chastokil

gistfile1.cpp

#include <iostream>
#include <string>
#include <fstream>

//#include <stdlib.h>

using namespace std;

int* generateHeightArray(int h, int mesLen) {
    int* idxs = new int[mesLen];

    int pos = 0;
    int offset = 1;
    for (int i = 0; i < mesLen; ++i) {
        idxs[i] = pos;
        pos += offset;
        if (pos == h - 1) offset = -1;
        if (pos == 0) offset = 1;
    }

//    for (int i = 0; i < mesLen; ++i) cout << idxs[i];
//    cout << endl;
    return idxs;
}

string encrypt(string m, int k) {
    int* idxs = generateHeightArray(k, m.length());

    string* arr = new string[k];
    for (int i = 0; i < k; ++i) {
        arr[i] = "";
    }

    for (int i = 0; i < m.length(); ++i) {
        arr[idxs[i]] += m[i];
    }

    string res = "";
    for (int i = k - 1; i >= 0; --i) {
        res += arr[i];
    }

    return res;
}

string encrypt(string m, int k, int len) {
	string res = "";
	int pos = 0;
	do {
		res+=encrypt(m.substr(pos,len),k);
		pos+=len;
	} while (pos <= m.length());
	return res;
}

string decrypt(string m, int k) {
    int mLen = m.length();

    int* idxs = generateHeightArray(k, mLen);

    int* lens = new int[k];
    for (int i = 0; i < k; ++i) {
        lens[i] = 0;
    }

    for (int i = 0; i < mLen; ++i) {
        lens[idxs[i]]++;
    }

    string* arr = new string[k];
    for (int i = 0; i < k; ++i) {
        arr[i] = "";
    }

    int pos = mLen;
    for (int i = 0; i < k; ++i) {
        pos -= lens[i];
        arr[i] = m.substr(pos, lens[i]);
//        cout << "current pos\t" << pos << "\tphrase\t" << arr[i] << endl;
    }

    string res = "";
    int* arrPos = new int[k];
    for (int i = 0; i < k; i++) {
        arrPos[i] = 0;
    }

//    for (int i = 0; i < k; i++) {
//        cout << "arr\t" << i << ":\t" << arr[i] << endl;
//    }
//    cout << endl;

    for (int i = 0; i < mLen; ++i) {
        res += arr[idxs[i]][arrPos[idxs[i]]];
        ++arrPos[idxs[i]];
    }
    return res;
}


string decrypt(string m, int k, int len) {
	string res = "";
	int pos = 0;
	do {
		res+=decrypt(m.substr(pos,len),k);
		pos+=len;
	} while (pos <= m.length());
	return res;
}

void printHelp() {
	cout << "Utility to crypt text using drabynka: 01232101232..." << endl;
    cout << "Usage:" << endl;
    cout << "lesenka e|d KEY LEN INPUT OUTPUT" << endl << endl;
    cout << "Command-line options: " << endl;
    cout << "\te - ecrypt file" << endl;
    cout << "\td - decrypt file" << endl;
    cout << endl;
    cout << "KEY - positive integer. key to crypt/decrypt with." << endl << endl;
	cout << "LEN - positive integer. length of block." << endl << endl;

    cout << "INPUT and OUTPUT are filenames." << endl;
}

int main(int argc, const char* argv[]) {

	/*for(int i=0;i<argc;++i)
		cout<<argv[i]<<endl;
*/
    if (argc != 6) {
        printHelp();
        return 1;
    }

    bool d = true;

	if (argv[1][0] != '-') {
		printHelp();
		return 1;
	}
    char command = argv[1][1];
    int key = atoi(argv[2]);
    if (key<=0) {
        printHelp();
        return -1;
    }
	int length = atoi(argv[3]);
	if (length<=0) {
        printHelp();
        return -1;
    }
    ifstream ifs(argv[4], ifstream::in);
    ofstream ofs(argv[5], ofstream::out);

    if (ifs == NULL || ofs == NULL) {
        printHelp();
        return -2;
    }

    switch (command) {
        case 'e':
            d = false;
        case 'd':
            cout << "Processing file:\t" << argv[4] << endl;

            while (ifs.good()) {
                string str;
                getline(ifs, str);
                if (d) {
                    ofs << decrypt(str, key, length);
                } else {
					ofs << encrypt(str, key, length);
                }
                if (!ifs.eof()) {
                    ofs<<endl;
                }
            }
            cout << "File " << argv[4] << " successfully " << (d ? "decrypted" : "encrypted") << "." << endl;
            break;
        default:
            printHelp();
            return 2;
    }

    ifs.close();
    ofs.close();
    return 0;
}