/*
 * urlencode.cpp
 *
 *  Created on: 2022年6月1日
 *      Author: dingxy
 */

#include "urlencode.h"
#include "assert.h"

unsigned char toHex(unsigned char c) {
    return c > 9? 'A'-10+c : '0'+c;
}
 
unsigned char fromHex(unsigned char h) {
    unsigned char c = 0;
    if(h>='A' && h<='Z') {
        c = h-'A'+10;
    }else if(h>='a' && h<='z') {
        c = h-'a'+10;
    } else if(h>='0' && h<='9') {
        c = h-'0';
    } else {
    }
    return c;
}
 
void encodeUrl(const string& str, string& result) {
    int len = str.length();
    for(int i=0; i<len; i++) {
        if(isalnum((unsigned char)str[i]) ||
                (str[i]=='.')||(str[i]=='-')||(str[i]=='*')||(str[i]=='_')) {
            result += str[i];
        } else if(str[i] == ' ') {
            result += '+';
        } else {
            result += '%';
            result += toHex((unsigned char)str[i] >> 4);
            result += toHex((unsigned char)str[i] & 0xF);
        }
    }
}
 
void encodeUrl(const char* str, string &result) {
    string tmp = str;
    encodeUrl(tmp, result);
}
 
void decodeUrl(const string& str, string &result) {
    result = "";
    int len = str.length();
    for(int i=0; i<len; i++) {
        if((str[i]=='.')||(str[i]=='-')||(str[i]=='*')||(str[i]=='_')) {
            result += str[i];
        } else if(str[i] == '+') {
            result += ' ';
        } else if(str[i] == '%') {
            assert(i+2 < len);
            unsigned char high = fromHex((unsigned char)str[++i]);
            unsigned char low = fromHex((unsigned char)str[++i]);
            result += ((high<<4) | low);
        } else if(isalnum((unsigned char)str[i])){
            result += str[i];
        } else {
        }
    }
}
 
void decodeUrl(const char* str, string &result) {
    string tmp = str;
    decodeUrl(tmp, result);
}