/***
 * 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 scala.tools.asm.util;

import java.io.FileInputStream;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;

import scala.tools.asm.Attribute;
import scala.tools.asm.ClassReader;
import scala.tools.asm.Handle;
import scala.tools.asm.Label;
import scala.tools.asm.Opcodes;
import scala.tools.asm.Type;

/**
 * A {@link Printer} that prints the ASM code to generate the classes if visits.
 *
 * @author Eric Bruneton
 */
public class ASMifier extends Printer {

    /**
     * The name of the visitor variable in the produced code.
     */
    protected final String name;

    /**
     * Identifier of the annotation visitor variable in the produced code.
     */
    protected final int id;

    /**
     * The label names. This map associates String values to Label keys. It is
     * used only in ASMifierMethodVisitor.
     */
    protected Map<Label, String> labelNames;

    /**
     * Pseudo access flag used to distinguish class access flags.
     */
    private static final int ACCESS_CLASS = 262144;

    /**
     * Pseudo access flag used to distinguish field access flags.
     */
    private static final int ACCESS_FIELD = 524288;

    /**
     * Pseudo access flag used to distinguish inner class flags.
     */
    private static final int ACCESS_INNER = 1048576;

    /**
     * Constructs a new {@link ASMifier}. <i>Subclasses must not use this
     * constructor</i>. Instead, they must use the
     * {@link #ASMifier(int, String, int)} version.
     */
    public ASMifier() {
        this(Opcodes.ASM4, "cw", 0);
    }

    /**
     * Constructs a new {@link ASMifier}.
     *
     * @param api the ASM API version implemented by this class. Must be one of
     *        {@link Opcodes#ASM4}.
     * @param name the name of the visitor variable in the produced code.
     * @param id identifier of the annotation visitor variable in the produced
     *        code.
     */
    protected ASMifier(final int api, final String name, final int id) {
        super(api);
        this.name = name;
        this.id = id;
    }

    /**
     * Prints the ASM source code to generate the given class to the standard
     * output. <p> Usage: ASMifier [-debug] &lt;binary
     * class name or class file name&gt;
     *
     * @param args the command line arguments.
     *
     * @throws Exception if the class cannot be found, or if an IO exception
     *         occurs.
     */
    public static void main(final String[] args) throws Exception {
        int i = 0;
        int flags = ClassReader.SKIP_DEBUG;

        boolean ok = true;
        if (args.length < 1 || args.length > 2) {
            ok = false;
        }
        if (ok && "-debug".equals(args[0])) {
            i = 1;
            flags = 0;
            if (args.length != 2) {
                ok = false;
            }
        }
        if (!ok) {
            System.err.println("Prints the ASM code to generate the given class.");
            System.err.println("Usage: ASMifier [-debug] "
                    + "<fully qualified class name or class file name>");
            return;
        }
        ClassReader cr;
        if (args[i].endsWith(".class") || args[i].indexOf('\\') > -1
                || args[i].indexOf('/') > -1)
        {
            cr = new ClassReader(new FileInputStream(args[i]));
        } else {
            cr = new ClassReader(args[i]);
        }
        cr.accept(new TraceClassVisitor(null,
                new ASMifier(),
                new PrintWriter(System.out)), flags);
    }

    // ------------------------------------------------------------------------
    // Classes
    // ------------------------------------------------------------------------

    @Override
    public void visit(
        final int version,
        final int access,
        final String name,
        final String signature,
        final String superName,
        final String[] interfaces)
    {
        String simpleName;
        int n = name.lastIndexOf('/');
        if (n == -1) {
            simpleName = name;
        } else {
            text.add("package asm." + name.substring(0, n).replace('/', '.')
                    + ";\n");
            simpleName = name.substring(n + 1);
        }
        text.add("import java.util.*;\n");
        text.add("import org.objectweb.asm.*;\n");
        text.add("import org.objectweb.asm.attrs.*;\n");
        text.add("public class " + simpleName + "Dump implements Opcodes {\n\n");
        text.add("public static byte[] dump () throws Exception {\n\n");
        text.add("ClassWriter cw = new ClassWriter(0);\n");
        text.add("FieldVisitor fv;\n");
        text.add("MethodVisitor mv;\n");
        text.add("AnnotationVisitor av0;\n\n");

        buf.setLength(0);
        buf.append("cw.visit(");
        switch (version) {
            case Opcodes.V1_1:
                buf.append("V1_1");
                break;
            case Opcodes.V1_2:
                buf.append("V1_2");
                break;
            case Opcodes.V1_3:
                buf.append("V1_3");
                break;
            case Opcodes.V1_4:
                buf.append("V1_4");
                break;
            case Opcodes.V1_5:
                buf.append("V1_5");
                break;
            case Opcodes.V1_6:
                buf.append("V1_6");
                break;
            case Opcodes.V1_7:
                buf.append("V1_7");
                break;
            default:
                buf.append(version);
                break;
        }
        buf.append(", ");
        appendAccess(access | ACCESS_CLASS);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(signature);
        buf.append(", ");
        appendConstant(superName);
        buf.append(", ");
        if (interfaces != null && interfaces.length > 0) {
            buf.append("new String[] {");
            for (int i = 0; i < interfaces.length; ++i) {
                buf.append(i == 0 ? " " : ", ");
                appendConstant(interfaces[i]);
            }
            buf.append(" }");
        } else {
            buf.append("null");
        }
        buf.append(");\n\n");
        text.add(buf.toString());
    }

    @Override
    public void visitSource(final String file, final String debug) {
        buf.setLength(0);
        buf.append("cw.visitSource(");
        appendConstant(file);
        buf.append(", ");
        appendConstant(debug);
        buf.append(");\n\n");
        text.add(buf.toString());
    }

    @Override
    public void visitOuterClass(
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append("cw.visitOuterClass(");
        appendConstant(owner);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(");\n\n");
        text.add(buf.toString());
    }

    @Override
    public ASMifier visitClassAnnotation(
        final String desc,
        final boolean visible)
    {
        return visitAnnotation(desc, visible);
    }

    @Override
    public void visitClassAttribute(final Attribute attr) {
        visitAttribute(attr);
    }

    @Override
    public void visitInnerClass(
        final String name,
        final String outerName,
        final String innerName,
        final int access)
    {
        buf.setLength(0);
        buf.append("cw.visitInnerClass(");
        appendConstant(name);
        buf.append(", ");
        appendConstant(outerName);
        buf.append(", ");
        appendConstant(innerName);
        buf.append(", ");
        appendAccess(access | ACCESS_INNER);
        buf.append(");\n\n");
        text.add(buf.toString());
    }

    @Override
    public ASMifier visitField(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final Object value)
    {
        buf.setLength(0);
        buf.append("{\n");
        buf.append("fv = cw.visitField(");
        appendAccess(access | ACCESS_FIELD);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(", ");
        appendConstant(signature);
        buf.append(", ");
        appendConstant(value);
        buf.append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("fv", 0);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public ASMifier visitMethod(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final String[] exceptions)
    {
        buf.setLength(0);
        buf.append("{\n");
        buf.append("mv = cw.visitMethod(");
        appendAccess(access);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(", ");
        appendConstant(signature);
        buf.append(", ");
        if (exceptions != null && exceptions.length > 0) {
            buf.append("new String[] {");
            for (int i = 0; i < exceptions.length; ++i) {
                buf.append(i == 0 ? " " : ", ");
                appendConstant(exceptions[i]);
            }
            buf.append(" }");
        } else {
            buf.append("null");
        }
        buf.append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("mv", 0);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public void visitClassEnd() {
        text.add("cw.visitEnd();\n\n");
        text.add("return cw.toByteArray();\n");
        text.add("}\n");
        text.add("}\n");
    }

    // ------------------------------------------------------------------------
    // Annotations
    // ------------------------------------------------------------------------

    @Override
    public void visit(final String name, final Object value) {
        buf.setLength(0);
        buf.append("av").append(id).append(".visit(");
        appendConstant(buf, name);
        buf.append(", ");
        appendConstant(buf, value);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitEnum(
        final String name,
        final String desc,
        final String value)
    {
        buf.setLength(0);
        buf.append("av").append(id).append(".visitEnum(");
        appendConstant(buf, name);
        buf.append(", ");
        appendConstant(buf, desc);
        buf.append(", ");
        appendConstant(buf, value);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public ASMifier visitAnnotation(
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append("{\n");
        buf.append("AnnotationVisitor av").append(id + 1).append(" = av");
        buf.append(id).append(".visitAnnotation(");
        appendConstant(buf, name);
        buf.append(", ");
        appendConstant(buf, desc);
        buf.append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("av", id + 1);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public ASMifier visitArray(final String name) {
        buf.setLength(0);
        buf.append("{\n");
        buf.append("AnnotationVisitor av").append(id + 1).append(" = av");
        buf.append(id).append(".visitArray(");
        appendConstant(buf, name);
        buf.append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("av", id + 1);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public void visitAnnotationEnd() {
        buf.setLength(0);
        buf.append("av").append(id).append(".visitEnd();\n");
        text.add(buf.toString());
    }

    // ------------------------------------------------------------------------
    // Fields
    // ------------------------------------------------------------------------

    @Override
    public ASMifier visitFieldAnnotation(
        final String desc,
        final boolean visible)
    {
        return visitAnnotation(desc, visible);
    }

    @Override
    public void visitFieldAttribute(final Attribute attr) {
        visitAttribute(attr);
    }

    @Override
    public void visitFieldEnd() {
        buf.setLength(0);
        buf.append(name).append(".visitEnd();\n");
        text.add(buf.toString());
    }

    // ------------------------------------------------------------------------
    // Methods
    // ------------------------------------------------------------------------

    @Override
    public ASMifier visitAnnotationDefault() {
        buf.setLength(0);
        buf.append("{\n")
                .append("av0 = ")
                .append(name)
                .append(".visitAnnotationDefault();\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("av", 0);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public ASMifier visitMethodAnnotation(
        final String desc,
        final boolean visible)
    {
        return visitAnnotation(desc, visible);
    }

    @Override
    public ASMifier visitParameterAnnotation(
        final int parameter,
        final String desc,
        final boolean visible)
    {
        buf.setLength(0);
        buf.append("{\n")
                .append("av0 = ").append(name).append(".visitParameterAnnotation(")
                .append(parameter)
                .append(", ");
        appendConstant(desc);
        buf.append(", ").append(visible).append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("av", 0);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    @Override
    public void visitMethodAttribute(final Attribute attr) {
        visitAttribute(attr);
    }

    @Override
    public void visitCode() {
        text.add(name + ".visitCode();\n");
    }

    @Override
    public void visitFrame(
        final int type,
        final int nLocal,
        final Object[] local,
        final int nStack,
        final Object[] stack)
    {
        buf.setLength(0);
        switch (type) {
            case Opcodes.F_NEW:
            case Opcodes.F_FULL:
                declareFrameTypes(nLocal, local);
                declareFrameTypes(nStack, stack);
                if (type == Opcodes.F_NEW) {
                    buf.append(name).append(".visitFrame(Opcodes.F_NEW, ");
                } else {
                    buf.append(name).append(".visitFrame(Opcodes.F_FULL, ");
                }
                buf.append(nLocal).append(", new Object[] {");
                appendFrameTypes(nLocal, local);
                buf.append("}, ").append(nStack).append(", new Object[] {");
                appendFrameTypes(nStack, stack);
                buf.append('}');
                break;
            case Opcodes.F_APPEND:
                declareFrameTypes(nLocal, local);
                buf.append(name).append(".visitFrame(Opcodes.F_APPEND,")
                        .append(nLocal)
                        .append(", new Object[] {");
                appendFrameTypes(nLocal, local);
                buf.append("}, 0, null");
                break;
            case Opcodes.F_CHOP:
                buf.append(name).append(".visitFrame(Opcodes.F_CHOP,")
                        .append(nLocal)
                        .append(", null, 0, null");
                break;
            case Opcodes.F_SAME:
                buf.append(name).append(".visitFrame(Opcodes.F_SAME, 0, null, 0, null");
                break;
            case Opcodes.F_SAME1:
                declareFrameTypes(1, stack);
                buf.append(name).append(".visitFrame(Opcodes.F_SAME1, 0, null, 1, new Object[] {");
                appendFrameTypes(1, stack);
                buf.append('}');
                break;
        }
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitInsn(final int opcode) {
        buf.setLength(0);
        buf.append(name).append(".visitInsn(").append(OPCODES[opcode]).append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitIntInsn(final int opcode, final int operand) {
        buf.setLength(0);
        buf.append(name)
                .append(".visitIntInsn(")
                .append(OPCODES[opcode])
                .append(", ")
                .append(opcode == Opcodes.NEWARRAY
                        ? TYPES[operand]
                        : Integer.toString(operand))
                .append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitVarInsn(final int opcode, final int var) {
        buf.setLength(0);
        buf.append(name)
                .append(".visitVarInsn(")
                .append(OPCODES[opcode])
                .append(", ")
                .append(var)
                .append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitTypeInsn(final int opcode, final String type) {
        buf.setLength(0);
        buf.append(name).append(".visitTypeInsn(").append(OPCODES[opcode]).append(", ");
        appendConstant(type);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitFieldInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append(this.name).append(".visitFieldInsn(").append(OPCODES[opcode]).append(", ");
        appendConstant(owner);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitMethodInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append(this.name).append(".visitMethodInsn(").append(OPCODES[opcode]).append(", ");
        appendConstant(owner);
        buf.append(", ");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitInvokeDynamicInsn(
        String name,
        String desc,
        Handle bsm,
        Object... bsmArgs)
    {
        buf.setLength(0);
        buf.append(this.name).append(".visitInvokeDynamicInsn(");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(", ");
        appendConstant(bsm);
        buf.append(", new Object[]{");
        for (int i = 0; i < bsmArgs.length; ++i) {
            appendConstant(bsmArgs[i]);
            if (i != bsmArgs.length - 1) {
                buf.append(", ");
            }
        }
        buf.append("});\n");
        text.add(buf.toString());
    }

    @Override
    public void visitJumpInsn(final int opcode, final Label label) {
        buf.setLength(0);
        declareLabel(label);
        buf.append(name).append(".visitJumpInsn(").append(OPCODES[opcode]).append(", ");
        appendLabel(label);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitLabel(final Label label) {
        buf.setLength(0);
        declareLabel(label);
        buf.append(name).append(".visitLabel(");
        appendLabel(label);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitLdcInsn(final Object cst) {
        buf.setLength(0);
        buf.append(name).append(".visitLdcInsn(");
        appendConstant(cst);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitIincInsn(final int var, final int increment) {
        buf.setLength(0);
        buf.append(name)
                .append(".visitIincInsn(")
                .append(var)
                .append(", ")
                .append(increment)
                .append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitTableSwitchInsn(
        final int min,
        final int max,
        final Label dflt,
        final Label... labels)
    {
        buf.setLength(0);
        for (int i = 0; i < labels.length; ++i) {
            declareLabel(labels[i]);
        }
        declareLabel(dflt);

        buf.append(name)
                .append(".visitTableSwitchInsn(")
                .append(min)
                .append(", ")
                .append(max)
                .append(", ");
        appendLabel(dflt);
        buf.append(", new Label[] {");
        for (int i = 0; i < labels.length; ++i) {
            buf.append(i == 0 ? " " : ", ");
            appendLabel(labels[i]);
        }
        buf.append(" });\n");
        text.add(buf.toString());
    }

    @Override
    public void visitLookupSwitchInsn(
        final Label dflt,
        final int[] keys,
        final Label[] labels)
    {
        buf.setLength(0);
        for (int i = 0; i < labels.length; ++i) {
            declareLabel(labels[i]);
        }
        declareLabel(dflt);

        buf.append(name).append(".visitLookupSwitchInsn(");
        appendLabel(dflt);
        buf.append(", new int[] {");
        for (int i = 0; i < keys.length; ++i) {
            buf.append(i == 0 ? " " : ", ").append(keys[i]);
        }
        buf.append(" }, new Label[] {");
        for (int i = 0; i < labels.length; ++i) {
            buf.append(i == 0 ? " " : ", ");
            appendLabel(labels[i]);
        }
        buf.append(" });\n");
        text.add(buf.toString());
    }

    @Override
    public void visitMultiANewArrayInsn(final String desc, final int dims) {
        buf.setLength(0);
        buf.append(name).append(".visitMultiANewArrayInsn(");
        appendConstant(desc);
        buf.append(", ").append(dims).append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitTryCatchBlock(
        final Label start,
        final Label end,
        final Label handler,
        final String type)
    {
        buf.setLength(0);
        declareLabel(start);
        declareLabel(end);
        declareLabel(handler);
        buf.append(name).append(".visitTryCatchBlock(");
        appendLabel(start);
        buf.append(", ");
        appendLabel(end);
        buf.append(", ");
        appendLabel(handler);
        buf.append(", ");
        appendConstant(type);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitLocalVariable(
        final String name,
        final String desc,
        final String signature,
        final Label start,
        final Label end,
        final int index)
    {
        buf.setLength(0);
        buf.append(this.name).append(".visitLocalVariable(");
        appendConstant(name);
        buf.append(", ");
        appendConstant(desc);
        buf.append(", ");
        appendConstant(signature);
        buf.append(", ");
        appendLabel(start);
        buf.append(", ");
        appendLabel(end);
        buf.append(", ").append(index).append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitLineNumber(final int line, final Label start) {
        buf.setLength(0);
        buf.append(name).append(".visitLineNumber(").append(line).append(", ");
        appendLabel(start);
        buf.append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitMaxs(final int maxStack, final int maxLocals) {
        buf.setLength(0);
        buf.append(name)
                .append(".visitMaxs(")
                .append(maxStack)
                .append(", ")
                .append(maxLocals)
                .append(");\n");
        text.add(buf.toString());
    }

    @Override
    public void visitMethodEnd() {
        buf.setLength(0);
        buf.append(name).append(".visitEnd();\n");
        text.add(buf.toString());
    }

    // ------------------------------------------------------------------------
    // Common methods
    // ------------------------------------------------------------------------

    public ASMifier visitAnnotation(
        final String desc,
        final boolean visible)
    {
        buf.setLength(0);
        buf.append("{\n")
                .append("av0 = ")
                .append(name)
                .append(".visitAnnotation(");
        appendConstant(desc);
        buf.append(", ").append(visible).append(");\n");
        text.add(buf.toString());
        ASMifier a = createASMifier("av", 0);
        text.add(a.getText());
        text.add("}\n");
        return a;
    }

    public void visitAttribute(final Attribute attr) {
        buf.setLength(0);
        buf.append("// ATTRIBUTE ").append(attr.type).append('\n');
        if (attr instanceof ASMifiable) {
            if (labelNames == null) {
                labelNames = new HashMap<Label, String>();
            }
            buf.append("{\n");
            ((ASMifiable) attr).asmify(buf, "attr", labelNames);
            buf.append(name).append(".visitAttribute(attr);\n");
            buf.append("}\n");
        }
        text.add(buf.toString());
    }

    // ------------------------------------------------------------------------
    // Utility methods
    // ------------------------------------------------------------------------

    protected ASMifier createASMifier(final String name, final int id)    {
        return new ASMifier(Opcodes.ASM4, name, id);
    }

    /**
     * Appends a string representation of the given access modifiers to {@link
     * #buf buf}.
     *
     * @param access some access modifiers.
     */
    void appendAccess(final int access) {
        boolean first = true;
        if ((access & Opcodes.ACC_PUBLIC) != 0) {
            buf.append("ACC_PUBLIC");
            first = false;
        }
        if ((access & Opcodes.ACC_PRIVATE) != 0) {
            buf.append("ACC_PRIVATE");
            first = false;
        }
        if ((access & Opcodes.ACC_PROTECTED) != 0) {
            buf.append("ACC_PROTECTED");
            first = false;
        }
        if ((access & Opcodes.ACC_FINAL) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_FINAL");
            first = false;
        }
        if ((access & Opcodes.ACC_STATIC) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_STATIC");
            first = false;
        }
        if ((access & Opcodes.ACC_SYNCHRONIZED) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            if ((access & ACCESS_CLASS) == 0) {
                buf.append("ACC_SYNCHRONIZED");
            } else {
                buf.append("ACC_SUPER");
            }
            first = false;
        }
        if ((access & Opcodes.ACC_VOLATILE) != 0
                && (access & ACCESS_FIELD) != 0)
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_VOLATILE");
            first = false;
        }
        if ((access & Opcodes.ACC_BRIDGE) != 0 && (access & ACCESS_CLASS) == 0
                && (access & ACCESS_FIELD) == 0)
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_BRIDGE");
            first = false;
        }
        if ((access & Opcodes.ACC_VARARGS) != 0 && (access & ACCESS_CLASS) == 0
                && (access & ACCESS_FIELD) == 0)
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_VARARGS");
            first = false;
        }
        if ((access & Opcodes.ACC_TRANSIENT) != 0
                && (access & ACCESS_FIELD) != 0)
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_TRANSIENT");
            first = false;
        }
        if ((access & Opcodes.ACC_NATIVE) != 0 && (access & ACCESS_CLASS) == 0
                && (access & ACCESS_FIELD) == 0)
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_NATIVE");
            first = false;
        }
        if ((access & Opcodes.ACC_ENUM) != 0
                && ((access & ACCESS_CLASS) != 0
                        || (access & ACCESS_FIELD) != 0 || (access & ACCESS_INNER) != 0))
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_ENUM");
            first = false;
        }
        if ((access & Opcodes.ACC_ANNOTATION) != 0
                && ((access & ACCESS_CLASS) != 0 || (access & ACCESS_INNER) != 0))
        {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_ANNOTATION");
            first = false;
        }
        if ((access & Opcodes.ACC_ABSTRACT) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_ABSTRACT");
            first = false;
        }
        if ((access & Opcodes.ACC_INTERFACE) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_INTERFACE");
            first = false;
        }
        if ((access & Opcodes.ACC_STRICT) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_STRICT");
            first = false;
        }
        if ((access & Opcodes.ACC_SYNTHETIC) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_SYNTHETIC");
            first = false;
        }
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            if (!first) {
                buf.append(" + ");
            }
            buf.append("ACC_DEPRECATED");
            first = false;
        }
        if (first) {
            buf.append('0');
        }
    }

    /**
     * Appends a string representation of the given constant to the given
     * buffer.
     *
     * @param cst an {@link Integer}, {@link Float}, {@link Long},
     *        {@link Double} or {@link String} object. May be <tt>null</tt>.
     */
    protected void appendConstant(final Object cst) {
        appendConstant(buf, cst);
    }

    /**
     * Appends a string representation of the given constant to the given
     * buffer.
     *
     * @param buf a string buffer.
     * @param cst an {@link Integer}, {@link Float}, {@link Long},
     *        {@link Double} or {@link String} object. May be <tt>null</tt>.
     */
    static void appendConstant(final StringBuffer buf, final Object cst) {
        if (cst == null) {
            buf.append("null");
        } else if (cst instanceof String) {
            appendString(buf, (String) cst);
        } else if (cst instanceof Type) {
            buf.append("Type.getType(\"");
            buf.append(((Type) cst).getDescriptor());
            buf.append("\")");
        } else if (cst instanceof Handle) {
            buf.append("new Handle(");
            Handle h = (Handle) cst;
            buf.append("Opcodes.").append(HANDLE_TAG[h.getTag()]).append(", \"");
            buf.append(h.getOwner()).append("\", \"");
            buf.append(h.getName()).append("\", \"");
            buf.append(h.getDesc()).append("\")");
        } else if (cst instanceof Byte) {
            buf.append("new Byte((byte)").append(cst).append(')');
        } else if (cst instanceof Boolean) {
            buf.append(((Boolean) cst).booleanValue() ? "Boolean.TRUE" : "Boolean.FALSE");
        } else if (cst instanceof Short) {
            buf.append("new Short((short)").append(cst).append(')');
        } else if (cst instanceof Character) {
            int c = ((Character) cst).charValue();
            buf.append("new Character((char)").append(c).append(')');
        } else if (cst instanceof Integer) {
            buf.append("new Integer(").append(cst).append(')');
        } else if (cst instanceof Float) {
            buf.append("new Float(\"").append(cst).append("\")");
        } else if (cst instanceof Long) {
            buf.append("new Long(").append(cst).append("L)");
        } else if (cst instanceof Double) {
            buf.append("new Double(\"").append(cst).append("\")");
        } else if (cst instanceof byte[]) {
            byte[] v = (byte[]) cst;
            buf.append("new byte[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]);
            }
            buf.append('}');
        } else if (cst instanceof boolean[]) {
            boolean[] v = (boolean[]) cst;
            buf.append("new boolean[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]);
            }
            buf.append('}');
        } else if (cst instanceof short[]) {
            short[] v = (short[]) cst;
            buf.append("new short[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append("(short)").append(v[i]);
            }
            buf.append('}');
        } else if (cst instanceof char[]) {
            char[] v = (char[]) cst;
            buf.append("new char[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",")
                        .append("(char)")
                        .append((int) v[i]);
            }
            buf.append('}');
        } else if (cst instanceof int[]) {
            int[] v = (int[]) cst;
            buf.append("new int[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]);
            }
            buf.append('}');
        } else if (cst instanceof long[]) {
            long[] v = (long[]) cst;
            buf.append("new long[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]).append('L');
            }
            buf.append('}');
        } else if (cst instanceof float[]) {
            float[] v = (float[]) cst;
            buf.append("new float[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]).append('f');
            }
            buf.append('}');
        } else if (cst instanceof double[]) {
            double[] v = (double[]) cst;
            buf.append("new double[] {");
            for (int i = 0; i < v.length; i++) {
                buf.append(i == 0 ? "" : ",").append(v[i]).append('d');
            }
            buf.append('}');
        }
    }

    private void declareFrameTypes(final int n, final Object[] o) {
        for (int i = 0; i < n; ++i) {
            if (o[i] instanceof Label) {
                declareLabel((Label) o[i]);
            }
        }
    }

    private void appendFrameTypes(final int n, final Object[] o) {
        for (int i = 0; i < n; ++i) {
            if (i > 0) {
                buf.append(", ");
            }
            if (o[i] instanceof String) {
                appendConstant(o[i]);
            } else if (o[i] instanceof Integer) {
                switch (((Integer) o[i]).intValue()) {
                    case 0:
                        buf.append("Opcodes.TOP");
                        break;
                    case 1:
                        buf.append("Opcodes.INTEGER");
                        break;
                    case 2:
                        buf.append("Opcodes.FLOAT");
                        break;
                    case 3:
                        buf.append("Opcodes.DOUBLE");
                        break;
                    case 4:
                        buf.append("Opcodes.LONG");
                        break;
                    case 5:
                        buf.append("Opcodes.NULL");
                        break;
                    case 6:
                        buf.append("Opcodes.UNINITIALIZED_THIS");
                        break;
                }
            } else {
                appendLabel((Label) o[i]);
            }
        }
    }

    /**
     * Appends a declaration of the given label to {@link #buf buf}. This
     * declaration is of the form "Label lXXX = new Label();". Does nothing if
     * the given label has already been declared.
     *
     * @param l a label.
     */
    protected void declareLabel(final Label l) {
        if (labelNames == null) {
            labelNames = new HashMap<Label, String>();
        }
        String name = labelNames.get(l);
        if (name == null) {
            name = "l" + labelNames.size();
            labelNames.put(l, name);
            buf.append("Label ").append(name).append(" = new Label();\n");
        }
    }

    /**
     * Appends the name of the given label to {@link #buf buf}. The given label
     * <i>must</i> already have a name. One way to ensure this is to always
     * call {@link #declareLabel declared} before calling this method.
     *
     * @param l a label.
     */
    protected void appendLabel(final Label l) {
        buf.append(labelNames.get(l));
    }
}
