C++写的encodeURIComponent

 最近在用c++，找了几个库没有找到与javascript的URI编码相对应的函数。自己写一个，只写了编码，测试可以在javascript里用decodeURIComponent正常解码。

/**
 * uri编码字符串.
 * 
 * \param in 必须是utf-8编码的！
 * \return uri编码后的字符串。
 */
std::string encodeURIComponent(std::string in)
{
    std::stringstream ssUri;
    for (char c : in)
    {
        //0-9A-Za-z-_.!~*'()
        if ((c >= 'a' && c <= 'z') 
            || (c >= 'A' && c <= 'Z') 
            || (c >= '0' && c <= '9')
            || c == '!' 
            || (c >= '\'' && c <= '*') 
            || c == '-' 
            || c == '.' 
            || c== '_' 
            || c== '~')
        {
            ssUri << c;
        }
        else
        {
            ssUri << "%";
            if ((c & 0xf0) == 0)
                ssUri << 0;
            ssUri << setiosflags(ios::uppercase) << hex << (c & 0xff);
        }
    }
    return ssUri.str();
}

后来写的解码：

/**
 * URI解码.
 * 
 * \param in    URI编码的字符串。
 * \return  解码后的字符串，是utf-8编码的。
 */
std::string decodeURIComponent(std::string in)
{
    int               readFlag = 0;
    int               code     = 0;
    std::stringstream ssUri;
    for (char c : in)
    {
        if ((readFlag == 0) && (c == '%'))
        {
            readFlag = 1;
            continue;
        }
        else if (readFlag == 1)
        {
            if (isxdigit(c))
            {
                if (isdigit(c))
                    code = c - '0';
                else if (c >= 'A' && c <= 'F')
                    code = (0x0a+(c - 'A'));
                else
                    return std::string();
                readFlag = 2;
                continue;
            }
            else
            {
                return std::string();
            }
        }
        else if (readFlag == 2)
        {
            if (isxdigit(c))
            {
                code <<= 4;
                if (isdigit(c))
                    code |= (c - '0');
                else if (c >= 'A' && c <= 'F')
                    code |= (0x0a+(c - 'A'));
                else
                    return std::string();
                ssUri << (char) (code & 0xff);
                code     = 0;
                readFlag = 0;
                continue;
            }
            else
            {
                return std::string();
            }
        }
        else
        {
            ssUri << c;
        }
    }
    return ssUri.str();
}