(原创)url编码实现

/**
* @param s 需要编码的url字符串
* @param len 需要编码的url的长度
* @param new_length 编码后的url的长度
* @return char * 返回编码后的url
* @note 存储编码后的url存储在一个新审请的内存中，
* 用完后，调用者应该释放它
*/
static char * urlencode(char *s, int len, int *new_length)
{
    printf( s);
    printf("n");

    char *from, *start, *end, *to;
    from = s;
    end = s + len;
    start = to = (char *) malloc(3 * len + 1);

    char hexchars[] = "0123456789ABCDEF";
    char c;

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

        if (c == ' ') {
            *to++ = '+';
        }
        else if ( ('0' <= c && c <= '9')
				  || ('a' <= c && c <= 'z')
                  || ('A' <= c && c <= 'Z')
                  || c == '/'
                  || c == '.'
                  || c == '-'
                  || c == '_'
                  || c == '='
                  || c == '&')
        {
            *to++ = c;
        }
        else {
            to[0] = '%';
            to[1] = hexchars[(c >> 4)&0xF];
            to[2] = hexchars[(c & 15)&0xF];
           to += 3;
        }
    }
    *to = 0;
    if (new_length) {
        *new_length = to - start;
    }
    return (char *) start;

}

static char* urlencode_v20(const char *s,char *pDes)
{
    char pTemp[1024*5];
	char pTemp2[1024];
    memset(pTemp,0,sizeof(pTemp));
	memset(pTemp2,0,sizeof(pTemp2));
    strcpy(pTemp,s);
    int nNewLen = 0;
    char *pUrlEncode = urlencode(pTemp, strlen(pTemp), &nNewLen);
    memset(pTemp,0,sizeof(pTemp));
    strcpy(pTemp,pUrlEncode);
    free(pUrlEncode);
    pUrlEncode = NULL;
    strcpy(pDes,pTemp);
    return pDes;
}