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.
/***
 * 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.commons;

import org.objectweb.asm.Handle;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

A MethodVisitor that can be used to approximate method size. 
Author:
Eugene Kuleshov/**
 * A {@link MethodVisitor} that can be used to approximate method size.
 * 
 * @author Eugene Kuleshov
 */
public class CodeSizeEvaluator extends MethodVisitor implements Opcodes {

    private int minSize;

    private int maxSize;

    public CodeSizeEvaluator(final MethodVisitor mv) {
        this(Opcodes.ASM4, mv);
    }

    protected CodeSizeEvaluator(final int api, final MethodVisitor mv) {
        super(api, mv);
    }

    public int getMinSize() {
        return this.minSize;
    }

    public int getMaxSize() {
        return this.maxSize;
    }

    @Override
    public void visitInsn(final int opcode) {
        minSize += 1;
        maxSize += 1;
        if (mv != null) {
            mv.visitInsn(opcode);
        }
    }

    @Override
    public void visitIntInsn(final int opcode, final int operand) {
        if (opcode == SIPUSH) {
            minSize += 3;
            maxSize += 3;
        } else {
            minSize += 2;
            maxSize += 2;
        }
        if (mv != null) {
            mv.visitIntInsn(opcode, operand);
        }
    }

    @Override
    public void visitVarInsn(final int opcode, final int var) {
        if (var < 4 && opcode != RET) {
            minSize += 1;
            maxSize += 1;
        } else if (var >= 256) {
            minSize += 4;
            maxSize += 4;
        } else {
            minSize += 2;
            maxSize += 2;
        }
        if (mv != null) {
            mv.visitVarInsn(opcode, var);
        }
    }

    @Override
    public void visitTypeInsn(final int opcode, final String type) {
        minSize += 3;
        maxSize += 3;
        if (mv != null) {
            mv.visitTypeInsn(opcode, type);
        }
    }

    @Override
    public void visitFieldInsn(final int opcode, final String owner,
            final String name, final String desc) {
        minSize += 3;
        maxSize += 3;
        if (mv != null) {
            mv.visitFieldInsn(opcode, owner, name, desc);
        }
    }

    @Override
    public void visitMethodInsn(final int opcode, final String owner,
            final String name, final String desc) {
        if (opcode == INVOKEINTERFACE) {
            minSize += 5;
            maxSize += 5;
        } else {
            minSize += 3;
            maxSize += 3;
        }
        if (mv != null) {
            mv.visitMethodInsn(opcode, owner, name, desc);
        }
    }

    @Override
    public void visitInvokeDynamicInsn(String name, String desc, Handle bsm,
            Object... bsmArgs) {
        minSize += 5;
        maxSize += 5;
        if (mv != null) {
            mv.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs);
        }
    }

    @Override
    public void visitJumpInsn(final int opcode, final Label label) {
        minSize += 3;
        if (opcode == GOTO || opcode == JSR) {
            maxSize += 5;
        } else {
            maxSize += 8;
        }
        if (mv != null) {
            mv.visitJumpInsn(opcode, label);
        }
    }

    @Override
    public void visitLdcInsn(final Object cst) {
        if (cst instanceof Long || cst instanceof Double) {
            minSize += 3;
            maxSize += 3;
        } else {
            minSize += 2;
            maxSize += 3;
        }
        if (mv != null) {
            mv.visitLdcInsn(cst);
        }
    }

    @Override
    public void visitIincInsn(final int var, final int increment) {
        if (var > 255 || increment > 127 || increment < -128) {
            minSize += 6;
            maxSize += 6;
        } else {
            minSize += 3;
            maxSize += 3;
        }
        if (mv != null) {
            mv.visitIincInsn(var, increment);
        }
    }

    @Override
    public void visitTableSwitchInsn(final int min, final int max,
            final Label dflt, final Label... labels) {
        minSize += 13 + labels.length * 4;
        maxSize += 16 + labels.length * 4;
        if (mv != null) {
            mv.visitTableSwitchInsn(min, max, dflt, labels);
        }
    }

    @Override
    public void visitLookupSwitchInsn(final Label dflt, final int[] keys,
            final Label[] labels) {
        minSize += 9 + keys.length * 8;
        maxSize += 12 + keys.length * 8;
        if (mv != null) {
            mv.visitLookupSwitchInsn(dflt, keys, labels);
        }
    }

    @Override
    public void visitMultiANewArrayInsn(final String desc, final int dims) {
        minSize += 4;
        maxSize += 4;
        if (mv != null) {
            mv.visitMultiANewArrayInsn(desc, dims);
        }
    }
}