IntervalSet.java
/*
* [The "BSD license"]
* Copyright (c) 2010 Terence Parr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.misc;
import org.antlr.analysis.Label;
import org.antlr.tool.Grammar;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
/** A set of integers that relies on ranges being common to do
* "run-length-encoded" like compression (if you view an IntSet like
* a BitSet with runs of 0s and 1s). Only ranges are recorded so that
* a few ints up near value 1000 don't cause massive bitsets, just two
* integer intervals.
*
* element values may be negative. Useful for sets of EPSILON and EOF.
*
* 0..9 char range is index pair ['\u0030','\u0039'].
* Multiple ranges are encoded with multiple index pairs. Isolated
* elements are encoded with an index pair where both intervals are the same.
*
* The ranges are ordered and disjoint so that 2..6 appears before 101..103.
*/
public class IntervalSet implements IntSet {
public static final IntervalSet COMPLETE_SET = IntervalSet.of(0,Label.MAX_CHAR_VALUE);
/** The list of sorted, disjoint intervals. */
protected List<Interval> intervals;
/** Create a set with no elements */
public IntervalSet() {
intervals = new ArrayList<Interval>(2); // most sets are 1 or 2 elements
}
public IntervalSet(List<Interval> intervals) {
this.intervals = intervals;
}
/** 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;
}
/** Add a single element to the set. An isolated element is stored
* as a range el..el.
*/
@Override
public void add(int el) {
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.create(a,b));
}
// copy on write so we can cache a..a intervals and sets of that
protected void add(Interval addition) {
//System.out.println("add "+addition+" to "+intervals.toString());
if ( addition.b<addition.a ) {
return;
}
// find position in list
// Use iterators as we modify list in place
for (ListIterator<Interval> 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);
}
/*
protected void add(Interval addition) {
//System.out.println("add "+addition+" to "+intervals.toString());
if ( addition.b<addition.a ) {
return;
}
// find position in list
//for (ListIterator iter = intervals.listIterator(); iter.hasNext();) {
int n = intervals.size();
for (int i=0; i<n; i++) {
Interval r = (Interval)intervals.get(i);
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);
intervals.set(i, bigger);
// make sure we didn't just create an interval that
// should be merged with next interval in list
if ( (i+1)<n ) {
i++;
Interval next = (Interval)intervals.get(i);
if ( bigger.adjacent(next)||!bigger.disjoint(next) ) {
// if we bump up against or overlap next, merge
intervals.remove(i); // remove next one
i--;
intervals.set(i, bigger.union(next)); // set to 3 merged ones
}
}
return;
}
if ( addition.startsBeforeDisjoint(r) ) {
// insert before r
intervals.add(i, 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);
}
*/
@Override
public void addAll(IntSet set) {
if ( set==null ) {
return;
}
if ( !(set instanceof IntervalSet) ) {
throw new IllegalArgumentException("can't add non IntSet ("+
set.getClass().getName()+
") to 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);
}
}
public IntervalSet complement(int minElement, int maxElement) {
return this.complement(IntervalSet.of(minElement,maxElement));
}
/** Given the set of possible values (rather than, say UNICODE or MAXINT),
* return a new set containing all elements in vocabulary, but not in
* this. The computation is (vocabulary - this).
*
* 'this' is assumed to be either a subset or equal to vocabulary.
*/
@Override
public IntervalSet complement(IntSet vocabulary) {
if ( vocabulary==null ) {
return null; // nothing in common with null set
}
if ( !(vocabulary instanceof IntervalSet ) ) {
throw new IllegalArgumentException("can't complement with non IntervalSet ("+
vocabulary.getClass().getName()+")");
}
IntervalSet vocabularyIS = ((IntervalSet)vocabulary);
int maxElement = vocabularyIS.getMaxElement();
IntervalSet compl = new IntervalSet();
int n = intervals.size();
if ( n ==0 ) {
return compl;
}
Interval first = intervals.get(0);
// add a range from 0 to first.a constrained to vocab
if ( first.a > 0 ) {
IntervalSet s = IntervalSet.of(0, first.a-1);
IntervalSet a = s.and(vocabularyIS);
compl.addAll(a);
}
for (int i=1; i<n; i++) { // from 2nd interval .. nth
Interval previous = intervals.get(i-1);
Interval current = intervals.get(i);
IntervalSet s = IntervalSet.of(previous.b+1, current.a-1);
IntervalSet a = s.and(vocabularyIS);
compl.addAll(a);
}
Interval last = intervals.get(n -1);
// add a range from last.b to maxElement constrained to vocab
if ( last.b < maxElement ) {
IntervalSet s = IntervalSet.of(last.b+1, maxElement);
IntervalSet a = s.and(vocabularyIS);
compl.addAll(a);
}
return compl;
}
/** Compute this-other via this&~other.
* Return a new set containing all elements in this but not in other.
* other is assumed to be a subset of this;
* anything that is in other but not in this will be ignored.
*/
@Override
public IntervalSet subtract(IntSet other) {
// assume the whole unicode range here for the complement
// because it doesn't matter. Anything beyond the max of this' set
// will be ignored since we are doing this & ~other. The intersection
// will be empty. The only problem would be when this' set max value
// goes beyond MAX_CHAR_VALUE, but hopefully the constant MAX_CHAR_VALUE
// will prevent this.
return this.and(((IntervalSet)other).complement(COMPLETE_SET));
}
/** return a new set containing all elements in this but not in other.
* Intervals may have to be broken up when ranges in this overlap
* with ranges in other. other is assumed to be a subset of this;
* anything that is in other but not in this will be ignored.
*
* Keep around, but 10-20-2005, I decided to make complement work w/o
* subtract and so then subtract can simply be a&~b
*
public IntSet subtract(IntSet other) {
if ( other==null || !(other instanceof IntervalSet) ) {
return null; // nothing in common with null set
}
IntervalSet diff = new IntervalSet();
// iterate down both interval lists
ListIterator thisIter = this.intervals.listIterator();
ListIterator otherIter = ((IntervalSet)other).intervals.listIterator();
Interval mine=null;
Interval theirs=null;
if ( thisIter.hasNext() ) {
mine = (Interval)thisIter.next();
}
if ( otherIter.hasNext() ) {
theirs = (Interval)otherIter.next();
}
while ( mine!=null ) {
//System.out.println("mine="+mine+", theirs="+theirs);
// CASE 1: nothing in theirs removes a chunk from mine
if ( theirs==null || mine.disjoint(theirs) ) {
// SUBCASE 1a: finished traversing theirs; keep adding mine now
if ( theirs==null ) {
// add everything in mine to difference since theirs done
diff.add(mine);
mine = null;
if ( thisIter.hasNext() ) {
mine = (Interval)thisIter.next();
}
}
else {
// SUBCASE 1b: mine is completely to the left of theirs
// so we can add to difference; move mine, but not theirs
if ( mine.startsBeforeDisjoint(theirs) ) {
diff.add(mine);
mine = null;
if ( thisIter.hasNext() ) {
mine = (Interval)thisIter.next();
}
}
// SUBCASE 1c: theirs is completely to the left of mine
else {
// keep looking in theirs
theirs = null;
if ( otherIter.hasNext() ) {
theirs = (Interval)otherIter.next();
}
}
}
}
else {
// CASE 2: theirs breaks mine into two chunks
if ( mine.properlyContains(theirs) ) {
// must add two intervals: stuff to left and stuff to right
diff.add(mine.a, theirs.a-1);
// don't actually add stuff to right yet as next 'theirs'
// might overlap with it
// The stuff to the right might overlap with next "theirs".
// so it is considered next
Interval right = new Interval(theirs.b+1, mine.b);
mine = right;
// move theirs forward
theirs = null;
if ( otherIter.hasNext() ) {
theirs = (Interval)otherIter.next();
}
}
// CASE 3: theirs covers mine; nothing to add to diff
else if ( theirs.properlyContains(mine) ) {
// nothing to add, theirs forces removal totally of mine
// just move mine looking for an overlapping interval
mine = null;
if ( thisIter.hasNext() ) {
mine = (Interval)thisIter.next();
}
}
// CASE 4: non proper overlap
else {
// overlap, but not properly contained
diff.add(mine.differenceNotProperlyContained(theirs));
// update iterators
boolean moveTheirs = true;
if ( mine.startsBeforeNonDisjoint(theirs) ||
theirs.b > mine.b )
{
// uh oh, right of theirs extends past right of mine
// therefore could overlap with next of mine so don't
// move theirs iterator yet
moveTheirs = false;
}
// always move mine
mine = null;
if ( thisIter.hasNext() ) {
mine = (Interval)thisIter.next();
}
if ( moveTheirs ) {
theirs = null;
if ( otherIter.hasNext() ) {
theirs = (Interval)otherIter.next();
}
}
}
}
}
return diff;
}
*/
/** TODO: implement this! */
@Override
public IntSet or(IntSet a) {
IntervalSet o = new IntervalSet();
o.addAll(this);
o.addAll(a);
//throw new NoSuchMethodError();
return o;
}
/** Return a new set with the intersection of this set with other. Because
* the intervals are sorted, we can use an iterator for each list and
* just walk them together. This is roughly O(min(n,m)) for interval
* list lengths n and m.
*/
@Override
public IntervalSet and(IntSet other) {
if ( other==null ) { //|| !(other instanceof IntervalSet) ) {
return null; // nothing in common with null set
}
List<Interval> myIntervals = this.intervals;
List<Interval> 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<mySize && j<theirSize ) {
Interval mine = myIntervals.get(i);
Interval theirs = theirIntervals.get(j);
//System.out.println("mine="+mine+" and theirs="+theirs);
if ( mine.startsBeforeDisjoint(theirs) ) {
// move this iterator looking for interval that might overlap
i++;
}
else if ( theirs.startsBeforeDisjoint(mine) ) {
// move other iterator looking for interval that might overlap
j++;
}
else if ( mine.properlyContains(theirs) ) {
// overlap, add intersection, get next theirs
if ( intersection==null ) {
intersection = new IntervalSet();
}
intersection.add(mine.intersection(theirs));
j++;
}
else if ( theirs.properlyContains(mine) ) {
// overlap, add intersection, get next mine
if ( intersection==null ) {
intersection = new IntervalSet();
}
intersection.add(mine.intersection(theirs));
i++;
}
else if ( !mine.disjoint(theirs) ) {
// overlap, add intersection
if ( intersection==null ) {
intersection = new IntervalSet();
}
intersection.add(mine.intersection(theirs));
// Move the iterator of lower range [a..b], but not
// the upper range as it may contain elements that will collide
// with the next iterator. So, if mine=[0..115] and
// theirs=[115..200], then intersection is 115 and move mine
// but not theirs as theirs may collide with the next range
// in thisIter.
// move both iterators to next ranges
if ( mine.startsAfterNonDisjoint(theirs) ) {
j++;
}
else if ( theirs.startsAfterNonDisjoint(mine) ) {
i++;
}
}
}
if ( intersection==null ) {
return new IntervalSet();
}
return intersection;
}
/** Is el in any range of this set? */
@Override
public boolean member(int el) {
int n = intervals.size();
for (int i = 0; i < n; i++) {
Interval I = intervals.get(i);
int a = I.a;
int b = I.b;
if ( el<a ) {
break; // list is sorted and el is before this interval; not here
}
if ( el>=a && el<=b ) {
return true; // found in this interval
}
}
return false;
/*
for (ListIterator iter = intervals.listIterator(); iter.hasNext();) {
Interval I = (Interval) iter.next();
if ( el<I.a ) {
break; // list is sorted and el is before this interval; not here
}
if ( el>=I.a && el<=I.b ) {
return true; // found in this interval
}
}
return false;
*/
}
/** return true if this set has no members */
@Override
public boolean isNil() {
return intervals==null || intervals.isEmpty();
}
/** If this set is a single integer, return it otherwise Label.INVALID */
@Override
public int getSingleElement() {
if ( intervals!=null && intervals.size()==1 ) {
Interval I = intervals.get(0);
if ( I.a == I.b ) {
return I.a;
}
}
return Label.INVALID;
}
public int getMaxElement() {
if ( isNil() ) {
return Label.INVALID;
}
Interval last = intervals.get(intervals.size()-1);
return last.b;
}
/** Return minimum element >= 0 */
public int getMinElement() {
if ( isNil() ) {
return Label.INVALID;
}
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++) {
if ( v>=0 ) return v;
}
}
return Label.INVALID;
}
/** Return a list of Interval objects. */
public List<Interval> getIntervals() {
return intervals;
}
/** 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 instanceof IntervalSet) ) {
return false;
}
IntervalSet other = (IntervalSet)obj;
return this.intervals.equals(other.intervals);
}
@Override
public String toString() {
return toString(null);
}
@Override
public String toString(Grammar g) {
StringBuilder buf = new StringBuilder();
if ( this.intervals==null || this.intervals.isEmpty() ) {
return "{}";
}
if ( this.intervals.size()>1 ) {
buf.append("{");
}
Iterator<Interval> iter = this.intervals.iterator();
while (iter.hasNext()) {
Interval I = iter.next();
int a = I.a;
int b = I.b;
if ( a==b ) {
if ( g!=null ) {
buf.append(g.getTokenDisplayName(a));
}
else {
buf.append(a);
}
}
else {
if ( g!=null ) {
buf.append(g.getTokenDisplayName(a)).append("..").append(g.getTokenDisplayName(b));
}
else {
buf.append(a).append("..").append(b);
}
}
if ( iter.hasNext() ) {
buf.append(", ");
}
}
if ( this.intervals.size()>1 ) {
buf.append("}");
}
return buf.toString();
}
@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;
}
@Override
public List<Integer> toList() {
List<Integer> values = new ArrayList<Integer>();
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(Utils.integer(v));
}
}
return values;
}
/** 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() {
int[] values = new int[size()];
int n = intervals.size();
int j = 0;
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[j] = v;
j++;
}
}
return values;
}
public org.antlr.runtime.BitSet toRuntimeBitSet() {
org.antlr.runtime.BitSet s =
new org.antlr.runtime.BitSet(getMaxElement()+1);
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++) {
s.add(v);
}
}
return s;
}
@Override
public void remove(int el) {
throw new NoSuchMethodError("IntervalSet.remove() unimplemented");
}
/*
protected void finalize() throws Throwable {
super.finalize();
System.out.println("size "+intervals.size()+" "+size());
}
*/
}