001 /* MBEL: The Microsoft Bytecode Engineering Library
002 * Copyright (C) 2003 The University of Arizona
003 * http://www.cs.arizona.edu/mbel/license.html
004 *
005 * This library is free software; you can redistribute it and/or
006 * modify it under the terms of the GNU Lesser General Public
007 * License as published by the Free Software Foundation; either
008 * version 2.1 of the License, or (at your option) any later version.
009 *
010 * This library is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
013 * Lesser General Public License for more details.
014 *
015 * You should have received a copy of the GNU Lesser General Public
016 * License along with this library; if not, write to the Free Software
017 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
018 */
019
020
021 package edu.arizona.cs.mbel.signature;
022
023 /** This class describes the return type of a method in a method signature
024 * @author Michael Stepp
025 */
026 public class ReturnTypeSignature extends Signature{
027 private ParameterInfo paramInfo;
028 // Signature fields
029 private java.util.Vector customMods; // CustomModifierSignatures
030 private TypeSignature type;
031 private byte elementType;
032 // elementType: meaning:
033 // TYPEONLY just Type without BYREF
034 // BYREF BYREF and Type
035 // TYPEDBYREF TYPEDBYREF
036 // VOID VOID
037
038 private ReturnTypeSignature(){
039 customMods = new java.util.Vector(10);
040 }
041
042 /** Makes a new ReturnTypeSignature object with the given type, possibly by reference
043 * @param typeSig the type of this return value
044 * @param byref true iff this value is returned by reference
045 */
046 public ReturnTypeSignature(TypeSignature typeSig, boolean byref) throws SignatureException{
047 this();
048 type = typeSig;
049 if (type==null)
050 throw new SignatureException("ReturnTypeSignature: Return type is null");
051 elementType = (byref ? ELEMENT_TYPE_BYREF : ELEMENT_TYPE_TYPEONLY);
052 }
053
054 /** Makes a new ReturnTypeSignature object with the given type code
055 * @param typecode must be one of ELEMENT_TYPE_TYPEDBYREF or ELEMENT_TYPE_VOID
056 */
057 public ReturnTypeSignature(byte typecode) throws SignatureException{
058 this();
059 if (typecode == ELEMENT_TYPE_TYPEDBYREF)
060 elementType = typecode;
061 else if (typecode==ELEMENT_TYPE_VOID)
062 elementType = typecode;
063 else
064 throw new SignatureException("ReturnTypeSignature: Invalid byte code given");
065 }
066
067
068 /** Factory method to parse a ReturnTypeSignature from a ByteBuffer blob
069 * @param buffer the buffer to read from
070 * @param group a TypeGroup for reconciling tokens to mbel references
071 * @return a ReturnTypeSignature representing the given blob, or null if there was a parse error
072 */
073 public static ReturnTypeSignature parse(edu.arizona.cs.mbel.ByteBuffer buffer, edu.arizona.cs.mbel.mbel.TypeGroup group){
074 ReturnTypeSignature blob = new ReturnTypeSignature();
075
076 int pos = buffer.getPosition();
077 CustomModifierSignature temp = CustomModifierSignature.parse(buffer, group);
078 while(temp!=null){
079 blob.customMods.add(temp);
080 pos = buffer.getPosition();
081 temp = CustomModifierSignature.parse(buffer, group);
082 }
083 buffer.setPosition(pos);
084
085 blob.elementType = ELEMENT_TYPE_TYPEONLY;
086 byte data = buffer.peek();
087 if (data==ELEMENT_TYPE_TYPEDBYREF){
088 // TYPEDBYREF
089 blob.elementType = data;
090 buffer.get();
091 }else if (data==ELEMENT_TYPE_VOID){
092 // VOID
093 blob.elementType = data;
094 buffer.get();
095 }else{
096 if (data==ELEMENT_TYPE_BYREF){
097 // BYREF Type
098 blob.elementType = data;
099 buffer.get();
100 }
101 blob.type = TypeSignature.parse(buffer, group);
102 if (blob.type == null)
103 return null;
104 }
105
106 return blob;
107 }
108
109 /** Returns the ParamInfo object of this return type (may be null)
110 */
111 public ParameterInfo getParameterInfo(){
112 return paramInfo;
113 }
114
115 /** Sets the ParamInfo object for this return type (may be null)
116 */
117 public void setParameterInfo(ParameterInfo info){
118 paramInfo = info;
119 }
120
121 /** Returns the type of returntype this is:
122 * Type: Meaning:
123 * ELEMENT_TYPE_TYPEONLY Return value is given by the TypeSignature
124 * ELEMENT_TYPE_BYREF Return value is given by the TypeSignature, passed by reference
125 * ELEMENT_TYPE_TYPEDBYREF Return value is typed by reference
126 * ELEMENT_TYPE_VOID Void return type
127 */
128 public int getElementType(){
129 return elementType;
130 }
131
132 /** Returns the type signature for this return type (may be null)
133 */
134 public TypeSignature getType(){
135 return type;
136 }
137
138 /** Getter method for the CustomModifiers applied to this ReturnTypeSignature
139 */
140 public CustomModifierSignature[] getCustomModifiers(){
141 CustomModifierSignature[] sigs = new CustomModifierSignature[customMods.size()];
142 for (int i=0;i<sigs.length;i++)
143 sigs[i] = (CustomModifierSignature)customMods.get(i);
144
145 return sigs;
146 }
147
148 /** Write this signature out to the given buffer in raw binary form
149 * @param buffer the buffer to write to
150 */
151 public void emit(edu.arizona.cs.mbel.ByteBuffer buffer, edu.arizona.cs.mbel.emit.ClassEmitter emitter){
152 for (int i=0;i<customMods.size();i++)
153 ((CustomModifierSignature)customMods.get(i)).emit(buffer, emitter);
154 if (elementType == ELEMENT_TYPE_BYREF){
155 buffer.put(ELEMENT_TYPE_BYREF);
156 type.emit(buffer, emitter);
157 }
158 else if (elementType == ELEMENT_TYPE_TYPEONLY)
159 type.emit(buffer, emitter);
160 else if (elementType == ELEMENT_TYPE_TYPEDBYREF)
161 buffer.put(ELEMENT_TYPE_TYPEDBYREF);
162 else if (elementType == ELEMENT_TYPE_VOID)
163 buffer.put(ELEMENT_TYPE_VOID);
164 }
165
166 /*
167 public void output(){
168 System.out.print("ReturnTypeSignature[");
169 for (int i=0;i<customMods.size();i++){
170 ((CustomModifierSignature)customMods.get(i)).output();
171 System.out.print(',');
172 }
173
174 if (elementType==ELEMENT_TYPE_TYPEONLY){
175 type.output();
176 }else if (elementType == ELEMENT_TYPE_BYREF){
177 System.out.print("BYREF,");
178 type.output();
179 }else if (elementType == ELEMENT_TYPE_TYPEDBYREF){
180 System.out.print("TYPEDBYREF");
181 }else{
182 System.out.print("VOID");
183 }
184 System.out.print("]");
185 }
186 */
187 }