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在开发文档编辑器经常会遇到各种编码转换的问题要解决，虽然windows api有相关的函数。但是参数多，使用复杂每次都要查手册，很容易出错。

所以把常用的转换封装一下，用C的语法实现。支持c/c++

注意这些函数都会在堆中创建并返回新的字串，所以返回的字符串在使用完以后要显示销毁使用free(xxx)否则会造成内存泄漏。

第一条宏是取消烦人的VS编译器强制要求使用xxx_s函数的宏。如果在非VS编译器下会被自动忽略。

#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>  #include <windows.h>  #include <locale.h>  #define BUFF_SIZE 1024  wchar_t * ANSIToUnicode(const char* str){	int textlen;	wchar_t * result;	textlen = MultiByteToWideChar(CP_ACP, 0, str, -1, NULL, 0);	result = (wchar_t *)malloc((textlen + 1)*sizeof(wchar_t));	memset(result, 0, (textlen + 1)*sizeof(wchar_t));	MultiByteToWideChar(CP_ACP, 0, str, -1, (LPWSTR)result, textlen);	return result;}char * UnicodeToANSI(const wchar_t* str){	char* result;	int textlen;	textlen = WideCharToMultiByte(CP_ACP, 0, str, -1, NULL, 0, NULL, NULL);	result = (char *)malloc((textlen + 1)*sizeof(char));	memset(result, 0, sizeof(char) * (textlen + 1));	WideCharToMultiByte(CP_ACP, 0, str, -1, result, textlen, NULL, NULL);	return result;}wchar_t * UTF8ToUnicode(const char* str){	int textlen;	wchar_t * result;	textlen = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);	result = (wchar_t *)malloc((textlen + 1)*sizeof(wchar_t));	memset(result, 0, (textlen + 1)*sizeof(wchar_t));	MultiByteToWideChar(CP_UTF8, 0, str, -1, (LPWSTR)result, textlen);	return result;}char * UnicodeToUTF8(const wchar_t* str){	char* result;	int textlen;	textlen = WideCharToMultiByte(CP_UTF8, 0, str, -1, NULL, 0, NULL, NULL);	result = (char *)malloc((textlen + 1)*sizeof(char));	memset(result, 0, sizeof(char) * (textlen + 1));	WideCharToMultiByte(CP_UTF8, 0, str, -1, result, textlen, NULL, NULL);	return result;}/*宽字符转换为多字符Unicode - ANSI*/char* w2m(const wchar_t* wcs){	int len;	char* buf;	len = wcstombs(NULL, wcs, 0);	if (len == 0)		return NULL;	buf = (char *)malloc(sizeof(char)*(len + 1));	memset(buf, 0, sizeof(char) *(len + 1));	len = wcstombs(buf, wcs, len + 1);	return buf;}/*多字符转换为宽字符ANSI - Unicode*/wchar_t* m2w(const char* mbs){	int len;	wchar_t* buf;	len = mbstowcs(NULL, mbs, 0);	if (len == 0)		return NULL;	buf = (wchar_t *)malloc(sizeof(wchar_t)*(len + 1));	memset(buf, 0, sizeof(wchar_t) *(len + 1));	len = mbstowcs(buf, mbs, len + 1);	return buf;}char* ANSIToUTF8(const char* str){	wchar_t * buf = ANSIToUnicode(str);	char * ret =  UnicodeToUTF8(buf);	free(buf);	return ret;}char* UTF8ToANSI(const char* str){	wchar_t * buf = UTF8ToUnicode(str);	char * ret = UnicodeToANSI(buf);	free(buf);	return ret;}int main(){	///*使用wcstombs和mbstowcs之前必须调用setlocale，以便决定内码*/	//setlocale(LC_ALL, ".936");	///*假定有一个Unicode(UTF-16LE)编码的文件，将其打开，重新编码为ANSI，写入aa.txt中，再继续编码回Unicode，写入aw.txt中*/	///*如果不存在a.txt文件，则程序出错，没有做错误处理*/	//char* filename = "a.txt";	//char* filenamea = "aa.txt";	//char* filenamew = "aw.txt";	//FILE*     input = fopen(filename, "rb");	//FILE*     inputa = fopen(filenamea, "wb");	//FILE*     inputw = fopen(filenamew, "wb");	//wchar_t * buf;	///*BOE设置，UTF-16LE的BOE为FEFF，如果不先将其读取出来，wcstombs会调用失败*/	//fgetwc(input);	//fputwc(0xFEFF, inputw);	///*开始读取文件*/	//while (!feof(input))	//{	//	buf = (wchar_t *)malloc(sizeof(wchar_t)*BUFF_SIZE);	//	memset(buf, 0, sizeof(wchar_t) * BUFF_SIZE);	//	fgetws(buf, BUFF_SIZE, input);	//	fputs(w2m(buf), inputa);	//	fputws(m2w(w2m(buf)), inputw);	//}	///*后续处理*/	//fclose(input);	//fclose(inputa);	//fclose(inputw);	//free(buf);	char str[] = "多选控件";	char * buf = ANSIToUTF8(str);	BYTE pbuf[255];	memcpy(pbuf, buf, strlen(buf) + 1);	int i = 0;	char outbuff[BUFF_SIZE];	FILE*     outfile = fopen("out.txt", "wb");	while (pbuf[i])	{		sprintf(outbuff, "0x%02x, ", pbuf[i++]);		fputs(outbuff, outfile);	}	sprintf(outbuff, "0x00}");	fputs(outbuff, outfile);	fclose(outfile);	free(buf);	return 0;}

//将单字节char*转化为宽字节wchar_t*  wchar_t* AnsiToUnicode( const char* szStr )  {      int nLen = MultiByteToWideChar( CP_ACP, MB_PRECOMPOSED, szStr, -1, NULL, 0 );      if (nLen == 0)      {          return NULL;      }      wchar_t* pResult = new wchar_t[nLen];      MultiByteToWideChar( CP_ACP, MB_PRECOMPOSED, szStr, -1, pResult, nLen );      return pResult;  }    //将宽字节wchar_t*转化为单字节char*  char* UnicodeToAnsi( const wchar_t* szStr )  {      int nLen = WideCharToMultiByte( CP_ACP, 0, szStr, -1, NULL, 0, NULL, NULL );      if (nLen == 0)      {          return NULL;      }      char* pResult = new char[nLen];      WideCharToMultiByte( CP_ACP, 0, szStr, -1, pResult, nLen, NULL, NULL );      return pResult;  }

//wstring=>stringstd::string WString2String(const std::wstring& ws){    std::string strLocale = setlocale(LC_ALL, "");    const wchar_t* wchSrc = ws.c_str();    size_t nDestSize = wcstombs(NULL, wchSrc, 0) + 1;    char *chDest = new char[nDestSize];    memset(chDest, 0, nDestSize);    wcstombs(chDest, wchSrc, nDestSize);    std::string strResult = chDest;    delete[]chDest;    setlocale(LC_ALL, strLocale.c_str());    return strResult;}// string => wstringstd::wstring String2WString(const std::string& s){    std::string strLocale = setlocale(LC_ALL, "");    const char* chSrc = s.c_str();    size_t nDestSize = mbstowcs(NULL, chSrc, 0) + 1;    wchar_t* wchDest = new wchar_t[nDestSize];    wmemset(wchDest, 0, nDestSize);    mbstowcs(wchDest, chSrc, nDestSize);    std::wstring wstrResult = wchDest;    delete[]wchDest;    setlocale(LC_ALL, strLocale.c_str());    return wstrResult;}

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