/*
* 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.xerces.impl.dtd.models;
/**
* This class is a very simple bitset class. The DFA content model code needs
* to support a bit set, but the java BitSet class is way, way overkill. Our
* bitset never needs to be expanded after creation, hash itself, etc...
*
* Since the vast majority of content models will never require more than 64
* bits, and since allocation of anything in Java is expensive, this class
* provides a hybrid implementation that uses two ints for instances that use
* 64 bits or fewer. It has a byte array reference member which will only be
* used if more than 64 bits are required.
*
* Note that the code that uses this class will never perform operations
* on sets of different sizes, so that check does not have to be made here.
*
* @xerces.internal
*
* @version $Id: CMStateSet.java 446752 2006-09-15 21:55:19Z mrglavas $
*/
// made this class public so it can be accessed by
// the XS content models from the schema package -neilg.
public class CMStateSet
{
// -------------------------------------------------------------------
// Constructors
// -------------------------------------------------------------------
public CMStateSet(int bitCount)
{
// Store the required bit count and insure its legal
fBitCount = bitCount;
if (fBitCount < 0)
throw new RuntimeException("ImplementationMessages.VAL_CMSI");
//
// See if we need to allocate the byte array or whether we can live
// within the 64 bit high performance scheme.
//
if (fBitCount > 64)
{
fByteCount = fBitCount / 8;
if (fBitCount % 8 != 0)
fByteCount++;
fByteArray = new byte[fByteCount];
}
// Init all the bits to zero
zeroBits();
}
// -------------------------------------------------------------------
// Public inherited methods
// -------------------------------------------------------------------
public String toString()
{
StringBuffer strRet = new StringBuffer();
try
{
strRet.append('{');
for (int index = 0; index < fBitCount; index++) {
if (getBit(index)) {
strRet.append(' ').append(index);
}
}
strRet.append(" }");
}
catch(RuntimeException exToCatch)
{
//
// We know this won't happen but we have to catch it to avoid it
// having to be in our 'throws' list.
//
}
return strRet.toString();
}
// -------------------------------------------------------------------
// Package final methods
// -------------------------------------------------------------------
// the XS content models from the schema package -neilg.
public final void intersection(CMStateSet setToAnd)
{
if (fBitCount < 65)
{
fBits1 &= setToAnd.fBits1;
fBits2 &= setToAnd.fBits2;
}
else
{
for (int index = fByteCount - 1; index >= 0; index--)
fByteArray[index] &= setToAnd.fByteArray[index];
}
}
public final boolean getBit(int bitToGet)
{
if (bitToGet >= fBitCount)
throw new RuntimeException("ImplementationMessages.VAL_CMSI");
if (fBitCount < 65)
{
final int mask = (0x1 << (bitToGet % 32));
if (bitToGet < 32)
return (fBits1 & mask) != 0;
else
return (fBits2 & mask) != 0;
}
else
{
// Create the mask and byte values
final byte mask = (byte)(0x1 << (bitToGet % 8));
final int ofs = bitToGet >> 3;
// And access the right bit and byte
return ((fByteArray[ofs] & mask) != 0);
}
}
public final boolean isEmpty()
{
if (fBitCount < 65)
{
return ((fBits1 == 0) && (fBits2 == 0));
}
else
{
for (int index = fByteCount - 1; index >= 0; index--)
{
if (fByteArray[index] != 0)
return false;
}
}
return true;
}
final boolean isSameSet(CMStateSet setToCompare)
{
if (fBitCount != setToCompare.fBitCount)
return false;
if (fBitCount < 65)
{
return ((fBits1 == setToCompare.fBits1)
&& (fBits2 == setToCompare.fBits2));
}
for (int index = fByteCount - 1; index >= 0; index--)
{
if (fByteArray[index] != setToCompare.fByteArray[index])
return false;
}
return true;
}
// the XS content models from the schema package -neilg.
public final void union(CMStateSet setToOr)
{
if (fBitCount < 65)
{
fBits1 |= setToOr.fBits1;
fBits2 |= setToOr.fBits2;
}
else
{
for (int index = fByteCount - 1; index >= 0; index--)
fByteArray[index] |= setToOr.fByteArray[index];
}
}
public final void setBit(int bitToSet)
{
if (bitToSet >= fBitCount)
throw new RuntimeException("ImplementationMessages.VAL_CMSI");
if (fBitCount < 65)
{
final int mask = (0x1 << (bitToSet % 32));
if (bitToSet < 32)
{
fBits1 &= ~mask;
fBits1 |= mask;
}
else
{
fBits2 &= ~mask;
fBits2 |= mask;
}
}
else
{
// Create the mask and byte values
final byte mask = (byte)(0x1 << (bitToSet % 8));
final int ofs = bitToSet >> 3;
// And access the right bit and byte
fByteArray[ofs] &= ~mask;
fByteArray[ofs] |= mask;
}
}
// the XS content models from the schema package -neilg.
public final void setTo(CMStateSet srcSet)
{
// They have to be the same size
if (fBitCount != srcSet.fBitCount)
throw new RuntimeException("ImplementationMessages.VAL_CMSI");
if (fBitCount < 65)
{
fBits1 = srcSet.fBits1;
fBits2 = srcSet.fBits2;
}
else
{
for (int index = fByteCount - 1; index >= 0; index--)
fByteArray[index] = srcSet.fByteArray[index];
}
}
// had to make this method public so it could be accessed from
// schema package - neilg.
public final void zeroBits()
{
if (fBitCount < 65)
{
fBits1 = 0;
fBits2 = 0;
}
else
{
for (int index = fByteCount - 1; index >= 0; index--)
fByteArray[index] = 0;
}
}
// -------------------------------------------------------------------
// Private data members
//
// fBitCount
// The count of bits that the outside world wants to support,
// so its the max bit index plus one.
//
// fByteCount
// If the bit count is > 64, then we use the fByteArray member to
// store the bits, and this indicates its size in bytes. Otherwise
// its value is meaningless.
//
// fBits1
// fBits2
// When the bit count is < 64 (very common), these hold the bits.
// Otherwise, the fByteArray member holds htem.
// -------------------------------------------------------------------
int fBitCount;
int fByteCount;
int fBits1;
int fBits2;
byte[] fByteArray;
/* Optimization(Jan, 2001) */
public boolean equals(Object o) {
if (!(o instanceof CMStateSet)) return false;
return isSameSet((CMStateSet)o);
}
public int hashCode() {
if (fBitCount < 65)
{
return fBits1+ fBits2 * 31;
}
else
{
int hash = 0;
for (int index = fByteCount - 1; index >= 0; index--)
hash = fByteArray[index] + hash * 31;
return hash;
}
}
/* Optimization(Jan, 2001) */
};
|
