urlEncoder

拷贝自php的源码，url编码

 //url decode
 //str:输入,输出
 //len:str输入字符串大小
 //返回值:str解码后字符串大小
 int php_url_decode(char *str, int len);

 //url encode
 //out:用户分配内存,大小len*3+1,保障0结尾
 //返回值:编码后字符串大小,不包含null
 int php_url_encode(char const *s, int len, char *out);

 #include "urlEncoder.h"

 #include <ctype.h>

 //////////////////////////////////////////////////////////////////////////
 //url encode decode
 static unsigned char hexchars[] = "0123456789ABCDEF";

 int php_htoi(char *s)
 {
     int value;
     int c;

     c = ((unsigned char *)s)[];
     if (isupper(c))
         c = tolower(c);
     value = (c >= '' && c <= '' ? c - '' : c - 'a' + ) * ;

     c = ((unsigned char *)s)[];
     if (isupper(c))
         c = tolower(c);
     value += c >= '' && c <= '' ? c - '' : c - 'a' + ;

     return (value);
 }

 int php_url_encode(char const *s, int len, char *out)
 {
     register unsigned char c;
     unsigned char *to, *start;
     unsigned char const *from, *end;

     from = (unsigned char *)s;
     end  = (unsigned char *)s + len;
     start = to = (unsigned char*)out;//(unsigned char *) calloc(1, 3*len+1);

     while (from < end)
     {
         c = *from++;

         if (c == ' ')
         {
             *to++ = '+';
         }
         else if ((c < '' && c != '-' && c != '.') ||
             (c < 'A' && c > '') ||
             (c > 'Z' && c < 'a' && c != '_') ||
             (c > 'z'))
         {
             to[] = '%';
             to[] = hexchars[c >> ];
             to[] = hexchars[c & ];
             to += ;
         }
         else
         {
             *to++ = c;
         }
     }
     *to = ;

     return to - start;
 }

 int php_url_decode(char *str, int len)
 {
     char *dest = str;
     char *data = str;

     while (len--)
     {
         if (*data == '+')
         {
             *dest = ' ';
         }
         else if (*data == '%' && len >=  && isxdigit((int) *(data + )) &&
             isxdigit((int) *(data + )))
         {
             *dest = (char) php_htoi(data + );
             data += ;
             len -= ;
         }
         else
         {
             *dest = *data;
         }
         data++;
         dest++;
     }
     *dest = '/0';
     return dest - str;
 }
 //end url encode decode
 //////////////////////////////////////////////////////////////////////////