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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.IO;
using System.Runtime.CompilerServices;
using System.Runtime.Serialization;
using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;
namespace System.Data.SqlTypes
{
internal enum SqlBytesCharsState
{
Null = 0,
Buffer = 1,
//IntPtr = 2,
Stream = 3,
}
[XmlSchemaProvider("GetXsdType")]
public sealed class SqlBytes : INullable, IXmlSerializable, ISerializable
{
// --------------------------------------------------------------
// Data members
// --------------------------------------------------------------
// SqlBytes has five possible states
// 1) SqlBytes is Null
// - m_stream must be null, m_lCuLen must be x_lNull.
// 2) SqlBytes contains a valid buffer,
// - m_rgbBuf must not be null,m_stream must be null
// 3) SqlBytes contains a valid pointer
// - m_rgbBuf could be null or not,
// if not null, content is garbage, should never look into it.
// - m_stream must be null.
// 4) SqlBytes contains a Stream
// - m_stream must not be null
// - m_rgbBuf could be null or not. if not null, content is garbage, should never look into it.
// - m_lCurLen must be x_lNull.
// 5) SqlBytes contains a Lazy Materialized Blob (ie, StorageState.Delayed)
//
internal byte[]? _rgbBuf; // Data buffer
private long _lCurLen; // Current data length
internal Stream? _stream;
private SqlBytesCharsState _state;
// The max data length that we support at this time.
private const long x_lMaxLen = int.MaxValue;
private const long x_lNull = -1L;
// --------------------------------------------------------------
// Constructor(s)
// --------------------------------------------------------------
// Public default constructor used for XML serialization
public SqlBytes()
{
SetNull();
}
// Create a SqlBytes with an in-memory buffer
public SqlBytes(byte[]? buffer)
{
_rgbBuf = buffer;
_stream = null;
if (_rgbBuf == null)
{
_state = SqlBytesCharsState.Null;
_lCurLen = x_lNull;
}
else
{
_state = SqlBytesCharsState.Buffer;
_lCurLen = _rgbBuf.Length;
}
AssertValid();
}
// Create a SqlBytes from a SqlBinary
public SqlBytes(SqlBinary value) : this(value.IsNull ? null : value.Value!)
{
}
public SqlBytes(Stream? s)
{
// Create a SqlBytes from a Stream
_rgbBuf = null;
_lCurLen = x_lNull;
_stream = s;
_state = (s == null) ? SqlBytesCharsState.Null : SqlBytesCharsState.Stream;
AssertValid();
}
// --------------------------------------------------------------
// Public properties
// --------------------------------------------------------------
// INullable
public bool IsNull
{
get
{
return _state == SqlBytesCharsState.Null;
}
}
// Property: the in-memory buffer of SqlBytes
// Return Buffer even if SqlBytes is Null.
public byte[]? Buffer
{
get
{
if (FStream())
{
CopyStreamToBuffer();
}
return _rgbBuf;
}
}
// Property: the actual length of the data
public long Length
{
get
{
return _state switch
{
SqlBytesCharsState.Null => throw new SqlNullValueException(),
SqlBytesCharsState.Stream => _stream!.Length,
_ => _lCurLen,
};
}
}
// Property: the max length of the data
// Return MaxLength even if SqlBytes is Null.
// When the buffer is also null, return -1.
// If containing a Stream, return -1.
public long MaxLength
{
get
{
return _state switch
{
SqlBytesCharsState.Stream => -1L,
_ => (_rgbBuf == null) ? -1L : _rgbBuf.Length,
};
}
}
// Property: get a copy of the data in a new byte[] array.
public byte[] Value
{
get
{
byte[] buffer;
switch (_state)
{
case SqlBytesCharsState.Null:
throw new SqlNullValueException();
case SqlBytesCharsState.Stream:
if (_stream!.Length > x_lMaxLen)
throw new SqlTypeException(SR.SqlMisc_BufferInsufficientMessage);
buffer = new byte[_stream.Length];
if (_stream.Position != 0)
_stream.Seek(0, SeekOrigin.Begin);
_stream.ReadExactly(buffer, 0, checked((int)_stream.Length));
break;
default:
buffer = new byte[_lCurLen];
Array.Copy(_rgbBuf!, buffer, (int)_lCurLen);
break;
}
return buffer;
}
}
// class indexer
public byte this[long offset]
{
get
{
ArgumentOutOfRangeException.ThrowIfNegative(offset);
ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual(offset, Length);
byte b = 0;
Read(offset, new Span<byte>(ref b));
return b;
}
set
{
Write(offset, new ReadOnlySpan<byte>(in value));
}
}
public StorageState Storage
{
get
{
return _state switch
{
SqlBytesCharsState.Null => throw new SqlNullValueException(),
SqlBytesCharsState.Stream => StorageState.Stream,
SqlBytesCharsState.Buffer => StorageState.Buffer,
_ => StorageState.UnmanagedBuffer,
};
}
}
public Stream Stream
{
get
{
return FStream() ? _stream! : new StreamOnSqlBytes(this);
}
set
{
_lCurLen = x_lNull;
_stream = value;
_state = (value == null) ? SqlBytesCharsState.Null : SqlBytesCharsState.Stream;
AssertValid();
}
}
// --------------------------------------------------------------
// Public methods
// --------------------------------------------------------------
public void SetNull()
{
_lCurLen = x_lNull;
_stream = null;
_state = SqlBytesCharsState.Null;
AssertValid();
}
// Set the current length of the data
// If the SqlBytes is Null, setLength will make it non-Null.
public void SetLength(long value)
{
ArgumentOutOfRangeException.ThrowIfNegative(value);
if (FStream())
{
_stream!.SetLength(value);
}
else
{
// If there is a buffer, even the value of SqlBytes is Null,
// still allow setting length to zero, which will make it not Null.
// If the buffer is null, raise exception
//
if (null == _rgbBuf)
throw new SqlTypeException(SR.SqlMisc_NoBufferMessage);
ArgumentOutOfRangeException.ThrowIfGreaterThan(value, _rgbBuf.Length);
if (IsNull)
{
// At this point we know that value is small enough
// Go back in buffer mode
_state = SqlBytesCharsState.Buffer;
}
_lCurLen = value;
}
AssertValid();
}
internal long Read(long offset, Span<byte> buffer)
{
if (IsNull)
throw new SqlNullValueException();
ArgumentOutOfRangeException.ThrowIfGreaterThan(offset, Length);
ArgumentOutOfRangeException.ThrowIfNegative(offset);
return ReadNoValidation(offset, buffer);
}
// Read data of specified length from specified offset into a buffer
public long Read(long offset, byte[] buffer, int offsetInBuffer, int count)
{
if (IsNull)
throw new SqlNullValueException();
// Validate the arguments
ArgumentNullException.ThrowIfNull(buffer);
ArgumentOutOfRangeException.ThrowIfGreaterThan(offset, Length);
ArgumentOutOfRangeException.ThrowIfNegative(offset);
ArgumentOutOfRangeException.ThrowIfGreaterThan(offsetInBuffer, Length);
ArgumentOutOfRangeException.ThrowIfNegative(offsetInBuffer);
ArgumentOutOfRangeException.ThrowIfNegative(count);
ArgumentOutOfRangeException.ThrowIfGreaterThan(count, buffer.Length - offsetInBuffer);
return ReadNoValidation(offset, buffer.AsSpan(offsetInBuffer, count));
}
private long ReadNoValidation(long offset, Span<byte> buffer)
{
if (_state == SqlBytesCharsState.Stream)
{
if (_stream!.Position != offset)
_stream.Seek(offset, SeekOrigin.Begin);
return _stream.Read(buffer);
}
// Adjust count based on data length
int count = Math.Min(buffer.Length, (int)(Length - offset));
Span<byte> span = _rgbBuf!.AsSpan((int)offset, count);
span.CopyTo(buffer);
return span.Length;
}
internal void Write(long offset, ReadOnlySpan<byte> buffer)
{
if (FStream())
{
if (_stream!.Position != offset)
_stream.Seek(offset, SeekOrigin.Begin);
_stream.Write(buffer);
}
else
{
if (_rgbBuf == null)
throw new SqlTypeException(SR.SqlMisc_NoBufferMessage);
ArgumentOutOfRangeException.ThrowIfNegative(offset);
if (offset > _rgbBuf.Length)
throw new SqlTypeException(SR.SqlMisc_BufferInsufficientMessage);
if (buffer.Length > _rgbBuf.Length - offset)
throw new SqlTypeException(SR.SqlMisc_BufferInsufficientMessage);
WriteNoValidation(offset, buffer);
}
}
// Write data of specified length into the SqlBytes from specified offset
public void Write(long offset, byte[] buffer, int offsetInBuffer, int count)
{
if (FStream())
{
if (_stream!.Position != offset)
_stream.Seek(offset, SeekOrigin.Begin);
_stream.Write(buffer, offsetInBuffer, count);
}
else
{
// Validate the arguments
ArgumentNullException.ThrowIfNull(buffer);
if (_rgbBuf == null)
throw new SqlTypeException(SR.SqlMisc_NoBufferMessage);
ArgumentOutOfRangeException.ThrowIfNegative(offset);
if (offset > _rgbBuf.Length)
throw new SqlTypeException(SR.SqlMisc_BufferInsufficientMessage);
ArgumentOutOfRangeException.ThrowIfNegative(offsetInBuffer);
ArgumentOutOfRangeException.ThrowIfGreaterThan(offsetInBuffer, buffer.Length);
ArgumentOutOfRangeException.ThrowIfNegative(count);
ArgumentOutOfRangeException.ThrowIfGreaterThan(count, buffer.Length - offsetInBuffer);
if (count > _rgbBuf.Length - offset)
throw new SqlTypeException(SR.SqlMisc_BufferInsufficientMessage);
WriteNoValidation(offset, buffer.AsSpan(offsetInBuffer, count));
}
AssertValid();
}
private void WriteNoValidation(long offset, ReadOnlySpan<byte> buffer)
{
if (IsNull)
{
// If NULL and there is buffer inside, we only allow writing from
// offset zero.
//
if (offset != 0)
throw new SqlTypeException(SR.SqlMisc_WriteNonZeroOffsetOnNullMessage);
// treat as if our current length is zero.
// Note this has to be done after all inputs are validated, so that
// we won't throw exception after this point.
//
_lCurLen = 0;
_state = SqlBytesCharsState.Buffer;
}
else if (offset > _lCurLen)
{
// Don't allow writing from an offset that this larger than current length.
// It would leave uninitialized data in the buffer.
//
throw new SqlTypeException(SR.SqlMisc_WriteOffsetLargerThanLenMessage);
}
if (buffer.Length != 0)
{
Span<byte> span = _rgbBuf.AsSpan((int)offset, buffer.Length);
buffer.CopyTo(span);
// If the last position that has been written is after
// the current data length, reset the length
if (_lCurLen < offset + buffer.Length)
_lCurLen = offset + buffer.Length;
}
}
public SqlBinary ToSqlBinary()
{
return IsNull ? SqlBinary.Null : new SqlBinary(Value);
}
// --------------------------------------------------------------
// Conversion operators
// --------------------------------------------------------------
// Alternative method: ToSqlBinary()
public static explicit operator SqlBinary(SqlBytes value)
{
return value.ToSqlBinary();
}
// Alternative method: constructor SqlBytes(SqlBinary)
public static explicit operator SqlBytes(SqlBinary value)
{
return new SqlBytes(value);
}
// --------------------------------------------------------------
// Private utility functions
// --------------------------------------------------------------
[Conditional("DEBUG")]
private void AssertValid()
{
Debug.Assert(_state >= SqlBytesCharsState.Null && _state <= SqlBytesCharsState.Stream);
if (IsNull)
{
}
else
{
Debug.Assert((_lCurLen >= 0 && _lCurLen <= x_lMaxLen) || FStream());
Debug.Assert(FStream() || (_rgbBuf != null && _lCurLen <= _rgbBuf.Length));
Debug.Assert(!FStream() || (_lCurLen == x_lNull));
}
}
// Copy the data from the Stream to the array buffer.
// If the SqlBytes doesn't hold a buffer or the buffer
// is not big enough, allocate new byte array.
private void CopyStreamToBuffer()
{
Debug.Assert(FStream());
long lStreamLen = _stream!.Length;
if (lStreamLen >= x_lMaxLen)
throw new SqlTypeException(SR.SqlMisc_WriteOffsetLargerThanLenMessage);
if (_rgbBuf == null || _rgbBuf.Length < lStreamLen)
_rgbBuf = new byte[lStreamLen];
if (_stream.Position != 0)
_stream.Seek(0, SeekOrigin.Begin);
_stream.ReadExactly(_rgbBuf, 0, (int)lStreamLen);
_stream = null;
_lCurLen = lStreamLen;
_state = SqlBytesCharsState.Buffer;
AssertValid();
}
// whether the SqlBytes contains a pointer
// whether the SqlBytes contains a Stream
internal bool FStream()
{
return _state == SqlBytesCharsState.Stream;
}
private void SetBuffer(byte[]? buffer)
{
_rgbBuf = buffer;
_lCurLen = (_rgbBuf == null) ? x_lNull : _rgbBuf.Length;
_stream = null;
_state = (_rgbBuf == null) ? SqlBytesCharsState.Null : SqlBytesCharsState.Buffer;
AssertValid();
}
// --------------------------------------------------------------
// XML Serialization
// --------------------------------------------------------------
XmlSchema? IXmlSerializable.GetSchema()
{
return null;
}
void IXmlSerializable.ReadXml(XmlReader r)
{
byte[]? value = null;
string? isNull = r.GetAttribute("nil", XmlSchema.InstanceNamespace);
if (isNull != null && XmlConvert.ToBoolean(isNull))
{
// Read the next value.
r.ReadElementString();
SetNull();
}
else
{
string base64 = r.ReadElementString();
if (base64 == null)
{
value = Array.Empty<byte>();
}
else
{
base64 = base64.Trim();
if (base64.Length == 0)
value = Array.Empty<byte>();
else
value = Convert.FromBase64String(base64);
}
}
SetBuffer(value);
}
void IXmlSerializable.WriteXml(XmlWriter writer)
{
if (IsNull)
{
writer.WriteAttributeString("xsi", "nil", XmlSchema.InstanceNamespace, "true");
}
else
{
byte[] value = Buffer!;
writer.WriteString(Convert.ToBase64String(value, 0, (int)(Length)));
}
}
public static XmlQualifiedName GetXsdType(XmlSchemaSet schemaSet)
{
return new XmlQualifiedName("base64Binary", XmlSchema.Namespace);
}
// --------------------------------------------------------------
// Serialization using ISerializable
// --------------------------------------------------------------
// State information is not saved. The current state is converted to Buffer and only the underlying
// array is serialized, except for Null, in which case this state is kept.
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
throw new PlatformNotSupportedException();
}
// --------------------------------------------------------------
// Static fields, properties
// --------------------------------------------------------------
// Get a Null instance.
// Since SqlBytes is mutable, have to be property and create a new one each time.
public static SqlBytes Null
{
get
{
return new SqlBytes((byte[]?)null);
}
}
} // class SqlBytes
// StreamOnSqlBytes is a stream build on top of SqlBytes, and
// provides the Stream interface. The purpose is to help users
// to read/write SqlBytes object. After getting the stream from
// SqlBytes, users could create a BinaryReader/BinaryWriter object
// to easily read and write primitive types.
internal sealed class StreamOnSqlBytes : Stream
{
// --------------------------------------------------------------
// Data members
// --------------------------------------------------------------
private SqlBytes _sb; // the SqlBytes object
private long _lPosition;
// --------------------------------------------------------------
// Constructor(s)
// --------------------------------------------------------------
internal StreamOnSqlBytes(SqlBytes sb)
{
_sb = sb;
_lPosition = 0;
}
// --------------------------------------------------------------
// Public properties
// --------------------------------------------------------------
// Always can read/write/seek, unless sb is null,
// which means the stream has been closed.
public override bool CanRead
{
get
{
return _sb != null && !_sb.IsNull;
}
}
public override bool CanSeek
{
get
{
return _sb != null;
}
}
public override bool CanWrite
{
get
{
return _sb != null && (!_sb.IsNull || _sb._rgbBuf != null);
}
}
public override long Length
{
get
{
CheckIfStreamClosed("get_Length");
return _sb.Length;
}
}
public override long Position
{
get
{
CheckIfStreamClosed("get_Position");
return _lPosition;
}
set
{
CheckIfStreamClosed("set_Position");
ArgumentOutOfRangeException.ThrowIfNegative(value);
ArgumentOutOfRangeException.ThrowIfGreaterThan(value, _sb.Length);
_lPosition = value;
}
}
// --------------------------------------------------------------
// Public methods
// --------------------------------------------------------------
public override long Seek(long offset, SeekOrigin origin)
{
CheckIfStreamClosed();
long lPosition;
switch (origin)
{
case SeekOrigin.Begin:
ArgumentOutOfRangeException.ThrowIfNegative(offset);
ArgumentOutOfRangeException.ThrowIfGreaterThan(offset, _sb.Length);
_lPosition = offset;
break;
case SeekOrigin.Current:
lPosition = _lPosition + offset;
ArgumentOutOfRangeException.ThrowIfNegative(lPosition, nameof(offset));
ArgumentOutOfRangeException.ThrowIfGreaterThan(lPosition, _sb.Length, nameof(offset));
_lPosition = lPosition;
break;
case SeekOrigin.End:
lPosition = _sb.Length + offset;
ArgumentOutOfRangeException.ThrowIfNegative(lPosition, nameof(offset));
ArgumentOutOfRangeException.ThrowIfGreaterThan(lPosition, _sb.Length, nameof(offset));
_lPosition = lPosition;
break;
default:
throw ADP.InvalidSeekOrigin(nameof(offset));
}
return _lPosition;
}
public override int Read(Span<byte> buffer)
{
CheckIfStreamClosed();
return ReadNoValidation(buffer);
}
// The Read/Write/ReadByte/WriteByte simply delegates to SqlBytes
public override int Read(byte[] buffer, int offset, int count)
{
CheckIfStreamClosed();
ValidateBufferArguments(buffer, offset, count);
return ReadNoValidation(buffer.AsSpan(offset, count));
}
private int ReadNoValidation(Span<byte> buffer)
{
int bytesRead = (int)_sb.Read(_lPosition, buffer);
_lPosition += bytesRead;
return bytesRead;
}
public override void Write(ReadOnlySpan<byte> buffer)
{
CheckIfStreamClosed();
WriteNoValidation(buffer);
}
public override void Write(byte[] buffer, int offset, int count)
{
CheckIfStreamClosed();
ValidateBufferArguments(buffer, offset, count);
WriteNoValidation(buffer);
}
private void WriteNoValidation(ReadOnlySpan<byte> buffer)
{
_sb.Write(_lPosition, buffer);
_lPosition += buffer.Length;
}
public override int ReadByte()
{
CheckIfStreamClosed();
// If at the end of stream, return -1, rather than call SqlBytes.ReadByte,
// which will throw exception. This is the behavior for Stream.
//
if (_lPosition >= _sb.Length)
return -1;
int ret = _sb[_lPosition];
_lPosition++;
return ret;
}
public override void WriteByte(byte value)
{
CheckIfStreamClosed();
_sb[_lPosition] = value;
_lPosition++;
}
public override void SetLength(long value)
{
CheckIfStreamClosed();
_sb.SetLength(value);
if (_lPosition > value)
_lPosition = value;
}
// Flush is a no-op for stream on SqlBytes, because they are all in memory
public override void Flush()
{
if (_sb.FStream())
_sb._stream!.Flush();
}
protected override void Dispose(bool disposing)
{
// When m_sb is null, it means the stream has been closed, and
// any opearation in the future should fail.
// This is the only case that m_sb is null.
try
{
_sb = null!;
}
finally
{
base.Dispose(disposing);
}
}
// --------------------------------------------------------------
// Private utility functions
// --------------------------------------------------------------
private bool FClosed()
{
return _sb == null;
}
private void CheckIfStreamClosed([CallerMemberName] string methodname = "")
{
if (FClosed())
throw ADP.StreamClosed(methodname);
}
} // class StreamOnSqlBytes
} // namespace System.Data.SqlTypes
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