win32中GBK、UTF8的互转

#include "stdafx.h"
#include <stdio.h>
#include <windows.h>

//GBK编码转换到UTF8编码
int GBKToUTF8(unsigned char * lpGBKStr,unsigned char * lpUTF8Str,int nUTF8StrLen)
{
 wchar_t * lpUnicodeStr = NULL;
 int nRetLen = 0;

 if(!lpGBKStr)  //如果GBK字符串为NULL则出错退出
  return 0;

 nRetLen = ::MultiByteToWideChar(CP_ACP,0,(char *)lpGBKStr,-1,NULL,NULL);  //获取转换到Unicode编码后所需要的字符空间长度
 lpUnicodeStr = new WCHAR[nRetLen + 1];  //为Unicode字符串空间
 nRetLen = ::MultiByteToWideChar(CP_ACP,0,(char *)lpGBKStr,-1,lpUnicodeStr,nRetLen);  //转换到Unicode编码
 if(!nRetLen)  //转换失败则出错退出
  return 0;

 nRetLen = ::WideCharToMultiByte(CP_UTF8,0,lpUnicodeStr,-1,NULL,0,NULL,NULL);  //获取转换到UTF8编码后所需要的字符空间长度

 if(!lpUTF8Str)  //输出缓冲区为空则返回转换后需要的空间大小
 {
  if(lpUnicodeStr)
   delete []lpUnicodeStr;
  return nRetLen;
 }

 if(nUTF8StrLen < nRetLen)  //如果输出缓冲区长度不够则退出
 {
  if(lpUnicodeStr)
   delete []lpUnicodeStr;
  return 0;
 }

 nRetLen = ::WideCharToMultiByte(CP_UTF8,0,lpUnicodeStr,-1,(char *)lpUTF8Str,nUTF8StrLen,NULL,NULL);  //转换到UTF8编码

 if(lpUnicodeStr)
  delete []lpUnicodeStr;

 return nRetLen;
}

// UTF8编码转换到GBK编码
int UTF8ToGBK(unsigned char * lpUTF8Str,unsigned char * lpGBKStr,int nGBKStrLen)
{
 wchar_t * lpUnicodeStr = NULL;
 int nRetLen = 0;

 if(!lpUTF8Str)  //如果UTF8字符串为NULL则出错退出
  return 0;

 nRetLen = ::MultiByteToWideChar(CP_UTF8,0,(char *)lpUTF8Str,-1,NULL,NULL);  //获取转换到Unicode编码后所需要的字符空间长度
 lpUnicodeStr = new WCHAR[nRetLen + 1];  //为Unicode字符串空间
 nRetLen = ::MultiByteToWideChar(CP_UTF8,0,(char *)lpUTF8Str,-1,lpUnicodeStr,nRetLen);  //转换到Unicode编码
 if(!nRetLen)  //转换失败则出错退出
  return 0;

 nRetLen = ::WideCharToMultiByte(CP_ACP,0,lpUnicodeStr,-1,NULL,NULL,NULL,NULL);  //获取转换到GBK编码后所需要的字符空间长度

 if(!lpGBKStr)  //输出缓冲区为空则返回转换后需要的空间大小
 {
  if(lpUnicodeStr)
   delete []lpUnicodeStr;
  return nRetLen;
 }

 if(nGBKStrLen < nRetLen)  //如果输出缓冲区长度不够则退出
 {
  if(lpUnicodeStr)
   delete []lpUnicodeStr;
  return 0;
 }

 nRetLen = ::WideCharToMultiByte(CP_ACP,0,lpUnicodeStr,-1,(char *)lpGBKStr,nRetLen,NULL,NULL);  //转换到GBK编码

 if(lpUnicodeStr)
  delete []lpUnicodeStr;

 return nRetLen;
}

int _tmain(int argc, _TCHAR* argv[])
{
 char cGBKStr[] = "上证指数!";
 char * lpGBKStr = NULL;
 char * lpUTF8Str = NULL;
 FILE * fp = NULL;
 int nRetLen = 0;

 nRetLen = GBKToUTF8((unsigned char *)cGBKStr,NULL,NULL);
 printf("转换后的字符串需要的空间长度为：%d ",nRetLen);
 lpUTF8Str = new char[nRetLen + 1];
 nRetLen = GBKToUTF8((unsigned char *)cGBKStr,(unsigned char *)lpUTF8Str,nRetLen);
 if(nRetLen)
 {
  printf("GBKToUTF8转换成功！");
 }
 else
 {
  printf("GBKToUTF8转换失败！");
  goto Ret0;
 }

 fp = fopen("C:\\GBK2UTF8.txt","wb");  //保存到文本文件
 fwrite(lpUTF8Str,nRetLen,1,fp);
 fclose(fp);

 getchar();  //先去打开那个文本文件看看，单击记事本的“文件”-“另存为”菜单，在对话框中看到编码框变为了“UTF-8”说明转换成功了

 nRetLen = UTF8ToGBK((unsigned char *)lpUTF8Str,NULL,NULL);  //再转回来
 printf("转换后的字符串需要的空间长度为：%d ",nRetLen);
 lpGBKStr = new char[nRetLen + 1];
 nRetLen = UTF8ToGBK((unsigned char *)lpUTF8Str,(unsigned char *)lpGBKStr,nRetLen);
 if(nRetLen)
 {
  printf("UTF8ToGBK转换成功！ ");
 }
 else
 {
  printf("UTF8ToGBK转换失败！ ");
  goto Ret0;
 }

 fp = fopen("C:\\UTF82GBK.txt","wb");  //保存到文本文件
 fwrite(lpGBKStr,nRetLen,1,fp);
 fclose(fp);

 getchar();  //再去打开文本文件看看，发现编码框又变为了“ANSI”说明转换成功了

Ret0:
 if(lpGBKStr)
  delete []lpGBKStr;

 if(lpUTF8Str)
  delete []lpUTF8Str;

 return 0;
}