c++ encode decode

 1 std::string UrlEncode(const std::string& szToEncode)
 2 {
 3     std::string src = szToEncode;
 4     char hex[] = "0123456789ABCDEF";
 5     string dst;
 6  
 7     for (size_t i = 0; i < src.size(); ++i)
 8     {
 9         unsigned char cc = src[i];
10         if (isascii(cc))
11         {
12             if (cc == ‘ ‘)
13             {
14                 dst += "%20";
15             }
16             else
17                 dst += cc;
18         }
19         else
20         {
21             unsigned char c = static_cast<unsigned char>(src[i]);
22             dst += ‘%‘;
23             dst += hex[c / 16];
24             dst += hex[c % 16];
25         }
26     }
27     return dst;
28 }
29  
30  
31 std::string UrlDecode(const std::string& szToDecode)
32 {
33     std::string result;
34     int hex = 0;
35     for (size_t i = 0; i < szToDecode.length(); ++i)
36     {
37         switch (szToDecode[i])
38         {
39         case ‘+‘:
40             result += ‘ ‘;
41             break;
42         case ‘%‘:
43             if (isxdigit(szToDecode[i + 1]) && isxdigit(szToDecode[i + 2]))
44             {
45                 std::string hexStr = szToDecode.substr(i + 1, 2);
46                 hex = strtol(hexStr.c_str(), 0, 16);
47                 //字母和数字[0-9a-zA-Z]、一些特殊符号[$-_.+!*‘(),] 、以及某些保留字[$&+,/:;=?@]
48                 //可以不经过编码直接用于URL
49                 if (!((hex >= 48 && hex <= 57) || //0-9
50                     (hex >=97 && hex <= 122) ||   //a-z
51                     (hex >=65 && hex <= 90) ||    //A-Z
52                     //一些特殊符号及保留字[$-_.+!*‘(),]  [$&+,/:;=?@]
53                     hex == 0x21 || hex == 0x24 || hex == 0x26 || hex == 0x27 || hex == 0x28 || hex == 0x29
54                     || hex == 0x2a || hex == 0x2b|| hex == 0x2c || hex == 0x2d || hex == 0x2e || hex == 0x2f
55                     || hex == 0x3A || hex == 0x3B|| hex == 0x3D || hex == 0x3f || hex == 0x40 || hex == 0x5f
56                     ))
57                 {
58                     result += char(hex);
59                     i += 2;
60                 }
61                 else result += ‘%‘;
62             }else {
63                 result += ‘%‘;
64             }
65             break;
66         default:
67             result += szToDecode[i];
68             break;
69         }
70     }
71     return result;
72 }