int offset, int[] destination, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 4 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != destination, "null destination");
Debug.Assert(startIndex + length <= destination.Length, "destination too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(ptr, destination, startIndex, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal long ReadInt64(int offset)
{
offset += BaseOffset;
ValidateCheck(offset, 8);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
long value;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
value = Marshal.ReadInt64(ptr, offset);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal IntPtr ReadIntPtr(int offset)
{
offset += BaseOffset;
ValidateCheck(offset, IntPtr.Size);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
IntPtr value;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
value = Marshal.ReadIntPtr(ptr, offset);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
return value;
}
internal unsafe float ReadSingle(int offset)
{
int value = ReadInt32(offset);
return BitConverter.Int32BitsToSingle(value);
}
protected override unsafe bool ReleaseHandle()
{
// NOTE: The SafeHandle class guarantees this will be called exactly once.
void* ptr = (void*)base.handle;
base.handle = IntPtr.Zero;
if (ptr is not null)
{
Interop.Kernel32.LocalFree(ptr);
}
return true;
}
private void StructureToPtr<T>(int offset, T structure)
{
Debug.Assert(null != structure, "null structure");
offset += BaseOffset;
ValidateCheck(offset, Marshal.SizeOf<T>());
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.StructureToPtr<T>(structure, ptr, false/*fDeleteOld*/);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteByte(int offset, byte value)
{
offset += BaseOffset;
ValidateCheck(offset, 1);
Debug.Assert(0 == offset % 4, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
Marshal.WriteByte(ptr, offset, value);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteBytes(int offset, byte[] source, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != source, "null source");
Debug.Assert(startIndex + length <= source.Length, "source too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(source, startIndex, ptr, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteCharArray(int offset, char[] source, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 2 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != source, "null source");
Debug.Assert(startIndex + length <= source.Length, "source too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(source, startIndex, ptr, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteDouble(int offset, double value)
{
WriteInt64(offset, BitConverter.DoubleToInt64Bits(value));
}
internal void WriteInt16(int offset, short value)
{
offset += BaseOffset;
ValidateCheck(offset, 2);
Debug.Assert(0 == offset % 2, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
Marshal.WriteInt16(ptr, offset, value);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteInt16Array(int offset, short[] source, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 2 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != source, "null source");
Debug.Assert(startIndex + length <= source.Length, "source too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(source, startIndex, ptr, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteInt32(int offset, int value)
{
offset += BaseOffset;
ValidateCheck(offset, 4);
Debug.Assert(0 == offset % 4, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
Marshal.WriteInt32(ptr, offset, value);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteInt32Array(int offset, int[] source, int startIndex, int length)
{
offset += BaseOffset;
Validate(offset, 4 * length);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
Debug.Assert(null != source, "null source");
Debug.Assert(startIndex + length <= source.Length, "source too small");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = ADP.IntPtrOffset(DangerousGetHandle(), offset);
Marshal.Copy(source, startIndex, ptr, length);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteInt64(int offset, long value)
{
offset += BaseOffset;
ValidateCheck(offset, 8);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
Marshal.WriteInt64(ptr, offset, value);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteIntPtr(int offset, IntPtr value)
{
offset += BaseOffset;
ValidateCheck(offset, IntPtr.Size);
Debug.Assert(0 == offset % IntPtr.Size, "invalid alignment");
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
DangerousAddRef(ref mustRelease);
IntPtr ptr = DangerousGetHandle();
Marshal.WriteIntPtr(ptr, offset, value);
}
finally
{
if (mustRelease)
{
DangerousRelease();
}
}
}
internal void WriteSingle(int offset, float value)
{
WriteInt32(offset, BitConverter.SingleToInt32Bits(value));
}
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);
}
internal void WriteGuid(int offset, Guid value)
{
// faster than Marshal.Copy(value.GetByteArray()
StructureToPtr(offset, value);
}
internal DateTime ReadDate(int offset)
{
short[] buffer = new short[3];
ReadInt16Array(offset, buffer, 0, 3);
return new DateTime(
unchecked((ushort)buffer[0]), // Year
unchecked((ushort)buffer[1]), // Month
unchecked((ushort)buffer[2])); // Day
}
internal void WriteDate(int offset, DateTime value)
{
short[] buffer = new short[3] {
unchecked((short)value.Year),
unchecked((short)value.Month),
unchecked((short)value.Day),
};
WriteInt16Array(offset, buffer, 0, 3);
}
internal TimeSpan ReadTime(int offset)
{
short[] buffer = new short[3];
ReadInt16Array(offset, buffer, 0, 3);
return new TimeSpan(
unchecked((ushort)buffer[0]), // Hours
unchecked((ushort)buffer[1]), // Minutes
unchecked((ushort)buffer[2])); // Seconds
}
internal void WriteTime(int offset, TimeSpan value)
{
short[] buffer = new short[3] {
unchecked((short)value.Hours),
unchecked((short)value.Minutes),
unchecked((short)value.Seconds),
};
WriteInt16Array(offset, buffer, 0, 3);
}
internal DateTime ReadDateTime(int offset)
{
short[] buffer = new short[6];
ReadInt16Array(offset, buffer, 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
return value.AddTicks(ticks / 100);
}
internal void WriteDateTime(int offset, DateTime value)
{
int ticks = (int)(value.Ticks % 10000000L) * 100;
short[] buffer = new 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);
WriteInt32(offset + 12, ticks);
}
internal decimal ReadNumeric(int offset)
{
byte[] bits = new byte[20];
ReadBytes(offset, bits, 1, 19);
int[] buffer = new int[4];
buffer[3] = ((int)bits[2]) << 16; // scale
if (0 == bits[3])
{
buffer[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))
{
throw ADP.NumericToDecimalOverflow();
}
return new decimal(buffer);
}
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);
}
[Conditional("DEBUG")]
protected void ValidateCheck(int offset, int count)
{
Validate(offset, count);
}
protected void Validate(int offset, int count)
{
if ((offset < 0) || (count < 0) || (Length < checked(offset + count)))
{
throw ADP.InternalError(ADP.InternalErrorCode.InvalidBuffer);
}
}
}
}
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