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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
namespace System.Text
{
using System.Runtime.Serialization;
using System.Security.Permissions;
using System.Text;
using System;
using System.Diagnostics.Contracts;
// A Decoder is used to decode a sequence of blocks of bytes into a
// sequence of blocks of characters. Following instantiation of a decoder,
// sequential blocks of bytes are converted into blocks of characters through
// calls to the GetChars method. The decoder maintains state between the
// conversions, allowing it to correctly decode byte sequences that span
// adjacent blocks.
//
// Instances of specific implementations of the Decoder abstract base
// class are typically obtained through calls to the GetDecoder method
// of Encoding objects.
//
[Serializable]
internal class DecoderNLS : Decoder, ISerializable
{
// Remember our encoding
protected Encoding m_encoding;
[NonSerialized] protected bool m_mustFlush;
[NonSerialized] internal bool m_throwOnOverflow;
[NonSerialized] internal int m_bytesUsed;
#region Serialization
// Constructor called by serialization. called during deserialization.
internal DecoderNLS(SerializationInfo info, StreamingContext context)
{
throw new NotSupportedException(
String.Format(
System.Globalization.CultureInfo.CurrentCulture,
Environment.GetResourceString("NotSupported_TypeCannotDeserialized"), this.GetType()));
}
#if FEATURE_SERIALIZATION
// ISerializable implementation. called during serialization.
[System.Security.SecurityCritical] // auto-generated_required
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
SerializeDecoder(info);
info.AddValue("encoding", this.m_encoding);
info.SetType(typeof(Encoding.DefaultDecoder));
}
#endif
#endregion Serialization
internal DecoderNLS( Encoding encoding )
{
this.m_encoding = encoding;
this.m_fallback = this.m_encoding.DecoderFallback;
this.Reset();
}
// This is used by our child deserializers
internal DecoderNLS( )
{
this.m_encoding = null;
this.Reset();
}
public override void Reset()
{
if (m_fallbackBuffer != null)
m_fallbackBuffer.Reset();
}
public override unsafe int GetCharCount(byte[] bytes, int index, int count)
{
return GetCharCount(bytes, index, count, false);
}
[System.Security.SecuritySafeCritical] // auto-generated
public override unsafe int GetCharCount(byte[] bytes, int index, int count, bool flush)
{
// Validate Parameters
if (bytes == null)
throw new ArgumentNullException("bytes",
Environment.GetResourceString("ArgumentNull_Array"));
if (index < 0 || count < 0)
throw new ArgumentOutOfRangeException((index<0 ? "index" : "count"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (bytes.Length - index < count)
throw new ArgumentOutOfRangeException("bytes",
Environment.GetResourceString("ArgumentOutOfRange_IndexCountBuffer"));
Contract.EndContractBlock();
// Avoid null fixed problem
if (bytes.Length == 0)
bytes = new byte[1];
// Just call pointer version
fixed (byte* pBytes = bytes)
return GetCharCount(pBytes + index, count, flush);
}
[System.Security.SecurityCritical] // auto-generated
public unsafe override int GetCharCount(byte* bytes, int count, bool flush)
{
// Validate parameters
if (bytes == null)
throw new ArgumentNullException("bytes",
Environment.GetResourceString("ArgumentNull_Array"));
if (count < 0)
throw new ArgumentOutOfRangeException("count",
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
Contract.EndContractBlock();
// Remember the flush
this.m_mustFlush = flush;
this.m_throwOnOverflow = true;
// By default just call the encoding version, no flush by default
return m_encoding.GetCharCount(bytes, count, this);
}
public override unsafe int GetChars(byte[] bytes, int byteIndex, int byteCount,
char[] chars, int charIndex)
{
return GetChars(bytes, byteIndex, byteCount, chars, charIndex, false);
}
[System.Security.SecuritySafeCritical] // auto-generated
public override unsafe int GetChars(byte[] bytes, int byteIndex, int byteCount,
char[] chars, int charIndex, bool flush)
{
// Validate Parameters
if (bytes == null || chars == null)
throw new ArgumentNullException(bytes == null ? "bytes" : "chars",
Environment.GetResourceString("ArgumentNull_Array"));
if (byteIndex < 0 || byteCount < 0)
throw new ArgumentOutOfRangeException((byteIndex<0 ? "byteIndex" : "byteCount"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if ( bytes.Length - byteIndex < byteCount)
throw new ArgumentOutOfRangeException("bytes",
Environment.GetResourceString("ArgumentOutOfRange_IndexCountBuffer"));
if (charIndex < 0 || charIndex > chars.Length)
throw new ArgumentOutOfRangeException("charIndex",
Environment.GetResourceString("ArgumentOutOfRange_Index"));
Contract.EndContractBlock();
// Avoid empty input fixed problem
if (bytes.Length == 0)
bytes = new byte[1];
int charCount = chars.Length - charIndex;
if (chars.Length == 0)
chars = new char[1];
// Just call pointer version
fixed (byte* pBytes = bytes)
fixed (char* pChars = chars)
// Remember that charCount is # to decode, not size of array
return GetChars(pBytes + byteIndex, byteCount,
pChars + charIndex, charCount, flush);
}
[System.Security.SecurityCritical] // auto-generated
public unsafe override int GetChars(byte* bytes, int byteCount,
char* chars, int charCount, bool flush)
{
// Validate parameters
if (chars == null || bytes == null)
throw new ArgumentNullException((chars == null ? "chars" : "bytes"),
Environment.GetResourceString("ArgumentNull_Array"));
if (byteCount < 0 || charCount < 0)
throw new ArgumentOutOfRangeException((byteCount<0 ? "byteCount" : "charCount"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
Contract.EndContractBlock();
// Remember our flush
m_mustFlush = flush;
m_throwOnOverflow = true;
// By default just call the encoding's version
return m_encoding.GetChars(bytes, byteCount, chars, charCount, this);
}
// This method is used when the output buffer might not be big enough.
// Just call the pointer version. (This gets chars)
[System.Security.SecuritySafeCritical] // auto-generated
public override unsafe void Convert(byte[] bytes, int byteIndex, int byteCount,
char[] chars, int charIndex, int charCount, bool flush,
out int bytesUsed, out int charsUsed, out bool completed)
{
// Validate parameters
if (bytes == null || chars == null)
throw new ArgumentNullException((bytes == null ? "bytes" : "chars"),
Environment.GetResourceString("ArgumentNull_Array"));
if (byteIndex < 0 || byteCount < 0)
throw new ArgumentOutOfRangeException((byteIndex<0 ? "byteIndex" : "byteCount"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (charIndex < 0 || charCount < 0)
throw new ArgumentOutOfRangeException((charIndex<0 ? "charIndex" : "charCount"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (bytes.Length - byteIndex < byteCount)
throw new ArgumentOutOfRangeException("bytes",
Environment.GetResourceString("ArgumentOutOfRange_IndexCountBuffer"));
if (chars.Length - charIndex < charCount)
throw new ArgumentOutOfRangeException("chars",
Environment.GetResourceString("ArgumentOutOfRange_IndexCountBuffer"));
Contract.EndContractBlock();
// Avoid empty input problem
if (bytes.Length == 0)
bytes = new byte[1];
if (chars.Length == 0)
chars = new char[1];
// Just call the pointer version (public overrides can't do this)
fixed (byte* pBytes = bytes)
{
fixed (char* pChars = chars)
{
Convert(pBytes + byteIndex, byteCount, pChars + charIndex, charCount, flush,
out bytesUsed, out charsUsed, out completed);
}
}
}
// This is the version that used pointers. We call the base encoding worker function
// after setting our appropriate internal variables. This is getting chars
[System.Security.SecurityCritical] // auto-generated
public unsafe override void Convert(byte* bytes, int byteCount,
char* chars, int charCount, bool flush,
out int bytesUsed, out int charsUsed, out bool completed)
{
// Validate input parameters
if (chars == null || bytes == null)
throw new ArgumentNullException(chars == null ? "chars" : "bytes",
Environment.GetResourceString("ArgumentNull_Array"));
if (byteCount < 0 || charCount < 0)
throw new ArgumentOutOfRangeException((byteCount<0 ? "byteCount" : "charCount"),
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
Contract.EndContractBlock();
// We don't want to throw
this.m_mustFlush = flush;
this.m_throwOnOverflow = false;
this.m_bytesUsed = 0;
// Do conversion
charsUsed = this.m_encoding.GetChars(bytes, byteCount, chars, charCount, this);
bytesUsed = this.m_bytesUsed;
// Its completed if they've used what they wanted AND if they didn't want flush or if we are flushed
completed = (bytesUsed == byteCount) && (!flush || !this.HasState) &&
(m_fallbackBuffer == null || m_fallbackBuffer.Remaining == 0);
// Our data thingys are now full, we can return
}
public bool MustFlush
{
get
{
return m_mustFlush;
}
}
// Anything left in our decoder?
internal virtual bool HasState
{
get
{
return false;
}
}
// Allow encoding to clear our must flush instead of throwing (in ThrowCharsOverflow)
internal void ClearMustFlush()
{
m_mustFlush = false;
}
}
}
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