/*

 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.vm.ci.code;

/**

 * A map from registers to frame slots. This can be used to describe where callee saved registers

 * are saved in a callee's frame.

 */

public final class RegisterSaveLayout {

    /**

     * Keys.

     */

    private final Register[] registers;

    /**

     * Slot indexes relative to stack pointer.

     */

    private final int[] slots;

    /**

     * Creates a map from registers to frame slots.

     *

     * @param registers the keys in the map

     * @param slots frame slot index for each register in {@code registers}

     */

    public RegisterSaveLayout(Register[] registers, int[] slots) {

        assert registers.length == slots.length;

        this.registers = registers;

        this.slots = slots;

        assert registersToSlots(false).size() == registers.length : "non-unique registers";

        assert new HashSet<>(registersToSlots(false).values()).size() == slots.length : "non-unqiue slots";

    }

    /**

     * Gets the frame slot index for a given register.

     *

     * @param register register to get the frame slot index for

     * @return frame slot index

     */

    public int registerToSlot(Register register) {

        for (int i = 0; i < registers.length; i++) {

            if (register.equals(registers[i])) {

                return slots[i];

            }

        }

        throw new IllegalArgumentException(register + " not saved by this layout: " + this);

    }

    /**

     * Gets this layout information as a {@link Map} from registers to slots.

     */

    public Map<Register, Integer> registersToSlots(boolean sorted) {

        Map<Register, Integer> result;

        if (sorted) {

            result = new TreeMap<>();

        } else {

            result = new HashMap<>();

        }

        for (int i = 0; i < registers.length; i++) {

            result.put(registers[i], slots[i]);

        }

        return result;

    }

    /**

     * Gets this layout information as a {@link Map} from slots to registers.

     */

    public Map<Integer, Register> slotsToRegisters(boolean sorted) {

        Map<Integer, Register> result;

        if (sorted) {

            result = new TreeMap<>();

        } else {

            result = new HashMap<>();

        }

        for (int i = 0; i < registers.length; i++) {

            result.put(slots[i], registers[i]);

        }

        return result;

    }

    @Override

    public int hashCode() {

        throw new UnsupportedOperationException();

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof RegisterSaveLayout) {

            RegisterSaveLayout that = (RegisterSaveLayout) obj;

            if (Arrays.equals(registers, that.registers) && Arrays.equals(slots, that.slots)) {

                return true;

            }

        }

        return false;

    }

    @Override

    public String toString() {

        return registersToSlots(true).toString();

    }

}