| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| */ |
| package org.apache.kerby.xdr.type; |
| |
| import org.apache.kerby.xdr.XdrDataType; |
| import org.apache.kerby.xdr.XdrFieldInfo; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * A discriminated union is a type composed of a discriminant followed |
| * by a type selected from a set of prearranged types according to the |
| * value of the discriminant. The type of discriminant is either "int", |
| * "unsigned int", or an enumerated type, such as "bool". The component |
| * types are called "arms" of the union and are preceded by the value of |
| * the discriminant that implies their encoding. Discriminated unions |
| * are declared as follows: |
| * |
| * union switch (discriminant-declaration) { |
| * case discriminant-value-A: |
| * arm-declaration-A; |
| * case discriminant-value-B: |
| * arm-declaration-B; |
| * ... |
| * default: default-declaration; |
| * } identifier; |
| * Each "case" keyword is followed by a legal value of the discriminant. |
| * The default arm is optional. If it is not specified, then a valid |
| * encoding of the union cannot take on unspecified discriminant values. |
| * The size of the implied arm is always a multiple of four bytes. |
| * |
| * The discriminated union is encoded as its discriminant followed by |
| * the encoding of the implied arm. |
| * 0 1 2 3 |
| * +---+---+---+---+---+---+---+---+ |
| * | discriminant | implied arm | |
| * +---+---+---+---+---+---+---+---+ |
| * |<---4 bytes--->| |
| */ |
| public abstract class XdrUnion extends AbstractXdrType<XdrUnion> { |
| /** |
| * [0] is the discriminant |
| * index, XdrDataType, value; |
| * [1] is the implied arm |
| */ |
| private XdrFieldInfo[] fieldInfos; |
| private XdrType[] fields; |
| |
| public XdrUnion(XdrDataType xdrDataType) { |
| super(xdrDataType); |
| this.fieldInfos = null; |
| this.fields = null; |
| } |
| |
| public XdrUnion(XdrDataType xdrDataType, |
| final XdrFieldInfo[] fieldInfos) { |
| super(xdrDataType); |
| this.fieldInfos = fieldInfos; |
| this.fields = new XdrType[fieldInfos.length]; |
| |
| getUnionInstance(this.fields, fieldInfos); |
| } |
| |
| protected abstract void getUnionInstance(final XdrType[] fields, final XdrFieldInfo[] fieldInfos); |
| |
| public XdrFieldInfo[] getXdrFieldInfos() { |
| return fieldInfos; |
| } |
| |
| @Override |
| protected int encodingBodyLength() throws IOException { |
| int allLen = 0; |
| for (int i = 0; i < fields.length; i++) { |
| AbstractXdrType field = (AbstractXdrType) fields[i]; |
| if (field != null) { |
| allLen += field.encodingLength(); |
| } |
| } |
| return allLen; |
| } |
| |
| @Override |
| protected void encodeBody(ByteBuffer buffer) throws IOException { |
| for (int i = 0; i < fields.length; ++i) { |
| XdrType field = fields[i]; |
| if (field != null) { |
| field.encode(buffer); |
| } |
| } |
| } |
| |
| @Override |
| public void decode(ByteBuffer content) throws IOException { |
| AbstractXdrType[] fields = getAllFields(); |
| Object[] value; |
| for (int i = 0; i < fields.length; i++) { |
| if (fields[i] != null) { |
| fields[i].decode(content); |
| int length = fields[i].encodingLength(); |
| byte[] array = content.array(); |
| byte[] newArray = new byte[array.length - length]; |
| System.arraycopy(array, length, newArray, 0, array.length - length); |
| content = ByteBuffer.wrap(newArray); |
| } |
| } |
| this.fields = fields; |
| setValue(fieldsToValues(fields)); |
| } |
| |
| protected abstract XdrUnion fieldsToValues(AbstractXdrType[] fields); |
| |
| protected abstract AbstractXdrType[] getAllFields(); |
| } |