org.apache.commons.jexl3.internal.LexicalScope Maven / Gradle / Ivy
/*
* 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.commons.jexl3.internal;
import java.util.BitSet;
/**
* The set of symbols declared in a lexical scope.
* The symbol identifiers are determined by the functional scope.
*/
public class LexicalScope {
/**
* Number of bits in a long.
*/
protected static final int LONGBITS = 64;
/**
* The mask of symbols in the frame.
*/
protected long symbols = 0L;
/**
* Symbols after 64.
*/
protected BitSet moreSymbols = null;
/**
* Create a scope.
*/
public LexicalScope() {
}
/**
* Frame copy ctor base.
*
* @param s the symbols mask
* @param ms the more symbols bitset
*/
protected LexicalScope(final long s, final BitSet ms) {
symbols = s;
moreSymbols = ms != null ? (BitSet) ms.clone() : null;
}
/**
* Ensure more symbpls can be stored.
*
* @return the set of more symbols
*/
protected final BitSet moreSymbols() {
if (moreSymbols == null) {
moreSymbols = new BitSet();
}
return moreSymbols;
}
/**
* Checks whether a symbol has already been declared.
*
* @param symbol the symbol
* @return true if declared, false otherwise
*/
public boolean hasSymbol(final int symbol) {
if (symbol < LONGBITS) {
return (symbols & (1L << symbol)) != 0L;
}
return moreSymbols != null && moreSymbols.get(symbol - LONGBITS);
}
/**
* Adds a symbol in this scope.
*
* @param symbol the symbol
* @return true if registered, false if symbol was already registered
*/
public boolean addSymbol(final int symbol) {
if (symbol < LONGBITS) {
if ((symbols & (1L << symbol)) != 0L) {
return false;
}
symbols |= (1L << symbol);
} else {
final int s = symbol - LONGBITS;
final BitSet ms = moreSymbols();
if (ms.get(s)) {
return false;
}
ms.set(s, true);
}
return true;
}
/**
* Clear all symbols.
*
* @param cleanSymbol a (optional, may be null) functor to call for each cleaned symbol
*/
public final void clearSymbols(final java.util.function.IntConsumer cleanSymbol) {
// undefine symbols getting out of scope
if (cleanSymbol != null) {
long clean = symbols;
while (clean != 0L) {
final int s = Long.numberOfTrailingZeros(clean);
clean &= ~(1L << s);
cleanSymbol.accept(s);
}
}
symbols = 0L;
if (moreSymbols != null) {
if (cleanSymbol != null) {
for (int s = moreSymbols.nextSetBit(0); s != -1; s = moreSymbols.nextSetBit(s + 1)) {
cleanSymbol.accept(s + LONGBITS);
}
}
moreSymbols.clear();
}
}
/**
* @return the number of symbols defined in this scope.
*/
public int getSymbolCount() {
return Long.bitCount(symbols) + (moreSymbols == null ? 0 : moreSymbols.cardinality());
}
}