250 lines
8.8 KiB
C#
250 lines
8.8 KiB
C#
|
// ==++==
|
||
|
|
//
|
||
|
|
// Copyright (c) Microsoft Corporation. All rights reserved.
|
||
|
|
//
|
||
|
|
// ==--==
|
||
|
|
// EncoderBestFitFallback.cs
|
||
|
|
//
|
||
|
|
// This is used internally to create best fit behavior as per the original windows best fit behavior.
|
||
|
|
//
|
||
|
|
namespace System.Text
|
||
|
|
{
|
||
|
|
using System;
|
||
|
|
using System.Globalization;
|
||
|
|
using System.Text;
|
||
|
|
using System.Threading;
|
||
|
|
using System.Diagnostics.Contracts;
|
||
|
|
|
||
|
|
[Serializable]
|
||
|
|
internal class InternalEncoderBestFitFallback : EncoderFallback
|
||
|
|
{
|
||
|
|
// Our variables
|
||
|
|
internal Encoding encoding = null;
|
||
|
|
internal char[] arrayBestFit = null;
|
||
|
|
|
||
|
|
internal InternalEncoderBestFitFallback(Encoding encoding)
|
||
|
|
{
|
||
|
|
// Need to load our replacement characters table.
|
||
|
|
this.encoding = encoding;
|
||
|
|
this.bIsMicrosoftBestFitFallback = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
public override EncoderFallbackBuffer CreateFallbackBuffer()
|
||
|
|
{
|
||
|
|
return new InternalEncoderBestFitFallbackBuffer(this);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Maximum number of characters that this instance of this fallback could return
|
||
|
|
public override int MaxCharCount
|
||
|
|
{
|
||
|
|
get
|
||
|
|
{
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public override bool Equals(Object value)
|
||
|
|
{
|
||
|
|
InternalEncoderBestFitFallback that = value as InternalEncoderBestFitFallback;
|
||
|
|
if (that != null)
|
||
|
|
{
|
||
|
|
return (this.encoding.CodePage == that.encoding.CodePage);
|
||
|
|
}
|
||
|
|
return (false);
|
||
|
|
}
|
||
|
|
|
||
|
|
public override int GetHashCode()
|
||
|
|
{
|
||
|
|
return this.encoding.CodePage;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
internal sealed class InternalEncoderBestFitFallbackBuffer : EncoderFallbackBuffer
|
||
|
|
{
|
||
|
|
// Our variables
|
||
|
|
private char cBestFit = '\0';
|
||
|
|
private InternalEncoderBestFitFallback oFallback;
|
||
|
|
private int iCount = -1;
|
||
|
|
private int iSize;
|
||
|
|
|
||
|
|
// Private object for locking instead of locking on a public type for SQL reliability work.
|
||
|
|
private static Object s_InternalSyncObject;
|
||
|
|
private static Object InternalSyncObject
|
||
|
|
{
|
||
|
|
get
|
||
|
|
{
|
||
|
|
if (s_InternalSyncObject == null)
|
||
|
|
{
|
||
|
|
Object o = new Object();
|
||
|
|
Interlocked.CompareExchange<Object>(ref s_InternalSyncObject, o, null);
|
||
|
|
}
|
||
|
|
return s_InternalSyncObject;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Constructor
|
||
|
|
public InternalEncoderBestFitFallbackBuffer(InternalEncoderBestFitFallback fallback)
|
||
|
|
{
|
||
|
|
this.oFallback = fallback;
|
||
|
|
|
||
|
|
if (oFallback.arrayBestFit == null)
|
||
|
|
{
|
||
|
|
// Lock so we don't confuse ourselves.
|
||
|
|
lock(InternalSyncObject)
|
||
|
|
{
|
||
|
|
// Double check before we do it again.
|
||
|
|
if (oFallback.arrayBestFit == null)
|
||
|
|
oFallback.arrayBestFit = fallback.encoding.GetBestFitUnicodeToBytesData();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Fallback methods
|
||
|
|
public override bool Fallback(char charUnknown, int index)
|
||
|
|
{
|
||
|
|
// If we had a buffer already we're being recursive, throw, it's probably at the suspect
|
||
|
|
// character in our array.
|
||
|
|
// Shouldn't be able to get here for all of our code pages, table would have to be messed up.
|
||
|
|
Contract.Assert(iCount < 1, "[InternalEncoderBestFitFallbackBuffer.Fallback(non surrogate)] Fallback char " + ((int)cBestFit).ToString("X4", CultureInfo.InvariantCulture) + " caused recursive fallback");
|
||
|
|
|
||
|
|
iCount = iSize = 1;
|
||
|
|
cBestFit = TryBestFit(charUnknown);
|
||
|
|
if (cBestFit == '\0')
|
||
|
|
cBestFit = '?';
|
||
|
|
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
public override bool Fallback(char charUnknownHigh, char charUnknownLow, int index)
|
||
|
|
{
|
||
|
|
// Double check input surrogate pair
|
||
|
|
if (!Char.IsHighSurrogate(charUnknownHigh))
|
||
|
|
throw new ArgumentOutOfRangeException("charUnknownHigh",
|
||
|
|
Environment.GetResourceString("ArgumentOutOfRange_Range",
|
||
|
|
0xD800, 0xDBFF));
|
||
|
|
|
||
|
|
if (!Char.IsLowSurrogate(charUnknownLow))
|
||
|
|
throw new ArgumentOutOfRangeException("CharUnknownLow",
|
||
|
|
Environment.GetResourceString("ArgumentOutOfRange_Range",
|
||
|
|
0xDC00, 0xDFFF));
|
||
|
|
Contract.EndContractBlock();
|
||
|
|
|
||
|
|
// If we had a buffer already we're being recursive, throw, it's probably at the suspect
|
||
|
|
// character in our array. 0 is processing last character, < 0 is not falling back
|
||
|
|
// Shouldn't be able to get here, table would have to be messed up.
|
||
|
|
Contract.Assert(iCount < 1, "[InternalEncoderBestFitFallbackBuffer.Fallback(surrogate)] Fallback char " + ((int)cBestFit).ToString("X4", CultureInfo.InvariantCulture) + " caused recursive fallback");
|
||
|
|
|
||
|
|
// Go ahead and get our fallback, surrogates don't have best fit
|
||
|
|
cBestFit = '?';
|
||
|
|
iCount = iSize = 2;
|
||
|
|
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Default version is overridden in EncoderReplacementFallback.cs
|
||
|
|
public override char GetNextChar()
|
||
|
|
{
|
||
|
|
// We want it to get < 0 because == 0 means that the current/last character is a fallback
|
||
|
|
// and we need to detect recursion. We could have a flag but we already have this counter.
|
||
|
|
iCount--;
|
||
|
|
|
||
|
|
// Do we have anything left? 0 is now last fallback char, negative is nothing left
|
||
|
|
if (iCount < 0)
|
||
|
|
return '\0';
|
||
|
|
|
||
|
|
// Need to get it out of the buffer.
|
||
|
|
// Make sure it didn't wrap from the fast count-- path
|
||
|
|
if (iCount == int.MaxValue)
|
||
|
|
{
|
||
|
|
iCount = -1;
|
||
|
|
return '\0';
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return the best fit character
|
||
|
|
return cBestFit;
|
||
|
|
}
|
||
|
|
|
||
|
|
public override bool MovePrevious()
|
||
|
|
{
|
||
|
|
// Exception fallback doesn't have anywhere to back up to.
|
||
|
|
if (iCount >= 0)
|
||
|
|
iCount++;
|
||
|
|
|
||
|
|
// Return true if we could do it.
|
||
|
|
return (iCount >= 0 && iCount <= iSize);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// How many characters left to output?
|
||
|
|
public override int Remaining
|
||
|
|
{
|
||
|
|
get
|
||
|
|
{
|
||
|
|
return (iCount > 0) ? iCount : 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Clear the buffer
|
||
|
|
[System.Security.SecuritySafeCritical] // overrides public transparent member
|
||
|
|
public override unsafe void Reset()
|
||
|
|
{
|
||
|
|
iCount = -1;
|
||
|
|
charStart = null;
|
||
|
|
bFallingBack = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
// private helper methods
|
||
|
|
private char TryBestFit(char cUnknown)
|
||
|
|
{
|
||
|
|
// Need to figure out our best fit character, low is beginning of array, high is 1 AFTER end of array
|
||
|
|
int lowBound = 0;
|
||
|
|
int highBound = oFallback.arrayBestFit.Length;
|
||
|
|
int index;
|
||
|
|
|
||
|
|
// Binary search the array
|
||
|
|
int iDiff;
|
||
|
|
while ((iDiff = (highBound - lowBound)) > 6)
|
||
|
|
{
|
||
|
|
// Look in the middle, which is complicated by the fact that we have 2 #s for each pair,
|
||
|
|
// so we don't want index to be odd because we want to be on word boundaries.
|
||
|
|
// Also note that index can never == highBound (because diff is rounded down)
|
||
|
|
index = ((iDiff / 2) + lowBound) & 0xFFFE;
|
||
|
|
|
||
|
|
char cTest = oFallback.arrayBestFit[index];
|
||
|
|
if (cTest == cUnknown)
|
||
|
|
{
|
||
|
|
// We found it
|
||
|
|
Contract.Assert(index + 1 < oFallback.arrayBestFit.Length,
|
||
|
|
"[InternalEncoderBestFitFallbackBuffer.TryBestFit]Expected replacement character at end of array");
|
||
|
|
return oFallback.arrayBestFit[index + 1];
|
||
|
|
}
|
||
|
|
else if (cTest < cUnknown)
|
||
|
|
{
|
||
|
|
// We weren't high enough
|
||
|
|
lowBound = index;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// We weren't low enough
|
||
|
|
highBound = index;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
for (index = lowBound; index < highBound; index += 2)
|
||
|
|
{
|
||
|
|
if (oFallback.arrayBestFit[index] == cUnknown)
|
||
|
|
{
|
||
|
|
// We found it
|
||
|
|
Contract.Assert(index + 1 < oFallback.arrayBestFit.Length,
|
||
|
|
"[InternalEncoderBestFitFallbackBuffer.TryBestFit]Expected replacement character at end of array");
|
||
|
|
return oFallback.arrayBestFit[index + 1];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Char wasn't in our table
|
||
|
|
return '\0';
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|