org.antlr.v4.runtime.misc.IntervalSet Maven / Gradle / Ivy
/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.runtime.misc;
import org.antlr.v4.runtime.Lexer;
import org.antlr.v4.runtime.Token;
import org.antlr.v4.runtime.Vocabulary;
import org.antlr.v4.runtime.VocabularyImpl;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.Set;
/**
* This class implements the {@link IntSet} backed by a sorted array of
* non-overlapping intervals. It is particularly efficient for representing
* large collections of numbers, where the majority of elements appear as part
* of a sequential range of numbers that are all part of the set. For example,
* the set { 1, 2, 3, 4, 7, 8 } may be represented as { [1, 4], [7, 8] }.
*
*
* This class is able to represent sets containing any combination of values in
* the range {@link Integer#MIN_VALUE} to {@link Integer#MAX_VALUE}
* (inclusive).
*/
public class IntervalSet implements IntSet {
public static final IntervalSet COMPLETE_CHAR_SET = IntervalSet.of(Lexer.MIN_CHAR_VALUE, Lexer.MAX_CHAR_VALUE);
static {
COMPLETE_CHAR_SET.setReadonly(true);
}
public static final IntervalSet EMPTY_SET = new IntervalSet();
static {
EMPTY_SET.setReadonly(true);
}
/** The list of sorted, disjoint intervals. */
protected List intervals;
protected boolean readonly;
public IntervalSet(List intervals) {
this.intervals = intervals;
}
public IntervalSet(IntervalSet set) {
this();
addAll(set);
}
public IntervalSet(int... els) {
if ( els==null ) {
intervals = new ArrayList(2); // most sets are 1 or 2 elements
}
else {
intervals = new ArrayList(els.length);
for (int e : els) add(e);
}
}
/** Create a set with a single element, el. */
public static IntervalSet of(int a) {
IntervalSet s = new IntervalSet();
s.add(a);
return s;
}
/** Create a set with all ints within range [a..b] (inclusive) */
public static IntervalSet of(int a, int b) {
IntervalSet s = new IntervalSet();
s.add(a,b);
return s;
}
public void clear() {
if ( readonly ) throw new IllegalStateException("can't alter readonly IntervalSet");
intervals.clear();
}
/** Add a single element to the set. An isolated element is stored
* as a range el..el.
*/
@Override
public void add(int el) {
if ( readonly ) throw new IllegalStateException("can't alter readonly IntervalSet");
add(el,el);
}
/** Add interval; i.e., add all integers from a to b to set.
* If b<a, do nothing.
* Keep list in sorted order (by left range value).
* If overlap, combine ranges. For example,
* If this is {1..5, 10..20}, adding 6..7 yields
* {1..5, 6..7, 10..20}. Adding 4..8 yields {1..8, 10..20}.
*/
public void add(int a, int b) {
add(Interval.of(a, b));
}
// copy on write so we can cache a..a intervals and sets of that
protected void add(Interval addition) {
if ( readonly ) throw new IllegalStateException("can't alter readonly IntervalSet");
//System.out.println("add "+addition+" to "+intervals.toString());
if ( addition.b iter = intervals.listIterator(); iter.hasNext();) {
Interval r = iter.next();
if ( addition.equals(r) ) {
return;
}
if ( addition.adjacent(r) || !addition.disjoint(r) ) {
// next to each other, make a single larger interval
Interval bigger = addition.union(r);
iter.set(bigger);
// make sure we didn't just create an interval that
// should be merged with next interval in list
while ( iter.hasNext() ) {
Interval next = iter.next();
if ( !bigger.adjacent(next) && bigger.disjoint(next) ) {
break;
}
// if we bump up against or overlap next, merge
iter.remove(); // remove this one
iter.previous(); // move backwards to what we just set
iter.set(bigger.union(next)); // set to 3 merged ones
iter.next(); // first call to next after previous duplicates the result
}
return;
}
if ( addition.startsBeforeDisjoint(r) ) {
// insert before r
iter.previous();
iter.add(addition);
return;
}
// if disjoint and after r, a future iteration will handle it
}
// ok, must be after last interval (and disjoint from last interval)
// just add it
intervals.add(addition);
}
/** combine all sets in the array returned the or'd value */
public static IntervalSet or(IntervalSet[] sets) {
IntervalSet r = new IntervalSet();
for (IntervalSet s : sets) r.addAll(s);
return r;
}
@Override
public IntervalSet addAll(IntSet set) {
if ( set==null ) {
return this;
}
if (set instanceof IntervalSet) {
IntervalSet other = (IntervalSet)set;
// walk set and add each interval
int n = other.intervals.size();
for (int i = 0; i < n; i++) {
Interval I = other.intervals.get(i);
this.add(I.a,I.b);
}
}
else {
for (int value : set.toList()) {
add(value);
}
}
return this;
}
public IntervalSet complement(int minElement, int maxElement) {
return this.complement(IntervalSet.of(minElement,maxElement));
}
/** {@inheritDoc} */
@Override
public IntervalSet complement(IntSet vocabulary) {
if ( vocabulary==null || vocabulary.isNil() ) {
return null; // nothing in common with null set
}
IntervalSet vocabularyIS;
if (vocabulary instanceof IntervalSet) {
vocabularyIS = (IntervalSet)vocabulary;
}
else {
vocabularyIS = new IntervalSet();
vocabularyIS.addAll(vocabulary);
}
return vocabularyIS.subtract(this);
}
@Override
public IntervalSet subtract(IntSet a) {
if (a == null || a.isNil()) {
return new IntervalSet(this);
}
if (a instanceof IntervalSet) {
return subtract(this, (IntervalSet)a);
}
IntervalSet other = new IntervalSet();
other.addAll(a);
return subtract(this, other);
}
/**
* Compute the set difference between two interval sets. The specific
* operation is {@code left - right}. If either of the input sets is
* {@code null}, it is treated as though it was an empty set.
*/
public static IntervalSet subtract(IntervalSet left, IntervalSet right) {
if (left == null || left.isNil()) {
return new IntervalSet();
}
IntervalSet result = new IntervalSet(left);
if (right == null || right.isNil()) {
// right set has no elements; just return the copy of the current set
return result;
}
int resultI = 0;
int rightI = 0;
while (resultI < result.intervals.size() && rightI < right.intervals.size()) {
Interval resultInterval = result.intervals.get(resultI);
Interval rightInterval = right.intervals.get(rightI);
// operation: (resultInterval - rightInterval) and update indexes
if (rightInterval.b < resultInterval.a) {
rightI++;
continue;
}
if (rightInterval.a > resultInterval.b) {
resultI++;
continue;
}
Interval beforeCurrent = null;
Interval afterCurrent = null;
if (rightInterval.a > resultInterval.a) {
beforeCurrent = new Interval(resultInterval.a, rightInterval.a - 1);
}
if (rightInterval.b < resultInterval.b) {
afterCurrent = new Interval(rightInterval.b + 1, resultInterval.b);
}
if (beforeCurrent != null) {
if (afterCurrent != null) {
// split the current interval into two
result.intervals.set(resultI, beforeCurrent);
result.intervals.add(resultI + 1, afterCurrent);
resultI++;
rightI++;
continue;
}
else {
// replace the current interval
result.intervals.set(resultI, beforeCurrent);
resultI++;
continue;
}
}
else {
if (afterCurrent != null) {
// replace the current interval
result.intervals.set(resultI, afterCurrent);
rightI++;
continue;
}
else {
// remove the current interval (thus no need to increment resultI)
result.intervals.remove(resultI);
continue;
}
}
}
// If rightI reached right.intervals.size(), no more intervals to subtract from result.
// If resultI reached result.intervals.size(), we would be subtracting from an empty set.
// Either way, we are done.
return result;
}
@Override
public IntervalSet or(IntSet a) {
IntervalSet o = new IntervalSet();
o.addAll(this);
o.addAll(a);
return o;
}
/** {@inheritDoc} */
@Override
public IntervalSet and(IntSet other) {
if ( other==null ) { //|| !(other instanceof IntervalSet) ) {
return null; // nothing in common with null set
}
List myIntervals = this.intervals;
List theirIntervals = ((IntervalSet)other).intervals;
IntervalSet intersection = null;
int mySize = myIntervals.size();
int theirSize = theirIntervals.size();
int i = 0;
int j = 0;
// iterate down both interval lists looking for nondisjoint intervals
while ( i getIntervals() {
return intervals;
}
@Override
public int hashCode() {
int hash = MurmurHash.initialize();
for (Interval I : intervals) {
hash = MurmurHash.update(hash, I.a);
hash = MurmurHash.update(hash, I.b);
}
hash = MurmurHash.finish(hash, intervals.size() * 2);
return hash;
}
/** Are two IntervalSets equal? Because all intervals are sorted
* and disjoint, equals is a simple linear walk over both lists
* to make sure they are the same. Interval.equals() is used
* by the List.equals() method to check the ranges.
*/
@Override
public boolean equals(Object obj) {
if ( obj==null || !(obj instanceof IntervalSet) ) {
return false;
}
IntervalSet other = (IntervalSet)obj;
return this.intervals.equals(other.intervals);
}
@Override
public String toString() { return toString(false); }
public String toString(boolean elemAreChar) {
StringBuilder buf = new StringBuilder();
if ( this.intervals==null || this.intervals.isEmpty() ) {
return "{}";
}
if ( this.size()>1 ) {
buf.append("{");
}
Iterator iter = this.intervals.iterator();
while (iter.hasNext()) {
Interval I = iter.next();
int a = I.a;
int b = I.b;
if ( a==b ) {
if ( a==Token.EOF ) buf.append("");
else if ( elemAreChar ) buf.append("'").appendCodePoint(a).append("'");
else buf.append(a);
}
else {
if ( elemAreChar ) buf.append("'").appendCodePoint(a).append("'..'").appendCodePoint(b).append("'");
else buf.append(a).append("..").append(b);
}
if ( iter.hasNext() ) {
buf.append(", ");
}
}
if ( this.size()>1 ) {
buf.append("}");
}
return buf.toString();
}
/**
* @deprecated Use {@link #toString(Vocabulary)} instead.
*/
@Deprecated
public String toString(String[] tokenNames) {
return toString(VocabularyImpl.fromTokenNames(tokenNames));
}
public String toString(Vocabulary vocabulary) {
StringBuilder buf = new StringBuilder();
if ( this.intervals==null || this.intervals.isEmpty() ) {
return "{}";
}
if ( this.size()>1 ) {
buf.append("{");
}
Iterator iter = this.intervals.iterator();
while (iter.hasNext()) {
Interval I = iter.next();
int a = I.a;
int b = I.b;
if ( a==b ) {
buf.append(elementName(vocabulary, a));
}
else {
for (int i=a; i<=b; i++) {
if ( i>a ) buf.append(", ");
buf.append(elementName(vocabulary, i));
}
}
if ( iter.hasNext() ) {
buf.append(", ");
}
}
if ( this.size()>1 ) {
buf.append("}");
}
return buf.toString();
}
/**
* @deprecated Use {@link #elementName(Vocabulary, int)} instead.
*/
@Deprecated
protected String elementName(String[] tokenNames, int a) {
return elementName(VocabularyImpl.fromTokenNames(tokenNames), a);
}
protected String elementName(Vocabulary vocabulary, int a) {
if (a == Token.EOF) {
return "";
}
else if (a == Token.EPSILON) {
return "";
}
else {
return vocabulary.getDisplayName(a);
}
}
@Override
public int size() {
int n = 0;
int numIntervals = intervals.size();
if ( numIntervals==1 ) {
Interval firstInterval = this.intervals.get(0);
return firstInterval.b-firstInterval.a+1;
}
for (int i = 0; i < numIntervals; i++) {
Interval I = intervals.get(i);
n += (I.b-I.a+1);
}
return n;
}
public IntegerList toIntegerList() {
IntegerList values = new IntegerList(size());
int n = intervals.size();
for (int i = 0; i < n; i++) {
Interval I = intervals.get(i);
int a = I.a;
int b = I.b;
for (int v=a; v<=b; v++) {
values.add(v);
}
}
return values;
}
@Override
public List toList() {
List values = new ArrayList();
int n = intervals.size();
for (int i = 0; i < n; i++) {
Interval I = intervals.get(i);
int a = I.a;
int b = I.b;
for (int v=a; v<=b; v++) {
values.add(v);
}
}
return values;
}
public Set toSet() {
Set s = new HashSet();
for (Interval I : intervals) {
int a = I.a;
int b = I.b;
for (int v=a; v<=b; v++) {
s.add(v);
}
}
return s;
}
/** Get the ith element of ordered set. Used only by RandomPhrase so
* don't bother to implement if you're not doing that for a new
* ANTLR code gen target.
*/
public int get(int i) {
int n = intervals.size();
int index = 0;
for (int j = 0; j < n; j++) {
Interval I = intervals.get(j);
int a = I.a;
int b = I.b;
for (int v=a; v<=b; v++) {
if ( index==i ) {
return v;
}
index++;
}
}
return -1;
}
public int[] toArray() {
return toIntegerList().toArray();
}
@Override
public void remove(int el) {
if ( readonly ) throw new IllegalStateException("can't alter readonly IntervalSet");
int n = intervals.size();
for (int i = 0; i < n; i++) {
Interval I = intervals.get(i);
int a = I.a;
int b = I.b;
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