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	/*
	* 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.
	*/

	/*
	* This file is available under and governed by the GNU General Public
	* License version 2 only, as published by the Free Software Foundation.
	* However, the following notice accompanied the original version of this
	* file:
	*
	* 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 jdk.internal.org.objectweb.asm;

	/**
	* A non standard class, field, method or Code attribute, as defined in the Java Virtual Machine
	* Specification (JVMS).
	*
	* @see <a href= "https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7">JVMS
	* 4.7</a>
	* @see <a href= "https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.3">JVMS
	* 4.7.3</a>
	* @author Eric Bruneton
	* @author Eugene Kuleshov
	*/
	public class Attribute {

	/** The type of this attribute, also called its name in the JVMS. */
	public final String type;

	/**
	* The raw content of this attribute, only used for unknown attributes (see {@link #isUnknown()}).
	* The 6 header bytes of the attribute (attribute_name_index and attribute_length) are <i>not</i>
	* included.
	*/
	private byte[] content;

	/**
	* The next attribute in this attribute list (Attribute instances can be linked via this field to
	* store a list of class, field, method or Code attributes). May be {@literal null}.
	*/
	Attribute nextAttribute;

	/**
	* Constructs a new empty attribute.
	*
	* @param type the type of the attribute.
	*/
	protected Attribute(final String type) {
	this.type = type;
	}

	/**
	* Returns {@literal true} if this type of attribute is unknown. This means that the attribute
	* content can't be parsed to extract constant pool references, labels, etc. Instead, the
	* attribute content is read as an opaque byte array, and written back as is. This can lead to
	* invalid attributes, if the content actually contains constant pool references, labels, or other
	* symbolic references that need to be updated when there are changes to the constant pool, the
	* method bytecode, etc. The default implementation of this method always returns {@literal true}.
	*
	* @return {@literal true} if this type of attribute is unknown.
	*/
	public boolean isUnknown() {
	return true;
	}

	/**
	* Returns {@literal true} if this type of attribute is a Code attribute.
	*
	* @return {@literal true} if this type of attribute is a Code attribute.
	*/
	public boolean isCodeAttribute() {
	return false;
	}

	/**
	* Returns the labels corresponding to this attribute.
	*
	* @return the labels corresponding to this attribute, or {@literal null} if this attribute is not
	* a Code attribute that contains labels.
	*/
	protected Label[] getLabels() {
	return new Label[0];
	}

	/**
	* Reads a {@link #type} attribute. This method must return a <i>new</i> {@link Attribute} object,
	* of type {@link #type}, corresponding to the 'length' bytes starting at 'offset', in the given
	* ClassReader.
	*
	* @param classReader the class that contains the attribute to be read.
	* @param offset index of the first byte of the attribute's content in {@link ClassReader}. The 6
	* attribute header bytes (attribute_name_index and attribute_length) are not taken into
	* account here.
	* @param length the length of the attribute's content (excluding the 6 attribute header bytes).
	* @param charBuffer the buffer to be used to call the ClassReader methods requiring a
	* 'charBuffer' parameter.
	* @param codeAttributeOffset index of the first byte of content of the enclosing Code attribute
	* in {@link ClassReader}, or -1 if the attribute to be read is not a Code attribute. The 6
	* attribute header bytes (attribute_name_index and attribute_length) are not taken into
	* account here.
	* @param labels the labels of the method's code, or {@literal null} if the attribute to be read
	* is not a Code attribute.
	* @return a <i>new</i> {@link Attribute} object corresponding to the specified bytes.
	*/
	protected Attribute read(
	final ClassReader classReader,
	final int offset,
	final int length,
	final char[] charBuffer,
	final int codeAttributeOffset,
	final Label[] labels) {
	Attribute attribute = new Attribute(type);
	attribute.content = new byte[length];
	System.arraycopy(classReader.classFileBuffer, offset, attribute.content, 0, length);
	return attribute;
	}

	/**
	* Returns the byte array form of the content of this attribute. The 6 header bytes
	* (attribute_name_index and attribute_length) must <i>not</i> be added in the returned
	* ByteVector.
	*
	* @param classWriter the class to which this attribute must be added. This parameter can be used
	* to add the items that corresponds to this attribute to the constant pool of this class.
	* @param code the bytecode of the method corresponding to this Code attribute, or {@literal null}
	* if this attribute is not a Code attribute. Corresponds to the 'code' field of the Code
	* attribute.
	* @param codeLength the length of the bytecode of the method corresponding to this code
	* attribute, or 0 if this attribute is not a Code attribute. Corresponds to the 'code_length'
	* field of the Code attribute.
	* @param maxStack the maximum stack size of the method corresponding to this Code attribute, or
	* -1 if this attribute is not a Code attribute.
	* @param maxLocals the maximum number of local variables of the method corresponding to this code
	* attribute, or -1 if this attribute is not a Code attribute.
	* @return the byte array form of this attribute.
	*/
	protected ByteVector write(
	final ClassWriter classWriter,
	final byte[] code,
	final int codeLength,
	final int maxStack,
	final int maxLocals) {
	return new ByteVector(content);
	}

	/**
	* Returns the number of attributes of the attribute list that begins with this attribute.
	*
	* @return the number of attributes of the attribute list that begins with this attribute.
	*/
	final int getAttributeCount() {
	int count = 0;
	Attribute attribute = this;
	while (attribute != null) {
	count += 1;
	attribute = attribute.nextAttribute;
	}
	return count;
	}

	/**
	* Returns the total size in bytes of all the attributes in the attribute list that begins with
	* this attribute. This size includes the 6 header bytes (attribute_name_index and
	* attribute_length) per attribute. Also adds the attribute type names to the constant pool.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @return the size of all the attributes in this attribute list. This size includes the size of
	* the attribute headers.
	*/
	final int computeAttributesSize(final SymbolTable symbolTable) {
	final byte[] code = null;
	final int codeLength = 0;
	final int maxStack = -1;
	final int maxLocals = -1;
	return computeAttributesSize(symbolTable, code, codeLength, maxStack, maxLocals);
	}

	/**
	* Returns the total size in bytes of all the attributes in the attribute list that begins with
	* this attribute. This size includes the 6 header bytes (attribute_name_index and
	* attribute_length) per attribute. Also adds the attribute type names to the constant pool.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @param code the bytecode of the method corresponding to these Code attributes, or {@literal
	* null} if they are not Code attributes. Corresponds to the 'code' field of the Code
	* attribute.
	* @param codeLength the length of the bytecode of the method corresponding to these code
	* attributes, or 0 if they are not Code attributes. Corresponds to the 'code_length' field of
	* the Code attribute.
	* @param maxStack the maximum stack size of the method corresponding to these Code attributes, or
	* -1 if they are not Code attributes.
	* @param maxLocals the maximum number of local variables of the method corresponding to these
	* Code attributes, or -1 if they are not Code attribute.
	* @return the size of all the attributes in this attribute list. This size includes the size of
	* the attribute headers.
	*/
	final int computeAttributesSize(
	final SymbolTable symbolTable,
	final byte[] code,
	final int codeLength,
	final int maxStack,
	final int maxLocals) {
	final ClassWriter classWriter = symbolTable.classWriter;
	int size = 0;
	Attribute attribute = this;
	while (attribute != null) {
	symbolTable.addConstantUtf8(attribute.type);
	size += 6 + attribute.write(classWriter, code, codeLength, maxStack, maxLocals).length;
	attribute = attribute.nextAttribute;
	}
	return size;
	}

	/**
	* Returns the total size in bytes of all the attributes that correspond to the given field,
	* method or class access flags and signature. This size includes the 6 header bytes
	* (attribute_name_index and attribute_length) per attribute. Also adds the attribute type names
	* to the constant pool.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @param accessFlags some field, method or class access flags.
	* @param signatureIndex the constant pool index of a field, method of class signature.
	* @return the size of all the attributes in bytes. This size includes the size of the attribute
	* headers.
	*/
	static int computeAttributesSize(
	final SymbolTable symbolTable, final int accessFlags, final int signatureIndex) {
	int size = 0;
	// Before Java 1.5, synthetic fields are represented with a Synthetic attribute.
	if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0
	&& symbolTable.getMajorVersion() < Opcodes.V1_5) {
	// Synthetic attributes always use 6 bytes.
	symbolTable.addConstantUtf8(Constants.SYNTHETIC);
	size += 6;
	}
	if (signatureIndex != 0) {
	// Signature attributes always use 8 bytes.
	symbolTable.addConstantUtf8(Constants.SIGNATURE);
	size += 8;
	}
	// ACC_DEPRECATED is ASM specific, the ClassFile format uses a Deprecated attribute instead.
	if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
	// Deprecated attributes always use 6 bytes.
	symbolTable.addConstantUtf8(Constants.DEPRECATED);
	size += 6;
	}
	return size;
	}

	/**
	* Puts all the attributes of the attribute list that begins with this attribute, in the given
	* byte vector. This includes the 6 header bytes (attribute_name_index and attribute_length) per
	* attribute.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @param output where the attributes must be written.
	*/
	final void putAttributes(final SymbolTable symbolTable, final ByteVector output) {
	final byte[] code = null;
	final int codeLength = 0;
	final int maxStack = -1;
	final int maxLocals = -1;
	putAttributes(symbolTable, code, codeLength, maxStack, maxLocals, output);
	}

	/**
	* Puts all the attributes of the attribute list that begins with this attribute, in the given
	* byte vector. This includes the 6 header bytes (attribute_name_index and attribute_length) per
	* attribute.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @param code the bytecode of the method corresponding to these Code attributes, or {@literal
	* null} if they are not Code attributes. Corresponds to the 'code' field of the Code
	* attribute.
	* @param codeLength the length of the bytecode of the method corresponding to these code
	* attributes, or 0 if they are not Code attributes. Corresponds to the 'code_length' field of
	* the Code attribute.
	* @param maxStack the maximum stack size of the method corresponding to these Code attributes, or
	* -1 if they are not Code attributes.
	* @param maxLocals the maximum number of local variables of the method corresponding to these
	* Code attributes, or -1 if they are not Code attribute.
	* @param output where the attributes must be written.
	*/
	final void putAttributes(
	final SymbolTable symbolTable,
	final byte[] code,
	final int codeLength,
	final int maxStack,
	final int maxLocals,
	final ByteVector output) {
	final ClassWriter classWriter = symbolTable.classWriter;
	Attribute attribute = this;
	while (attribute != null) {
	ByteVector attributeContent =
	attribute.write(classWriter, code, codeLength, maxStack, maxLocals);
	// Put attribute_name_index and attribute_length.
	output.putShort(symbolTable.addConstantUtf8(attribute.type)).putInt(attributeContent.length);
	output.putByteArray(attributeContent.data, 0, attributeContent.length);
	attribute = attribute.nextAttribute;
	}
	}

	/**
	* Puts all the attributes that correspond to the given field, method or class access flags and
	* signature, in the given byte vector. This includes the 6 header bytes (attribute_name_index and
	* attribute_length) per attribute.
	*
	* @param symbolTable where the constants used in the attributes must be stored.
	* @param accessFlags some field, method or class access flags.
	* @param signatureIndex the constant pool index of a field, method of class signature.
	* @param output where the attributes must be written.
	*/
	static void putAttributes(
	final SymbolTable symbolTable,
	final int accessFlags,
	final int signatureIndex,
	final ByteVector output) {
	// Before Java 1.5, synthetic fields are represented with a Synthetic attribute.
	if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0
	&& symbolTable.getMajorVersion() < Opcodes.V1_5) {
	output.putShort(symbolTable.addConstantUtf8(Constants.SYNTHETIC)).putInt(0);
	}
	if (signatureIndex != 0) {
	output
	.putShort(symbolTable.addConstantUtf8(Constants.SIGNATURE))
	.putInt(2)
	.putShort(signatureIndex);
	}
	if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
	output.putShort(symbolTable.addConstantUtf8(Constants.DEPRECATED)).putInt(0);
	}
	}

	/** A set of attribute prototypes (attributes with the same type are considered equal). */
	static final class Set {

	private static final int SIZE_INCREMENT = 6;

	private int size;
	private Attribute[] data = new Attribute[SIZE_INCREMENT];

	void addAttributes(final Attribute attributeList) {
	Attribute attribute = attributeList;
	while (attribute != null) {
	if (!contains(attribute)) {
	add(attribute);
	}
	attribute = attribute.nextAttribute;
	}
	}

	Attribute[] toArray() {
	Attribute[] result = new Attribute[size];
	System.arraycopy(data, 0, result, 0, size);
	return result;
	}

	private boolean contains(final Attribute attribute) {
	for (int i = 0; i < size; ++i) {
	if (data[i].type.equals(attribute.type)) {
	return true;
	}
	}
	return false;
	}

	private void add(final Attribute attribute) {
	if (size >= data.length) {
	Attribute[] newData = new Attribute[data.length + SIZE_INCREMENT];
	System.arraycopy(data, 0, newData, 0, size);
	data = newData;
	}
	data[size++] = attribute;
	}
	}
	}

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