Hi,
UnmanagedMemoryStream class implementation.
Thnx,
Sri
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//------------------------------------------------------------------------------
//
// System.IO.UnmanagedMemoryStream.cs
//
// Copyright (C) 2006 Sridhar Kulkarni, All Rights Reserved
//
// Author: Sridhar Kulkarni ([EMAIL PROTECTED])
// Created: Monday, July 10, 2006
//
//------------------------------------------------------------------------------
//
// Copyright (C) 2005-2006 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
#if NET_2_0
using System;
using System.IO;
using System.Runtime.InteropServices;
namespace System.IO
{
[CLSCompliantAttribute(false)]
public class UnmanagedMemoryStream : Stream{
private bool canwrite;
private bool canread;
private int length;
private bool closed;
private bool canseek = false;
private long capacity;
private FileAccess fileaccess;
private MemoryStream memstream = null;
private byte* initialpointer;
private byte* currentpointer;
private bool initialposition;
private long currentposition;
private byte* membyteptr; //Local ptr for reallocation of memory;
#region Constructor
protected UnmanagedMemoryStream() {
if (memstream == null){
memstream = new MemoryStream();
canread = true;
canwrite = false;
initialposition = 0;
canseek = true;
closed = false;
currentposition = initialposition;
}
}
public unsafe UnmanagedMemoryStream (byte* pointer, long len){
if (pointer == null)
throw new ArgumentNullException("The pointer value is a null
reference ");
if (len < 0)
throw new ArgumentOutOfRangeException("The length value is
less than zero");
if (memstream == null){
canread = true;
canwrite = false;
length = len;
capacity = len;
initialposition = 0;
currentposition = initialposition;
canseek = true;
closed = false;
initialpointer = pointer;
currentpointer = initialpointer;
}
}
public unsafe UnmanagedMemoryStream (byte* pointer, long len,
long cap, FileAccess access){
if (pointer == null)
throw new ArgumentNullException("The pointer value is a null
reference");
if (len < 0)
throw new ArgumentOutOfRangeException("The length value is
less than zero");
if (capacity < 0)
throw new ArgumentOutOfRangeException("The capacity value is
less than zero");
if (len > capacity)
throw new ArgumentOutOfRangeException("The length value is
greater than the capacity value");
fileaccess = access;
length = len;
capacity = cap;
initialposition = 0;
currentposition = initialposition;
canseek = true;
initialpointer = pointer;
currentpointer = initialpointer;
closed = false;
if (access = FileAccess.Read)
canread = true;
if (access = FileAccess.Write){
canread = false;
canwrite = true;
}
if (access = FileAccess.ReadWrite){
canwrite = true;
canread = true;
}
}
#endregion
#region Properties
public override bool CanRead {
get{
if(closed)
return false;
else
return (canread);
}
}
public override bool CanSeek {
get{
return ((closed) ? false : true);
}
}
public override bool CanWrite {
get{
if (closed)
return (false);
else
return (canwrite);
}
}
public long Capacity {
get{
if (closed)
throw new ObjectDisposedException("The stream is
closed");
else
return (capacity);
}
}
public override long Length {
get{
if (closed)
throw new ObjectDisposedException("The stream is
closed");
else
return (length);
}
}
public override long Position {
get{
if (closed)
throw new ObjectDisposedException("The stream is
closed");
else
return (currentposition);
}
set{
if (closed)
throw new ObjectDisposedException("The stream is
closed");
if (value < 0 || value > (long)Int32.MaxValue)
throw new ArgumentOutOfRangeException("value that is
less than zero, or the position is larger than Int32.MaxValue");
else
currentposition = value;
}
}
public unsafe byte* PositionPointer {
get{
return(currentpointer);
}
set{
if (value > capacity)
throw new IndexOutOfRangeException("The current position
is larger than the capacity of the stream");
if (value <0 && value > capacity)
throw new ArgumentOutOfRangeException("The position is
being set is not a valid position in the current stream");
if (value < 0)
throw new IOException("The position is being set is not
a valid position in the current stream");
currentpointer += value;
}
}
#endregion
#region Methods
public override int Read ([InAttribute] [OutAttribute] byte[]
buffer,
int offset, int count){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (!canread)
throw new NotSupportedException("Read property is false");
if (buffer == null)
throw new ArgumentNullException("The buffer parameter is set
to a null reference");
if (offset < 0 || count < 0)
throw new ArgumentOutOfRangeException("The offset or count
parameter is less than zero");
if ((buffer.Length - offset) < count)
throw new ArgumentException("The length of the buffer array
minus the offset parameter is less than the count parameter");
//TODO: reading stream
if (currentposition == capacity)
return (0);
Marshal.Copy(initialpointer, buffer, offset, length);
currentposition += length;
currentpointer += length;
return (buffer.GetLength(0));
}
public override int ReadByte (){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (currentposition == capacity)
throw new NotSupportedException("The current position is at
the end of the stream");
if (!canread)
throw new NotSupportedException("The underlying memory does
not support reading");
//TODO:Advance one byte
int byteread;
int templength = 0;
if (templength == length)
return (-1);
else{
byteread = (int)Marshal.ReadByte(bytepointer);
currentposition++;
currentpointer++;
templength++;
return(byteread);
}
}
public override long Seek (long offset, SeekOrigin loc){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (offset > capacity)
throw new ArgumentOutOfRangeException("The offset value is
larger than the maximum size of the stream");
int refpoint;
switch(loc){
case SeekOrigin.Begin:
if (offset < 0)
throw new IOException("An attempt was made to seek
before the beginning of the stream");
refpoint = initialposition;
break;
case SeekOrigin.Current:
refpoint = currentposition;
break;
case SeekOrigin.End:
refpoint = length;
break;
default:
throw new ArgumentException("Invalid SeekOrigin
option");
break;
}
refpoint =+ (int)offset;
if (refpoint < initialposition)
throw new IOException("An attempt was made to seek before
the beginning of the stream");
currentposition = refpoint;
return(currentposition);
}
public override void SetLength (long value){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (value < 0 || value > capacity)
throw new ArgumentOutOfRangeException("The specified value
is negetive exceeds the capacity of the stream");
if (!canwrite)
throw new NotSupportedException("write property is set to
false");
length = value;
}
public override void Flush (){
if (closed)
throw new ObjectDisposedException("The stream is closed");
//This method performs no action for this class
//but is included as part of the Stream base class
}
public void Dispose (){
Dispose(true);
}
protected override void Dispose (bool disposing){
bytepointer = null;
currentposition = null;
initialposition = null;
closed = true;
}
public override void Write (byte[] buffer, int offset, int count){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (buffer == null)
throw new ArgumentNullException("The buffer parameter is a
null reference");
if (count > capacity)
throw new ArgumentOutOfRangeException("The count value is
greater than the capacity of the stream");
if (!canwrite)
throw new NotSupportedException("write property is set to
false");
if (offset < 0 || count < 0)
throw new ArgumentOutOfRangeException("One of the specified
parameters is less than zero");
if ((buffer.Length - offset) < count)
throw new ArgumentException("The length of the buffer array
minus the offset parameter is less than the count parameter");
//COPY data from managed buffer to unmanaged mem pointer
Marshal.Copy(buffer, offset, bytepointer, length);
currentposition += length;
currentpointer += length;
}
public override void WriteByte (byte value){
if (closed)
throw new ObjectDisposedException("The stream is closed");
if (!canwrite)
throw new NotSupportedException("write property is set to
false");
if (currentposition == capacity)
throw new NotSupportedException("The current position is at
the end of the capacity of the stream");
Marshal.WriteByte(bytepointer, value);
currentposition++;
currentpointer++;
}
#endregion
}
}
#endif
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