emulib.plugins.cpu.DecodedInstruction Maven / Gradle / Ivy

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/*
 * KISS, YAGNI, DRY
 *
 * (c) Copyright 2006-2017, Peter Jakubčo
 * (c) Copyright 2012, M. Sulír
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
package emulib.plugins.cpu;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

/**
 * A decoded, but not yet disassembled instruction.
 */
public class DecodedInstruction {
    private final Map constants = new TreeMap<>();
    private final Map strings = new TreeMap<>();
    private final Map bits = new TreeMap<>();
    private byte[] image;

    /**
     * Adds the recognized string-returning variant to the instruction.
     * @param key the key (rule code)
     * @param string the string which the recognized variant returned
     * @param constant the constant obtained from the string
     */
    public void add(int key, String string, int constant) {
        constants.put(key, constant);
        strings.put(key, string);
    }

    /**
     * Adds the recognized subrule-returning variant to the instruction.
     * @param key the rule code
     * @param bits the bit sequence, padded to whole bytes
     */
    public void add(int key, byte[] bits) {
        this.bits.put(key, bits);
    }

    /**
     * Returns true if the instruction contains the specified key.
     * @param key the rule code
     * @return true if the instruction contains the key, false otherwise
     */
    public boolean hasKey(int key) {
        return bits.containsKey(key) || constants.containsKey(key);
    }

    /**
     * Returns the constant value to which the given key is mapped.
     * @param key the key
     * @return the constant; or -1 if the key is not mapped to a constant
     */
    public int get(int key) {
        Integer value = constants.get(key);
        return (value != null) ? value : -1;
    }

    /**
     * Returns the string value to which the given key is mapped.
     * @param key the key
     * @return the string; or null if the key is not mapped to a string
     */
    public String getString(int key) {
        return strings.get(key);
    }

    /**
     * Returns the bit sequence to which the given key is mapped.
     * @param key the key
     * @return the bit sequence; or null if the key is not mapped to bits
     */
    public byte[] getBits(int key) {
        return bits.get(key);
    }

    /**
     * Returns the bit sequence to which the given key is mapped.
     * @param key the key
     * @param reverseBytes reverse the byte order - this is useful to convert
     *        the data from Little to Big Endian (Java uses Big Endian)
     * @return the bit sequence; or null if the key is not mapped to bits
     */
    public byte[] getBits(int key, boolean reverseBytes) {
        byte[] data = bits.get(key);

        if (reverseBytes && data != null) {
            return reverseBytes(data);
        } else {
            return data;
        }
    }

    /**
     * Returns the binary image of the whole instruction.
     * @return the binary image
     */
    public byte[] getImage() {
        return image;
    }

    /**
     * Sets the binary image of the whole instruction.
     * @param image the binary image
     */
    public void setImage(byte[] image) {
        this.image = image;
    }

    /**
     * Returns the length of the instruction in the memory.
     * @return the length, in bytes
     */
    public int getLength() {
        return image.length;
    }

    /**
     * Returns the set of all keys contained in this instruction.
     * @return the set of keys
     */
    public Set getKeys() {
        Set keys = new HashSet<>(constants.keySet());
        keys.addAll(bits.keySet());
        return keys;
    }

    /**
     * Returns bytes in the reversed order.
     * @param data the data
     * @return the bytes in the reversed order
     */
    private byte[] reverseBytes(byte[] data) {
        byte[] result = new byte[data.length];

        for (int i = 0; i < result.length; i++) {
            result[i] = data[data.length - i - 1];
        }

        return result;
    }
}