本文介绍了一个改进版的CStdioFileEx类，该类解决了原始CStdioFile在处理中文时的问题，并提供了Unicode文件读写的支持。通过自定义的函数，如GetUnicodeStringFromMultiByteString和GetMultiByteStringFromUnicodeString，该类能够更好地处理不同编码的文件。
// javascript缩放图片，双击小图看大图
Code
void CStaticUtilities::WebPreViewImageFile(CWebBrowser2 &browser, const CString &strImageFileUrl, const CString &strLocalCache, bool bForceRefreshLocal)
{
CString strDocomentHtml, strBrowseUrl=strImageFileUrl;
strBrowseUrl.Trim();
long nWidth=browser.GetWidth();
long nHeight=browser.GetHeight();
strDocomentHtml.Format( _T("<!DOCTYPE HTML PUBLIC ""-//W3C//DTD HTML 4.0 Transitional//EN"">"r"n")
_T("<HTML><HEAD>"r"n<META http-equiv=Content-Type content=""text/html; charset=unicode"">"r"n")
_T("<META content=""MSHTML 6.00.2900.2872"" name=GENERATOR></HEAD>"r"n<BODY>"r"n")
_T("<script language=""JavaScript""> "r"n")
_T("<!--"r"nfunction onImagedbclick(TheImage)"r"n {"r"n url = TheImage.src "r"nwindow.open(url, ""_blank"");"r"n }"r"n")
_T("var flag=false;"r"nfunction DrawImage(ImgD){"r"nvar image=new Image();"r"nvar iwidth = %d;"r"n var iheight = %d;"r"n")
_T("image.src=ImgD.src;"r"nif(image.width>0 && image.height>0){"r"nflag=true;"r"nif(image.width/image.height>= iwidth/iheight){"r"n")
_T("if(image.width>iwidth){"r"nImgD.width=iwidth;"r"nImgD.height=(image.height*iwidth)/image.width;"r"n}else{"r"nImgD.width=image.width;"r"n")
_T("ImgD.height=image.height;"r"n}"r"n}"r"nelse{"r"nif(image.height>iheight){"r"n")
_T("ImgD.height=iheight;"r"nImgD.width=(image.width*iheight)/image.height;"r"n}else{"r"nImgD.width=image.width;"r"n")
_T("ImgD.height=image.height;"r"n}"r"n}"r"n}"r"n}"r"n//-->"r"n</script>"r"n ")
_T("<table><tr><td align=""center"">")
_T("<IMG vspace=0 hspace=0 src=""%s"" align=center border=0 title=""Double click to view original picture"" ")
_T(" ondblclick=""javascript:onImagedbclick(this);"" onload = ""javascript:DrawImage(this);"" ></td></tr></table></BODY></HTML>"),
nWidth-s_nWidthMargin, nHeight-s_nHeithMargin, strBrowseUrl);
TCHAR szPath[MAX_PATH];
GetTempPath(MAX_PATH,szPath);
CString strPath = szPath;
strPath +=_T("tempHtmlImageSmallPreview.htm");
CStdioFileEx htmlFileEx;
htmlFileEx.Open(strPath, CStdioFileEx::modeWriteUnicode | CFile::modeCreate | CFile::modeReadWrite);
htmlFileEx.WriteString(strDocomentHtml);
htmlFileEx.Close();
browser.Navigate(strPath, NULL, NULL, NULL, NULL);
}
// 原始CStdioFile对中文不支持，CStdioFileEx能支持中文
// CStdioFileEx.h
Code
#define nUNICODE_BOM 0xFEFF // Unicode "byte order mark" which goes at start of file
#define sNEWLINE _T(""r"n") // New line characters
#define sDEFAULT_UNICODE_FILLER_CHAR "#" // Filler char used when no conversion from Unicode to local code page is possible
class CStdioFileEx: public CStdioFile
{
public:
CStdioFileEx();
CStdioFileEx( LPCTSTR lpszFileName, UINT nOpenFlags );
virtual BOOL Open( LPCTSTR lpszFileName, UINT nOpenFlags, CFileException* pError = NULL );
virtual BOOL ReadString(CString& rString);
virtual void WriteString( LPCTSTR lpsz );
bool IsFileUnicodeText() { return m_bIsUnicodeText; }
unsigned long GetCharCount();
// Additional flag to allow Unicode text writing
static const UINT modeWriteUnicode;
void SetCodePage(IN const UINT nCodePage);
// static utility functions
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetUnicodeStringFromMultiByteString()
//
// --------------------------------------------------------------------------------------------
// Returns: int - num. of chars written (0 means error)
// Parameters: char * szMultiByteString (IN) Multi-byte input string
// wchar_t* szUnicodeString (OUT) Unicode outputstring
// int nUnicodeBufferSize (IN) Size of Unicode output buffer (chars) (IN)
// int nCodePage (IN) Code page used to perform conversion
// Default = -1 (Get local code page).
//
// Purpose: Gets a Unicode string from a MultiByte string.
// Notes: None.
// Exceptions: None.
//
static int GetUnicodeStringFromMultiByteString(IN LPCSTR szMultiByteString, OUT wchar_t* szUnicodeString, IN int nUnicodeBufferSize, IN int nCodePage=-1);
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetMultiByteStringFromUnicodeString()
//
// --------------------------------------------------------------------------------------------
// Returns: int - number of characters written. 0 means error
// Parameters: wchar_t * szUnicodeString (IN) Unicode input string
// char* szMultiByteString (OUT) Multibyte output string
// int nMultiByteBufferSize (IN) Multibyte buffer size
// int nCodePage (IN) Code page used to perform conversion
// Default = -1 (Get local code page).
//
// Purpose: Gets a MultiByte string from a Unicode string.
// Notes: .
// Exceptions: None.
//
static int GetMultiByteStringFromUnicodeString(wchar_t * szUnicodeString,char* szMultiByteString,
int nMultiByteBufferSize,int nCodePage=-1);
//---------------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetRequiredMultiByteLengthForUnicodeString()
//
//---------------------------------------------------------------------------------------------------
// Returns: int
// Parameters: wchar_t * szUnicodeString,int nCodePage=-1
//
// Purpose: Obtains the multi-byte buffer size needed to accommodate a converted Unicode string.
// Notes: We can't assume that the buffer length is simply equal to the number of characters
// because that wouldn't accommodate multibyte characters!
//
static int GetRequiredMultiByteLengthForUnicodeString(wchar_t * szUnicodeString,int nCodePage=-1);
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::IsFileUnicode()
//
// --------------------------------------------------------------------------------------------
// Returns: bool
// Parameters: const CString& sFilePath
//
// Purpose: Determines whether a file is Unicode by reading the first character and detecting
// whether it's the Unicode byte marker.
// Notes: None.
// Exceptions: None.
//
static bool IsFileUnicode(const CString& sFilePath);
static UINT GetCurrentLocaleCodePage();
protected:
UINT ProcessFlags(const CString& sFilePath, UINT& nOpenFlags);
bool m_bIsUnicodeText;
UINT m_nFlags;
int m_nFileCodePage;
};
// CStdioFileEx.cpp
Code
// Version 1.1 23 August 2003. Incorporated fixes from Dennis Jeryd.
// Version 1.3 19 February 2005. Incorporated fixes from Howard J Oh and some of my own.
// Version 1.4 26 February 2005. Fixed stupid screw-up in code from 1.3.
// Version 1.5 18 November 2005. - Incorporated fixes from Andy Goodwin.
// - Allows code page to be specified for reading/writing
// - Properly calculates multibyte buffer size instead of
// assuming lstrlen(s).
// - Should handle UTF8 properly.
//
// Copyright David Pritchard 2003-2005. davidpritchard@ctv.es
//
// You can use this class freely, but please keep my ego happy
// by leaving this comment in place.
//
//////////////////////////////////////////////////////////////////////
#include "stdafx.h"
#include "StdioFileEx.h"
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
/*static*/ const UINT CStdioFileEx::modeWriteUnicode = 0x20000; // Add this flag to write in Unicode
CStdioFileEx::CStdioFileEx(): CStdioFile()
{
m_bIsUnicodeText = false;
m_nFileCodePage = -1;
}
CStdioFileEx::CStdioFileEx(LPCTSTR lpszFileName,UINT nOpenFlags)
:CStdioFile(lpszFileName, ProcessFlags(lpszFileName, nOpenFlags))
{
m_nFileCodePage = -1;
}
void CStdioFileEx::SetCodePage(IN const UINT nCodePage)
{
m_nFileCodePage = (int)nCodePage;
}
BOOL CStdioFileEx::Open(LPCTSTR lpszFileName,UINT nOpenFlags,CFileException* pError /*=NULL*/)
{
// Process any Unicode stuff
ProcessFlags(lpszFileName, nOpenFlags);
return CStdioFile::Open(lpszFileName, nOpenFlags, pError);
}
BOOL CStdioFileEx::ReadString(CString& rString)
{
const int nMAX_LINE_CHARS = 4096;
BOOL bReadData = FALSE;
LPTSTR lpsz;
int nLen = 0;
wchar_t* pszUnicodeString = NULL;
char * pszMultiByteString= NULL;
int nChars = 0;
try
{
// If at position 0, discard byte-order mark before reading
if (!m_pStream || (GetPosition() == 0 && m_bIsUnicodeText))
{
wchar_t cDummy;
// Read(&cDummy, sizeof(_TCHAR));
Read(&cDummy, sizeof(wchar_t));
}
// If compiled for Unicode
#ifdef _UNICODE
if (m_bIsUnicodeText)
{
// Do standard stuff - Unicode to Unicode. Seems to work OK.
bReadData = CStdioFile::ReadString(rString);
}
else
{
pszUnicodeString = new wchar_t[nMAX_LINE_CHARS];
pszMultiByteString= new char[nMAX_LINE_CHARS];
// Initialise to something safe
memset(pszUnicodeString, 0, sizeof(wchar_t) * nMAX_LINE_CHARS);
memset(pszMultiByteString, 0, sizeof(char) * nMAX_LINE_CHARS);
// Read the string
bReadData = (NULL != fgets(pszMultiByteString, nMAX_LINE_CHARS, m_pStream));
if (bReadData)
{
// Convert multibyte to Unicode, using the specified code page
nChars = GetUnicodeStringFromMultiByteString(pszMultiByteString, pszUnicodeString, nMAX_LINE_CHARS, m_nFileCodePage);
if (nChars > 0)
{
rString = (CString)pszUnicodeString;
}
}
}
#else
if (!m_bIsUnicodeText)
{
// Do standard stuff -- read ANSI in ANSI
bReadData = CStdioFile::ReadString(rString);
// Get the current code page
UINT nLocaleCodePage = GetCurrentLocaleCodePage();
// If we got it OK
if (nLocaleCodePage > 0)
{
// if file code page does not match the system code page, we need to do a double conversion!
if (nLocaleCodePage != (UINT)m_nFileCodePage)
{
int nStringBufferChars = rString.GetLength() + 1;
pszUnicodeString = new wchar_t[nStringBufferChars];
// Initialise to something safe
memset(pszUnicodeString, 0, sizeof(wchar_t) * nStringBufferChars);
// Convert to Unicode using the file code page
nChars = GetUnicodeStringFromMultiByteString(rString, pszUnicodeString, nStringBufferChars, m_nFileCodePage);
// Convert back to multibyte using the system code page
// (This doesn't really confer huge advantages except to avoid "mangling" of non-convertible special
// characters. So, if a file in the E.European code page is displayed on a system using the
// western European code page, special accented characters which the system cannot display will be
// replaced by the default character (a hash or something), rather than being incorrectly mapped to
// other, western European accented characters).
if (nChars > 0)
{
// Calculate how much we need for the MB buffer (it might be larger)
nStringBufferChars = GetRequiredMultiByteLengthForUnicodeString(pszUnicodeString,nLocaleCodePage);
pszMultiByteString= new char[nStringBufferChars];
nChars = GetMultiByteStringFromUnicodeString(pszUnicodeString, pszMultiByteString, nStringBufferChars, nLocaleCodePage);
rString = (CString)pszMultiByteString;
}
}
}
}
else
{
pszUnicodeString = new wchar_t[nMAX_LINE_CHARS];
// Initialise to something safe
memset(pszUnicodeString, 0, sizeof(wchar_t) * nMAX_LINE_CHARS);
// Read as Unicode, convert to ANSI
// Bug fix by Dennis Jeryd 06/07/2003: initialise bReadData
bReadData = (NULL != fgetws(pszUnicodeString, nMAX_LINE_CHARS, m_pStream));
if (bReadData)
{
// Calculate how much we need for the multibyte string
int nRequiredMBBuffer = GetRequiredMultiByteLengthForUnicodeString(pszUnicodeString,m_nFileCodePage);
pszMultiByteString= new char[nRequiredMBBuffer];
nChars = GetMultiByteStringFromUnicodeString(pszUnicodeString, pszMultiByteString, nRequiredMBBuffer, m_nFileCodePage);
if (nChars > 0)
{
rString = (CString)pszMultiByteString;
}
}
}
#endif
// Then remove end-of-line character if in Unicode text mode
if (bReadData)
{
// Copied from FileTxt.cpp but adapted to Unicode and then adapted for end-of-line being just '"r'.
nLen = rString.GetLength();
if (nLen > 1 && rString.Mid(nLen-2) == sNEWLINE)
{
rString.GetBufferSetLength(nLen-2);
}
else
{
lpsz = rString.GetBuffer(0);
if (nLen != 0 && (lpsz[nLen-1] == _T('"r') || lpsz[nLen-1] == _T('"n')))
{
rString.GetBufferSetLength(nLen-1);
}
}
}
}
// Ensure we always delete in case of exception
catch()
{
if (pszUnicodeString) delete [] pszUnicodeString;
if (pszMultiByteString) delete [] pszMultiByteString;
throw;
}
if (pszUnicodeString) delete [] pszUnicodeString;
if (pszMultiByteString) delete [] pszMultiByteString;
return bReadData;
}
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::WriteString()
//
// --------------------------------------------------------------------------------------------
// Returns: void
// Parameters: LPCTSTR lpsz
//
// Purpose: Writes string to file either in Unicode or multibyte, depending on whether the caller specified the
// CStdioFileEx::modeWriteUnicode flag. Override of base class function.
// Notes: If writing in Unicode we need to:
// a) Write the Byte-order-mark at the beginning of the file
// b) Write all strings in byte-mode
// - If we were compiled in Unicode, we need to convert Unicode to multibyte if
// we want to write in multibyte
// - If we were compiled in multi-byte, we need to convert multibyte to Unicode if
// we want to write in Unicode.
// Exceptions: None.
//
void CStdioFileEx::WriteString(LPCTSTR lpsz)
{
wchar_t* pszUnicodeString = NULL;
char * pszMultiByteString= NULL;
try
{
// If writing Unicode and at the start of the file, need to write byte mark
if (m_nFlags & CStdioFileEx::modeWriteUnicode)
{
// If at position 0, write byte-order mark before writing anything else
if (!m_pStream || GetPosition() == 0)
{
wchar_t cBOM = (wchar_t)nUNICODE_BOM;
CFile::Write(&cBOM, sizeof(wchar_t));
}
}
// If compiled in Unicode
#ifdef _UNICODE
// If writing Unicode, no conversion needed
if (m_nFlags & CStdioFileEx::modeWriteUnicode)
{
// Write in byte mode
CFile::Write(lpsz, lstrlen(lpsz) * sizeof(wchar_t));
}
// Else if we don't want to write Unicode, need to convert
else
{
int nChars = lstrlen(lpsz) + 1; // Why plus 1? Because yes
// int nBufferSize = nChars * sizeof(char); // leave space for multi-byte chars
int nCharsWritten = 0;
int nBufferSize = 0;
pszUnicodeString = new wchar_t[nChars];
// Copy string to Unicode buffer
lstrcpy(pszUnicodeString, lpsz);
// Work out how much space we need for the multibyte conversion
nBufferSize = GetRequiredMultiByteLengthForUnicodeString(pszUnicodeString, m_nFileCodePage);
pszMultiByteString= new char[nBufferSize];
// Get multibyte string
nCharsWritten = GetMultiByteStringFromUnicodeString(pszUnicodeString, pszMultiByteString, nBufferSize, m_nFileCodePage);
if (nCharsWritten > 0)
{
// Do byte-mode write using actual chars written (fix by Howard J Oh)
// CFile::Write((const void*)pszMultiByteString, lstrlen(lpsz));
CFile::Write((const void*)pszMultiByteString,
nCharsWritten*sizeof(char));
}
}
// Else if *not* compiled in Unicode
#else
// If writing Unicode, need to convert
if (m_nFlags & CStdioFileEx::modeWriteUnicode)
{
int nChars = lstrlen(lpsz) + 1; // Why plus 1? Because yes
int nBufferSize = nChars * sizeof(wchar_t);
int nCharsWritten = 0;
pszUnicodeString = new wchar_t[nChars];
pszMultiByteString= new char[nChars];
// Copy string to multibyte buffer
lstrcpy(pszMultiByteString, lpsz);
nCharsWritten = GetUnicodeStringFromMultiByteString(pszMultiByteString, pszUnicodeString, nChars, m_nFileCodePage);
if (nCharsWritten > 0)
{
// Do byte-mode write using actual chars written (fix by Howard J Oh)
// CFile::Write(pszUnicodeString, lstrlen(lpsz) * sizeof(wchar_t));
CFile::Write(pszUnicodeString, nCharsWritten*sizeof(wchar_t));
}
else
{
ASSERT(false);
}
}
// Else if we don't want to write Unicode, no conversion needed, unless the code page differs
else
{
// // Do standard stuff
// CStdioFile::WriteString(lpsz);
// Get the current code page
UINT nLocaleCodePage = GetCurrentLocaleCodePage();
// If we got it OK, and if file code page does not match the system code page, we need to do a double conversion!
if (nLocaleCodePage > 0 && nLocaleCodePage != (UINT)m_nFileCodePage)
{
int nChars = lstrlen(lpsz) + 1; // Why plus 1? Because yes
pszUnicodeString = new wchar_t[nChars];
// Initialise to something safe
memset(pszUnicodeString, 0, sizeof(wchar_t) * nChars);
// Convert to Unicode using the locale code page (the code page we are using in memory)
nChars = GetUnicodeStringFromMultiByteString((LPCSTR)(const char*)lpsz, pszUnicodeString, nChars, nLocaleCodePage);
// Convert back to multibyte using the file code page
// (Note that you can't reliably read a non-Unicode file written in code page A on a system using a code page B,
// modify the file and write it back using code page A, unless you disable all this double-conversion code.
// In effect, you have to choose between a mangled character display and mangled file writing).
if (nChars > 0)
{
// Calculate how much we need for the MB buffer (it might be larger)
nChars = GetRequiredMultiByteLengthForUnicodeString(pszUnicodeString, m_nFileCodePage);
pszMultiByteString= new char[nChars];
memset(pszMultiByteString, 0, sizeof(char) * nChars);
nChars = GetMultiByteStringFromUnicodeString(pszUnicodeString, pszMultiByteString, nChars, m_nFileCodePage);
// Do byte-mode write. This avoids annoying "interpretation" of "n's as "r"n
CFile::Write((const void*)pszMultiByteString, nChars * sizeof(char));
}
}
else
{
// Do byte-mode write. This avoids annoying "interpretation" of "n's as "r"n
CFile::Write((const void*)lpsz, lstrlen(lpsz)*sizeof(char));
}
}
#endif
}
// Ensure we always clean up
catch()
{
if (pszUnicodeString) delete [] pszUnicodeString;
if (pszMultiByteString) delete [] pszMultiByteString;
throw;
}
if (pszUnicodeString) delete [] pszUnicodeString;
if (pszMultiByteString) delete [] pszMultiByteString;
}
UINT CStdioFileEx::ProcessFlags(const CString& sFilePath, UINT& nOpenFlags)
{
m_bIsUnicodeText = false;
// If we have writeUnicode we must have write or writeRead as well
#ifdef _DEBUG
if (nOpenFlags & CStdioFileEx::modeWriteUnicode)
{
ASSERT(nOpenFlags & CFile::modeWrite || nOpenFlags & CFile::modeReadWrite);
}
#endif
// If reading in text mode and not creating ; fixed by Dennis Jeryd 6/8/03
if (nOpenFlags & CFile::typeText && !(nOpenFlags & CFile::modeCreate) && !(nOpenFlags & CFile::modeWrite ))
{
m_bIsUnicodeText = IsFileUnicode(sFilePath);
// If it's Unicode, switch to binary mode
if (m_bIsUnicodeText)
{
nOpenFlags ^= CFile::typeText;
nOpenFlags |= CFile::typeBinary;
}
}
m_nFlags = nOpenFlags;
return nOpenFlags;
}
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::IsFileUnicode()
//
// --------------------------------------------------------------------------------------------
// Returns: bool
// Parameters: const CString& sFilePath
//
// Purpose: Determines whether a file is Unicode by reading the first character and detecting
// whether it's the Unicode byte marker.
// Notes: None.
// Exceptions: None.
//
/*static*/ bool CStdioFileEx::IsFileUnicode(const CString& sFilePath)
{
CFile file;
bool bIsUnicode = false;
wchar_t cFirstChar;
CFileException exFile;
// Open file in binary mode and read first character
if (file.Open(sFilePath, CFile::typeBinary | CFile::modeRead, &exFile))
{
// If byte is Unicode byte-order marker, let's say it's Unicode
if (file.Read(&cFirstChar, sizeof(wchar_t)) > 0 && cFirstChar == (wchar_t)nUNICODE_BOM)
{
bIsUnicode = true;
}
file.Close();
}
else
{
// Handle error here if you like
}
return bIsUnicode;
}
unsigned long CStdioFileEx::GetCharCount()
{
int nCharSize;
unsigned long nByteCount, nCharCount = 0;
if (m_pStream)
{
// Get size of chars in file
nCharSize = m_bIsUnicodeText ? sizeof(wchar_t): sizeof(char);
// If Unicode, remove byte order mark from count
nByteCount = GetLength();
if (m_bIsUnicodeText)
{
nByteCount = nByteCount - sizeof(wchar_t);
}
// Calc chars
nCharCount = (nByteCount / nCharSize);
}
return nCharCount;
}
// Get the current user磗 code page
UINT CStdioFileEx::GetCurrentLocaleCodePage()
{
_TCHAR szLocalCodePage[10];
UINT nLocaleCodePage = 0;
int nLocaleChars = ::GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_IDEFAULTANSICODEPAGE, szLocalCodePage, 10);
// If OK
if (nLocaleChars > 0)
{
nLocaleCodePage = (UINT)_ttoi(szLocalCodePage);
ASSERT(nLocaleCodePage > 0);
}
else
{
ASSERT(false);
}
// O means either: no ANSI code page (Unicode-only locale?) or failed to get locale
// In the case of Unicode-only locales, what do multibyte apps do? Answers on a postcard.
return nLocaleCodePage;
}
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetUnicodeStringFromMultiByteString()
//
// --------------------------------------------------------------------------------------------
// Returns: int - num. of chars written (0 means error)
// Parameters: char * szMultiByteString (IN) Multi-byte input string
// wchar_t* szUnicodeString (OUT) Unicode outputstring
// int nUnicodeBufferSize (IN) Size of Unicode output buffer in chars(IN)
// UINT nCodePage (IN) Code page used to perform conversion
// Default = -1 (Get local code page).
//
// Purpose: Gets a Unicode string from a MultiByte string.
// Notes: None.
// Exceptions: None.
//
int CStdioFileEx::GetUnicodeStringFromMultiByteString(IN LPCSTR szMultiByteString, OUT wchar_t* szUnicodeString, IN int nUnicodeBufferSize, IN int nCodePage)
{
bool bOK = true;
int nCharsWritten = 0;
if (szUnicodeString && szMultiByteString)
{
// If no code page specified, take default for system
if (nCodePage == -1)
{
nCodePage = GetACP();
}
try
{
// Zero out buffer first. NB: nUnicodeBufferSize is NUMBER OF CHARS, NOT BYTES!
memset((void*)szUnicodeString, '"0', sizeof(wchar_t) *
nUnicodeBufferSize);
// When converting to UTF8, don't set any flags (see Q175392).
nCharsWritten = MultiByteToWideChar((UINT)nCodePage,
(nCodePage==CP_UTF8 ? 0:MB_PRECOMPOSED), // Flags
szMultiByteString,-1,szUnicodeString,nUnicodeBufferSize);
}
catch()
{
TRACE(_T("Controlled exception in MultiByteToWideChar!"n"));
}
}
// Now fix nCharsWritten
if (nCharsWritten > 0)
{
nCharsWritten--;
}
ASSERT(nCharsWritten > 0);
return nCharsWritten;
}
// --------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetMultiByteStringFromUnicodeString()
//
// --------------------------------------------------------------------------------------------
// Returns: int - number of characters written. 0 means error
// Parameters: wchar_t * szUnicodeString (IN) Unicode input string
// char* szMultiByteString (OUT) Multibyte output string
// int nMultiByteBufferSize (IN) Multibyte buffer size (chars)
// UINT nCodePage (IN) Code page used to perform conversion
// Default = -1 (Get local code page).
//
// Purpose: Gets a MultiByte string from a Unicode string
// Notes: Added fix by Andy Goodwin: make buffer into int.
// Exceptions: None.
//
int CStdioFileEx::GetMultiByteStringFromUnicodeString(wchar_t * szUnicodeString, char* szMultiByteString,
int nMultiByteBufferSize, int nCodePage)
{
BOOL bUsedDefChar = FALSE;
int nCharsWritten = 0;
// Fix by Andy Goodwin: don't do anything if buffer is 0
if ( nMultiByteBufferSize > 0 )
{
if (szUnicodeString && szMultiByteString)
{
// Zero out buffer first
memset((void*)szMultiByteString, '"0', nMultiByteBufferSize);
// If no code page specified, take default for system
if (nCodePage == -1)
{
nCodePage = GetACP();
}
try
{
// If writing to UTF8, flags, default char and boolean flag must be NULL
nCharsWritten = WideCharToMultiByte((UINT)nCodePage,
(nCodePage==CP_UTF8 ? 0 : WC_COMPOSITECHECK | WC_SEPCHARS), // Flags
szUnicodeString,-1,
szMultiByteString,
nMultiByteBufferSize,
(nCodePage==CP_UTF8 ? NULL:sDEFAULT_UNICODE_FILLER_CHAR), // Filler char
(nCodePage==CP_UTF8 ? NULL: &bUsedDefChar)); // Did we use filler char?
// If no chars were written and the buffer is not 0, error!
if (nCharsWritten == 0 && nMultiByteBufferSize > 0)
{
TRACE1("Error in WideCharToMultiByte: %d"n", ::GetLastError());
}
}
catch()
{
TRACE(_T("Controlled exception in WideCharToMultiByte!"n"));
}
}
}
// Now fix nCharsWritten
if (nCharsWritten > 0)
{
nCharsWritten--;
}
return nCharsWritten;
}
//---------------------------------------------------------------------------------------------------
//
// CStdioFileEx::GetRequiredMultiByteLengthForUnicodeString()
//
//---------------------------------------------------------------------------------------------------
// Returns: int
// Parameters: wchar_t * szUnicodeString,int nCodePage=-1
//
// Purpose: Obtains the multi-byte buffer size needed to accommodate a converted Unicode string.
// Notes: We can't assume that the buffer length is simply equal to the number of characters
// because that wouldn't accommodate multibyte characters!
//
/*static*/ int CStdioFileEx::GetRequiredMultiByteLengthForUnicodeString(wchar_t * szUnicodeString,int nCodePage /*=-1*/)
{
int nCharsNeeded = 0;
try
{
// If no code page specified, take default for system
if (nCodePage == -1)
{
nCodePage = GetACP();
}
// If writing to UTF8, flags, default char and boolean flag must be NULL
nCharsNeeded = WideCharToMultiByte((UINT)nCodePage,
(nCodePage==CP_UTF8 ? 0 : WC_COMPOSITECHECK | WC_SEPCHARS), // Flags
szUnicodeString,-1,
NULL,
0, // Calculate required buffer, please!
(nCodePage==CP_UTF8 ? NULL:sDEFAULT_UNICODE_FILLER_CHAR), // Filler char
NULL);
}
catch()
{
TRACE(_T("Controlled exception in WideCharToMultiByte!"n"));
}
return nCharsNeeded;
}
参考文献：
【1】 http://www.codeproject.com/KB/files/stdiofileex.aspx
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