CtrlAltAndCharacterPattern.java

/*
 * This file is part of lanterna (http://code.google.com/p/lanterna/).
 *
 * lanterna is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 2010-2017 Martin Berglund
 */
package com.googlecode.lanterna.input;

import java.util.List;

/**
 * Character pattern that matches characters pressed while ALT and CTRL keys are held down
 * 
 * @author Martin, Andreas
 */
public class CtrlAltAndCharacterPattern implements CharacterPattern {

    @Override
    public Matching match(List<Character> seq) {
        int size = seq.size();
        if (size > 2 || seq.get(0) != KeyDecodingProfile.ESC_CODE) {
            return null; // nope
        }
        if (size == 1) {
            return Matching.NOT_YET; // maybe later
        }
        char ch = seq.get(1);
        if (ch < 32 && ch != 0x08) {
            // Control-chars: exclude Esc(^[), but still include ^\, ^], ^^ and ^_
            char ctrlCode;
            switch (ch) {
            case KeyDecodingProfile.ESC_CODE: return null; // nope
            case 0:  /* ^@ */ ctrlCode = ' '; break;
            case 28: /* ^\ */ ctrlCode = '\\'; break;
            case 29: /* ^] */ ctrlCode = ']'; break;
            case 30: /* ^^ */ ctrlCode = '^'; break;
            case 31: /* ^_ */ ctrlCode = '_'; break;
            default: ctrlCode = (char)('a' - 1 + ch);
            }
            KeyStroke ks = new KeyStroke( ctrlCode, true, true);
            return new Matching( ks ); // yep
        } else if (ch == 0x7f || ch == 0x08) {
            KeyStroke ks = new KeyStroke( KeyType.Backspace, false, true);
            return new Matching( ks ); // yep
        } else {
            return null; // nope
        }
    }
}