com.sun.tools.javac.jvm.Pool Maven / Gradle / Ivy
/*
* Copyright 1999-2005 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.tools.javac.jvm;
import java.util.*;
import com.sun.tools.javac.util.*;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.code.Type;
/** An internal structure that corresponds to the constant pool of a classfile.
*
* This is NOT part of any API supported by Sun Microsystems. 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.
*/
@Version("@(#)Pool.java 1.29 07/05/05")
public class Pool {
public static final int MAX_ENTRIES = 0xFFFF;
public static final int MAX_STRING_LENGTH = 0xFFFF;
/** Index of next constant to be entered.
*/
int pp;
/** The initial pool buffer.
*/
Object[] pool;
/** A hashtable containing all constants in the pool.
*/
Map indices;
/** Construct a pool with given number of elements and element array.
*/
public Pool(int pp, Object[] pool) {
this.pp = pp;
this.pool = pool;
this.indices = new HashMap(pool.length);
for (int i = 1; i < pp; i++) {
if (pool[i] != null) indices.put(pool[i], i);
}
}
/** Construct an empty pool.
*/
public Pool() {
this(1, new Object[64]);
}
/** Return the number of entries in the constant pool.
*/
public int numEntries() {
return pp;
}
/** Remove everything from this pool.
*/
public void reset() {
pp = 1;
indices.clear();
}
/** Double pool buffer in size.
*/
private void doublePool() {
Object[] newpool = new Object[pool.length * 2];
System.arraycopy(pool, 0, newpool, 0, pool.length);
pool = newpool;
}
/** Place an object in the pool, unless it is already there.
* If object is a symbol also enter its owner unless the owner is a
* package. Return the object's index in the pool.
*/
public int put(Object value) {
if (value instanceof MethodSymbol)
value = new Method((MethodSymbol)value);
else if (value instanceof VarSymbol)
value = new Variable((VarSymbol)value);
// assert !(value instanceof Type.TypeVar);
Integer index = indices.get(value);
if (index == null) {
// System.err.println("put " + value + " " + value.getClass());//DEBUG
index = pp;
indices.put(value, index);
if (pp == pool.length) doublePool();
pool[pp++] = value;
if (value instanceof Long || value instanceof Double) {
if (pp == pool.length) doublePool();
pool[pp++] = null;
}
}
return index.intValue();
}
/** Return the given object's index in the pool,
* or -1 if object is not in there.
*/
public int get(Object o) {
Integer n = indices.get(o);
return n == null ? -1 : n.intValue();
}
static class Method extends DelegatedSymbol {
MethodSymbol m;
Method(MethodSymbol m) {
super(m);
this.m = m;
}
public boolean equals(Object other) {
if (!(other instanceof Method)) return false;
MethodSymbol o = ((Method)other).m;
return
o.name == m.name &&
o.owner == m.owner &&
o.type.equals(m.type);
}
public int hashCode() {
return
m.name.hashCode() * 33 +
m.owner.hashCode() * 9 +
m.type.hashCode();
}
}
static class Variable extends DelegatedSymbol {
VarSymbol v;
Variable(VarSymbol v) {
super(v);
this.v = v;
}
public boolean equals(Object other) {
if (!(other instanceof Variable)) return false;
VarSymbol o = ((Variable)other).v;
return
o.name == v.name &&
o.owner == v.owner &&
o.type.equals(v.type);
}
public int hashCode() {
return
v.name.hashCode() * 33 +
v.owner.hashCode() * 9 +
v.type.hashCode();
}
}
}