#include "cryptomap.h"
#include "wordsource.h"
#include "globals.h"

const int CryptoMap::ALPH_SIZE = 128;
const char CryptoMap::BLANK = '*';

tvector<char> CryptoMap::ourMap(ALPH_SIZE, BLANK);
tvector<bool> CryptoMap::ourUsed(ALPH_SIZE,false);

CryptoMap::CryptoMap()
// post: empty map    
{

}

string CryptoMap::decode(const string& code)
// post: return string that's a decoded version of code    
{
    string copy(code);
    unsigned k;
    for(k=0; k < copy.length(); k++) {
	copy[k] = ourMap[copy[k]];
    }
    return copy;
}

bool CryptoMap::mappable(const string& code, const string& clear)
// pre: code.length() == clear.length()
// post: return true if code maps to clear consistently with
//       current global mapping, otherwise return false, if true returned
//       then the mapping code->clear is recorded in the global mapping    
{
    unsigned int k;
    myCodeChars.clear();
    if (code.length() != clear.length()) return false;

    
    for(k=0; k < code.length(); k++) {
	if (! ourUsed[clear[k]] && ourMap[code[k]] == BLANK) {
	    ourMap[code[k]] = clear[k];
	    ourUsed[clear[k]] = true;
	    myCodeChars.push_back(code[k]);
	    myClearChars.push_back(clear[k]);
	}
	else if (ourMap[code[k]] != clear[k]) {
	    unmap();
	    return false;
	}
    }
    return true;
}

void CryptoMap::unmap()
// post: last mapping is undone    
{
    int k;
    for(k=0; k < myCodeChars.size(); k++) {
	ourMap[myCodeChars[k]] = BLANK;
	ourUsed[myClearChars[k]] = false;
    }
    myCodeChars.clear();
    myClearChars.clear();
}