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Diffstat (limited to 'bcel-builder/src/org/aspectj/apache/bcel/classfile/ConstantPool.java')
| -rw-r--r-- | bcel-builder/src/org/aspectj/apache/bcel/classfile/ConstantPool.java | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/bcel-builder/src/org/aspectj/apache/bcel/classfile/ConstantPool.java b/bcel-builder/src/org/aspectj/apache/bcel/classfile/ConstantPool.java new file mode 100644 index 000000000..6f32c089a --- /dev/null +++ b/bcel-builder/src/org/aspectj/apache/bcel/classfile/ConstantPool.java @@ -0,0 +1,372 @@ +package org.aspectj.apache.bcel.classfile; + +/* ==================================================================== + * The Apache Software License, Version 1.1 + * + * Copyright (c) 2001 The Apache Software Foundation. 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. The end-user documentation included with the redistribution, + * if any, must include the following acknowledgment: + * "This product includes software developed by the + * Apache Software Foundation (http://www.apache.org/)." + * Alternately, this acknowledgment may appear in the software itself, + * if and wherever such third-party acknowledgments normally appear. + * + * 4. The names "Apache" and "Apache Software Foundation" and + * "Apache BCEL" must not be used to endorse or promote products + * derived from this software without prior written permission. For + * written permission, please contact apache@apache.org. + * + * 5. Products derived from this software may not be called "Apache", + * "Apache BCEL", nor may "Apache" appear in their name, without + * prior written permission of the Apache Software Foundation. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR + * ITS 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. + * ==================================================================== + * + * This software consists of voluntary contributions made by many + * individuals on behalf of the Apache Software Foundation. For more + * information on the Apache Software Foundation, please see + * <http://www.apache.org/>. + */ + +import org.aspectj.apache.bcel.Constants; +import java.io.*; + +/** + * This class represents the constant pool, i.e., a table of constants, of + * a parsed classfile. It may contain null references, due to the JVM + * specification that skips an entry after an 8-byte constant (double, + * long) entry. Those interested in generating constant pools + * programatically should see <a href="../generic/ConstantPoolGen.html"> + * ConstantPoolGen</a>. + + * @version $Id: ConstantPool.java,v 1.1 2004/11/18 14:48:11 aclement Exp $ + * @see Constant + * @see org.aspectj.apache.bcel.generic.ConstantPoolGen + * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> + */ +public class ConstantPool implements Cloneable, Node, Serializable { + private int constant_pool_count; + private Constant[] constant_pool; + + /** + * @param constant_pool Array of constants + */ + public ConstantPool(Constant[] constant_pool) + { + setConstantPool(constant_pool); + } + + /** + * Read constants from given file stream. + * + * @param file Input stream + * @throws IOException + * @throws ClassFormatException + */ + ConstantPool(DataInputStream file) throws IOException, ClassFormatException + { + byte tag; + + constant_pool_count = file.readUnsignedShort(); + constant_pool = new Constant[constant_pool_count]; + + /* constant_pool[0] is unused by the compiler and may be used freely + * by the implementation. + */ + for(int i=1; i < constant_pool_count; i++) { + constant_pool[i] = Constant.readConstant(file); + + /* Quote from the JVM specification: + * "All eight byte constants take up two spots in the constant pool. + * If this is the n'th byte in the constant pool, then the next item + * will be numbered n+2" + * + * Thus we have to increment the index counter. + */ + tag = constant_pool[i].getTag(); + if((tag == Constants.CONSTANT_Double) || (tag == Constants.CONSTANT_Long)) + i++; + } + } + + /** + * Called by objects that are traversing the nodes of the tree implicitely + * defined by the contents of a Java class. I.e., the hierarchy of methods, + * fields, attributes, etc. spawns a tree of objects. + * + * @param v Visitor object + */ + public void accept(Visitor v) { + v.visitConstantPool(this); + } + + /** + * Resolve constant to a string representation. + * + * @param constant Constant to be printed + * @return String representation + */ + public String constantToString(Constant c) + throws ClassFormatException + { + String str; + int i; + byte tag = c.getTag(); + + switch(tag) { + case Constants.CONSTANT_Class: + i = ((ConstantClass)c).getNameIndex(); + c = getConstant(i, Constants.CONSTANT_Utf8); + str = Utility.compactClassName(((ConstantUtf8)c).getBytes(), false); + break; + + case Constants.CONSTANT_String: + i = ((ConstantString)c).getStringIndex(); + c = getConstant(i, Constants.CONSTANT_Utf8); + str = "\"" + escape(((ConstantUtf8)c).getBytes()) + "\""; + break; + + case Constants.CONSTANT_Utf8: str = ((ConstantUtf8)c).getBytes(); break; + case Constants.CONSTANT_Double: str = "" + ((ConstantDouble)c).getBytes(); break; + case Constants.CONSTANT_Float: str = "" + ((ConstantFloat)c).getBytes(); break; + case Constants.CONSTANT_Long: str = "" + ((ConstantLong)c).getBytes(); break; + case Constants.CONSTANT_Integer: str = "" + ((ConstantInteger)c).getBytes(); break; + + case Constants.CONSTANT_NameAndType: + str = (constantToString(((ConstantNameAndType)c).getNameIndex(), + Constants.CONSTANT_Utf8) + " " + + constantToString(((ConstantNameAndType)c).getSignatureIndex(), + Constants.CONSTANT_Utf8)); + break; + + case Constants.CONSTANT_InterfaceMethodref: case Constants.CONSTANT_Methodref: + case Constants.CONSTANT_Fieldref: + str = (constantToString(((ConstantCP)c).getClassIndex(), + Constants.CONSTANT_Class) + "." + + constantToString(((ConstantCP)c).getNameAndTypeIndex(), + Constants.CONSTANT_NameAndType)); + break; + + default: // Never reached + throw new RuntimeException("Unknown constant type " + tag); + } + + return str; + } + + private static final String escape(String str) { + int len = str.length(); + StringBuffer buf = new StringBuffer(len + 5); + char[] ch = str.toCharArray(); + + for(int i=0; i < len; i++) { + switch(ch[i]) { + case '\n' : buf.append("\\n"); break; + case '\r' : buf.append("\\r"); break; + case '\t' : buf.append("\\t"); break; + case '\b' : buf.append("\\b"); break; + case '"' : buf.append("\\\""); break; + default: buf.append(ch[i]); + } + } + + return buf.toString(); + } + + + /** + * Retrieve constant at `index' from constant pool and resolve it to + * a string representation. + * + * @param index of constant in constant pool + * @param tag expected type + * @return String representation + */ + public String constantToString(int index, byte tag) + throws ClassFormatException + { + Constant c = getConstant(index, tag); + return constantToString(c); + } + + /** + * Dump constant pool to file stream in binary format. + * + * @param file Output file stream + * @throws IOException + */ + public void dump(DataOutputStream file) throws IOException + { + file.writeShort(constant_pool_count); + + for(int i=1; i < constant_pool_count; i++) + if(constant_pool[i] != null) + constant_pool[i].dump(file); + } + + /** + * Get constant from constant pool. + * + * @param index Index in constant pool + * @return Constant value + * @see Constant + */ + public Constant getConstant(int index) { + if (index >= constant_pool.length || index < 0) + throw new ClassFormatException("Invalid constant pool reference: " + + index + ". Constant pool size is: " + + constant_pool.length); + return constant_pool[index]; + } + + /** + * Get constant from constant pool and check whether it has the + * expected type. + * + * @param index Index in constant pool + * @param tag Tag of expected constant, i.e., its type + * @return Constant value + * @see Constant + * @throws ClassFormatException + */ + public Constant getConstant(int index, byte tag) + throws ClassFormatException + { + Constant c; + + c = getConstant(index); + + if(c == null) + throw new ClassFormatException("Constant pool at index " + index + " is null."); + + if(c.getTag() == tag) + return c; + else + throw new ClassFormatException("Expected class `" + Constants.CONSTANT_NAMES[tag] + + "' at index " + index + " and got " + c); + } + + /** + * @return Array of constants. + * @see Constant + */ + public Constant[] getConstantPool() { return constant_pool; } + /** + * Get string from constant pool and bypass the indirection of + * `ConstantClass' and `ConstantString' objects. I.e. these classes have + * an index field that points to another entry of the constant pool of + * type `ConstantUtf8' which contains the real data. + * + * @param index Index in constant pool + * @param tag Tag of expected constant, either ConstantClass or ConstantString + * @return Contents of string reference + * @see ConstantClass + * @see ConstantString + * @throws ClassFormatException + */ + public String getConstantString(int index, byte tag) + throws ClassFormatException + { + Constant c; + int i; + + c = getConstant(index, tag); + + /* This switch() is not that elegant, since the two classes have the + * same contents, they just differ in the name of the index + * field variable. + * But we want to stick to the JVM naming conventions closely though + * we could have solved these more elegantly by using the same + * variable name or by subclassing. + */ + switch(tag) { + case Constants.CONSTANT_Class: i = ((ConstantClass)c).getNameIndex(); break; + case Constants.CONSTANT_String: i = ((ConstantString)c).getStringIndex(); break; + default: + throw new RuntimeException("getConstantString called with illegal tag " + tag); + } + + // Finally get the string from the constant pool + c = getConstant(i, Constants.CONSTANT_Utf8); + return ((ConstantUtf8)c).getBytes(); + } + /** + * @return Length of constant pool. + */ + public int getLength() + { + return constant_pool_count; + } + + /** + * @param constant Constant to set + */ + public void setConstant(int index, Constant constant) { + constant_pool[index] = constant; + } + + /** + * @param constant_pool + */ + public void setConstantPool(Constant[] constant_pool) { + this.constant_pool = constant_pool; + constant_pool_count = (constant_pool == null)? 0 : constant_pool.length; + } + /** + * @return String representation. + */ + public String toString() { + StringBuffer buf = new StringBuffer(); + + for(int i=1; i < constant_pool_count; i++) + buf.append(i + ")" + constant_pool[i] + "\n"); + + return buf.toString(); + } + + /** + * @return deep copy of this constant pool + */ + public ConstantPool copy() { + ConstantPool c = null; + + try { + c = (ConstantPool)clone(); + } catch(CloneNotSupportedException e) {} + + c.constant_pool = new Constant[constant_pool_count]; + + for(int i=1; i < constant_pool_count; i++) { + if(constant_pool[i] != null) + c.constant_pool[i] = constant_pool[i].copy(); + } + + return c; + } +} |