/*
 * Copyright (c) 2008, 2016, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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 com.sun.tools.classfile;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import static com.sun.tools.classfile.Annotation.*;
import static com.sun.tools.classfile.ConstantPool.*;
import static com.sun.tools.classfile.StackMapTable_attribute.*;
import static com.sun.tools.classfile.StackMapTable_attribute.verification_type_info.*;

Write a ClassFile data structure to a file or stream.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 * Write a ClassFile data structure to a file or stream.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class ClassWriter {
    public ClassWriter() {
        attributeWriter = new AttributeWriter();
        constantPoolWriter = new ConstantPoolWriter();
        out = new ClassOutputStream();
    }

    
Write a ClassFile data structure to a file.
Params:
classFile – the classfile object to be written
f – the file
Throws:
IOException – if an error occurs while writing the file/**
     * Write a ClassFile data structure to a file.
     * @param classFile the classfile object to be written
     * @param f the file
     * @throws IOException if an error occurs while writing the file
     */
    public void write(ClassFile classFile, File f) throws IOException {
        try (FileOutputStream f_out = new FileOutputStream(f)) {
            write(classFile, f_out);
        }
    }

    
Write a ClassFile data structure to a stream.
Params:
classFile – the classfile object to be written
s – the stream
Throws:
IOException – if an error occurs while writing the file/**
     * Write a ClassFile data structure to a stream.
     * @param classFile the classfile object to be written
     * @param s the stream
     * @throws IOException if an error occurs while writing the file
     */
    public void write(ClassFile classFile, OutputStream s) throws IOException {
        this.classFile = classFile;
        out.reset();
        write();
        out.writeTo(s);
    }

    protected void write() throws IOException {
        writeHeader();
        writeConstantPool();
        writeAccessFlags(classFile.access_flags);
        writeClassInfo();
        writeFields();
        writeMethods();
        writeAttributes(classFile.attributes);
    }

    protected void writeHeader() {
        out.writeInt(classFile.magic);
        out.writeShort(classFile.minor_version);
        out.writeShort(classFile.major_version);
    }

    protected void writeAccessFlags(AccessFlags flags) {
        out.writeShort(flags.flags);
    }

    protected void writeAttributes(Attributes attributes) {
        int size = attributes.size();
        out.writeShort(size);
        for (Attribute attr: attributes)
            attributeWriter.write(attr, out);
    }

    protected void writeClassInfo() {
        out.writeShort(classFile.this_class);
        out.writeShort(classFile.super_class);
        int[] interfaces = classFile.interfaces;
        out.writeShort(interfaces.length);
        for (int i: interfaces)
            out.writeShort(i);
    }

    protected void writeDescriptor(Descriptor d) {
        out.writeShort(d.index);
    }

    protected void writeConstantPool() {
        ConstantPool pool = classFile.constant_pool;
        int size = pool.size();
        out.writeShort(size);
        for (CPInfo cpInfo: pool.entries())
            constantPoolWriter.write(cpInfo, out);
    }

    protected void writeFields() throws IOException {
        Field[] fields = classFile.fields;
        out.writeShort(fields.length);
        for (Field f: fields)
            writeField(f);
    }

    protected void writeField(Field f) throws IOException {
        writeAccessFlags(f.access_flags);
        out.writeShort(f.name_index);
        writeDescriptor(f.descriptor);
        writeAttributes(f.attributes);
    }

    protected void writeMethods() throws IOException {
        Method[] methods = classFile.methods;
        out.writeShort(methods.length);
        for (Method m: methods) {
            writeMethod(m);
        }
    }

    protected void writeMethod(Method m) throws IOException {
        writeAccessFlags(m.access_flags);
        out.writeShort(m.name_index);
        writeDescriptor(m.descriptor);
        writeAttributes(m.attributes);
    }

    protected ClassFile classFile;
    protected ClassOutputStream out;
    protected AttributeWriter attributeWriter;
    protected ConstantPoolWriter constantPoolWriter;

    
Subtype of ByteArrayOutputStream with the convenience methods of
a DataOutputStream. Since ByteArrayOutputStream does not throw
IOException, there are no exceptions from the additional
convenience methods either,
/**
     * Subtype of ByteArrayOutputStream with the convenience methods of
     * a DataOutputStream. Since ByteArrayOutputStream does not throw
     * IOException, there are no exceptions from the additional
     * convenience methods either,
     */
    protected static class ClassOutputStream extends ByteArrayOutputStream {
        public ClassOutputStream() {
            d = new DataOutputStream(this);
        }

        public void writeByte(int value) {
            try {
                d.writeByte(value);
            } catch (IOException ignore) {
            }
        }

        public void writeShort(int value) {
            try {
                d.writeShort(value);
            } catch (IOException ignore) {
            }
        }

        public void writeInt(int value) {
            try {
                d.writeInt(value);
            } catch (IOException ignore) {
            }
        }

        public void writeLong(long value) {
            try {
                d.writeLong(value);
            } catch (IOException ignore) {
            }
        }

        public void writeFloat(float value) {
            try {
                d.writeFloat(value);
            } catch (IOException ignore) {
            }
        }

        public void writeDouble(double value) {
            try {
                d.writeDouble(value);
            } catch (IOException ignore) {
            }
        }

        public void writeUTF(String value) {
            try {
                d.writeUTF(value);
            } catch (IOException ignore) {
            }
        }

        public void writeTo(ClassOutputStream s) {
            try {
                super.writeTo(s);
            } catch (IOException ignore) {
            }
        }

        private final DataOutputStream d;
    }

    
Writer for the entries in the constant pool.
/**
     * Writer for the entries in the constant pool.
     */
    protected static class ConstantPoolWriter
           implements ConstantPool.Visitor<Integer,ClassOutputStream> {
        protected int write(CPInfo info, ClassOutputStream out) {
            out.writeByte(info.getTag());
            return info.accept(this, out);
        }

        @Override
        public Integer visitClass(CONSTANT_Class_info info, ClassOutputStream out) {
            out.writeShort(info.name_index);
            return 1;
        }

        @Override
        public Integer visitDouble(CONSTANT_Double_info info, ClassOutputStream out) {
            out.writeDouble(info.value);
            return 2;
        }

        @Override
        public Integer visitFieldref(CONSTANT_Fieldref_info info, ClassOutputStream out) {
            writeRef(info, out);
            return 1;
        }

        @Override
        public Integer visitFloat(CONSTANT_Float_info info, ClassOutputStream out) {
            out.writeFloat(info.value);
            return 1;
        }

        @Override
        public Integer visitInteger(CONSTANT_Integer_info info, ClassOutputStream out) {
            out.writeInt(info.value);
            return 1;
        }

        @Override
        public Integer visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, ClassOutputStream out) {
            writeRef(info, out);
            return 1;
        }

        @Override
        public Integer visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, ClassOutputStream out) {
            out.writeShort(info.bootstrap_method_attr_index);
            out.writeShort(info.name_and_type_index);
            return 1;
        }

        @Override
        public Integer visitLong(CONSTANT_Long_info info, ClassOutputStream out) {
            out.writeLong(info.value);
            return 2;
        }

        @Override
        public Integer visitMethodHandle(CONSTANT_MethodHandle_info info, ClassOutputStream out) {
            out.writeByte(info.reference_kind.tag);
            out.writeShort(info.reference_index);
            return 1;
        }

        @Override
        public Integer visitMethodType(CONSTANT_MethodType_info info, ClassOutputStream out) {
            out.writeShort(info.descriptor_index);
            return 1;
        }

        @Override
        public Integer visitMethodref(CONSTANT_Methodref_info info, ClassOutputStream out) {
            return writeRef(info, out);
        }

        @Override
        public Integer visitModule(CONSTANT_Module_info info, ClassOutputStream out) {
            out.writeShort(info.name_index);
            return 1;
        }

        @Override
        public Integer visitNameAndType(CONSTANT_NameAndType_info info, ClassOutputStream out) {
            out.writeShort(info.name_index);
            out.writeShort(info.type_index);
            return 1;
        }

        @Override
        public Integer visitPackage(CONSTANT_Package_info info, ClassOutputStream out) {
            out.writeShort(info.name_index);
            return 1;
        }

        @Override
        public Integer visitString(CONSTANT_String_info info, ClassOutputStream out) {
            out.writeShort(info.string_index);
            return 1;
        }

        @Override
        public Integer visitUtf8(CONSTANT_Utf8_info info, ClassOutputStream out) {
            out.writeUTF(info.value);
            return 1;
        }

        protected Integer writeRef(CPRefInfo info, ClassOutputStream out) {
            out.writeShort(info.class_index);
            out.writeShort(info.name_and_type_index);
            return 1;
        }
    }

    
Writer for the different types of attribute.
/**
     * Writer for the different types of attribute.
     */
    protected static class AttributeWriter implements Attribute.Visitor<Void,ClassOutputStream> {
        public void write(Attributes attributes, ClassOutputStream out) {
            int size = attributes.size();
            out.writeShort(size);
            for (Attribute a: attributes)
                write(a, out);
        }

        // Note: due to the use of shared resources, this method is not reentrant.
        public void write(Attribute attr, ClassOutputStream out) {
            out.writeShort(attr.attribute_name_index);
            sharedOut.reset();
            attr.accept(this, sharedOut);
            out.writeInt(sharedOut.size());
            sharedOut.writeTo(out);
        }

        protected ClassOutputStream sharedOut = new ClassOutputStream();
        protected AnnotationWriter annotationWriter = new AnnotationWriter();

        @Override
        public Void visitDefault(DefaultAttribute attr, ClassOutputStream out) {
            out.write(attr.info, 0, attr.info.length);
            return null;
        }

        @Override
        public Void visitAnnotationDefault(AnnotationDefault_attribute attr, ClassOutputStream out) {
            annotationWriter.write(attr.default_value, out);
            return null;
        }

        @Override
        public Void visitBootstrapMethods(BootstrapMethods_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.bootstrap_method_specifiers.length);
            for (BootstrapMethods_attribute.BootstrapMethodSpecifier bsm : attr.bootstrap_method_specifiers) {
                out.writeShort(bsm.bootstrap_method_ref);
                int bsm_args_count = bsm.bootstrap_arguments.length;
                out.writeShort(bsm_args_count);
                for (int i : bsm.bootstrap_arguments) {
                    out.writeShort(i);
                }
            }
            return null;
        }

        @Override
        public Void visitCharacterRangeTable(CharacterRangeTable_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.character_range_table.length);
            for (CharacterRangeTable_attribute.Entry e: attr.character_range_table)
                writeCharacterRangeTableEntry(e, out);
            return null;
        }

        protected void writeCharacterRangeTableEntry(CharacterRangeTable_attribute.Entry entry, ClassOutputStream out) {
            out.writeShort(entry.start_pc);
            out.writeShort(entry.end_pc);
            out.writeInt(entry.character_range_start);
            out.writeInt(entry.character_range_end);
            out.writeShort(entry.flags);
        }

        @Override
        public Void visitCode(Code_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.max_stack);
            out.writeShort(attr.max_locals);
            out.writeInt(attr.code.length);
            out.write(attr.code, 0, attr.code.length);
            out.writeShort(attr.exception_table.length);
            for (Code_attribute.Exception_data e: attr.exception_table)
                writeExceptionTableEntry(e, out);
            new AttributeWriter().write(attr.attributes, out);
            return null;
        }

        protected void writeExceptionTableEntry(Code_attribute.Exception_data exception_data, ClassOutputStream out) {
            out.writeShort(exception_data.start_pc);
            out.writeShort(exception_data.end_pc);
            out.writeShort(exception_data.handler_pc);
            out.writeShort(exception_data.catch_type);
        }

        @Override
        public Void visitCompilationID(CompilationID_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.compilationID_index);
            return null;
        }

        @Override
        public Void visitConstantValue(ConstantValue_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.constantvalue_index);
            return null;
        }

        @Override
        public Void visitDeprecated(Deprecated_attribute attr, ClassOutputStream out) {
            return null;
        }

        @Override
        public Void visitEnclosingMethod(EnclosingMethod_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.class_index);
            out.writeShort(attr.method_index);
            return null;
        }

        @Override
        public Void visitExceptions(Exceptions_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.exception_index_table.length);
            for (int i: attr.exception_index_table)
                out.writeShort(i);
            return null;
        }

        @Override
        public Void visitInnerClasses(InnerClasses_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.classes.length);
            for (InnerClasses_attribute.Info info: attr.classes)
                writeInnerClassesInfo(info, out);
            return null;
        }

        protected void writeInnerClassesInfo(InnerClasses_attribute.Info info, ClassOutputStream out) {
            out.writeShort(info.inner_class_info_index);
            out.writeShort(info.outer_class_info_index);
            out.writeShort(info.inner_name_index);
            writeAccessFlags(info.inner_class_access_flags, out);
        }

        @Override
        public Void visitLineNumberTable(LineNumberTable_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.line_number_table.length);
            for (LineNumberTable_attribute.Entry e: attr.line_number_table)
                writeLineNumberTableEntry(e, out);
            return null;
        }

        protected void writeLineNumberTableEntry(LineNumberTable_attribute.Entry entry, ClassOutputStream out) {
            out.writeShort(entry.start_pc);
            out.writeShort(entry.line_number);
        }

        @Override
        public Void visitLocalVariableTable(LocalVariableTable_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.local_variable_table.length);
            for (LocalVariableTable_attribute.Entry e: attr.local_variable_table)
                writeLocalVariableTableEntry(e, out);
            return null;
        }

        protected void writeLocalVariableTableEntry(LocalVariableTable_attribute.Entry entry, ClassOutputStream out) {
            out.writeShort(entry.start_pc);
            out.writeShort(entry.length);
            out.writeShort(entry.name_index);
            out.writeShort(entry.descriptor_index);
            out.writeShort(entry.index);
        }

        @Override
        public Void visitLocalVariableTypeTable(LocalVariableTypeTable_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.local_variable_table.length);
            for (LocalVariableTypeTable_attribute.Entry e: attr.local_variable_table)
                writeLocalVariableTypeTableEntry(e, out);
            return null;
        }

        protected void writeLocalVariableTypeTableEntry(LocalVariableTypeTable_attribute.Entry entry, ClassOutputStream out) {
            out.writeShort(entry.start_pc);
            out.writeShort(entry.length);
            out.writeShort(entry.name_index);
            out.writeShort(entry.signature_index);
            out.writeShort(entry.index);
        }

        @Override
        public Void visitMethodParameters(MethodParameters_attribute attr, ClassOutputStream out) {
            out.writeByte(attr.method_parameter_table.length);
            for (MethodParameters_attribute.Entry e : attr.method_parameter_table) {
                out.writeShort(e.name_index);
                out.writeShort(e.flags);
            }
            return null;
        }

        @Override
        public Void visitModule(Module_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.module_name);
            out.writeShort(attr.module_flags);
            out.writeShort(attr.module_version_index);

            out.writeShort(attr.requires.length);
            for (Module_attribute.RequiresEntry e: attr.requires) {
                out.writeShort(e.requires_index);
                out.writeShort(e.requires_flags);
                out.writeShort(e.requires_version_index);
            }

            out.writeShort(attr.exports.length);
            for (Module_attribute.ExportsEntry e: attr.exports) {
                out.writeShort(e.exports_index);
                out.writeShort(e.exports_flags);
                out.writeShort(e.exports_to_index.length);
                for (int index: e.exports_to_index)
                    out.writeShort(index);
            }

            out.writeShort(attr.opens.length);
            for (Module_attribute.OpensEntry e: attr.opens) {
                out.writeShort(e.opens_index);
                out.writeShort(e.opens_flags);
                out.writeShort(e.opens_to_index.length);
                for (int index: e.opens_to_index)
                    out.writeShort(index);
            }

            out.writeShort(attr.uses_index.length);
            for (int index: attr.uses_index) {
                out.writeShort(index);
            }

            out.writeShort(attr.provides.length);
            for (Module_attribute.ProvidesEntry e: attr.provides) {
                out.writeShort(e.provides_index);
                out.writeShort(e.with_count);
                for (int with : e.with_index) {
                    out.writeShort(with);
                }
            }

            return null;
        }

        @Override
        public Void visitModuleHashes(ModuleHashes_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.algorithm_index);
            out.writeShort(attr.hashes_table.length);
            for (ModuleHashes_attribute.Entry e: attr.hashes_table) {
                out.writeShort(e.module_name_index);
                out.writeShort(e.hash.length);
                for (byte b: e.hash) {
                    out.writeByte(b);
                }
            }
            return null;
        }

        @Override
        public Void visitModuleMainClass(ModuleMainClass_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.main_class_index);
            return null;
        }

        @Override
        public Void visitModulePackages(ModulePackages_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.packages_count);
            for (int i: attr.packages_index)
                out.writeShort(i);
            return null;
        }

        @Override
        public Void visitModuleResolution(ModuleResolution_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.resolution_flags);
            return null;
        }

        @Override
        public Void visitModuleTarget(ModuleTarget_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.target_platform_index);
            return null;
        }

        @Override
        public Void visitRuntimeInvisibleAnnotations(RuntimeInvisibleAnnotations_attribute attr, ClassOutputStream out) {
            annotationWriter.write(attr.annotations, out);
            return null;
        }

        @Override
        public Void visitRuntimeInvisibleParameterAnnotations(RuntimeInvisibleParameterAnnotations_attribute attr, ClassOutputStream out) {
            out.writeByte(attr.parameter_annotations.length);
            for (Annotation[] annos: attr.parameter_annotations)
                annotationWriter.write(annos, out);
            return null;
        }

        @Override
        public Void visitRuntimeInvisibleTypeAnnotations(RuntimeInvisibleTypeAnnotations_attribute attr, ClassOutputStream out) {
            annotationWriter.write(attr.annotations, out);
            return null;
        }

        @Override
        public Void visitRuntimeVisibleAnnotations(RuntimeVisibleAnnotations_attribute attr, ClassOutputStream out) {
            annotationWriter.write(attr.annotations, out);
            return null;
        }

        @Override
        public Void visitRuntimeVisibleParameterAnnotations(RuntimeVisibleParameterAnnotations_attribute attr, ClassOutputStream out) {
            out.writeByte(attr.parameter_annotations.length);
            for (Annotation[] annos: attr.parameter_annotations)
                annotationWriter.write(annos, out);
            return null;
        }

        @Override
        public Void visitRuntimeVisibleTypeAnnotations(RuntimeVisibleTypeAnnotations_attribute attr, ClassOutputStream out) {
            annotationWriter.write(attr.annotations, out);
            return null;
        }

        @Override
        public Void visitSignature(Signature_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.signature_index);
            return null;
        }

        @Override
        public Void visitSourceDebugExtension(SourceDebugExtension_attribute attr, ClassOutputStream out) {
            out.write(attr.debug_extension, 0, attr.debug_extension.length);
            return null;
        }

        @Override
        public Void visitSourceFile(SourceFile_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.sourcefile_index);
            return null;
        }

        @Override
        public Void visitSourceID(SourceID_attribute attr, ClassOutputStream out) {
            out.writeShort(attr.sourceID_index);
            return null;
        }

        @Override
        public Void visitStackMap(StackMap_attribute attr, ClassOutputStream out) {
            if (stackMapWriter == null)
                stackMapWriter = new StackMapTableWriter();

            out.writeShort(attr.entries.length);
            for (stack_map_frame f: attr.entries)
                stackMapWriter.write(f, out);
            return null;
        }

        @Override
        public Void visitStackMapTable(StackMapTable_attribute attr, ClassOutputStream out) {
            if (stackMapWriter == null)
                stackMapWriter = new StackMapTableWriter();

            out.writeShort(attr.entries.length);
            for (stack_map_frame f: attr.entries)
                stackMapWriter.write(f, out);
            return null;
        }

        @Override
        public Void visitSynthetic(Synthetic_attribute attr, ClassOutputStream out) {
            return null;
        }

        protected void writeAccessFlags(AccessFlags flags, ClassOutputStream p) {
            sharedOut.writeShort(flags.flags);
        }

        protected StackMapTableWriter stackMapWriter;
    }

    
Writer for the frames of StackMap and StackMapTable attributes.
/**
     * Writer for the frames of StackMap and StackMapTable attributes.
     */
    protected static class StackMapTableWriter
            implements stack_map_frame.Visitor<Void,ClassOutputStream> {

        public void write(stack_map_frame frame, ClassOutputStream out) {
            out.write(frame.frame_type);
            frame.accept(this, out);
        }

        @Override
        public Void visit_same_frame(same_frame frame, ClassOutputStream p) {
            return null;
        }

        @Override
        public Void visit_same_locals_1_stack_item_frame(same_locals_1_stack_item_frame frame, ClassOutputStream out) {
            writeVerificationTypeInfo(frame.stack[0], out);
            return null;
        }

        @Override
        public Void visit_same_locals_1_stack_item_frame_extended(same_locals_1_stack_item_frame_extended frame, ClassOutputStream out) {
            out.writeShort(frame.offset_delta);
            writeVerificationTypeInfo(frame.stack[0], out);
            return null;
        }

        @Override
        public Void visit_chop_frame(chop_frame frame, ClassOutputStream out) {
            out.writeShort(frame.offset_delta);
            return null;
        }

        @Override
        public Void visit_same_frame_extended(same_frame_extended frame, ClassOutputStream out) {
            out.writeShort(frame.offset_delta);
            return null;
        }

        @Override
        public Void visit_append_frame(append_frame frame, ClassOutputStream out) {
            out.writeShort(frame.offset_delta);
            for (verification_type_info l: frame.locals)
                writeVerificationTypeInfo(l, out);
            return null;
        }

        @Override
        public Void visit_full_frame(full_frame frame, ClassOutputStream out) {
            out.writeShort(frame.offset_delta);
            out.writeShort(frame.locals.length);
            for (verification_type_info l: frame.locals)
                writeVerificationTypeInfo(l, out);
            out.writeShort(frame.stack.length);
            for (verification_type_info s: frame.stack)
                writeVerificationTypeInfo(s, out);
            return null;
        }

        protected void writeVerificationTypeInfo(verification_type_info info,
                ClassOutputStream out)  {
            out.write(info.tag);
            switch (info.tag) {
            case ITEM_Top:
            case ITEM_Integer:
            case ITEM_Float:
            case ITEM_Long:
            case ITEM_Double:
            case ITEM_Null:
            case ITEM_UninitializedThis:
                break;

            case ITEM_Object:
                Object_variable_info o = (Object_variable_info) info;
                out.writeShort(o.cpool_index);
                break;

            case ITEM_Uninitialized:
                Uninitialized_variable_info u = (Uninitialized_variable_info) info;
                out.writeShort(u.offset);
                break;

            default:
                throw new Error();
            }
        }
    }

    
Writer for annotations and the values they contain.
/**
     * Writer for annotations and the values they contain.
     */
    protected static class AnnotationWriter
            implements Annotation.element_value.Visitor<Void,ClassOutputStream> {
        public void write(Annotation[] annos, ClassOutputStream out) {
            out.writeShort(annos.length);
            for (Annotation anno: annos)
                write(anno, out);
        }

        public void write(TypeAnnotation[] annos, ClassOutputStream out) {
            out.writeShort(annos.length);
            for (TypeAnnotation anno: annos)
                write(anno, out);
        }

        public void write(Annotation anno, ClassOutputStream out) {
            out.writeShort(anno.type_index);
            out.writeShort(anno.element_value_pairs.length);
            for (element_value_pair p: anno.element_value_pairs)
                write(p, out);
        }

        public void write(TypeAnnotation anno, ClassOutputStream out) {
            write(anno.position, out);
            write(anno.annotation, out);
        }

        public void write(element_value_pair pair, ClassOutputStream out) {
            out.writeShort(pair.element_name_index);
            write(pair.value, out);
        }

        public void write(element_value ev, ClassOutputStream out) {
            out.writeByte(ev.tag);
            ev.accept(this, out);
        }

        @Override
        public Void visitPrimitive(Primitive_element_value ev, ClassOutputStream out) {
            out.writeShort(ev.const_value_index);
            return null;
        }

        @Override
        public Void visitEnum(Enum_element_value ev, ClassOutputStream out) {
            out.writeShort(ev.type_name_index);
            out.writeShort(ev.const_name_index);
            return null;
        }

        @Override
        public Void visitClass(Class_element_value ev, ClassOutputStream out) {
            out.writeShort(ev.class_info_index);
            return null;
        }

        @Override
        public Void visitAnnotation(Annotation_element_value ev, ClassOutputStream out) {
            write(ev.annotation_value, out);
            return null;
        }

        @Override
        public Void visitArray(Array_element_value ev, ClassOutputStream out) {
            out.writeShort(ev.num_values);
            for (element_value v: ev.values)
                write(v, out);
            return null;
        }

        // TODO: Move this to TypeAnnotation to be closer with similar logic?
        private void write(TypeAnnotation.Position p, ClassOutputStream out) {
            out.writeByte(p.type.targetTypeValue());
            switch (p.type) {
            // instanceof
            case INSTANCEOF:
            // new expression
            case NEW:
            // constructor/method reference receiver
            case CONSTRUCTOR_REFERENCE:
            case METHOD_REFERENCE:
                out.writeShort(p.offset);
                break;
            // local variable
            case LOCAL_VARIABLE:
            // resource variable
            case RESOURCE_VARIABLE:
                int table_length = p.lvarOffset.length;
                out.writeShort(table_length);
                for (int i = 0; i < table_length; ++i) {
                    out.writeShort(1);  // for table length
                    out.writeShort(p.lvarOffset[i]);
                    out.writeShort(p.lvarLength[i]);
                    out.writeShort(p.lvarIndex[i]);
                }
                break;
            // exception parameter
            case EXCEPTION_PARAMETER:
                out.writeShort(p.exception_index);
                break;
            // method receiver
            case METHOD_RECEIVER:
                // Do nothing
                break;
            // type parameters
            case CLASS_TYPE_PARAMETER:
            case METHOD_TYPE_PARAMETER:
                out.writeByte(p.parameter_index);
                break;
            // type parameters bounds
            case CLASS_TYPE_PARAMETER_BOUND:
            case METHOD_TYPE_PARAMETER_BOUND:
                out.writeByte(p.parameter_index);
                out.writeByte(p.bound_index);
                break;
            // class extends or implements clause
            case CLASS_EXTENDS:
                out.writeShort(p.type_index);
                break;
            // throws
            case THROWS:
                out.writeShort(p.type_index);
                break;
            // method parameter
            case METHOD_FORMAL_PARAMETER:
                out.writeByte(p.parameter_index);
                break;
            // type cast
            case CAST:
            // method/constructor/reference type argument
            case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT:
            case METHOD_INVOCATION_TYPE_ARGUMENT:
            case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT:
            case METHOD_REFERENCE_TYPE_ARGUMENT:
                out.writeShort(p.offset);
                out.writeByte(p.type_index);
                break;
            // We don't need to worry about these
            case METHOD_RETURN:
            case FIELD:
                break;
            case UNKNOWN:
                throw new AssertionError("ClassWriter: UNKNOWN target type should never occur!");
            default:
                throw new AssertionError("ClassWriter: Unknown target type for position: " + p);
            }

            { // Append location data for generics/arrays.
                // TODO: check for overrun?
                out.writeByte((byte)p.location.size());
                for (int i : TypeAnnotation.Position.getBinaryFromTypePath(p.location))
                    out.writeByte((byte)i);
            }
        }
    }
}