Leaked source code of windows server 2003
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/*++
Copyright (c) 1991-2000, Microsoft Corporation All rights reserved.
Module Name:
utf.c
Abstract:
This file contains functions that convert UTF strings to Unicode
strings and Unicode string to UTF strings.
External Routines found in this file:
UTFCPInfo
UTFToUnicode
UnicodeToUTF
Revision History:
02-06-96 JulieB Created.
03-20-99 SamerA Surrogate support.
--*/
//
// Include Files.
//
#include "nls.h"
#include "nlssafe.h"
#include "utf.h"
//
// Forward Declarations.
//
int
UTF7ToUnicode(
LPCSTR lpSrcStr,
int cchSrc,
LPWSTR lpDestStr,
int cchDest);
int
UTF8ToUnicode(
LPCSTR lpSrcStr,
int cchSrc,
LPWSTR lpDestStr,
int cchDest,
DWORD dwFlags);
int
UnicodeToUTF7(
LPCWSTR lpSrcStr,
int cchSrc,
LPSTR lpDestStr,
int cchDest);
int
UnicodeToUTF8(
LPCWSTR lpSrcStr,
int cchSrc,
LPSTR lpDestStr,
int cchDest);
//-------------------------------------------------------------------------//
// EXTERNAL ROUTINES //
//-------------------------------------------------------------------------//
////////////////////////////////////////////////////////////////////////////
//
// UTFCPInfo
//
// Gets the CPInfo for the given UTF code page.
//
// 10-23-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
BOOL UTFCPInfo(
UINT CodePage,
LPCPINFO lpCPInfo,
BOOL fExVer)
{
int ctr;
//
// Invalid Parameter Check:
// - validate code page
// - lpCPInfo is NULL
//
if ( (CodePage < CP_UTF7) || (CodePage > CP_UTF8) ||
(lpCPInfo == NULL) )
{
SetLastError(ERROR_INVALID_PARAMETER);
return (0);
}
switch (CodePage)
{
case ( CP_UTF7 ) :
{
lpCPInfo->MaxCharSize = 5;
break;
}
case ( CP_UTF8 ) :
{
lpCPInfo->MaxCharSize = 4;
break;
}
}
(lpCPInfo->DefaultChar)[0] = '?';
(lpCPInfo->DefaultChar)[1] = (BYTE)0;
for (ctr = 0; ctr < MAX_LEADBYTES; ctr++)
{
(lpCPInfo->LeadByte)[ctr] = (BYTE)0;
}
if (fExVer)
{
LPCPINFOEXW lpCPInfoEx = (LPCPINFOEXW)lpCPInfo;
lpCPInfoEx->UnicodeDefaultChar = L'?';
lpCPInfoEx->CodePage = CodePage;
}
return (TRUE);
}
////////////////////////////////////////////////////////////////////////////
//
// UTFToUnicode
//
// Maps a UTF character string to its wide character string counterpart.
//
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UTFToUnicode(
UINT CodePage,
DWORD dwFlags,
LPCSTR lpMultiByteStr,
int cbMultiByte,
LPWSTR lpWideCharStr,
int cchWideChar)
{
int rc = 0;
//
// Invalid Parameter Check:
// - validate code page
// - length of MB string is 0
// - wide char buffer size is negative
// - MB string is NULL
// - length of WC string is NOT zero AND
// (WC string is NULL OR src and dest pointers equal)
//
if ( (CodePage < CP_UTF7) || (CodePage > CP_UTF8) ||
(cbMultiByte == 0) || (cchWideChar < 0) ||
(lpMultiByteStr == NULL) ||
((cchWideChar != 0) &&
((lpWideCharStr == NULL) ||
(lpMultiByteStr == (LPSTR)lpWideCharStr))) )
{
SetLastError(ERROR_INVALID_PARAMETER);
return (0);
}
//
// Invalid Flags Check:
// - UTF7: flags not 0.
// - UTF8: flags not 0 nor MB_ERR_INVALID_CHARS.
//
if (CodePage == CP_UTF8)
{
// UTF8
if ((dwFlags & ~MB_ERR_INVALID_CHARS) != 0)
{
SetLastError(ERROR_INVALID_FLAGS);
return (0);
}
}
else if (dwFlags != 0)
{
// UTF7
SetLastError(ERROR_INVALID_FLAGS);
return (0);
}
//
// If cbMultiByte is -1, then the string is null terminated and we
// need to get the length of the string. Add one to the length to
// include the null termination. (This will always be at least 1.)
//
if (cbMultiByte <= -1)
{
cbMultiByte = strlen(lpMultiByteStr) + 1;
}
switch (CodePage)
{
case ( CP_UTF7 ) :
{
rc = UTF7ToUnicode( lpMultiByteStr,
cbMultiByte,
lpWideCharStr,
cchWideChar );
break;
}
case ( CP_UTF8 ) :
{
rc = UTF8ToUnicode( lpMultiByteStr,
cbMultiByte,
lpWideCharStr,
cchWideChar,
dwFlags);
break;
}
}
return (rc);
}
////////////////////////////////////////////////////////////////////////////
//
// UnicodeToUTF
//
// Maps a Unicode character string to its UTF string counterpart.
//
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UnicodeToUTF(
UINT CodePage,
DWORD dwFlags,
LPCWSTR lpWideCharStr,
int cchWideChar,
LPSTR lpMultiByteStr,
int cbMultiByte,
LPCSTR lpDefaultChar,
LPBOOL lpUsedDefaultChar)
{
int rc = 0;
//
// Invalid Parameter Check:
// - validate code page
// - length of WC string is 0
// - multibyte buffer size is negative
// - WC string is NULL
// - length of WC string is NOT zero AND
// (MB string is NULL OR src and dest pointers equal)
// - lpDefaultChar and lpUsedDefaultChar not NULL
//
if ( (CodePage < CP_UTF7) || (CodePage > CP_UTF8) ||
(cchWideChar == 0) || (cbMultiByte < 0) ||
(lpWideCharStr == NULL) ||
((cbMultiByte != 0) &&
((lpMultiByteStr == NULL) ||
(lpWideCharStr == (LPWSTR)lpMultiByteStr))) ||
(lpDefaultChar != NULL) || (lpUsedDefaultChar != NULL) )
{
SetLastError(ERROR_INVALID_PARAMETER);
return (0);
}
//
// Invalid Flags Check:
// - flags not 0
//
if (dwFlags != 0)
{
SetLastError(ERROR_INVALID_FLAGS);
return (0);
}
//
// If cchWideChar is -1, then the string is null terminated and we
// need to get the length of the string. Add one to the length to
// include the null termination. (This will always be at least 1.)
//
if (cchWideChar <= -1)
{
cchWideChar = NlsStrLenW(lpWideCharStr) + 1;
}
switch (CodePage)
{
case ( CP_UTF7 ) :
{
rc = UnicodeToUTF7( lpWideCharStr,
cchWideChar,
lpMultiByteStr,
cbMultiByte );
break;
}
case ( CP_UTF8 ) :
{
rc = UnicodeToUTF8( lpWideCharStr,
cchWideChar,
lpMultiByteStr,
cbMultiByte );
break;
}
}
return (rc);
}
//-------------------------------------------------------------------------//
// INTERNAL ROUTINES //
//-------------------------------------------------------------------------//
////////////////////////////////////////////////////////////////////////////
//
// UTF7ToUnicode
//
// Maps a UTF-7 character string to its wide character string counterpart.
//
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UTF7ToUnicode(
LPCSTR lpSrcStr,
int cchSrc,
LPWSTR lpDestStr,
int cchDest)
{
//CHAR is signed, so we have to cast lpSrcStr to an unsigned char below.
BYTE* pUTF7 = (BYTE*)lpSrcStr;
BOOL fShift = FALSE;
DWORD dwBit = 0; // 32-bit buffer to hold temporary bits
int iPos = 0; // 6-bit position pointer in the buffer
int cchWC = 0; // # of Unicode code points generated
while ((cchSrc--) && ((cchDest == 0) || (cchWC < cchDest)))
{
if (*pUTF7 > ASCII)
{
//
// Error - non ASCII char, so zero extend it.
//
if (cchDest)
{
lpDestStr[cchWC] = (WCHAR)*pUTF7;
}
cchWC++;
// Terminate the shifted sequence.
fShift = FALSE;
}
else if (!fShift)
{
//
// Not in shifted sequence.
//
if (*pUTF7 == SHIFT_IN)
{
if (cchSrc && (pUTF7[1] == SHIFT_OUT))
{
//
// "+-" means "+"
//
if (cchDest)
{
lpDestStr[cchWC] = (WCHAR)*pUTF7;
}
pUTF7++;
cchSrc--;
cchWC++;
}
else
{
//
// Start a new shift sequence.
//
fShift = TRUE;
}
}
else
{
//
// No need to shift.
//
if (cchDest)
{
lpDestStr[cchWC] = (WCHAR)*pUTF7;
}
cchWC++;
}
}
else
{
//
// Already in shifted sequence.
//
if (nBitBase64[*pUTF7] == -1)
{
//
// Any non Base64 char also ends shift state.
//
if (*pUTF7 != SHIFT_OUT)
{
//
// Not "-", so write it to the buffer.
//
if (cchDest)
{
lpDestStr[cchWC] = (WCHAR)*pUTF7;
}
cchWC++;
}
//
// Reset bits.
//
fShift = FALSE;
dwBit = 0;
iPos = 0;
}
else
{
//
// Store the bits in the 6-bit buffer and adjust the
// position pointer.
//
dwBit |= ((DWORD)nBitBase64[*pUTF7]) << (26 - iPos);
iPos += 6;
}
//
// Output the 16-bit Unicode value.
//
while (iPos >= 16)
{
if (cchDest)
{
if (cchWC < cchDest)
{
lpDestStr[cchWC] = (WCHAR)(dwBit >> 16);
}
else
{
break;
}
}
cchWC++;
dwBit <<= 16;
iPos -= 16;
}
if (iPos >= 16)
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
pUTF7++;
}
//
// Make sure the destination buffer was large enough.
//
if (cchDest && (cchSrc >= 0))
{
if (cchSrc == 0 && fShift && *(pUTF7--) == SHIFT_OUT)
{
//
// Do nothing here.
// If we are in shift-in mode previously, and the last byte is a shift-out byte ('-'),
// we should absorb this byte. So don't set error.
//
} else
{
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
}
//
// Return the number of Unicode characters written.
//
return (cchWC);
}
////////////////////////////////////////////////////////////////////////////
//
// UTF8ToUnicode
//
// Maps a UTF-8 character string to its wide character string counterpart.
//
// 04-22-2002 ShawnSte Fix bug 533476 where final characters are broken.
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UTF8ToUnicode(
LPCSTR lpSrcStr,
int cchSrc,
LPWSTR lpDestStr,
int cchDest,
DWORD dwFlags
)
{
int nTB = 0; // # trail bytes to follow
int cchWC = 0; // # of Unicode code points generated
CONST BYTE* pUTF8 = (CONST BYTE*)lpSrcStr;
DWORD dwUnicodeChar; // Our character with room for full surrogate char
BOOL bSurrogatePair = FALSE; // Indicate we'r collecting a surrogate pair
BOOL bCheckInvalidBytes = (dwFlags & MB_ERR_INVALID_CHARS);
BYTE UTF8;
// Note that we can't test destination buffer length here because we may have to
// iterate through thousands of broken characters which won't be output, even though
// the buffer has no more room.
while (cchSrc--)
{
//
// See if there are any trail bytes.
//
if (BIT7(*pUTF8) == 0)
{
//
// Found ASCII.
//
if (cchDest)
{
// In this function always test buffer size before using it
if (cchWC >= cchDest)
{
// Error: Buffer too small, we didn't process this character
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
lpDestStr[cchWC] = (WCHAR)*pUTF8;
}
nTB = bSurrogatePair = 0;
cchWC++;
}
else if (BIT6(*pUTF8) == 0)
{
//
// Found a trail byte.
// Note : Ignore the trail byte if there was no lead byte.
//
if (nTB != 0)
{
//
// Decrement the trail byte counter.
//
nTB--;
// Add room for trail byte and add the trail byte falue
dwUnicodeChar <<= 6;
dwUnicodeChar |= LOWER_6_BIT(*pUTF8);
// If we're done then we may need to store the data
if (nTB == 0)
{
if (bSurrogatePair)
{
if (cchDest)
{
if ((cchWC + 1) >= cchDest)
{
// Error: Buffer too small, we didn't process this character
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
lpDestStr[cchWC] = (WCHAR)
(((dwUnicodeChar - 0x10000) >> 10) + HIGH_SURROGATE_START);
lpDestStr[cchWC+1] = (WCHAR)
((dwUnicodeChar - 0x10000)%0x400 + LOW_SURROGATE_START);
}
//
// End of sequence. Advance the output counter, turn off surrogateness
//
cchWC += 2;
bSurrogatePair = FALSE;
}
else
{
if (cchDest)
{
if (cchWC >= cchDest)
{
// Error: Buffer too small, we didn't process this character
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
lpDestStr[cchWC] = (WCHAR)dwUnicodeChar;
}
//
// End of sequence. Advance the output counter.
//
cchWC++;
}
}
}
else
{
if (bCheckInvalidBytes)
{
SetLastError(ERROR_NO_UNICODE_TRANSLATION);
return (0);
}
// error - not expecting a trail byte. That is, there is a trailing byte without leading byte.
bSurrogatePair = FALSE;
}
}
else
{
//
// Found a lead byte.
//
if (nTB > 0)
{
// error - A leading byte before the previous sequence is completed.
if (bCheckInvalidBytes)
{
SetLastError(ERROR_NO_UNICODE_TRANSLATION);
return (0);
}
//
// Error - previous sequence not finished.
//
nTB = 0;
bSurrogatePair = FALSE;
// Put this character back so that we can start over another sequence.
cchSrc++;
pUTF8--;
}
else
{
//
// Calculate the number of bytes to follow.
// Look for the first 0 from left to right.
//
UTF8 = *pUTF8;
while (BIT7(UTF8) != 0)
{
UTF8 <<= 1;
nTB++;
}
// Recover the data from the byte
UTF8 >>= nTB;
//
// Check for non-shortest form.
//
switch (nTB)
{
case 1:
nTB = 0;
break;
case 2:
// Make sure that bit 8 ~ bit 11 is not all zero.
// 110XXXXx 10xxxxxx
if ((*pUTF8 & 0x1e) == 0)
{
nTB = 0;
}
break;
case 3:
// Look ahead to check for non-shortest form.
// 1110XXXX 10Xxxxxx 10xxxxxx
if (cchSrc >= 2)
{
if (((*pUTF8 & 0x0f) == 0) && (*(pUTF8 + 1) & 0x20) == 0)
{
nTB = 0;
}
}
break;
case 4:
//
// This is a surrogate unicode pair
//
if (cchSrc >= 3)
{
WORD word = (((WORD)*pUTF8) << 8) | *(pUTF8 + 1);
// Look ahead to check for non-shortest form.
// 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx
// Check if the 5 X bits are all zero.
// 0x0730 == 00000111 00110000
if ( (word & 0x0730) == 0 ||
// If the 21st bit is 1, we have extra work
( (word & 0x0400) == 0x0400 &&
// The 21st bit is 1.
// Make sure that the resulting Unicode is within the valid surrogate range.
// The 4 byte code sequence can hold up to 21 bits, and the maximum valid code point range
// that Unicode (with surrogate) could represent are from U+000000 ~ U+10FFFF.
// Therefore, if the 21 bit (the most significant bit) is 1, we should verify that the 17 ~ 20
// bit are all zero.
// I.e., in 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx,
// XXXXX can only be 10000.
// 0x0330 = 0000 0011 0011 0000
(word & 0x0330) != 0 ) )
{
// Not shortest form
nTB = 0;
}
else
{
// A real surrogate pair
bSurrogatePair = TRUE;
}
}
break;
default:
//
// If the bits is greater than 4, this is an invalid
// UTF8 lead byte.
//
nTB = 0;
break;
}
if (nTB != 0)
{
//
// Store the value from the first byte and decrement
// the number of bytes to follow.
//
dwUnicodeChar = UTF8;
nTB--;
} else
{
if (bCheckInvalidBytes)
{
SetLastError(ERROR_NO_UNICODE_TRANSLATION);
return (0);
}
}
}
}
pUTF8++;
}
if ((bCheckInvalidBytes && nTB != 0) || (cchWC == 0))
{
// About (cchWC == 0):
// Because we now throw away non-shortest form, it is possible that we generate 0 chars.
// In this case, we have to set error to ERROR_NO_UNICODE_TRANSLATION so that we conform
// to the spec of MultiByteToWideChar.
SetLastError(ERROR_NO_UNICODE_TRANSLATION);
return (0);
}
//
// Return the number of Unicode characters written.
//
return (cchWC);
}
////////////////////////////////////////////////////////////////////////////
//
// UnicodeToUTF7
//
// Maps a Unicode character string to its UTF-7 string counterpart.
//
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UnicodeToUTF7(
LPCWSTR lpSrcStr,
int cchSrc,
LPSTR lpDestStr,
int cchDest)
{
LPCWSTR lpWC = lpSrcStr;
BOOL fShift = FALSE;
DWORD dwBit = 0; // 32-bit buffer
int iPos = 0; // 6-bit position in buffer
int cchU7 = 0; // # of UTF7 chars generated
while ((cchSrc--) && ((cchDest == 0) || (cchU7 < cchDest)))
{
if ((*lpWC > ASCII) || (fShiftChar[*lpWC]))
{
//
// Need shift. Store 16 bits in buffer.
//
dwBit |= ((DWORD)*lpWC) << (16 - iPos);
iPos += 16;
if (!fShift)
{
//
// Not in shift state, so add "+".
//
if (cchDest)
{
lpDestStr[cchU7] = SHIFT_IN;
}
cchU7++;
//
// Go into shift state.
//
fShift = TRUE;
}
//
// Output 6 bits at a time as Base64 chars.
//
while (iPos >= 6)
{
if (cchDest)
{
if (cchU7 < cchDest)
{
//
// 26 = 32 - 6
//
lpDestStr[cchU7] = cBase64[(int)(dwBit >> 26)];
}
else
{
break;
}
}
cchU7++;
dwBit <<= 6; // remove from bit buffer
iPos -= 6; // adjust position pointer
}
if (iPos >= 6)
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
else
{
//
// No need to shift.
//
if (fShift)
{
//
// End the shift sequence.
//
fShift = FALSE;
if (iPos != 0)
{
//
// Some bits left in dwBit.
//
if (cchDest)
{
if ((cchU7 + 1) < cchDest)
{
lpDestStr[cchU7++] = cBase64[(int)(dwBit >> 26)];
lpDestStr[cchU7++] = SHIFT_OUT;
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
else
{
cchU7 += 2;
}
dwBit = 0; // reset bit buffer
iPos = 0; // reset postion pointer
}
else
{
//
// Simply end the shift sequence.
//
if (cchDest)
{
lpDestStr[cchU7++] = SHIFT_OUT;
}
else
{
cchU7++;
}
}
}
//
// Write the character to the buffer.
// If the character is "+", then write "+-".
//
if (cchDest)
{
if (cchU7 < cchDest)
{
lpDestStr[cchU7++] = (char)*lpWC;
if (*lpWC == SHIFT_IN)
{
if (cchU7 < cchDest)
{
lpDestStr[cchU7++] = SHIFT_OUT;
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
else
{
cchU7++;
if (*lpWC == SHIFT_IN)
{
cchU7++;
}
}
}
lpWC++;
}
//
// See if we're still in the shift state.
//
if (fShift)
{
if (iPos != 0)
{
//
// Some bits left in dwBit.
//
if (cchDest)
{
if ((cchU7 + 1) < cchDest)
{
lpDestStr[cchU7++] = cBase64[(int)(dwBit >> 26)];
lpDestStr[cchU7++] = SHIFT_OUT;
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
}
}
else
{
cchU7 += 2;
}
}
else
{
//
// Simply end the shift sequence.
//
if (cchDest)
{
if (cchU7 < cchDest)
{
lpDestStr[cchU7++] = SHIFT_OUT;
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
}
}
else
{
cchU7++;
}
}
}
//
// Make sure the destination buffer was large enough.
//
if (cchDest && (cchSrc >= 0))
{
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
//
// Return the number of UTF-7 characters written.
//
return (cchU7);
}
////////////////////////////////////////////////////////////////////////////
//
// UnicodeToUTF8
//
// Maps a Unicode character string to its UTF-8 string counterpart.
//
// 02-06-96 JulieB Created.
////////////////////////////////////////////////////////////////////////////
int UnicodeToUTF8(
LPCWSTR lpSrcStr,
int cchSrc,
LPSTR lpDestStr,
int cchDest)
{
LPCWSTR lpWC = lpSrcStr;
int cchU8 = 0; // # of UTF8 chars generated
DWORD dwSurrogateChar;
WCHAR wchHighSurrogate = 0;
BOOL bHandled;
while ((cchSrc--) && ((cchDest == 0) || (cchU8 < cchDest)))
{
bHandled = FALSE;
//
// Check if high surrogate is available
//
if ((*lpWC >= HIGH_SURROGATE_START) && (*lpWC <= HIGH_SURROGATE_END))
{
if (cchDest)
{
// Another high surrogate, then treat the 1st as normal
// Unicode character.
if (wchHighSurrogate)
{
if ((cchU8 + 2) < cchDest)
{
lpDestStr[cchU8++] = UTF8_1ST_OF_3 | HIGHER_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | MIDDLE_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | LOWER_6_BIT(wchHighSurrogate);
}
else
{
// not enough buffer
cchSrc++;
break;
}
}
}
else
{
cchU8 += 3;
}
wchHighSurrogate = *lpWC;
bHandled = TRUE;
}
if (!bHandled && wchHighSurrogate)
{
if ((*lpWC >= LOW_SURROGATE_START) && (*lpWC <= LOW_SURROGATE_END))
{
// wheee, valid surrogate pairs
if (cchDest)
{
if ((cchU8 + 3) < cchDest)
{
dwSurrogateChar = (((wchHighSurrogate-0xD800) << 10) + (*lpWC - 0xDC00) + 0x10000);
lpDestStr[cchU8++] = (UTF8_1ST_OF_4 |
(unsigned char)(dwSurrogateChar >> 18)); // 3 bits from 1st byte
lpDestStr[cchU8++] = (UTF8_TRAIL |
(unsigned char)((dwSurrogateChar >> 12) & 0x3f)); // 6 bits from 2nd byte
lpDestStr[cchU8++] = (UTF8_TRAIL |
(unsigned char)((dwSurrogateChar >> 6) & 0x3f)); // 6 bits from 3rd byte
lpDestStr[cchU8++] = (UTF8_TRAIL |
(unsigned char)(0x3f & dwSurrogateChar)); // 6 bits from 4th byte
}
else
{
// not enough buffer
cchSrc++;
break;
}
}
else
{
// we already counted 3 previously (in high surrogate)
cchU8 ++;
}
bHandled = TRUE;
}
else
{
// Bad Surrogate pair : ERROR
// Just process wchHighSurrogate , and the code below will
// process the current code point
if (cchDest)
{
if ((cchU8 + 2) < cchDest)
{
lpDestStr[cchU8++] = UTF8_1ST_OF_3 | HIGHER_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | MIDDLE_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | LOWER_6_BIT(wchHighSurrogate);
}
else
{
// not enough buffer
cchSrc++;
break;
}
}
}
wchHighSurrogate = 0;
}
if (!bHandled)
{
if (*lpWC <= ASCII)
{
//
// Found ASCII.
//
if (cchDest)
{
if (cchU8 < cchDest)
{
lpDestStr[cchU8] = (char)*lpWC;
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
cchU8++;
}
else if (*lpWC <= UTF8_2_MAX)
{
//
// Found 2 byte sequence if < 0x07ff (11 bits).
//
if (cchDest)
{
if ((cchU8 + 1) < cchDest)
{
//
// Use upper 5 bits in first byte.
// Use lower 6 bits in second byte.
//
lpDestStr[cchU8++] = UTF8_1ST_OF_2 | (*lpWC >> 6);
lpDestStr[cchU8++] = UTF8_TRAIL | LOWER_6_BIT(*lpWC);
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
else
{
cchU8 += 2;
}
}
else
{
//
// Found 3 byte sequence.
//
if (cchDest)
{
if ((cchU8 + 2) < cchDest)
{
//
// Use upper 4 bits in first byte.
// Use middle 6 bits in second byte.
// Use lower 6 bits in third byte.
//
lpDestStr[cchU8++] = UTF8_1ST_OF_3 | HIGHER_6_BIT(*lpWC);
lpDestStr[cchU8++] = UTF8_TRAIL | MIDDLE_6_BIT(*lpWC);
lpDestStr[cchU8++] = UTF8_TRAIL | LOWER_6_BIT(*lpWC);
}
else
{
//
// Error - buffer too small.
//
cchSrc++;
break;
}
}
else
{
cchU8 += 3;
}
}
}
lpWC++;
}
//
// If the last character was a high surrogate, then handle it as a normal
// unicode character.
//
if ((cchSrc < 0) && (wchHighSurrogate != 0))
{
if (cchDest)
{
if ((cchU8 + 2) < cchDest)
{
lpDestStr[cchU8++] = UTF8_1ST_OF_3 | HIGHER_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | MIDDLE_6_BIT(wchHighSurrogate);
lpDestStr[cchU8++] = UTF8_TRAIL | LOWER_6_BIT(wchHighSurrogate);
}
else
{
cchSrc++;
}
}
}
//
// Make sure the destination buffer was large enough.
//
if (cchDest && (cchSrc >= 0))
{
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return (0);
}
//
// Return the number of UTF-8 characters written.
//
return (cchU8);
}