ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2011 INRIA, France Telecom
All rights reserved.
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modification, are permitted provided that the following conditions
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   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holders nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.tree.analysis;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.InvokeDynamicInsnNode;
import org.objectweb.asm.tree.LdcInsnNode;
import org.objectweb.asm.tree.MethodInsnNode;

An Interpreter for SourceValue values. 
Author:
Eric Bruneton/**
 * An {@link Interpreter} for {@link SourceValue} values.
 * 
 * @author Eric Bruneton
 */
public class SourceInterpreter extends Interpreter<SourceValue> implements
        Opcodes {

    public SourceInterpreter() {
        super(ASM4);
    }

    protected SourceInterpreter(final int api) {
        super(api);
    }

    @Override
    public SourceValue newValue(final Type type) {
        if (type == Type.VOID_TYPE) {
            return null;
        }
        return new SourceValue(type == null ? 1 : type.getSize());
    }

    @Override
    public SourceValue newOperation(final AbstractInsnNode insn) {
        int size;
        switch (insn.getOpcode()) {
        case LCONST_0:
        case LCONST_1:
        case DCONST_0:
        case DCONST_1:
            size = 2;
            break;
        case LDC:
            Object cst = ((LdcInsnNode) insn).cst;
            size = cst instanceof Long || cst instanceof Double ? 2 : 1;
            break;
        case GETSTATIC:
            size = Type.getType(((FieldInsnNode) insn).desc).getSize();
            break;
        default:
            size = 1;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue copyOperation(final AbstractInsnNode insn,
            final SourceValue value) {
        return new SourceValue(value.getSize(), insn);
    }

    @Override
    public SourceValue unaryOperation(final AbstractInsnNode insn,
            final SourceValue value) {
        int size;
        switch (insn.getOpcode()) {
        case LNEG:
        case DNEG:
        case I2L:
        case I2D:
        case L2D:
        case F2L:
        case F2D:
        case D2L:
            size = 2;
            break;
        case GETFIELD:
            size = Type.getType(((FieldInsnNode) insn).desc).getSize();
            break;
        default:
            size = 1;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue binaryOperation(final AbstractInsnNode insn,
            final SourceValue value1, final SourceValue value2) {
        int size;
        switch (insn.getOpcode()) {
        case LALOAD:
        case DALOAD:
        case LADD:
        case DADD:
        case LSUB:
        case DSUB:
        case LMUL:
        case DMUL:
        case LDIV:
        case DDIV:
        case LREM:
        case DREM:
        case LSHL:
        case LSHR:
        case LUSHR:
        case LAND:
        case LOR:
        case LXOR:
            size = 2;
            break;
        default:
            size = 1;
        }
        return new SourceValue(size, insn);
    }

    @Override
    public SourceValue ternaryOperation(final AbstractInsnNode insn,
            final SourceValue value1, final SourceValue value2,
            final SourceValue value3) {
        return new SourceValue(1, insn);
    }

    @Override
    public SourceValue naryOperation(final AbstractInsnNode insn,
            final List<? extends SourceValue> values) {
        int size;
        int opcode = insn.getOpcode();
        if (opcode == MULTIANEWARRAY) {
            size = 1;
        } else {
            String desc = (opcode == INVOKEDYNAMIC) ? ((InvokeDynamicInsnNode) insn).desc
                    : ((MethodInsnNode) insn).desc;
            size = Type.getReturnType(desc).getSize();
        }
        return new SourceValue(size, insn);
    }

    @Override
    public void returnOperation(final AbstractInsnNode insn,
            final SourceValue value, final SourceValue expected) {
    }

    @Override
    public SourceValue merge(final SourceValue d, final SourceValue w) {
        if (d.insns instanceof SmallSet && w.insns instanceof SmallSet) {
            Set<AbstractInsnNode> s = ((SmallSet<AbstractInsnNode>) d.insns)
                    .union((SmallSet<AbstractInsnNode>) w.insns);
            if (s == d.insns && d.size == w.size) {
                return d;
            } else {
                return new SourceValue(Math.min(d.size, w.size), s);
            }
        }
        if (d.size != w.size || !d.insns.containsAll(w.insns)) {
            HashSet<AbstractInsnNode> s = new HashSet<AbstractInsnNode>();
            s.addAll(d.insns);
            s.addAll(w.insns);
            return new SourceValue(Math.min(d.size, w.size), s);
        }
        return d;
    }
}