url编解码小记 (url_encode, url_decode)

来源：互联网发布：js调用手机重力感应编辑：程序博客网时间：2024/06/06 00:53

原理：为了方便url传输过程中的可识别程度，主要分为两块进行，一块是可识别标准字符，一块是特殊字符及其它多字节，对于可识别的不变动，对于不可识别的只进行了转16进制操作再利用相应的规则进行拼接显示。

方法:

//URL编解码inline unsigned char to_hex(const unsigned char &x){  return x > 9 ? x + 55: x + 48;}inline unsigned char from_hex(const unsigned char &x){  return isdigit(x) ? x-'0' : x-'A'+10;}inline std::string url_encode(const std::string &in ){  std::string out;  for( size_t ix = 0; ix < in.size(); ix++ )  {    unsigned char buf[4];    memset( buf, 0, 4 );    if( isalnum( (unsigned char)in[ix] ) ){     buf[0] = in[ix];    } else {     buf[0] = '%';     buf[1] = to_hex( (unsigned char)in[ix] >> 4 );     buf[2] = to_hex( (unsigned char)in[ix] % 16);    }    out += (char *)buf;  }  return out;}inline std::string url_decode(const std::string &in){  std::string out;  for( size_t ix = 0; ix < in.size(); ix++ )  {    unsigned char ch = 0;    if(in[ix]=='%')    {     ch = (from_hex(in[ix+1])<<4);     ch |= from_hex(in[ix+2]);     ix += 2;    } else {     ch = in[ix];    }    out += (char)ch;  }  return out;}