base16 编码 和 解码

/**
 * Tencent is pleased to support the open source community by making Tars available.
 *
 * Copyright (C) 2016THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the BSD 3-Clause License (the "License"); you may not use this file except 
 * in compliance with the License. You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/BSD-3-Clause
 *
 * Unless required by applicable law or agreed to in writing, software distributed 
 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
 * CONDITIONS OF ANY KIND, either express or implied. See the License for the 
 * specific language governing permissions and limitations under the License.
 */

解码的代码，参考了腾讯开源框架tars工程的 tc_cgi.cpp 代码 

#include <iostream>

using namespace std;


//16进制转为char 
char x2c(const string& sWhat)
{
    register char digit;

    if (sWhat.length() < 2)
    {
        return '\0';
    }

    digit = (sWhat[0] >= 'A' ? ((sWhat[0] & 0xdf) - 'A') + 10 : (sWhat[0] - '0'));
    digit *= 16;
    digit += (sWhat[1] >= 'A' ? ((sWhat[1] & 0xdf) - 'A') + 10 : (sWhat[1] - '0'));

    return (digit);
}



string Base16Decode(const string& sUrl)
{
    string sDecodeUrl;
    register string::size_type pos = 0;
    string::size_type len = sUrl.length();

    sDecodeUrl = "";

    while (pos < len)
    {
        if (sUrl[pos] == '+')
        {
            sDecodeUrl += ' ';
            ++pos;
        }
        else if (sUrl[pos] == '%')
        {
            sDecodeUrl += x2c(sUrl.substr(pos + 1));
            pos += 3;
        }
        else
        {
            sDecodeUrl += sUrl[pos];

            ++pos;
        }
    }

    return sDecodeUrl;
}

string Base16Encode(const string& sUrl)
{
    static char HEX_TABLE[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    string result;
    for (size_t i = 0; i < sUrl.length(); i++)
    {
        char c = sUrl[i];
        if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
            result.append(1, c);
        else
        {
            result.append(1, '%');
            result.append(1, HEX_TABLE[(c >> 4) & 0x0f]);
            result.append(1, HEX_TABLE[c & 0x0f]);
        }
    }

    return result;
}

int main() {
    string str1 = "HenryAbc123";
    string str2 = "何亮到此一游abcde123";

    string out1 = Base16Encode(str1);
    string out2 = Base16Encode(str2);
    cout << "=====================begin encode:" << endl;
    cout << "out1:"<<out1 << endl;
    cout << "out2:"<<out2 << endl;
    cout << "=====================begin decode:" << endl;
    
    string decodeStr1 = Base16Decode(out1);
    string decodeStr2 = Base16Decode(out2);
    cout << "decodeStr1:" << decodeStr1 << endl;
    cout << "decodeStr2:" << decodeStr2 << endl;


    cout << "Base 16 test end!" << endl;
    return 0;
}

=======屏==幕==输==出========= output:

=====================begin encode:
out1:HenryAbc123
out2:%BA%CE%C1%C1%B5%BD%B4%CB%D2%BB%D3%CEabcde123
=====================begin decode:
decodeStr1:HenryAbc123
decodeStr2:何亮到此一游abcde123
Base 16 test end!