C++的URL转换

url_encoding.cpp

#include <iostream>
#include <string>
#include <cstring>

using namespace std;

const int CHARSET_NULL = 0;
const int CHARSET_ANSI = 1252; //ISO-8859-1
const int CHARSET_ASCII = CHARSET_ANSI;
const int CHARSET_GBK = 936;
const int CHARSET_UTF8 = 65001;
const int CHARSET_MIXED = 65536;

const int UTF8_3BYTES_PREFIX_MARK = 0xE0;
const int UTF8_OTHER_BYTE_MASK = 0x80;

int get_charset(const char *origin)
{
    //unsigned char c = origin[0]; // UTF8_PREFIX_MARK
    bool utf8Flag = false;
    bool gbkFlag = false;
    int length = strlen(origin);
    bool existsCodeGT80 = false;
    for (int index=0; index<length; index++)
    {
        unsigned char uc = origin[index];
        if (uc >= 0x80)
        {
            existsCodeGT80 = true;
            if (uc & UTF8_3BYTES_PREFIX_MARK == UTF8_3BYTES_PREFIX_MARK)
            {
                //说明可能是UTF-8，检查后面两个字符
                //TODO 检查是否越界
                unsigned char uc2nd = origin[index+1];
                unsigned char uc3rd = origin[index+2];
                if ( (uc2nd & UTF8_OTHER_BYTE_MASK==UTF8_OTHER_BYTE_MASK) && 
                    (uc3rd & UTF8_OTHER_BYTE_MASK==UTF8_OTHER_BYTE_MASK) ) 
                {
                    utf8Flag = true;
                    break;
                }
            }
            if (uc >= 0x81 && uc <= 0xFE)
            {
                //说明可能是GB2312或者GBK，检查第二个字节
                //TODO 检查是否越界
                unsigned char uc2nd = origin[index+1];
                if ( ( uc >= 0xA1 && uc <= 0xA9 && uc2nd >= 0xA1 && uc2nd <= 0xFE ) || 
                    ( uc >= 0xB0 && uc <= 0xF7 && uc2nd >= 0xA1 && uc2nd <= 0xFE ) || 
                    ( uc >= 0x81 && uc <= 0xA0 && uc2nd >= 0x40 && uc2nd <= 0xFE && uc2nd != 0x7F ) || 
                    ( uc >= 0xAA && uc <= 0xFE && uc2nd >= 0x40 && uc2nd <= 0xA0 && uc2nd != 0x7F ) || 
                    ( uc >= 0xA8 && uc <= 0xA9 && uc2nd >= 0x40 && uc2nd <= 0xA0 && uc2nd != 0x7F ) )
                {
                    gbkFlag = true;
                    break;
                }
            }
        }
    }
    if (!existsCodeGT80)
    {
        return CHARSET_ANSI;
    }
    if (utf8Flag == true && gbkFlag == false)
    {
        return CHARSET_UTF8;
    }
    else if (utf8Flag == false && gbkFlag == true)
    {
        return CHARSET_GBK;
    }
    else if (utf8Flag == true && gbkFlag == true)
    {
        return CHARSET_MIXED;
    }
    return CHARSET_NULL;
}

string url_encoding_gbk(const char *origin)
{
    string encoded = "";
}

string to_hex(unsigned char d)
{
    string hex = "";
    int high, low;
    high = d / 16;
    low = d % 16;
    if (high>=0 && high<=9) hex+=('0'+high);
    if (high>=10 && high<16) hex+=('A'+high-10);
    if (low>=0 && low<=9) hex+=('0'+low);
    if (low>=10 && low<16) hex+=('A'+low-10);
    return hex;
}

int to_urlcode(unsigned char c, string& urlcode, bool skip, int charset)
{
    int codeLenght = 1;
    if (skip)
    {
        urlcode = "%" + to_hex(c);
    }
    else
    {
        if (c >= 0x20 && c<= 0x2F) 
        {
            urlcode = "%" + to_hex(c);
        }
        else if (c == 0x3A)
        {
            urlcode = "%3A";
        }
        else if (c == 0x3B)
        {
            urlcode = "%3B";
        }
        else if (c == 0x3D)
        {
            urlcode = "%3D";
        }
        else if (c == 0x3F)
        {
            urlcode = "%3F";
        }
        else if (c == 0x40)
        {
            urlcode = "%40";
        }
        else if (c == 0x5B)
        {
            urlcode = "%5B";
        }
        else if (c == 0x5C)
        {
            urlcode = "%5C";
        }
        else if (c == 0x5D)
        {
            urlcode = "%5D";
        }
        else if (c >= 0x80)
        {
            urlcode = "%" + to_hex(c);
            if (charset == CHARSET_GBK)
            {
                codeLenght = 2;
            }
            else if (charset == CHARSET_UTF8)
            {
                codeLenght = 3;
            }
            if (skip)
            {
                codeLenght = 0;
            }
        }
        else
        {
            urlcode = c;
        }
    }
    return codeLenght;
}

string url_encoding(const char *origin)
{
    cout << "Charset: ";
    string encoded = "";
    int length = strlen(origin);
    int charset = get_charset(origin);
    if ( charset == CHARSET_ASCII )
    {
        cout << "ASCII" << endl;
    }
    else if ( charset == CHARSET_UTF8 )
    {
        cout << "UTF-8" << endl;
    }
    else if ( charset == CHARSET_GBK )
    {
        cout << "GBK" << endl;
    }
    else if ( charset == CHARSET_MIXED )
    {
        cout << "混合编码" << endl;
        //TODO 混合编码暂时按照算UTF-8算
        charset = CHARSET_UTF8;
    }
    else 
    {
        cout << "无效的编码！" << charset << endl;
    }
    int skipLeft = 0;
    for (int index=0; index<length; index++)
    {
        string encodedPart = "";
        int skipAddition = to_urlcode(origin[index], encodedPart, skipLeft>0, charset) - 1;
        cout << "0x" << hex << (unsigned int)(origin[index] & 0xFF) << " : " << encodedPart << " " << skipAddition << endl;
        encoded += encodedPart;
        if (skipLeft>0) skipLeft--;
        skipLeft += skipAddition;
    }
    return encoded;
}

int main()
{
    string url = "https://www.google.com/search?num=50&newwindow=1&safe=strict&q=urlencoding 特殊字符昇&oq=urlencoding 特殊字符昇&gs_l=serp.3...222.3060.0.3195.16.9.0.0.0.0.586.586.5-1.1.0....0...1c.1j4.64.serp..15.1.584.8KYDVu9BU3Q";
    url = "urlencoding 特殊字符昇&oq";
    cout << url_encoding(url.c_str()) << endl;
}