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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
#if FEATURE_CODEPAGES_FILE // requires BaseCodePageEncooding
namespace System.Text
{
using System;
using System.Diagnostics.Contracts;
using System.Text;
using System.Threading;
using System.Globalization;
using System.Runtime.Serialization;
using System.Security;
using System.Security.Permissions;
// SBCSCodePageEncoding
[Serializable]
internal class SBCSCodePageEncoding : BaseCodePageEncoding, ISerializable
{
// Pointers to our memory section parts
[NonSerialized]
[SecurityCritical]
unsafe char* mapBytesToUnicode = null; // char 256
[NonSerialized]
[SecurityCritical]
unsafe byte* mapUnicodeToBytes = null; // byte 65536
[NonSerialized]
[SecurityCritical]
unsafe int* mapCodePageCached = null; // to remember which CP is cached
const char UNKNOWN_CHAR=(char)0xFFFD;
// byteUnknown is used for default fallback only
[NonSerialized]
byte byteUnknown;
[NonSerialized]
char charUnknown;
[System.Security.SecurityCritical] // auto-generated
public SBCSCodePageEncoding(int codePage) : this(codePage, codePage)
{
}
[System.Security.SecurityCritical] // auto-generated
internal SBCSCodePageEncoding(int codePage, int dataCodePage) : base(codePage, dataCodePage)
{
}
// Constructor called by serialization.
// Note: We use the base GetObjectData however
[System.Security.SecurityCritical] // auto-generated
internal SBCSCodePageEncoding(SerializationInfo info, StreamingContext context) : base(0)
{
// Actually this can't ever get called, CodePageEncoding is our proxy
Contract.Assert(false, "Didn't expect to make it to SBCSCodePageEncoding serialization constructor");
throw new ArgumentNullException("this");
}
// We have a managed code page entry, so load our tables
// SBCS data section looks like:
//
// char[256] - what each byte maps to in unicode. No support for surrogates. 0 is undefined code point
// (except 0 for byte 0 is expected to be a real 0)
//
// byte/char* - Data for best fit (unicode->bytes), again no best fit for Unicode
// 1st WORD is Unicode // of 1st character position
// Next bytes are best fit byte for that position. Position is incremented after each byte
// byte < 0x20 means skip the next n positions. (Where n is the byte #)
// byte == 1 means that next word is another unicode code point #
// byte == 0 is unknown. (doesn't override initial WCHAR[256] table!
[System.Security.SecurityCritical] // auto-generated
protected override unsafe void LoadManagedCodePage()
{
// Should be loading OUR code page
Contract.Assert(pCodePage->CodePage == this.dataTableCodePage,
"[SBCSCodePageEncoding.LoadManagedCodePage]Expected to load data table code page");
// Make sure we're really a 1 byte code page
if (pCodePage->ByteCount != 1)
throw new NotSupportedException(
Environment.GetResourceString("NotSupported_NoCodepageData", CodePage));
// Remember our unknown bytes & chars
byteUnknown = (byte)pCodePage->ByteReplace;
charUnknown = pCodePage->UnicodeReplace;
// Get our mapped section 65536 bytes for unicode->bytes, 256 * 2 bytes for bytes->unicode
// Plus 4 byte to remember CP # when done loading it. (Don't want to get IA64 or anything out of alignment)
byte *pMemorySection = GetSharedMemory(65536*1 + 256*2 + 4 + iExtraBytes);
mapBytesToUnicode = (char*)pMemorySection;
mapUnicodeToBytes = (byte*)(pMemorySection + 256 * 2);
mapCodePageCached = (int*)(pMemorySection + 256 * 2 + 65536 * 1 + iExtraBytes);
// If its cached (& filled in) we don't have to do anything else
if (*mapCodePageCached != 0)
{
Contract.Assert(*mapCodePageCached == this.dataTableCodePage,
"[DBCSCodePageEncoding.LoadManagedCodePage]Expected mapped section cached page to be same as data table code page. Cached : " +
*mapCodePageCached + " Expected:" + this.dataTableCodePage);
if (*mapCodePageCached != this.dataTableCodePage)
throw new OutOfMemoryException(
Environment.GetResourceString("Arg_OutOfMemoryException"));
// If its cached (& filled in) we don't have to do anything else
return;
}
// Need to read our data file and fill in our section.
// WARNING: Multiple code pieces could do this at once (so we don't have to lock machine-wide)
// so be careful here. Only stick legal values in here, don't stick temporary values.
// Read our data file and set mapBytesToUnicode and mapUnicodeToBytes appropriately
// First table is just all 256 mappings
char* pTemp = (char*)&(pCodePage->FirstDataWord);
for (int b = 0; b < 256; b++)
{
// Don't want to force 0's to map Unicode wrong. 0 byte == 0 unicode already taken care of
if (pTemp[b] != 0 || b == 0)
{
mapBytesToUnicode[b] = pTemp[b];
if (pTemp[b] != UNKNOWN_CHAR)
mapUnicodeToBytes[pTemp[b]] = (byte)b;
}
else
{
mapBytesToUnicode[b] = UNKNOWN_CHAR;
}
}
// We're done with our mapped section, set our flag so others don't have to rebuild table.
*mapCodePageCached = this.dataTableCodePage;
}
// 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;
}
}
// Read in our best fit table
[System.Security.SecurityCritical] // auto-generated
protected unsafe override void ReadBestFitTable()
{
// Lock so we don't confuse ourselves.
lock(InternalSyncObject)
{
// If we got a best fit array already, then don't do this
if (arrayUnicodeBestFit == null)
{
//
// Read in Best Fit table.
//
// First check the SBCS->Unicode best fit table, which starts right after the
// 256 word data table. This table looks like word, word where 1st word is byte and 2nd
// word is replacement for that word. It ends when byte == 0.
byte* pData = (byte*)&(pCodePage->FirstDataWord);
pData += 512;
// Need new best fit array
char[] arrayTemp = new char[256];
for (int i = 0; i < 256; i++)
arrayTemp[i] = mapBytesToUnicode[i];
// See if our words are zero
ushort byteTemp;
while ((byteTemp = *((ushort*)pData)) != 0)
{
Contract.Assert(arrayTemp[byteTemp] == UNKNOWN_CHAR, String.Format(CultureInfo.InvariantCulture,
"[SBCSCodePageEncoding::ReadBestFitTable] Expected unallocated byte (not 0x{2:X2}) for best fit byte at 0x{0:X2} for code page {1}",
byteTemp, CodePage, (int)arrayTemp[byteTemp]));
pData += 2;
arrayTemp[byteTemp] = *((char*)pData);
pData += 2;
}
// Remember our new array
arrayBytesBestFit = arrayTemp;
// It was on 0, it needs to be on next byte
pData+=2;
byte* pUnicodeToSBCS = pData;
// Now count our characters from our Unicode->SBCS best fit table,
// which is right after our 256 byte data table
int iBestFitCount = 0;
// Now do the UnicodeToBytes Best Fit mapping (this is the one we normally think of when we say "best fit")
// pData should be pointing at the first data point for Bytes->Unicode table
int unicodePosition = *((ushort*)pData);
pData += 2;
while (unicodePosition < 0x10000)
{
// Get the next byte
byte input = *pData;
pData++;
// build our table:
if (input == 1)
{
// Use next 2 bytes as our byte position
unicodePosition = *((ushort*)pData);
pData+=2;
}
else if (input < 0x20 && input > 0 && input != 0x1e)
{
// Advance input characters
unicodePosition += input;
}
else
{
// Use this character if it isn't zero
if (input > 0)
iBestFitCount++;
// skip this unicode position in any case
unicodePosition++;
}
}
// Make an array for our best fit data
arrayTemp = new char[iBestFitCount*2];
// Now actually read in the data
// reset pData should be pointing at the first data point for Bytes->Unicode table
pData = pUnicodeToSBCS;
unicodePosition = *((ushort*)pData);
pData += 2;
iBestFitCount = 0;
while (unicodePosition < 0x10000)
{
// Get the next byte
byte input = *pData;
pData++;
// build our table:
if (input == 1)
{
// Use next 2 bytes as our byte position
unicodePosition = *((ushort*)pData);
pData+=2;
}
else if (input < 0x20 && input > 0 && input != 0x1e)
{
// Advance input characters
unicodePosition += input;
}
else
{
// Check for escape for glyph range
if (input == 0x1e)
{
// Its an escape, so just read next byte directly
input = *pData;
pData++;
}
// 0 means just skip me
if (input > 0)
{
// Use this character
arrayTemp[iBestFitCount++] = (char)unicodePosition;
// Have to map it to Unicode because best fit will need unicode value of best fit char.
arrayTemp[iBestFitCount++] = mapBytesToUnicode[input];
// This won't work if it won't round trip.
Contract.Assert(arrayTemp[iBestFitCount-1] != (char)0,
String.Format(CultureInfo.InvariantCulture,
"[SBCSCodePageEncoding.ReadBestFitTable] No valid Unicode value {0:X4} for round trip bytes {1:X4}, encoding {2}",
(int)mapBytesToUnicode[input], (int)input, CodePage));
}
unicodePosition++;
}
}
// Remember it
arrayUnicodeBestFit = arrayTemp;
}
}
}
// GetByteCount
// Note: We start by assuming that the output will be the same as count. Having
// an encoder or fallback may change that assumption
[System.Security.SecurityCritical] // auto-generated
internal override unsafe int GetByteCount(char* chars, int count, EncoderNLS encoder)
{
// Just need to ASSERT, this is called by something else internal that checked parameters already
Contract.Assert(count >= 0, "[SBCSCodePageEncoding.GetByteCount]count is negative");
Contract.Assert(chars != null, "[SBCSCodePageEncoding.GetByteCount]chars is null");
// Assert because we shouldn't be able to have a null encoder.
Contract.Assert(encoderFallback != null, "[SBCSCodePageEncoding.GetByteCount]Attempting to use null fallback");
CheckMemorySection();
// Need to test fallback
EncoderReplacementFallback fallback = null;
// Get any left over characters
char charLeftOver = (char)0;
if (encoder != null)
{
charLeftOver = encoder.charLeftOver;
Contract.Assert(charLeftOver == 0 || Char.IsHighSurrogate(charLeftOver),
"[SBCSCodePageEncoding.GetByteCount]leftover character should be high surrogate");
fallback = encoder.Fallback as EncoderReplacementFallback;
// Verify that we have no fallbackbuffer, actually for SBCS this is always empty, so just assert
Contract.Assert(!encoder.m_throwOnOverflow || !encoder.InternalHasFallbackBuffer ||
encoder.FallbackBuffer.Remaining == 0,
"[SBCSCodePageEncoding.GetByteCount]Expected empty fallback buffer at start");
}
else
{
// If we aren't using default fallback then we may have a complicated count.
fallback = this.EncoderFallback as EncoderReplacementFallback;
}
if ((fallback != null && fallback.MaxCharCount == 1)/* || bIsBestFit*/)
{
// Replacement fallback encodes surrogate pairs as two ?? (or two whatever), so return size is always
// same as input size.
// Note that no existing SBCS code pages map code points to supplimentary characters, so this is easy.
// We could however have 1 extra byte if the last call had an encoder and a funky fallback and
// if we don't use the funky fallback this time.
// Do we have an extra char left over from last time?
if (charLeftOver > 0)
count++;
return (count);
}
// It had a funky fallback, so its more complicated
// Need buffer maybe later
EncoderFallbackBuffer fallbackBuffer = null;
// prepare our end
int byteCount = 0;
char* charEnd = chars + count;
// We may have a left over character from last time, try and process it.
if (charLeftOver > 0)
{
// Since left over char was a surrogate, it'll have to be fallen back.
// Get Fallback
Contract.Assert(encoder != null, "[SBCSCodePageEncoding.GetByteCount]Expect to have encoder if we have a charLeftOver");
fallbackBuffer = encoder.FallbackBuffer;
fallbackBuffer.InternalInitialize(chars, charEnd, encoder, false);
// This will fallback a pair if *chars is a low surrogate
fallbackBuffer.InternalFallback(charLeftOver, ref chars);
}
// Now we may have fallback char[] already from the encoder
// Go ahead and do it, including the fallback.
char ch;
while ((ch = (fallbackBuffer == null) ? '\0' : fallbackBuffer.InternalGetNextChar()) != 0 ||
chars < charEnd)
{
// First unwind any fallback
if (ch == 0)
{
// No fallback, just get next char
ch = *chars;
chars++;
}
// get byte for this char
byte bTemp = mapUnicodeToBytes[ch];
// Check for fallback, this'll catch surrogate pairs too.
if (bTemp == 0 && ch != (char)0)
{
if (fallbackBuffer == null)
{
// Create & init fallback buffer
if (encoder == null)
fallbackBuffer = this.encoderFallback.CreateFallbackBuffer();
else
fallbackBuffer = encoder.FallbackBuffer;
// chars has moved so we need to remember figure it out so Exception fallback
// index will be correct
fallbackBuffer.InternalInitialize(charEnd - count, charEnd, encoder, false);
}
// Get Fallback
fallbackBuffer.InternalFallback(ch, ref chars);
continue;
}
// We'll use this one
byteCount++;
}
Contract.Assert(fallbackBuffer == null || fallbackBuffer.Remaining == 0,
"[SBCSEncoding.GetByteCount]Expected Empty fallback buffer at end");
return (int)byteCount;
}
[System.Security.SecurityCritical] // auto-generated
internal override unsafe int GetBytes(char* chars, int charCount,
byte* bytes, int byteCount, EncoderNLS encoder)
{
// Just need to ASSERT, this is called by something else internal that checked parameters already
Contract.Assert(bytes != null, "[SBCSCodePageEncoding.GetBytes]bytes is null");
Contract.Assert(byteCount >= 0, "[SBCSCodePageEncoding.GetBytes]byteCount is negative");
Contract.Assert(chars != null, "[SBCSCodePageEncoding.GetBytes]chars is null");
Contract.Assert(charCount >= 0, "[SBCSCodePageEncoding.GetBytes]charCount is negative");
// Assert because we shouldn't be able to have a null encoder.
Contract.Assert(encoderFallback != null, "[SBCSCodePageEncoding.GetBytes]Attempting to use null encoder fallback");
CheckMemorySection();
// Need to test fallback
EncoderReplacementFallback fallback = null;
// Get any left over characters
char charLeftOver = (char)0;
if (encoder != null)
{
charLeftOver = encoder.charLeftOver;
Contract.Assert(charLeftOver == 0 || Char.IsHighSurrogate(charLeftOver),
"[SBCSCodePageEncoding.GetBytes]leftover character should be high surrogate");
fallback = encoder.Fallback as EncoderReplacementFallback;
// Verify that we have no fallbackbuffer, for SBCS its always empty, so just assert
Contract.Assert(!encoder.m_throwOnOverflow || !encoder.InternalHasFallbackBuffer ||
encoder.FallbackBuffer.Remaining == 0,
"[SBCSCodePageEncoding.GetBytes]Expected empty fallback buffer at start");
// if (encoder.m_throwOnOverflow && encoder.InternalHasFallbackBuffer &&
// encoder.FallbackBuffer.Remaining > 0)
// throw new ArgumentException(Environment.GetResourceString("Argument_EncoderFallbackNotEmpty",
// this.EncodingName, encoder.Fallback.GetType()));
}
else
{
// If we aren't using default fallback then we may have a complicated count.
fallback = this.EncoderFallback as EncoderReplacementFallback;
}
// prepare our end
char* charEnd = chars + charCount;
byte* byteStart = bytes;
char* charStart = chars;
// See if we do the fast default or slightly slower fallback
if (fallback != null && fallback.MaxCharCount == 1)
{
// Make sure our fallback character is valid first
byte bReplacement = mapUnicodeToBytes[fallback.DefaultString[0]];
// Check for replacements in range, otherwise fall back to slow version.
if (bReplacement != 0)
{
// We should have exactly as many output bytes as input bytes, unless there's a left
// over character, in which case we may need one more.
// If we had a left over character will have to add a ? (This happens if they had a funky
// fallback last time, but not this time.) (We can't spit any out though
// because with fallback encoder each surrogate is treated as a seperate code point)
if (charLeftOver > 0)
{
// Have to have room
// Throw even if doing no throw version because this is just 1 char,
// so buffer will never be big enough
if (byteCount == 0)
ThrowBytesOverflow(encoder, true);
// This'll make sure we still have more room and also make sure our return value is correct.
*(bytes++) = bReplacement;
byteCount--; // We used one of the ones we were counting.
}
// This keeps us from overrunning our output buffer
if (byteCount < charCount)
{
// Throw or make buffer smaller?
ThrowBytesOverflow(encoder, byteCount < 1);
// Just use what we can
charEnd = chars + byteCount;
}
// Simple way
while (chars < charEnd)
{
char ch2 = *chars;
chars++;
byte bTemp = mapUnicodeToBytes[ch2];
// Check for fallback
if (bTemp == 0 && ch2 != (char)0)
*bytes = bReplacement;
else
*bytes = bTemp;
bytes++;
}
// Clear encoder
if (encoder != null)
{
encoder.charLeftOver = (char)0;
encoder.m_charsUsed = (int)(chars-charStart);
}
return (int)(bytes - byteStart);
}
}
// Slower version, have to do real fallback.
// For fallback we may need a fallback buffer, we know we aren't default fallback
EncoderFallbackBuffer fallbackBuffer = null;
// prepare our end
byte* byteEnd = bytes + byteCount;
// We may have a left over character from last time, try and process it.
if (charLeftOver > 0)
{
// Since left over char was a surrogate, it'll have to be fallen back.
// Get Fallback
Contract.Assert(encoder != null, "[SBCSCodePageEncoding.GetBytes]Expect to have encoder if we have a charLeftOver");
fallbackBuffer = encoder.FallbackBuffer;
fallbackBuffer.InternalInitialize(chars, charEnd, encoder, true);
// This will fallback a pair if *chars is a low surrogate
fallbackBuffer.InternalFallback(charLeftOver, ref chars);
if (fallbackBuffer.Remaining > byteEnd - bytes)
{
// Throw it, if we don't have enough for this we never will
ThrowBytesOverflow(encoder, true);
}
}
// Now we may have fallback char[] already from the encoder fallback above
// Go ahead and do it, including the fallback.
char ch;
while ((ch = (fallbackBuffer == null) ? '\0' : fallbackBuffer.InternalGetNextChar()) != 0 ||
chars < charEnd)
{
// First unwind any fallback
if (ch == 0)
{
// No fallback, just get next char
ch = *chars;
chars++;
}
// get byte for this char
byte bTemp = mapUnicodeToBytes[ch];
// Check for fallback, this'll catch surrogate pairs too.
if (bTemp == 0 && ch != (char)0)
{
// Get Fallback
if ( fallbackBuffer == null )
{
// Create & init fallback buffer
if (encoder == null)
fallbackBuffer = this.encoderFallback.CreateFallbackBuffer();
else
fallbackBuffer = encoder.FallbackBuffer;
// chars has moved so we need to remember figure it out so Exception fallback
// index will be correct
fallbackBuffer.InternalInitialize(charEnd - charCount, charEnd, encoder, true);
}
// Make sure we have enough room. Each fallback char will be 1 output char
// (or recursion exception will be thrown)
fallbackBuffer.InternalFallback(ch, ref chars);
if (fallbackBuffer.Remaining > byteEnd - bytes)
{
// Didn't use this char, reset it
Contract.Assert(chars > charStart,
"[SBCSCodePageEncoding.GetBytes]Expected chars to have advanced (fallback)");
chars--;
fallbackBuffer.InternalReset();
// Throw it & drop this data
ThrowBytesOverflow(encoder, chars == charStart);
break;
}
continue;
}
// We'll use this one
// Bounds check
if (bytes >= byteEnd)
{
// didn't use this char, we'll throw or use buffer
Contract.Assert(fallbackBuffer == null || fallbackBuffer.bFallingBack == false,
"[SBCSCodePageEncoding.GetBytes]Expected to NOT be falling back");
if (fallbackBuffer == null || fallbackBuffer.bFallingBack == false)
{
Contract.Assert(chars > charStart,
"[SBCSCodePageEncoding.GetBytes]Expected chars to have advanced (normal)");
chars--; // don't use last char
}
ThrowBytesOverflow(encoder, chars == charStart); // throw ?
break; // don't throw, stop
}
// Go ahead and add it
*bytes = bTemp;
bytes++;
}
// encoder stuff if we have one
if (encoder != null)
{
// Fallback stuck it in encoder if necessary, but we have to clear MustFlush cases
if (fallbackBuffer != null && !fallbackBuffer.bUsedEncoder)
// Clear it in case of MustFlush
encoder.charLeftOver = (char)0;
// Set our chars used count
encoder.m_charsUsed = (int)(chars - charStart);
}
// Expect Empty fallback buffer for SBCS
Contract.Assert(fallbackBuffer == null || fallbackBuffer.Remaining == 0,
"[SBCSEncoding.GetBytes]Expected Empty fallback buffer at end");
return (int)(bytes - byteStart);
}
// This is internal and called by something else,
[System.Security.SecurityCritical] // auto-generated
internal override unsafe int GetCharCount(byte* bytes, int count, DecoderNLS decoder)
{
// Just assert, we're called internally so these should be safe, checked already
Contract.Assert(bytes != null, "[SBCSCodePageEncoding.GetCharCount]bytes is null");
Contract.Assert(count >= 0, "[SBCSCodePageEncoding.GetCharCount]byteCount is negative");
CheckMemorySection();
// See if we have best fit
bool bUseBestFit = false;
// Only need decoder fallback buffer if not using default replacement fallback or best fit fallback.
DecoderReplacementFallback fallback = null;
if (decoder == null)
{
fallback = this.DecoderFallback as DecoderReplacementFallback;
bUseBestFit = this.DecoderFallback.IsMicrosoftBestFitFallback;
}
else
{
fallback = decoder.Fallback as DecoderReplacementFallback;
bUseBestFit = decoder.Fallback.IsMicrosoftBestFitFallback;
Contract.Assert(!decoder.m_throwOnOverflow || !decoder.InternalHasFallbackBuffer ||
decoder.FallbackBuffer.Remaining == 0,
"[SBCSCodePageEncoding.GetChars]Expected empty fallback buffer at start");
}
if (bUseBestFit || (fallback != null && fallback.MaxCharCount == 1))
{
// Just return length, SBCS stay the same length because they don't map to surrogate
// pairs and we don't have a decoder fallback.
return count;
}
// Might need one of these later
DecoderFallbackBuffer fallbackBuffer = null;
// Have to do it the hard way.
// Assume charCount will be == count
int charCount = count;
byte[] byteBuffer = new byte[1];
// Do it our fast way
byte* byteEnd = bytes + count;
// Quick loop
while (bytes < byteEnd)
{
// Faster if don't use *bytes++;
char c;
c = mapBytesToUnicode[*bytes];
bytes++;
// If unknown we have to do fallback count
if (c == UNKNOWN_CHAR)
{
// Must have a fallback buffer
if (fallbackBuffer == null)
{
// Need to adjust count so we get real start
if (decoder == null)
fallbackBuffer = this.DecoderFallback.CreateFallbackBuffer();
else
fallbackBuffer = decoder.FallbackBuffer;
fallbackBuffer.InternalInitialize(byteEnd - count, null);
}
// Use fallback buffer
byteBuffer[0] = *(bytes - 1);
charCount--; // We'd already reserved one for *(bytes-1)
charCount += fallbackBuffer.InternalFallback(byteBuffer, bytes);
}
}
// Fallback buffer must be empty
Contract.Assert(fallbackBuffer == null || fallbackBuffer.Remaining == 0,
"[SBCSEncoding.GetCharCount]Expected Empty fallback buffer at end");
// Converted sequence is same length as input
return charCount;
}
[System.Security.SecurityCritical] // auto-generated
internal override unsafe int GetChars(byte* bytes, int byteCount,
char* chars, int charCount, DecoderNLS decoder)
{
// Just need to ASSERT, this is called by something else internal that checked parameters already
Contract.Assert(bytes != null, "[SBCSCodePageEncoding.GetChars]bytes is null");
Contract.Assert(byteCount >= 0, "[SBCSCodePageEncoding.GetChars]byteCount is negative");
Contract.Assert(chars != null, "[SBCSCodePageEncoding.GetChars]chars is null");
Contract.Assert(charCount >= 0, "[SBCSCodePageEncoding.GetChars]charCount is negative");
CheckMemorySection();
// See if we have best fit
bool bUseBestFit = false;
// Do it fast way if using ? replacement or best fit fallbacks
byte* byteEnd = bytes + byteCount;
byte* byteStart = bytes;
char* charStart = chars;
// Only need decoder fallback buffer if not using default replacement fallback or best fit fallback.
DecoderReplacementFallback fallback = null;
if (decoder == null)
{
fallback = this.DecoderFallback as DecoderReplacementFallback;
bUseBestFit = this.DecoderFallback.IsMicrosoftBestFitFallback;
}
else
{
fallback = decoder.Fallback as DecoderReplacementFallback;
bUseBestFit = decoder.Fallback.IsMicrosoftBestFitFallback;
Contract.Assert(!decoder.m_throwOnOverflow || !decoder.InternalHasFallbackBuffer ||
decoder.FallbackBuffer.Remaining == 0,
"[SBCSCodePageEncoding.GetChars]Expected empty fallback buffer at start");
}
if (bUseBestFit || (fallback != null && fallback.MaxCharCount == 1))
{
// Try it the fast way
char replacementChar;
if (fallback == null)
replacementChar = '?'; // Best fit alwasy has ? for fallback for SBCS
else
replacementChar = fallback.DefaultString[0];
// Need byteCount chars, otherwise too small buffer
if (charCount < byteCount)
{
// Need at least 1 output byte, throw if must throw
ThrowCharsOverflow(decoder, charCount < 1);
// Not throwing, use what we can
byteEnd = bytes + charCount;
}
// Quick loop, just do '?' replacement because we don't have fallbacks for decodings.
while (bytes < byteEnd)
{
char c;
if (bUseBestFit)
{
if (arrayBytesBestFit == null)
{
ReadBestFitTable();
}
c = arrayBytesBestFit[*bytes];
}
else
c = mapBytesToUnicode[*bytes];
bytes++;
if (c == UNKNOWN_CHAR)
// This is an invalid byte in the ASCII encoding.
*chars = replacementChar;
else
*chars = c;
chars++;
}
// bytes & chars used are the same
if (decoder != null)
decoder.m_bytesUsed = (int)(bytes - byteStart);
return (int)(chars - charStart);
}
// Slower way's going to need a fallback buffer
DecoderFallbackBuffer fallbackBuffer = null;
byte[] byteBuffer = new byte[1];
char* charEnd = chars + charCount;
// Not quite so fast loop
while (bytes < byteEnd)
{
// Faster if don't use *bytes++;
char c = mapBytesToUnicode[*bytes];
bytes++;
// See if it was unknown
if (c == UNKNOWN_CHAR)
{
// Make sure we have a fallback buffer
if (fallbackBuffer == null)
{
if (decoder == null)
fallbackBuffer = this.DecoderFallback.CreateFallbackBuffer();
else
fallbackBuffer = decoder.FallbackBuffer;
fallbackBuffer.InternalInitialize(byteEnd - byteCount, charEnd);
}
// Use fallback buffer
Contract.Assert(bytes > byteStart,
"[SBCSCodePageEncoding.GetChars]Expected bytes to have advanced already (unknown byte)");
byteBuffer[0] = *(bytes - 1);
// Fallback adds fallback to chars, but doesn't increment chars unless the whole thing fits.
if (!fallbackBuffer.InternalFallback(byteBuffer, bytes, ref chars))
{
// May or may not throw, but we didn't get this byte
bytes--; // unused byte
fallbackBuffer.InternalReset(); // Didn't fall this back
ThrowCharsOverflow(decoder, bytes == byteStart); // throw?
break; // don't throw, but stop loop
}
}
else
{
// Make sure we have buffer space
if (chars >= charEnd)
{
Contract.Assert(bytes > byteStart,
"[SBCSCodePageEncoding.GetChars]Expected bytes to have advanced already (known byte)");
bytes--; // unused byte
ThrowCharsOverflow(decoder, bytes == byteStart); // throw?
break; // don't throw, but stop loop
}
*(chars) = c;
chars++;
}
}
// Might have had decoder fallback stuff.
if (decoder != null)
decoder.m_bytesUsed = (int)(bytes - byteStart);
// Expect Empty fallback buffer for GetChars
Contract.Assert(fallbackBuffer == null || fallbackBuffer.Remaining == 0,
"[SBCSEncoding.GetChars]Expected Empty fallback buffer at end");
return (int)(chars - charStart);
}
public override int GetMaxByteCount(int charCount)
{
if (charCount < 0)
throw new ArgumentOutOfRangeException("charCount",
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
Contract.EndContractBlock();
// Characters would be # of characters + 1 in case high surrogate is ? * max fallback
long byteCount = (long)charCount + 1;
if (EncoderFallback.MaxCharCount > 1)
byteCount *= EncoderFallback.MaxCharCount;
// 1 to 1 for most characters. Only surrogates with fallbacks have less.
if (byteCount > 0x7fffffff)
throw new ArgumentOutOfRangeException("charCount", Environment.GetResourceString("ArgumentOutOfRange_GetByteCountOverflow"));
return (int)byteCount;
}
public override int GetMaxCharCount(int byteCount)
{
if (byteCount < 0)
throw new ArgumentOutOfRangeException("byteCount",
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
Contract.EndContractBlock();
// Just return length, SBCS stay the same length because they don't map to surrogate
long charCount = (long)byteCount;
// 1 to 1 for most characters. Only surrogates with fallbacks have less, unknown fallbacks could be longer.
if (DecoderFallback.MaxCharCount > 1)
charCount *= DecoderFallback.MaxCharCount;
if (charCount > 0x7fffffff)
throw new ArgumentOutOfRangeException("byteCount", Environment.GetResourceString("ArgumentOutOfRange_GetCharCountOverflow"));
return (int)charCount;
}
// True if and only if the encoding only uses single byte code points. (Ie, ASCII, 1252, etc)
public override bool IsSingleByte
{
get
{
return true;
}
}
[System.Runtime.InteropServices.ComVisible(false)]
public override bool IsAlwaysNormalized(NormalizationForm form)
{
// Most of these code pages could be decomposed or have compatibility mappings for KC, KD, & D
// additionally the allow unassigned forms and IDNA wouldn't work either, so C is our choice.
if (form == NormalizationForm.FormC)
{
// Form C is only true for some code pages. They have to have all 256 code points assigned
// and not map to unassigned or combinable code points.
switch (CodePage)
{
// Return true for some code pages.
case 1252: // (Latin I - ANSI)
case 1250: // (Eastern Europe - ANSI)
case 1251: // (Cyrillic - ANSI)
case 1254: // (Turkish - ANSI)
case 1256: // (Arabic - ANSI)
case 28591: // (ISO 8859-1 Latin I)
case 437: // (United States - OEM)
case 737: // (Greek (aka 437G) - OEM)
case 775: // (Baltic - OEM)
case 850: // (Multilingual (Latin I) - OEM)
case 852: // (Slovak (Latin II) - OEM)
case 855: // (Cyrillic - OEM)
case 858: // (Multilingual (Latin I) - OEM + Euro)
case 860: // (Portuguese - OEM)
case 861: // (Icelandic - OEM)
case 862: // (Hebrew - OEM)
case 863: // (Canadian French - OEM)
case 865: // (Nordic - OEM)
case 866: // (Russian - OEM)
case 869: // (Modern Greek - OEM)
case 10007: // (Cyrillic - MAC)
case 10017: // (Ukraine - MAC)
case 10029: // (Latin II - MAC)
case 28592: // (ISO 8859-2 Eastern Europe)
case 28594: // (ISO 8859-4 Baltic)
case 28595: // (ISO 8859-5 Cyrillic)
case 28599: // (ISO 8859-9 Latin Alphabet No.5)
case 28603: // (ISO/IEC 8859-13:1998 (Lithuanian))
case 28605: // (ISO 8859-15 Latin 9 (IBM923=IBM819+Euro))
case 037: // (IBM EBCDIC U.S./Canada)
case 500: // (IBM EBCDIC International)
case 870: // (IBM EBCDIC Latin-2 Multilingual/ROECE)
case 1026: // (IBM EBCDIC Latin-5 Turkey)
case 1047: // (IBM Latin-1/Open System)
case 1140: // (IBM EBCDIC U.S./Canada (037+Euro))
case 1141: // (IBM EBCDIC Germany (20273(IBM273)+Euro))
case 1142: // (IBM EBCDIC Denmark/Norway (20277(IBM277+Euro))
case 1143: // (IBM EBCDIC Finland/Sweden (20278(IBM278)+Euro))
case 1144: // (IBM EBCDIC Italy (20280(IBM280)+Euro))
case 1145: // (IBM EBCDIC Latin America/Spain (20284(IBM284)+Euro))
case 1146: // (IBM EBCDIC United Kingdom (20285(IBM285)+Euro))
case 1147: // (IBM EBCDIC France (20297(IBM297+Euro))
case 1148: // (IBM EBCDIC International (500+Euro))
case 1149: // (IBM EBCDIC Icelandic (20871(IBM871+Euro))
case 20273: // (IBM EBCDIC Germany)
case 20277: // (IBM EBCDIC Denmark/Norway)
case 20278: // (IBM EBCDIC Finland/Sweden)
case 20280: // (IBM EBCDIC Italy)
case 20284: // (IBM EBCDIC Latin America/Spain)
case 20285: // (IBM EBCDIC United Kingdom)
case 20297: // (IBM EBCDIC France)
case 20871: // (IBM EBCDIC Icelandic)
case 20880: // (IBM EBCDIC Cyrillic)
case 20924: // (IBM Latin-1/Open System (IBM924=IBM1047+Euro))
case 21025: // (IBM EBCDIC Cyrillic (Serbian, Bulgarian))
case 720: // (Arabic - Transparent ASMO)
case 20866: // (Russian - KOI8)
case 21866: // (Ukrainian - KOI8-U)
return true;
}
}
// False for IDNA and unknown
return false;
}
}
}
#endif // FEATURE_CODEPAGES_FILE
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