C++实现UrlEncode和UrlDecode

 #include "stdafx.h"
#include <iostream>
#include <windows.h>
#include <string>
using namespace std;
std::string UrlEncode(const std::string& szToEncode)
{
std::string src = szToEncode;
char hex[] = "0123456789ABCDEF";
string dst;
for (size_t i = 0; i < src.size(); ++i)
{
unsigned char cc = src[i];
if (isascii(cc))
{
if (cc == ' ')
{
dst += "%20";
}
else
dst += cc;
}
else
{
unsigned char c = static_cast<unsigned char>(src[i]);
dst += '%';
dst += hex[c / 16];
dst += hex[c % 16];
}
}
return dst;
}
std::string UrlDecode(const std::string& szToDecode)
{
std::string result;
int hex = 0;
for (size_t i = 0; i < szToDecode.length(); ++i)
{
switch (szToDecode[i])
{
case '+':
result += ' ';
break;
case '%':
if (isxdigit(szToDecode[i + 1]) && isxdigit(szToDecode[i + 2]))
{
std::string hexStr = szToDecode.substr(i + 1, 2);
hex = strtol(hexStr.c_str(), 0, 16);
//字母和数字[0-9a-zA-Z]、一些特殊符号[$-_.+!*'(),] 、以及某些保留字[$&+,/:;=?@]
//可以不经过编码直接用于URL
if (!((hex >= 48 && hex <= 57) || //0-9
(hex >=97 && hex <= 122) || //a-z
(hex >=65 && hex <= 90) || //A-Z
//一些特殊符号及保留字[$-_.+!*'(),] [$&+,/:;=?@]
hex == 0x21 || hex == 0x24 || hex == 0x26 || hex == 0x27 || hex == 0x28 || hex == 0x29
|| hex == 0x2a || hex == 0x2b|| hex == 0x2c || hex == 0x2d || hex == 0x2e || hex == 0x2f
|| hex == 0x3A || hex == 0x3B|| hex == 0x3D || hex == 0x3f || hex == 0x40 || hex == 0x5f
))
{
result += char(hex);
i += 2;
}
else result += '%';
}else {
result += '%';
}
break;
default:
result += szToDecode[i];
break;
}
}
return result;
}
/*
int main()
{
string test_str1 = "爽爽";
string test_str2 = UrlEncode(test_str1);
cout << test_str2 << endl;
}
*/