1.問題提出

??? 在學編程序時，曾經有人問過“你可以編一個記事本程序嗎?”當時很不屑一顧，但是隨著學習MFC的深入，了解到記事本程序也并非易事，難點就是四種編碼之間的轉換。

對于編碼，這是一個令初學者頭疼的問題，特別是對于編碼的轉換，更是難以捉摸。筆者為了完成畢業設計中的一個編碼轉換模塊，研究了中文編碼和常見的字符集后，決定解決"記事本"程序的編碼問題，更進一步完成GB2312、Big5、GBK、Unicode 、Unicode big endian、UTF-8共6種編碼之間的任意轉換。

2.問題解決?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

(1)編碼基礎知識

a.了解編碼和字符集

這部分內容，我不在贅述，可參見CSDN Ancky的專欄中《各種字符集和編碼詳解》

博客地址:http://blog.csdn.net/ancky/article/details/2034809

b.單字節、雙字節、多字節

這部分內容，可參見我先前翻譯的博文《C++字符串完全指南--第一部分:win32?字符編碼》

博客地址:http://blog.csdn.net/ziyuanxiazai123/article/details/7482360

c.區域和代碼頁

這部分內容，可參見博客 ? ?? http://hi.baidu.com/tzpwater/blog/item/bd4abb0b60bff1db3ac7636a.html

d.中文編碼GB2312、GBK、Big5，這部分內容請參見CSDN? lengshine 博客中《GB2312、GBK、Big5漢字編碼
》，博客地址:http://blog.csdn.net/lengshine/article/details/5470545

e.Windows程序的字符編碼

這部分內容，可參見博客http://blog.sina.com.cn/s/blog_4e3197f20100a6z2.html 中《Windows程序的字符編碼》

(2)編碼總結

a.六種編碼的特點

六種編碼的特點如下圖所示:

b.編碼存儲差別

ANSI(在簡體中文中默認為GB2312)、Unicode、Unicode big endian 、UTF-8存儲存在差別。

以中文"你好"二字為例，他們存貯格式如下圖所示:

c.GB2312、Big5、GBK編碼的區別

三者中漢字均采用二個字節表示，但是字節表示的值范圍有所不同，如下圖所示:

(3)編碼轉換方式

6種編碼互相轉換，由排列組合知識知道共有30個方向的轉換.筆者采用的轉換方法,

多字節文件與Unicode文件轉換如下圖所示:

多字節文件之間轉換如下圖所示:

(4)編碼轉換使用的三個函數

a.MultiByteToWideChar

該函數完成多字節字符串向Unicode寬字符串的轉換.

函數原型為:

int MultiByteToWideChar(UINT CodePage,???????? // 代碼頁DWORD dwFlags,???????? // 轉換標志LPCSTR lpMultiByteStr, // 待轉換的字符串int cbMultiByte,?????? // 待轉換字符串的字節數目LPWSTR lpWideCharStr,? // 轉換后寬字符串的存儲空間int cchWideChar??????? // 轉換后寬字符串的存儲空間大小? 以寬字符大小為單位
);
b.WideCharToMultiByte
該函數完成Unicode寬字符串到多字節字符串的轉換，使用方法具體參見MSDN。
以上兩個函數可以完成大部分的字符串轉換，可以將其封裝成多字節和寬字節之間的轉換函數:
[cpp] view plaincopyprint?
wchar_t*?Coder::MByteToWChar(UINT?CodePage,LPCSTR?lpcszSrcStr)??
{??
????LPWSTR?lpcwsStrDes=NULL;??
????int???len=MultiByteToWideChar(CodePage,0,lpcszSrcStr,-1,NULL,0);??
????lpcwsStrDes=new?wchar_t[len+1];??
????if(!lpcwsStrDes)??
????????return?NULL;??
????memset(lpcwsStrDes,0,sizeof(wchar_t)*(len+1));??
????len=MultiByteToWideChar(CodePage,0,lpcszSrcStr,-1,lpcwsStrDes,len);??
????if(len)??
????????return?lpcwsStrDes;??
????else??
????{?????
????????delete[]?lpcwsStrDes;??
????????return?NULL;??
????}??
}??
??
char*?Coder::WCharToMByte(UINT?CodePage,LPCWSTR?lpcwszSrcStr)??
{??
????char*?lpszDesStr=NULL;??
????int?len=WideCharToMultiByte(CodePage,0,lpcwszSrcStr,-1,NULL,0,NULL,NULL);??
????lpszDesStr=new?char[len+1];??
????memset(lpszDesStr,0,sizeof(char)*(len+1));??
????if(!lpszDesStr)??
????????return?NULL;??
????len=WideCharToMultiByte(CodePage,0,lpcwszSrcStr,-1,lpszDesStr,len,NULL,NULL);??
????if(len)??
????????return?lpszDesStr;??
????else??
????{?????
????????delete[]?lpszDesStr;??
????????return?NULL;??
????}??
}???
c.LCMapString
依賴于本地機器的字符轉換函數，尤其是中文編碼在轉換時要依賴于本地機器，
直接利用上述a、b中敘述的函數會產生錯誤,例如直接從GB2312轉換到Big5，利用
MultiByteToWideChar函數將GB2312轉換到Unicode字符串，然后從Unicode字符串利用函數
WideCharToMultiByte轉換成Big5,將會發生錯誤，錯誤的結果如下圖所示:
因此中文編碼轉換時適當使用LCMapString函數，才能完成正確的轉換.
例如:
[cpp] view plaincopyprint?
//簡體中文?GB2312?轉換成?繁體中文BIG5??
char*?Coder::GB2312ToBIG5(const?char*?szGB2312Str)??
{?????????
????????LCID?lcid?=?MAKELCID(MAKELANGID(LANG_CHINESE,SUBLANG_CHINESE_SIMPLIFIED),SORT_CHINESE_PRC);??
????????int?nLength?=?LCMapString(lcid,LCMAP_TRADITIONAL_CHINESE,szGB2312Str,-1,NULL,0);??
????????char*?pBuffer=new?char[nLength+1];??
????????if(!pBuffer)??
????????????return?NULL;??
????????LCMapString(lcid,LCMAP_TRADITIONAL_CHINESE,szGB2312Str,-1,pBuffer,nLength);??
????????pBuffer[nLength]=0;??
????????wchar_t*?pUnicodeBuff?=?MByteToWChar(CP_GB2312,pBuffer);??
????????char*?pBIG5Buff?=?WCharToMByte(CP_BIG5,pUnicodeBuff);??
????????delete[]?pBuffer;??
????????delete[]?pUnicodeBuff;??
????????return?pBIG5Buff;??
}???
(5)編碼實現
實現Coder類完成編碼轉換工作.
Coder類的代碼清單如下:
[cpp] view plaincopyprint?
//?Coder.h:?interface?for?the?Coder?class.??
//??
//??
??
#if?!defined(AFX_ENCODING_H__2AC955FB_9F8F_4871_9B77_C6C65730507F__INCLUDED_)??
#define?AFX_ENCODING_H__2AC955FB_9F8F_4871_9B77_C6C65730507F__INCLUDED_??
??
#if?_MSC_VER?>?1000??
#pragma?once??
#endif?//?_MSC_VER?>?1000??
//-----------------------------------------------------------------------------------------------??
//程序用途：實現GB2312、big5、GBK、Unicode、Unicode?big?endian、UTF-8六種編碼的任意裝換??????
//程序作者：湖北師范學院計算機科學與技術學院??王定橋???????????????????????????????????
//核心算法：根據不同編碼特點向其他編碼轉換??
//測試結果:在Windows7?VC6.0環境下測試通過???????????????????????????????????????????????????????
//制作時間：2012-04-24???????????????????????????????????????????????
//代碼版權:代碼公開供學習交流使用??歡迎指正錯誤??改善算法??
//-----------------------------------------------------------------------------------------------??
//Windows代碼頁??
typedef?enum?CodeType??
{??
????CP_GB2312=936,??
????CP_BIG5=950,??
????CP_GBK=0??
}CodePages;??
//txt文件編碼??
typedef?enum?TextCodeType??
{?????
????GB2312=0,??
????BIG5=1,??
????GBK=2,??
????UTF8=3,??
????UNICODE=4,??
????UNICODEBIGENDIAN=5,??
????DefaultCodeType=-1??
}TextCode;??
class?Coder????
{??
public:??
????Coder();??
????virtual?~Coder();??
public:??
????//默認一次轉換字節大小??
????UINT??PREDEFINEDSIZE;??
????//指定轉換時默認一次轉換字節大小??
????void?SetDefaultConvertSize(UINT?nCount);??
????//編碼類型轉換為字符串??
????CString??CodeTypeToString(TextCode?tc);??
????//文件轉到另一種文件??
????BOOL?????FileToOtherFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo,TextCode??tcCur=DefaultCodeType);??
????//Unicode?和Unicode?big?endian文件之間轉換??
????BOOL?????UnicodeEndianFileConvert(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo);??
????//多字節文件之間的轉換??
????BOOL?????MBFileToMBFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo,TextCode??tcCur=DefaultCodeType);??
????//Unicode和Unicode?big?endian文件向多字節文件轉換??
????BOOL?????UnicodeFileToMBFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo);??
????//多字節文件向Unicode和Unicode?big?endian文件轉換??
????BOOL?????MBFileToUnicodeFile(CString?filesourcepath,CString?filesavepath,TextCode?tcTo,TextCode??tcCur=DefaultCodeType);??
????//獲取文件編碼類型??
????TextCode?GetCodeType(CString?filepath);??
????//繁體中文BIG5?轉換成?簡體中文?GB2312??
????char*?BIG5ToGB2312(const?char*?szBIG5Str);??
????//簡體中文?GB2312?轉換成?繁體中文BIG5??
????char*?GB2312ToBIG5(const?char*?szGB2312Str);??
????//簡繁中文GBK編碼轉換成簡體中文GB2312??
????char*?GBKToGB2312(const?char?*szGBkStr);??
????//簡體中文GB2312編碼轉換成簡繁中文GBK??
????char*????GB2312ToGBK(const?char?*szGB2312Str);??
????//簡繁中文GBK轉換成繁體中文Big5??
????char*?????GBKToBIG5(const?char?*szGBKStr);??
????//繁體中文BIG5轉換到簡繁中文GBK??
????char*?????BIG5ToGBK(const?char?*szBIG5Str);??
????//寬字符串向多字節字符串轉換??
????char*?????WCharToMByte(UINT?CodePage,LPCWSTR?lpcwszSrcStr);??
????//多字節字符串向寬字符串轉換??
????wchar_t*??MByteToWChar(UINT?CodePage,LPCSTR?lpcszSrcStr);??
protected:??
????//獲取編碼類型對應的代碼頁??
????UINT?GetCodePage(TextCode?tccur);??
????//多字節向多字節轉換??
????char*??MByteToMByte(UINT?CodePageCur,UINT?CodePageTo,const?char*?szSrcStr);??
????//Unicode和Unicode?big?endian字符串之間的轉換??
????void???UnicodeEndianConvert(LPWSTR??lpwszstr);??
????//文件頭常量字節數組??
????const??static???byte?UNICODEBOM[2];??
????const??static???byte?UNICODEBEBOM[2];??
????const??static???byte?UTF8BOM[3];??
??};??
??
#endif?//?!defined(AFX_ENCODING_H__2AC955FB_9F8F_4871_9B77_C6C65730507F__INCLUDED_)??
[cpp] view plaincopyprint?
//?Coder.cpp:?implementation?of?the?Coder?class.??
//??
//??
??
#include?"stdafx.h"??
#include?"Coder.h"??
#include?"Encoding.h"??
??
#ifdef?_DEBUG??
#undef?THIS_FILE??
static?char?THIS_FILE[]=__FILE__;??
#define?new?DEBUG_NEW??
#endif??
??
//??
//?Construction/Destruction??
//??
//初始化文件頭常量??
/*static*/?const?????byte?Coder::UNICODEBOM[2]={0xFF,0xFE};??
/*static*/?const?????byte?Coder::UNICODEBEBOM[2]={0xFE,0xFF};??
/*static*/?const?????byte?Coder::UTF8BOM[3]={0xEF,0xBB,0xBF};??
Coder::Coder()??
{??
???PREDEFINEDSIZE=2097152;//默認一次轉換字節大小?2M字節??
}??
Coder::~Coder()??
{??
????
}??
//繁體中文BIG5?轉換成?簡體中文?GB2312??
char*?Coder::BIG5ToGB2312(const?char*?szBIG5Str)??
{?????????
????????CString?msg;??
????????LCID?lcid?=?MAKELCID(MAKELANGID(LANG_CHINESE,SUBLANG_CHINESE_SIMPLIFIED),SORT_CHINESE_PRC);??
????????wchar_t*?szUnicodeBuff?=MByteToWChar(CP_BIG5,szBIG5Str);??
????????char*?szGB2312Buff?=WCharToMByte(CP_GB2312,szUnicodeBuff);??
????????int?nLength?=?LCMapString(lcid,LCMAP_SIMPLIFIED_CHINESE,?szGB2312Buff,-1,NULL,0);??
????????char*?pBuffer?=?new?char[nLength?+?1];??
????????if(!pBuffer)??
??????????return?NULL;??
????????memset(pBuffer,0,sizeof(char)*(nLength+1));??
????????LCMapString(0x0804,LCMAP_SIMPLIFIED_CHINESE,szGB2312Buff,-1,pBuffer,nLength);??
????????delete[]?szUnicodeBuff;??
????????delete[]?szGB2312Buff;??
????????return?pBuffer;??
}??
//?GB2312?轉?GBK??
char*?Coder::GB2312ToGBK(const?char?*szGB2312Str)??
{??
???????int?nStrLen?=?strlen(szGB2312Str);??
???????if(!nStrLen)??
???????????return?NULL;??
???????LCID?wLCID?=?MAKELCID(MAKELANGID(LANG_CHINESE,?SUBLANG_CHINESE_SIMPLIFIED),?SORT_CHINESE_PRC);??
???????int?nReturn?=?LCMapString(wLCID,?LCMAP_TRADITIONAL_CHINESE,?szGB2312Str,?nStrLen,?NULL,?0);??
???????if(!nReturn)??
??????????return?NULL;??
???????char?*pcBuf?=?new?char[nReturn?+?1];??
???????if(!pcBuf)??
??????????return?NULL;??
???????memset(pcBuf,0,sizeof(char)*(nReturn?+?1));??
???????wLCID?=?MAKELCID(MAKELANGID(LANG_CHINESE,?SUBLANG_CHINESE_SIMPLIFIED),?SORT_CHINESE_PRC);??
???????LCMapString(wLCID,?LCMAP_TRADITIONAL_CHINESE,?szGB2312Str,?nReturn,?pcBuf,?nReturn);??
???????return?pcBuf;??
}??
//?GBK?轉換成?GB2312??
char*?Coder::GBKToGB2312(const?char?*szGBKStr)??
{??
????int?nStrLen?=?strlen(szGBKStr);??
????if(!nStrLen)??
????????return?NULL;??
????LCID?wLCID?=?MAKELCID(MAKELANGID(LANG_CHINESE,?SUBLANG_CHINESE_SIMPLIFIED),?SORT_CHINESE_BIG5);??
????int?nReturn?=?LCMapString(wLCID,?LCMAP_SIMPLIFIED_CHINESE,?szGBKStr,?nStrLen,?NULL,?0);??
????if(!nReturn)??
????????return?NULL;??
????char?*pcBuf?=?new?char[nReturn?+?1];??
????memset(pcBuf,0,sizeof(char)*(nReturn?+?1));??
????wLCID?=?MAKELCID(MAKELANGID(LANG_CHINESE,?SUBLANG_CHINESE_SIMPLIFIED),?SORT_CHINESE_BIG5);??
????LCMapString(wLCID,?LCMAP_SIMPLIFIED_CHINESE,?szGBKStr,?nReturn,?pcBuf,?nReturn);??
????return?pcBuf;??
}??
//簡繁中文GBK轉換成繁體中文Big5??
char*???Coder::GBKToBIG5(const?char?*szGBKStr)??
{?????
????char?*pTemp=NULL;??
????char?*pBuffer=NULL;??
????pTemp=GBKToGB2312(szGBKStr);??
????pBuffer=GB2312ToBIG5(pTemp);??
????delete[]?pTemp;??
????return?pBuffer;??
}??
//繁體中文BIG5轉換到簡繁中文GBK??
char*???Coder::BIG5ToGBK(const?char?*szBIG5Str)??
{??
??????char?*pTemp=NULL;??
??????char?*pBuffer=NULL;??
??????pTemp=BIG5ToGB2312(szBIG5Str);??
??????pBuffer=GB2312ToGBK(pTemp);??
??????delete[]?pTemp;??
??????return?pBuffer;??
}??
//簡體中文?GB2312?轉換成?繁體中文BIG5??
char*?Coder::GB2312ToBIG5(const?char*?szGB2312Str)??
{?????????
????????LCID?lcid?=?MAKELCID(MAKELANGID(LANG_CHINESE,SUBLANG_CHINESE_SIMPLIFIED),SORT_CHINESE_PRC);??
????????int?nLength?=?LCMapString(lcid,LCMAP_TRADITIONAL_CHINESE,szGB2312Str,-1,NULL,0);??
????????char*?pBuffer=new?char[nLength+1];??
????????if(!pBuffer)??
????????????return?NULL;??
????????LCMapString(lcid,LCMAP_TRADITIONAL_CHINESE,szGB2312Str,-1,pBuffer,nLength);??
????????pBuffer[nLength]=0;??
????????wchar_t*?pUnicodeBuff?=?MByteToWChar(CP_GB2312,pBuffer);??
????????char*?pBIG5Buff?=?WCharToMByte(CP_BIG5,pUnicodeBuff);??
????????delete[]?pBuffer;??
????????delete[]?pUnicodeBuff;??
????????return?pBIG5Buff;??
}???
//獲取文件編碼類型??
//Unicode編碼文件通過讀取文件頭判別??
//中文編碼通過統計文件編碼類別來判別??判別次數最多為30次????
//中文編碼的判別存在誤差??
TextCode?Coder::GetCodeType(CString?filepath)??
{??
????CFile?file;??
????byte??buf[3];//unsigned?char??
????TextCode?tctemp;??
????if(file.Open(filepath,CFile::modeRead))??
????{??????
????????file.Read(buf,3);??
????????if(buf[0]==UTF8BOM[0]?&&?buf[1]==UTF8BOM[1]?&&?buf[2]==UTF8BOM[2])??
????????????return?UTF8;??
????????else??
????????if(buf[0]==UNICODEBOM[0]?&&buf[1]==UNICODEBOM[1]?)??
????????????return?UNICODE?;??
????????else??
????????if(buf[0]==UNICODEBEBOM[0]?&&buf[1]==UNICODEBEBOM[1]?)??
????????????return?UNICODEBIGENDIAN;??
????????else??
????????{?????
????????????int?time=30;??
????????????while(file.Read(buf,2)?&&time?)??
????????????{?????
????????????????if?(?(buf[0]>=176?&&?buf[0]<=247)?&&?(buf[1]>=160?&&?buf[1]<=254)?)??
????????????????????????????tctemp=GB2312;????
????????????????else??
????????????????????if?(?(buf[0]>=129?&&?buf[0]<=255)?&&?(??(?buf[1]>=64?&&?buf[1]<=126)??||??(?buf[1]>=161?&&?buf[1]<=254)?)?)??
????????????????????????????tctemp=BIG5;??
????????????????????else??
????????????????????????if?(?(buf[0]>=129?&&?buf[0]?<=254)?&&?(buf[1]>=64?&&?buf[1]<=254))??
????????????????????????????tctemp=GBK;???
????????????????time--;??
????????????????file.Seek(100,CFile::current);//跳過一定字節??利于統計全文??
????????????}??
????????????return?tctemp;??
????????}??
????}??
????else??
????????return?GB2312;??
}??
//多字節文件轉換為UNICODE、UNICODE?big?endian文件??
BOOL?Coder::MBFileToUnicodeFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo,TextCode?tcCur)??
{??
???TextCode?curtc;??
???CFile?filesource,filesave;;??
???char?????*pChSrc=NULL;??
???char?????*pChTemp=NULL;??
???wchar_t??*pwChDes=NULL;??
???DWORD??filelength,readlen,len;??
???int????bufferlen,strlength;??
???UINT?CodePage;??
???//由于存在誤差??允許用戶自定義轉換??
???if(tcCur!=DefaultCodeType)??
???????curtc=tcCur;??
???else??
???????curtc=GetCodeType(filesourcepath);??
???if(curtc>UTF8?||?tcTo<?UNICODE?||?curtc==tcTo)??
???????return?FALSE;??
???//源文件打開失敗或者源文件無內容?后者保存文件建立失敗???均返回轉換失敗??
???if(!filesource.Open(filesourcepath,CFile::modeRead)?||?0==(filelength=filesource.GetLength()))??
???????return?FALSE;??
???if(?!filesave.Open(filesavepath,CFile::modeCreate|CFile::modeWrite))??
????????return?FALSE;??
???//預分配內存??分配失敗則轉換失敗??
???if(filelength<PREDEFINEDSIZE)??
???????bufferlen=filelength;??
???else??
???????bufferlen=PREDEFINEDSIZE;??
???pChSrc=new?char[bufferlen+1];??
???if(!pChSrc)??
????????????return?FALSE;??
???//根據當前文件類別指定轉換代碼頁??
???switch(curtc)??
???{??
???case?GB2312:??
???????CodePage=CP_GB2312;??
???????break;??
???case?GBK:??
???????CodePage=CP_GB2312;//特殊處理??
???????break;??
???case?BIG5:??
???????CodePage=CP_BIG5;??
???????break;??
???case?UTF8:??
???????CodePage=CP_UTF8;??
???????break;??
???default:??
???????break;??
????}??
???//UTF8文件跳過文件??
???if(UTF8==curtc)??
???????filesource.Seek(3*sizeof(byte),CFile::begin);??
???//寫入文件頭??
???if(UNICODEBIGENDIAN==tcTo)??
???????filesave.Write(&UNICODEBEBOM,2*sizeof(byte));??
???else??
???????filesave.Write(&UNICODEBOM,2*sizeof(byte));??
???//讀取文件??分段轉換知道結束??
???while(filelength>0)??
???{??
???????memset(pChSrc,0,?sizeof(char)*(bufferlen+1));??
???????if(filelength>PREDEFINEDSIZE)??
???????????len=PREDEFINEDSIZE;??
???????else??
???????????len=filelength;??
???????readlen=filesource.Read(pChSrc,len);??
???????if(!readlen)??
????????????break;??
???????//GBK轉換為GB2312處理??
???????if(GBK==curtc)??
???????{?????
???????????pChTemp=pChSrc;??
???????????pChSrc=GBKToGB2312(pChSrc);??
???????}??
???????pwChDes=MByteToWChar(CodePage,pChSrc);??
???????if(pwChDes)??
???????{??
???????????if(UNICODEBIGENDIAN==tcTo)??
???????????????UnicodeEndianConvert(pwChDes);??
???????????strlength=wcslen(pwChDes)*2;//這里注意寫入文件的長度??
???????????filesave.Write(pwChDes,strlength);??
???????????filesave.Flush();??
???????????filelength-=readlen;??
???????}??
???????else??
???????????break;??
???}??
???delete[]?pChSrc;??
???delete[]?pChTemp;??
???delete[]?pwChDes;??
???return?TRUE;??
}??
//??
wchar_t*?Coder::MByteToWChar(UINT?CodePage,LPCSTR?lpcszSrcStr)??
{??
????LPWSTR?lpcwsStrDes=NULL;??
????int???len=MultiByteToWideChar(CodePage,0,lpcszSrcStr,-1,NULL,0);??
????lpcwsStrDes=new?wchar_t[len+1];??
????if(!lpcwsStrDes)??
????????return?NULL;??
????memset(lpcwsStrDes,0,sizeof(wchar_t)*(len+1));??
????len=MultiByteToWideChar(CodePage,0,lpcszSrcStr,-1,lpcwsStrDes,len);??
????if(len)??
????????return?lpcwsStrDes;??
????else??
????{?????
????????delete[]?lpcwsStrDes;??
????????return?NULL;??
????}??
}??
??
char*?Coder::WCharToMByte(UINT?CodePage,LPCWSTR?lpcwszSrcStr)??
{??
????char*?lpszDesStr=NULL;??
????int?len=WideCharToMultiByte(CodePage,0,lpcwszSrcStr,-1,NULL,0,NULL,NULL);??
????lpszDesStr=new?char[len+1];??
????memset(lpszDesStr,0,sizeof(char)*(len+1));??
????if(!lpszDesStr)??
????????return?NULL;??
????len=WideCharToMultiByte(CodePage,0,lpcwszSrcStr,-1,lpszDesStr,len,NULL,NULL);??
????if(len)??
????????return?lpszDesStr;??
????else??
????{?????
????????delete[]?lpszDesStr;??
????????return?NULL;??
????}??
}???
//Unicode?和Unicode?big?endian之間字節序的轉換??
void?Coder::UnicodeEndianConvert(LPWSTR?lpwszstr)??
{??????
?????wchar_t??wchtemp[2];????
?????long?????index;???
?????int?len=wcslen(lpwszstr);??
?????if(!len)??
?????????return;??
???//交換高低字節?直到遇到結束符??
???index=0;??
???while(?index<len)??
???{??
???????wchtemp[0]=lpwszstr[index];??
???????wchtemp[1]=lpwszstr[index+1];??
?????????
???????unsigned?char?high,?low;??
???????high?=?(wchtemp[0]?&?0xFF00)?>>8;??
???????low??=?wchtemp[0]?&?0x00FF;??
???????wchtemp[0]?=?(?low?<<8)?|?high;??
???????high?=?(wchtemp[1]?&?0xFF00)?>>8;??
???????low??=?wchtemp[1]?&?0x00FF;??
???????wchtemp[1]?=?(?low?<<8)?|?high;??
?????????
???????lpwszstr[index]=wchtemp[0];??
???????lpwszstr[index+1]=wchtemp[1];??
???????index+=2;??
???}??
}??
//Unicode和Unicode?big?endian文件向多字節文件轉換??
BOOL?Coder::UnicodeFileToMBFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo)??
{?????
????TextCode?curtc;??
????CFile?filesource,filesave;;??
????char????*pChDes=NULL;??
????char????*pChTemp=NULL;??
????wchar_t?*pwChSrc=NULL;??
????DWORD??filelength,readlen,len;??
????int????bufferlen,strlength;??
????UINT?CodePage;??
????curtc=GetCodeType(filesourcepath);??
????//文件轉換類型錯誤?則轉換失敗??
????if(curtc<=UTF8?||??tcTo>UTF8?||?curtc==tcTo)??
????????return?FALSE;??
????//源文件打開失敗或者源文件無內容?后者保存文件建立失敗???均轉換失敗??
????if(!filesource.Open(filesourcepath,CFile::modeRead)?||?0==(filelength=filesource.GetLength()))??
????????return?FALSE;??
????if(?!filesave.Open(filesavepath,CFile::modeCreate|CFile::modeWrite))??
????????return?FALSE;??
????//預分配內存??分配失敗則轉換失敗??
????if(filelength<PREDEFINEDSIZE)??
????????bufferlen=filelength;??
????else??
????????bufferlen=PREDEFINEDSIZE;??
????pwChSrc=new?wchar_t[(bufferlen/2)+1];??
????if(!pwChSrc)??
????????return?FALSE;??
????//預先決定代碼頁??
????switch(tcTo)??
????{?????
????case?GB2312:??
????????CodePage=CP_GB2312;??
????????break;??
????case?GBK:??
????????CodePage=CP_GB2312;//特殊處理??
????????break;??
????case?BIG5:???
????????CodePage=CP_GB2312;//特殊處理??
????????break;??
????case?UTF8:??
????????CodePage=CP_UTF8;??
????????break;??
????default:??
????????break;??
????????}??
????filesource.Seek(sizeof(wchar_t),CFile::begin);??
????while(filelength>0)??
????{??
????????memset(pwChSrc,0,sizeof(wchar_t)*((bufferlen/2)+1));??
????????if(filelength>PREDEFINEDSIZE)??
????????????len=PREDEFINEDSIZE;??
????????else??
????????????len=filelength;??
????????readlen=filesource.Read(pwChSrc,len);??
????????if(!readlen)??
????????????break;??
????????if(UNICODEBIGENDIAN==curtc)??
????????????UnicodeEndianConvert(pwChSrc);??
????????pChDes=WCharToMByte(CodePage,pwChSrc);??
????????//GBK無法直接轉換??BIG5直接轉換會產生錯誤??二者均先轉到GB2312然后再轉到目的類型??
????????if(GBK==tcTo)??
????????{??
????????????pChTemp=pChDes;??
????????????pChDes=GB2312ToGBK(pChDes);??
????????}??
????????if(BIG5==tcTo)??
????????{??
????????????pChTemp=pChDes;??
????????????pChDes=GB2312ToBIG5(pChDes);??
????????}??
????????if(pChDes)??
????????{?????
????????????strlength=strlen(pChDes);??
????????????filesave.Write(pChDes,strlength);??
????????????filesave.Flush();??
????????????filelength-=readlen;??
????????}??
????????else??
????????????break;??
????}??
????delete[]?pChDes;??
????delete[]?pChTemp;??
????delete[]?pwChSrc;??
????return?TRUE;??
}??
//多字節文件轉為多字節文件??
//多字節轉為多字節時，一般先轉為UNICODE類型，再轉換到指定目的類型，實行兩次轉換??
BOOL?Coder::MBFileToMBFile(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo,TextCode??tcCur)??
{??
????BOOL?bret=FALSE;??
????TextCode?curtc;??
????CFile?filesource,filesave;??
????char????*pChDes=NULL;??
????char????*pChSrc=NULL;??
????DWORD??filelength,readlen,len;??
????int????bufferlen,strlength;??
????UINT???CodePageCur,CodePageTo;??
????//由于存在誤差??允許用戶自定義轉換??
????if(DefaultCodeType!=tcCur)??
?????????curtc=tcCur;??
????else??
????????curtc=GetCodeType(filesourcepath);??
????//轉換類型錯誤??則返回轉換失敗??
????if(curtc>UTF8?||?tcTo>UTF8?||?curtc==tcTo)??
????????return?FALSE;??
????//源文件打開失敗或者源文件無內容?后者保存文件建立失敗???均返回轉換失敗??
????if(!filesource.Open(filesourcepath,CFile::modeRead)?||?0==(filelength=filesource.GetLength()))??
????????return?FALSE;??
????if(?!filesave.Open(filesavepath,CFile::modeCreate|CFile::modeWrite))??
????????return?FALSE;??
????//預分配內存??分配失敗則轉換失敗??
????if(filelength<PREDEFINEDSIZE)??
????????bufferlen=filelength;??
????else??
????????bufferlen=PREDEFINEDSIZE;??
????pChSrc=new?char[bufferlen+1];??
????if(!pChSrc)??
????????????return?FALSE;??
????if(UTF8==curtc)??
????????filesource.Seek(3*sizeof(byte),CFile::begin);??
????CodePageCur=GetCodePage(curtc);??
????CodePageTo=GetCodePage(tcTo);??
????while(filelength>0)??
????{?????
????????memset(pChSrc,0,sizeof(char)*(bufferlen+1));??
????????if(filelength>PREDEFINEDSIZE)??
????????????len=PREDEFINEDSIZE;??
????????else??
????????????len=filelength;??
????????readlen=filesource.Read(pChSrc,len);??
????????if(!readlen)??
????????????break;??
????????pChDes=MByteToMByte(CodePageCur,CodePageTo,pChSrc);??
????????if(pChDes)??
????????{?????
????????????strlength=strlen(pChDes);??
????????????filesave.Write(pChDes,strlength);??
????????????filelength-=readlen;??
????????}??
????????else??
????????????break;??
????}??
????delete[]?pChSrc;??
????delete[]?pChDes;??
????return?TRUE;??
}??
//Unicode?和Unicode?big?endian文件之間轉換??
BOOL?Coder::UnicodeEndianFileConvert(CString?filesourcepath,?CString?filesavepath,TextCode?tcTo)??
{??
????TextCode?curtc=GetCodeType(filesourcepath);??
????if(curtc!=UNICODE?&&?curtc!=UNICODEBIGENDIAN)??
????????return?FALSE;??
????if(curtc==tcTo)??
????????return?FALSE;??
????CFile?filesource,filesave;;??
????wchar_t?*pwChDes;??
????DWORD?length;??
????if(!filesource.Open(filesourcepath,CFile::modeRead)?||?!filesave.Open(filesavepath,CFile::modeCreate|CFile::modeWrite))??
????????return?FALSE;??
????length=filesource.GetLength();??
????if(!length)??
????????return?FALSE;??
????pwChDes=new?wchar_t[(length/2)+1];??
????if(!pwChDes)??
????????return?FALSE;??
????memset(pwChDes,0,sizeof(wchar_t)*((length/2)+1));??
????filesource.Read(pwChDes,length);??
????UnicodeEndianConvert(pwChDes);??
????length=wcslen(pwChDes)*2;??
????if(UNICODE==tcTo)??
????????filesave.Write(&UNICODEBOM,2*sizeof(byte));??
????else??
????????filesave.Write(&UNICODEBEBOM,2*sizeof(byte));??
????filesave.Write(pwChDes,length);??
????filesave.Flush();??
????delete[]?pwChDes;??
????return?TRUE;??
}??
//文件轉到另一種文件??
//6種格式文件兩兩轉換??共計30種轉換??
BOOL?Coder::FileToOtherFile(CString?filesourcepath,?CString?filesavepath,?TextCode?tcTo,TextCode??tcCur)??
{?????
????TextCode?curtc;??
????BOOL?bret=FALSE;??
????if(DefaultCodeType!=tcCur)??
????????curtc=tcCur;??
????else??
????????curtc=GetCodeType(filesourcepath);??
????if(curtc==tcTo)??
????????return?FALSE;??
????//UNICODE和UNICODE?big?endian文件之間轉換?共2種??
????if(curtc>=UNICODE&&?tcTo>=UNICODE)??
????????????bret=UnicodeEndianFileConvert(filesourcepath,filesavepath,tcTo);??
????else??
????????//多字節文件向?UNICODE和UNICODE?big?endian文件之間轉換?共8種??
????????if(curtc<UNICODE?&&?tcTo>=UNICODE)??
????????????bret=MBFileToUnicodeFile(filesourcepath,filesavepath,tcTo,curtc);??
????else??
????????//UNICODE和UNICODE?big?endian文件向多字節文件轉換?共8種??
????????if(curtc>=UNICODE?&&?tcTo<UNICODE)??
????????????bret=UnicodeFileToMBFile(filesourcepath,filesavepath,tcTo);??
????else??
????????//多字節文件之間轉換?共12種??
????????if(curtc<UNICODE?&&?tcTo<UNICODE)??
????????????bret=MBFileToMBFile(filesourcepath,filesavepath,tcTo,curtc);??
????return?bret;??
}??
//編碼類型轉換為字符串??
CString?Coder::CodeTypeToString(TextCode?tc)??
{??
??????CString?strtype;??
??????switch(tc)??
??????{??
??????case?GB2312:??
???????????strtype=_T("GB2312");??
???????????break;??
??????case?BIG5:??
??????????strtype=_T("Big5");??
???????????break;??
??????case?GBK:??
??????????strtype=_T("GBK");??
???????????break;??
??????case?UTF8:??
??????????strtype=_T("UTF-8");??
???????????break;??
??????case?UNICODE:??
??????????strtype=_T("Unicode");??
???????????break;??
??????case?UNICODEBIGENDIAN:??
??????????strtype=_T("Unicode?big?endian");??
???????????break;??
??????}??
??????return?strtype;??
}??
//多字節向多字節轉換??
char*?Coder::MByteToMByte(UINT?CodePageCur,?UINT?CodePageTo,?const?char*?szSrcStr)??
{??
????char????*pchDes=NULL;??
????char????*pchTemp=NULL;??
????wchar_t?*pwchtemp=NULL;??
????//三種中文編碼之間轉換??
????if(CodePageCur!=CP_UTF8??&&?CodePageTo!=CP_UTF8)??
????{??
????????switch(CodePageCur)??
????????{??
????????????case?CP_GB2312:??
????????????????{??
????????????????????if(CP_BIG5==CodePageTo)???
???????????????????????pchDes=GB2312ToBIG5(szSrcStr);??
????????????????????else??
???????????????????????pchDes=GB2312ToGBK(szSrcStr);??
????????????????????break;??
????????????????}??
????????????case?CP_BIG5:??
????????????????{?????
????????????????????if(CP_GB2312==CodePageTo)??
????????????????????????pchDes=BIG5ToGB2312(szSrcStr);??
????????????????????else??
????????????????????????pchDes=BIG5ToGBK(szSrcStr);??
????????????????????break;??
????????????????}??
????????????case?CP_GBK:??
????????????????{?????
????????????????????if(CP_GB2312==CodePageTo)??
????????????????????????pchDes=GBKToGB2312(szSrcStr);??
????????????????????else??
????????????????????????pchDes=GBKToBIG5(szSrcStr);??
????????????????????break;??
????????????????}??
????????}??
????}??
????else??
????{????//從UTF-8轉到其他多字節??直接轉到GB2312?其他形式用GB2312做中間形式??
?????????if(CP_UTF8==CodePageCur)??
?????????{????
????????????pwchtemp=MByteToWChar(CodePageCur,szSrcStr);??
????????????if(CP_GB2312==CodePageTo)??
????????????{??
????????????????pchDes=WCharToMByte(CP_GB2312,pwchtemp);??
????????????}??
????????????else??
????????????{??????
????????????????pchTemp=WCharToMByte(CP_GB2312,pwchtemp);??
?????????????????if(CP_GBK==CodePageTo)??
????????????????????pchDes=GB2312ToGBK(pchTemp);??
?????????????????else??
????????????????????pchDes=GB2312ToBIG5(pchTemp);??
????????????}??
?????????}??
?????????//從其他多字節轉到UTF-8??
?????????else???
?????????{??????
??????????????if(CP_GBK==CodePageCur)??
??????????????{?????
??
??????????????????pchTemp=GBKToGB2312(szSrcStr);??
??????????????????pwchtemp=MByteToWChar(CP_GB2312,pchTemp);??
??????????????}??
??????????????else??
????????????????pwchtemp=MByteToWChar(CodePageCur,szSrcStr);??
??????????????pchDes=WCharToMByte(CodePageTo,pwchtemp);??
?????????}??
????}??
????delete[]?pchTemp;??
????delete[]?pwchtemp;??
????return?pchDes;??
}??
//獲取編碼類型對應的代碼頁??
UINT?Coder::GetCodePage(TextCode?tccur)??
{??
??????UINT?CodePage;??
??????switch(tccur)??
??????{??
??????case?GB2312:??
??????????CodePage=CP_GB2312;??
??????????break;??
??????case?BIG5:??
??????????CodePage=CP_BIG5;??
??????????break;??
??????case?GBK:??
??????????CodePage=CP_GBK;??
??????????break;??
??????case?UTF8:??
??????????CodePage=CP_UTF8;??
??????????break;??
??????case?UNICODEBIGENDIAN:??
??????case?UNICODE:??
???????????break;??
????}??
??????return?CodePage;??
}??
//指定轉換時默認一次轉換字節大小??
void?Coder::SetDefaultConvertSize(UINT?nCount)??
{??????
?????if(nCount!=0)??
????????PREDEFINEDSIZE=nCount;??
}??
3.運行效果                                                                                   
在win7 VC 6.0下測試六種編碼的轉換測試通過，30個方向的轉換如下圖所示:



測試程序運行效果如下圖所示:





GB2312轉換到GBK編碼效果如下圖所示:






UTF-8轉換到Big5編碼的效果如下圖所示:




本文代碼及轉碼程序下載 ：http://download.csdn.net/user/ziyuanxiazai123


4.尚未解決的問題?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????


(1)LCMapString函數的理解還不完全熟悉，其中參數偏多，理解需要一定基礎知識。
(2)為什么記事本程序的轉碼后存在些亂碼,亂碼是正確的嗎?因為我的程序使用了中間過渡形式，因此沒有任何亂碼。
(3)是否有更簡單和清晰的方式實現編碼轉換，待進一步研究。