ksymon/src/main/java/com/loomcom/symon/MemoryRange.java

/*
 * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.loomcom.symon;

import com.loomcom.symon.exceptions.*;

/**
 * MemoryRange is a simple container class representing a literal
 * range of memory, with a staraddress, and an end address.  It has
 * guards against creating impossible memory ranges, and implements
 * some useful methods for checking address inclusion and range
 * overlaps.
 */
public class MemoryRange implements Comparable<MemoryRange> {

    /**
     * The starting address of the memory range.
     */
    public int startAddress;
    /**
     * The ending address of the memory range.
     */
    public int endAddress;

    public MemoryRange(int startAddress, int endAddress)
            throws MemoryRangeException {
        if (startAddress < 0 || endAddress < 0) {
            throw new MemoryRangeException("Addresses cannot be less than 0.");
        }
        if (startAddress >= endAddress) {
            throw new MemoryRangeException("End address must be greater " +
                    "than start address.");
        }
        this.startAddress = startAddress;
        this.endAddress = endAddress;
    }

    /**
     * @return the starting address.
     */
    public int startAddress() {
        return startAddress;
    }

    /**
     * @return the ending address.
     */
    public int endAddress() {
        return endAddress;
    }

    /**
     * Checks for address inclusion in the range.
     *
     * @return true if the address is included within this range,
     * false otherwise.
     */
    public boolean includes(int address) {
        return (address <= endAddress &&
                address >= startAddress);
    }

    /**
     * Checks for overlapping memory ranges.
     *
     * @return true if this range overlaps in any way with the other.
     */
    public boolean overlaps(MemoryRange other) {
        return (this.includes(other.startAddress()) ||
                other.includes(this.startAddress()));
    }

    // Implementation of Comparable interface
    public int compareTo(MemoryRange other) {
        if (other == null) {
            throw new NullPointerException("Cannot compare to null.");
        }
        if (this == other) {
            return 0;
        }
        Integer thisStartAddr = this.startAddress();
        Integer thatStartAddr = other.startAddress();
        return thisStartAddr.compareTo(thatStartAddr);
    }

    public String toString() {
        return "@" + String.format("0x%04x", startAddress) + "-" +
                String.format("0x%04x", endAddress);
    }
}