C/C++ 字符编码的转换(ut8、gb2312)

//这是个类strCoding (strCoding.h文件)
#pragma once
#include<iostream>
#include<string>
#include<windows.h>
usingnamespace std;

class strCoding
{
public:
    strCoding(void);
   ~strCoding(void);
  
   void UTF_8ToGB2312(string&pOut, char *pText,int pLen);//utf_8转为gb2312
   void GB2312ToUTF_8(string& pOut,char*pText, int pLen); //gb2312 转utf_8
   string UrlGB2312(char* str);                          //urlgb2312编码
   string UrlUTF8(char* str);                            //urlutf8 编码
   string UrlUTF8Decode(string str);                 //urlutf8解码
   string UrlGB2312Decode(string str);               //urlgb2312解码
 
private:
   void Gb2312ToUnicode(WCHAR* pOut,char*gbBuffer);
   void UTF_8ToUnicode(WCHAR* pOut,char*pText);
   void UnicodeToUTF_8(char* pOut,WCHAR* pText);
   void UnicodeToGB2312(char* pOut,WCHAR uData);
   char  CharToInt(char ch);
   char StrToBin(char*str);

};

//这是个类strCoding (strCoding.cpp文件)
#include"StdAfx.h"

#include".\strcoding.h"



strCoding::strCoding(void)
{
}

strCoding::~strCoding(void)
{
}
void strCoding::Gb2312ToUnicode(WCHAR* pOut,char *gbBuffer)
{
    ::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,pOut,1);
   return;
}
void strCoding::UTF_8ToUnicode(WCHAR* pOut,char *pText)
{
   char* uchar= (char*)pOut;
    
    uchar[1]= ((pText[0]& 0x0F)<< 4)+ ((pText[1]>> 2)& 0x0F);
    uchar[0]= ((pText[1]& 0x03)<< 6)+ (pText[2]& 0x3F);

   return;
}

void strCoding::UnicodeToUTF_8(char* pOut,WCHAR* pText)
{
   // 注意 WCHAR高低字的顺序,低字节在前，高字节在后
   char* pchar= (char*)pText;

    pOut[0]= (0xE0| ((pchar[1]& 0xF0)>> 4));
    pOut[1]= (0x80| ((pchar[1]& 0x0F)<< 2))+ ((pchar[0]& 0xC0)>> 6);
    pOut[2]= (0x80| (pchar[0]& 0x3F));

   return;
}
void strCoding::UnicodeToGB2312(char* pOut,WCHAR uData)
{
    WideCharToMultiByte(CP_ACP,NULL,&uData,1,pOut,sizeof(WCHAR),NULL,NULL);
   return;
}

//做为解Url使用
char strCoding:: CharToInt(char ch){
       if(ch>='0'&& ch<='9')return (char)(ch-'0');
       if(ch>='a'&& ch<='f')return (char)(ch-'a'+10);
       if(ch>='A'&& ch<='F')return (char)(ch-'A'+10);
       return -1;
}
char strCoding::StrToBin(char*str){
       char tempWord[2];
       char chn;

        tempWord[0]= CharToInt(str[0]);                        //make the B to 11 -- 00001011
        tempWord[1]= CharToInt(str[1]);                        //make the 0 to 0  -- 00000000

        chn= (tempWord[0]<< 4)| tempWord[1];               //to change the BO to 10110000

       return chn;
}


//UTF_8 转gb2312
void strCoding::UTF_8ToGB2312(string&pOut, char *pText,int pLen)
{
    char buf[4];
    char* rst= newchar[pLen + (pLen >>2) +2];
    memset(buf,0,4);
    memset(rst,0,pLen+ (pLen >> 2)+ 2);

   int i =0;
   int j = 0;
     
   while(i < pLen)
   {
       if(*(pText+ i) >= 0)
       {
           
            rst[j++]= pText[i++];
        }
       else                
       {
            WCHAR Wtemp;

           
            UTF_8ToUnicode(&Wtemp,pText+ i);
             
            UnicodeToGB2312(buf,Wtemp);
           
            unsignedshort int tmp =0;
            tmp= rst[j] = buf[0];
            tmp= rst[j+1]= buf[1];
            tmp= rst[j+2]= buf[2];

           //newBuf[j] = Ctemp[0];
           //newBuf[j + 1] = Ctemp[1];

            i+= 3;   
            j+= 2;  
        }
       
  }
    rst[j]='\0';
   pOut= rst;
    delete []rst;
}

//GB2312 转为 UTF-8
void strCoding::GB2312ToUTF_8(string& pOut,char *pText, int pLen)
{
   char buf[4];
    memset(buf,0,4);

    pOut.clear();

   int i = 0;
   while(i < pLen)
   {
       //如果是英文直接复制就可以
       if( pText[i] >= 0)
       {
           char asciistr[2]={0};
            asciistr[0]= (pText[i++]);
            pOut.append(asciistr);
        }
       else
       {
            WCHAR pbuffer;
            Gb2312ToUnicode(&pbuffer,pText+i);

            UnicodeToUTF_8(buf,&pbuffer);

            pOut.append(buf);

            i+= 2;
        }
    }

   return;
}
//把str编码为网页中的 GB2312 url encode ,英文不变，汉字双字节  如%3D%AE%88
string strCoding::UrlGB2312(char* str)
{
   string dd;
    size_t len= strlen(str);
   for (size_t i=0;i<len;i++)
   {
       if(isalnum((BYTE)str[i]))
       {
           char tempbuff[2];
            sprintf(tempbuff,"%c",str[i]);
            dd.append(tempbuff);
        }
       else if (isspace((BYTE)str[i]))
       {
            dd.append("+");
        }
       else
       {
           char tempbuff[4];
            sprintf(tempbuff,"%%%X%X",((BYTE*)str)[i]>>4,((BYTE*)str)[i]%16);
            dd.append(tempbuff);
        }

    }
   return dd;
}

//把str编码为网页中的 UTF-8 url encode ,英文不变，汉字三字节  如%3D%AE%88

string strCoding::UrlUTF8(char* str)
{
   string tt;
   string dd;
    GB2312ToUTF_8(tt,str,(int)strlen(str));

    size_t len=tt.length();
   for (size_t i=0;i<len;i++)
   {
       if(isalnum((BYTE)tt.at(i)))
       {
           char tempbuff[2]={0};
            sprintf(tempbuff,"%c",(BYTE)tt.at(i));
            dd.append(tempbuff);
        }
       else if (isspace((BYTE)tt.at(i)))
       {
            dd.append("+");
        }
       else
       {
           char tempbuff[4];
            sprintf(tempbuff,"%%%X%X",((BYTE)tt.at(i))>>4,((BYTE)tt.at(i))%16);
            dd.append(tempbuff);
        }

    }
   return dd;
}
//把url GB2312解码
string strCoding::UrlGB2312Decode(string str)
{
  string output="";
       char tmp[2];
       int i=0,idx=0,ndx,len=str.length();
       
       while(i<len){
               if(str[i]=='%'){
                        tmp[0]=str[i+1];
                        tmp[1]=str[i+2];
                        output+= StrToBin(tmp);
                        i=i+3;
                }
               else if(str[i]=='+'){
                        output+='';
                        i++;
                }
               else{
                        output+=str[i];
                        i++;
                }
        }
       
       return output;
}
//把url utf8解码
string strCoding::UrlUTF8Decode(string str)
{
    string output="";

   string temp =UrlGB2312Decode(str);//

    UTF_8ToGB2312(output,(char*)temp.data(),strlen(temp.data()));

   return output;

}

//test
#include"stdafx.h"
#include"strCoding.h"

usingnamespace std;


int main()
{
   
     strCoding cfm;
    string keyword="大家好,欢迎你";
    string Temp="";
    string Output="";

    //把关键字做url的utf8编码
     Temp= cfm.UrlUTF8((char*)keyword.data());
     cout<<Temp<<endl;
   
    //把url的utf8编码的结果解码
     Temp=cfm.UrlUTF8Decode(Temp);
     cout<<Temp<<endl;

    //把关键字做url的gb2312编码
     Temp=cfm.UrlGB2312((char*)keyword.data());
     cout<<Temp<<endl;
    
    //把url的gb2312编码的结果解码
     Temp=cfm.UrlGB2312Decode(Temp);
     cout<<Temp<<endl;


    //把关键字GB2312转UTF_8
   
     cfm.GB2312ToUTF_8(Output,(char*)keyword.data(),strlen(keyword.data()));
     cout<<Output<<endl;

    //把GB2312转UTF_8转为中文
     cfm.UTF_8ToGB2312(Temp,(char*)Output.data(),strlen(Output.data()));
     cout<<Temp<<endl;


   //system("pasue");
     getchar();

   return 0;
   //
}