C++ 编码转换

CEncode.h文件

#ifndef _CENCODE_H_
#define _CENCODE_H_

#include <iostream>
#include <string>
#include <windows.h>
using namespace std;

class CEncode
{
public:
    //Converting a WChar string to a Ansi string
    static    std::string WChar2Ansi(LPCWSTR pwszSrc);

    //Converting a Ansi string to WChar string
    static std::wstring Ansi2WChar(LPCSTR pszSrc, int nLen);

    //Unicode to ANSI
    static std::string UnicodeToANSI(const wstring& wstr);

    // Unicode to UTF-8
    static std::string UnicodeToUTF8( const wstring& wstr );

    // ANSI to Unicode
    static std::wstring ANSIToUnicode( const string& str );

    //UTF-8 to Unicode
    static std::wstring UTF8ToUnicode(const string& inUtf8);

    //GBK to UTF-8
    static std::string GBKToUTF8(const std::string& strGBK);

    //UTF-8 to GBK
    static std::string UTF8ToGBK(const std::string& strUTF8);

    //UTF-8 to GB2312
    static std::string UTF8ToGB2312(const char* utf8);

    //GB2312 to UTF-8
    static std::string GB2312ToUTF8(const char* gb2312);

};
#endif

CEncode.cpp文件

#include "CEncode.h"

std::string CEncode::WChar2Ansi(LPCWSTR pwszSrc)
{
    int nLen = WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, NULL, 0, NULL, NULL);

    if (nLen<= 0) return std::string("");

    char* pszDst = new char[nLen];

    if (NULL == pszDst) return std::string("");

    WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, pszDst, nLen, NULL, NULL);

    pszDst[nLen -1] = 0;

    std::string strTemp(pszDst);

    delete [] pszDst;

    return strTemp;
}

std::wstring CEncode::Ansi2WChar(LPCSTR pszSrc, int nLen)
{
    int nSize = MultiByteToWideChar(CP_ACP, 0, (LPCSTR)pszSrc, nLen, 0, 0);

    if(nSize <= 0) return NULL;

    WCHAR *pwszDst = new WCHAR[nSize+1];

    if( NULL == pwszDst) return NULL;

    MultiByteToWideChar(CP_ACP, 0,(LPCSTR)pszSrc, nLen, pwszDst, nSize);

    pwszDst[nSize] = 0;

    if( pwszDst[0] == 0xFEFF) // skip Oxfeff
        for(int i = 0; i < nSize; i ++)
            pwszDst[i] = pwszDst[i+1];

    wstring wcharString(pwszDst);

    delete pwszDst;

    return wcharString;
}

std::string CEncode::UnicodeToANSI(const wstring& wstr)
{
    int Length;
    Length = ::WideCharToMultiByte(CP_ACP,0,wstr.c_str(),-1,NULL,0,NULL,0);

    char *pChar= new char[Length+1];
    memset(pChar,0,Length+1);

    ::WideCharToMultiByte(CP_ACP,0,wstr.c_str(),-1,pChar,Length,NULL,0);

    string str = pChar;
    delete [] pChar;
    return str;
}


std::string CEncode::UnicodeToUTF8( const wstring& wstr )
{
    int    Length;
    // wide char to multi char
    Length = ::WideCharToMultiByte( CP_UTF8,0,wstr.c_str(),-1,NULL,0,NULL,NULL );

    char* pElementText = new char[Length + 1];
    memset( ( void* )pElementText, 0, sizeof( char ) * ( Length + 1 ) );
    ::WideCharToMultiByte( CP_UTF8,0,wstr.c_str(),-1,pElementText,Length,NULL,NULL );

    string strText;
    strText = pElementText;
    delete[] pElementText;
    return strText;
}

std::wstring CEncode::ANSIToUnicode( const string& str )
{
    int  unicodeLen = ::MultiByteToWideChar( CP_ACP,0,str.c_str(),-1,NULL,0 ); 

    wchar_t *  pUnicode; 
    pUnicode = new  wchar_t[unicodeLen+1]; 
    memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t)); 

    ::MultiByteToWideChar( CP_ACP,0,str.c_str(),-1,(LPWSTR)pUnicode,unicodeLen ); 

    wstring  wstr; 
    wstr = ( wchar_t* )pUnicode;
    delete[]  pUnicode;

    return  wstr;
}

wstring CEncode::UTF8ToUnicode(const string& inUtf8)
{
    int  unicodeLen = ::MultiByteToWideChar( CP_UTF8,0,inUtf8.c_str(),-1,NULL,0 ); 

    wchar_t *  pUnicode; 
    pUnicode = new  wchar_t[unicodeLen+1]; 
    memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t)); 

    ::MultiByteToWideChar( CP_UTF8,0,inUtf8.c_str(),-1,(LPWSTR)pUnicode,unicodeLen ); 

    wstring  wstr; 
    wstr = ( wchar_t* )pUnicode;
    delete[]  pUnicode;

    return  wstr;
}


std::string CEncode::GBKToUTF8(const std::string& strGBK) 
{ 
    string strOutUTF8 = ""; 
    WCHAR * str1;
    int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0); 
    str1 = new WCHAR[n]; 
    MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n); 

    n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL);
    char * str2 = new char[n]; 
    WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL); 
    strOutUTF8 = str2; 
    delete[]str1; 
    str1 = NULL; 
    delete[]str2;
    str2 = NULL; 
    return strOutUTF8;
}



std::string CEncode::UTF8ToGB2312(const char* utf8)
{
    int len = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, 0);

    wchar_t* wstr = new wchar_t[len+1];

    memset(wstr, 0, len+1);

    MultiByteToWideChar(CP_UTF8, 0, utf8, -1, wstr, len);

    len = WideCharToMultiByte(CP_ACP, 0, wstr, -1, NULL, 0, NULL, NULL);

    char* str = new char[len+1];

    memset(str, 0, len+1);

    WideCharToMultiByte(CP_ACP, 0, wstr, -1, str, len, NULL, NULL);
    if(wstr) delete[] wstr;

    string temp = str;
    return temp;
}


std::string CEncode::GB2312ToUTF8(const char* gb2312)
{
    int len = MultiByteToWideChar(CP_ACP, 0, gb2312, -1, NULL, 0);

    wchar_t* wstr = new wchar_t[len+1];

    memset(wstr, 0, len+1);

    MultiByteToWideChar(CP_ACP, 0, gb2312, -1, wstr, len);

    len = WideCharToMultiByte(CP_UTF8, 0, wstr, -1, NULL, 0, NULL, NULL);

    char* str = new char[len+1];

    memset(str, 0, len+1);

    WideCharToMultiByte(CP_UTF8, 0, wstr, -1, str, len, NULL, NULL);

    if(wstr) delete[] wstr;

    string temp = str;
    return temp;
}

 补充:http://blog.csdn.net/sjy88813/article/details/6662879