/*
* Copyright (c) 2015, 2018, Oracle and/or its affiliates. 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.
*
* 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.
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*/
package sun.jvm.hotspot.utilities;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.utilities.*;
public class CompactHashTable extends VMObject {
static {
VM.registerVMInitializedObserver(new Observer() {
public void update(Observable o, Object data) {
initialize(VM.getVM().getTypeDataBase());
}
});
}
private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
Type type = db.lookupType("SymbolCompactHashTable");
baseAddressField = type.getAddressField("_base_address");
bucketCountField = type.getCIntegerField("_bucket_count");
entryCountField = type.getCIntegerField("_entry_count");
bucketsField = type.getAddressField("_buckets");
entriesField = type.getAddressField("_entries");
uintSize = db.lookupType("u4").getSize();
}
// Fields
private static CIntegerField bucketCountField;
private static CIntegerField entryCountField;
private static AddressField baseAddressField;
private static AddressField bucketsField;
private static AddressField entriesField;
private static long uintSize;
private static int BUCKET_OFFSET_MASK = 0x3FFFFFFF;
private static int BUCKET_TYPE_SHIFT = 30;
private static int VALUE_ONLY_BUCKET_TYPE = 1;
public CompactHashTable(Address addr) {
super(addr);
}
private int bucketCount() {
return (int)bucketCountField.getValue(addr);
}
private boolean isValueOnlyBucket(int bucket_info) {
return (bucket_info >> BUCKET_TYPE_SHIFT) == VALUE_ONLY_BUCKET_TYPE;
}
private int bucketOffset(int bucket_info) {
return bucket_info & BUCKET_OFFSET_MASK;
}
public Symbol probe(byte[] name, long hash) {
if (bucketCount() <= 0) {
// This CompactHashTable is not in use
return null;
}
long symOffset;
Symbol sym;
Address baseAddress = baseAddressField.getValue(addr);
Address bucket = bucketsField.getValue(addr);
long index = hash % bucketCount();
int bucketInfo = (int)bucket.getCIntegerAt(index * uintSize, uintSize, true);
int bucketOffset = bucketOffset(bucketInfo);
int nextBucketInfo = (int)bucket.getCIntegerAt((index+1) * uintSize, uintSize, true);
int nextBucketOffset = bucketOffset(nextBucketInfo);
Address entry = entriesField.getValue(addr).addOffsetTo(bucketOffset * uintSize);
if (isValueOnlyBucket(bucketInfo)) {
symOffset = entry.getCIntegerAt(0, uintSize, true);
sym = Symbol.create(baseAddress.addOffsetTo(symOffset));
if (sym.equals(name)) {
return sym;
}
} else {
Address entryMax = entriesField.getValue(addr).addOffsetTo(nextBucketOffset * uintSize);
while (entry.lessThan(entryMax)) {
long symHash = entry.getCIntegerAt(0, uintSize, true);
if (symHash == hash) {
symOffset = entry.getCIntegerAt(uintSize, uintSize, true);
Address symAddr = baseAddress.addOffsetTo(symOffset);
sym = Symbol.create(symAddr);
if (sym.equals(name)) {
return sym;
}
}
entry = entry.addOffsetTo(2 * uintSize);
}
}
return null;
}
public interface SymbolVisitor {
public void visit(Symbol sym);
}
public void symbolsDo(SymbolVisitor visitor) {
long symOffset;
Symbol sym;
Address baseAddress = baseAddressField.getValue(addr);
Address bucket = bucketsField.getValue(addr);
for (long index = 0; index < bucketCount(); index++) {
int bucketInfo = (int)bucket.getCIntegerAt(index * uintSize, uintSize, true);
int bucketOffset = bucketOffset(bucketInfo);
int nextBucketInfo = (int)bucket.getCIntegerAt((index+1) * uintSize, uintSize, true);
int nextBucketOffset = bucketOffset(nextBucketInfo);
Address entry = entriesField.getValue(addr).addOffsetTo(bucketOffset * uintSize);
if (isValueOnlyBucket(bucketInfo)) {
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