forked from jasder/antlr
* Updated documentation for IntSet
* Reimplemented IntervalSet.subtract and IntervalSet.complement to operate over the complete range of supported values * Expanded several methods in IntervalSet to operate on any IntSet * Mark COMPLETE_CHAR_SET and EMPTY_SET as read-only
This commit is contained in:
Sam Harwell
parent
51430018d0
commit
2920ad0d1a
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@ -32,49 +32,166 @@ package org.antlr.v4.runtime.misc;
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import java.util.List;
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/** A generic set of ints.
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/**
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* A generic set of integers.
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*
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* @see IntervalSet
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* @see IntervalSet
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*/
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public interface IntSet {
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/** Add an element to the set */
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void add(int el);
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/**
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* Adds the specified value to the current set.
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*
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* @param el the value to add
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*
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* @exception IllegalStateException if the current set is read-only
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*/
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void add(int el);
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/** Add all elements from incoming set to this set. Can limit
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* to set of its own type. Return "this" so we can chain calls.
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*/
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IntSet addAll(IntSet set);
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/**
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* Modify the current {@link IntSet} object to contain all elements that are
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* present in itself, the specified {@code set}, or both.
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*
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* @param set The set to add to the current set. A {@code null} argument is
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* treated as though it were an empty set.
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* @return {@code this} (to support chained calls)
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*
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* @exception IllegalStateException if the current set is read-only
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*/
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@NotNull
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IntSet addAll(@Nullable IntSet set);
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/** Return the intersection of this set with the argument, creating
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* a new set.
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*/
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IntSet and(IntSet a);
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/**
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* Return a new {@link IntSet} object containing all elements that are
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* present in both the current set and the specified set {@code a}.
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*
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* @param a The set to intersect with the current set. A {@code null}
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* argument is treated as though it were an empty set.
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* @return A new {@link IntSet} instance containing the intersection of the
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* current set and {@code a}. The value {@code null} may be returned in
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* place of an empty result set.
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*/
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@Nullable
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IntSet and(@Nullable IntSet a);
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IntSet complement(IntSet elements);
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/**
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* Return a new {@link IntSet} object containing all elements that are
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* present in {@code elements} but not present in the current set. The
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* following expressions are equivalent for input non-null {@link IntSet}
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* instances {@code x} and {@code y}.
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*
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* <ul>
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* <li>{@code x.complement(y)}</li>
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* <li>{@code y.subtract(x)}</li>
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* </ul>
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*
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* @param elements The set to compare with the current set. A {@code null}
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* argument is treated as though it were an empty set.
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* @return A new {@link IntSet} instance containing the elements present in
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* {@code elements} but not present in the current set. The value
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* {@code null} may be returned in place of an empty result set.
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*/
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@Nullable
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IntSet complement(@Nullable IntSet elements);
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IntSet or(IntSet a);
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/**
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* Return a new {@link IntSet} object containing all elements that are
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* present in the current set, the specified set {@code a}, or both.
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*
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* <p>
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* This method is similar to {@link #addAll(IntSet)}, but returns a new
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* {@link IntSet} instance instead of modifying the current set.</p>
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*
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* @param a The set to union with the current set. A {@code null} argument
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* is treated as though it were an empty set.
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* @return A new {@link IntSet} instance containing the union of the current
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* set and {@code a}. The value {@code null} may be returned in place of an
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* empty result set.
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*/
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@Nullable
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IntSet or(@Nullable IntSet a);
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IntSet subtract(IntSet a);
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/**
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* Return a new {@link IntSet} object containing all elements that are
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* present in the current set but not present in the input set {@code a}.
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* The following expressions are equivalent for input non-null
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* {@link IntSet} instances {@code x} and {@code y}.
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*
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* <ul>
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* <li>{@code y.subtract(x)}</li>
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* <li>{@code x.complement(y)}</li>
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* </ul>
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*
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* @param elements The set to compare with the current set. A {@code null}
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* argument is treated as though it were an empty set.
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* @return A new {@link IntSet} instance containing the elements present in
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* {@code elements} but not present in the current set. The value
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* {@code null} may be returned in place of an empty result set.
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*/
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@Nullable
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IntSet subtract(@Nullable IntSet a);
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/** Return the size of this set (not the underlying implementation's
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* allocated memory size, for example).
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*/
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int size();
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/**
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* Return the total number of elements represented by the current set.
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*
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* @return the total number of elements represented by the current set,
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* regardless of the manner in which the elements are stored.
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*/
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int size();
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boolean isNil();
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/**
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* Returns {@code true} if this set contains no elements.
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*
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* @return {@code true} if the current set contains no elements; otherwise,
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* {@code false}.
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*/
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boolean isNil();
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@Override
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boolean equals(Object obj);
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/**
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* {@inheritDoc}
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*/
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@Override
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boolean equals(Object obj);
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int getSingleElement();
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/**
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* Returns the single value contained in the set, if {@link #size} is 1;
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* otherwise, returns {@link Token#INVALID_TYPE}.
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*
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* @return the single value contained in the set, if {@link #size} is 1;
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* otherwise, returns {@link Token#INVALID_TYPE}.
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*/
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int getSingleElement();
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boolean contains(int el);
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/**
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* Returns {@code true} if the set contains the specified element.
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*
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* @param el The element to check for.
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* @return {@code true} if the set contains {@code el}; otherwise {@code false}.
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*/
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boolean contains(int el);
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/** remove this element from this set */
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void remove(int el);
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/**
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* Removes the specified value from the current set. If the current set does
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* not contain the element, no changes are made.
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*
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* @param el the value to remove
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*
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* @exception IllegalStateException if the current set is read-only
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*/
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void remove(int el);
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List<Integer> toList();
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/**
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* Return a list containing the elements represented by the current set. The
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* list is returned in ascending numerical order.
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*
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* @return A list containing all element present in the current set, sorted
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* in ascending numerical order.
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*/
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@NotNull
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List<Integer> toList();
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@Override
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String toString();
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/**
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* {@inheritDoc}
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*/
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@Override
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String toString();
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}
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@ -39,28 +39,28 @@ import java.util.List;
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import java.util.ListIterator;
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import java.util.Set;
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/** A set of integers that relies on ranges being common to do
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* "run-length-encoded" like compression (if you view an IntSet like
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* a BitSet with runs of 0s and 1s). Only ranges are recorded so that
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* a few ints up near value 1000 don't cause massive bitsets, just two
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* integer intervals.
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/**
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* This class implements the {@link IntSet} backed by a sorted array of
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* non-overlapping intervals. It is particularly efficient for representing
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* large collections of numbers, where the majority of elements appear as part
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* of a sequential range of numbers that are all part of the set. For example,
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* the set { 1, 2, 3, 4, 7, 8 } may be represented as { [1, 4], [7, 8] }.
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*
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* element values may be negative. Useful for sets of EPSILON and EOF.
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*
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* 0..9 char range is index pair ['\u0030','\u0039'].
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* Multiple ranges are encoded with multiple index pairs. Isolated
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* elements are encoded with an index pair where both intervals are the same.
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*
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* The ranges are ordered and disjoint so that 2..6 appears before 101..103.
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* <p>
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* This class is able to represent sets containing any combination of values in
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* the range {@link Integer#MIN_VALUE} to {@link Integer#MAX_VALUE}
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* (inclusive).</p>
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*/
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public class IntervalSet implements IntSet {
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public static final IntervalSet COMPLETE_CHAR_SET = IntervalSet.of(0, Lexer.MAX_CHAR_VALUE);
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public static final IntervalSet KNOWN_NEGATIVE_ELEMENTS =
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new IntervalSet().or(IntervalSet.of(Token.EOF)).or(IntervalSet.of(Token.EPSILON));
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public static final IntervalSet COMPLETE_SET =
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IntervalSet.of(0, Lexer.MAX_CHAR_VALUE).or(KNOWN_NEGATIVE_ELEMENTS);
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public static final IntervalSet COMPLETE_CHAR_SET = IntervalSet.of(Lexer.MIN_CHAR_VALUE, Lexer.MAX_CHAR_VALUE);
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static {
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COMPLETE_CHAR_SET.setReadonly(true);
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}
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public static final IntervalSet EMPTY_SET = new IntervalSet();
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static {
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EMPTY_SET.setReadonly(true);
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}
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/** The list of sorted, disjoint intervals. */
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protected List<Interval> intervals;
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@ -185,18 +185,22 @@ public class IntervalSet implements IntSet {
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if ( set==null ) {
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return this;
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}
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if ( !(set instanceof IntervalSet) ) {
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throw new IllegalArgumentException("can't add non IntSet ("+
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set.getClass().getName()+
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") to IntervalSet");
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}
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IntervalSet other = (IntervalSet)set;
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// walk set and add each interval
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int n = other.intervals.size();
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for (int i = 0; i < n; i++) {
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Interval I = other.intervals.get(i);
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this.add(I.a,I.b);
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if (set instanceof IntervalSet) {
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IntervalSet other = (IntervalSet)set;
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// walk set and add each interval
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int n = other.intervals.size();
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for (int i = 0; i < n; i++) {
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Interval I = other.intervals.get(i);
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this.add(I.a,I.b);
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}
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}
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else {
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for (int value : set.toList()) {
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add(value);
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}
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}
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return this;
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}
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@ -204,71 +208,120 @@ public class IntervalSet implements IntSet {
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return this.complement(IntervalSet.of(minElement,maxElement));
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}
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/** Given the set of possible values (rather than, say UNICODE or MAXINT),
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* return a new set containing all elements in vocabulary, but not in
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* this. The computation is (vocabulary - this).
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*
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* 'this' is assumed to be either a subset or equal to vocabulary.
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*
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* complement() does not add EOF or EPSILON or any other negative number
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* to the complement.
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*/
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/** {@inheritDoc */
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@Override
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public IntervalSet complement(IntSet vocabulary) {
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if ( vocabulary==null ) {
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return null; // nothing in common with null set
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}
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if ( !(vocabulary instanceof IntervalSet ) ) {
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throw new IllegalArgumentException("can't complement with non IntervalSet ("+
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vocabulary.getClass().getName()+")");
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if ( vocabulary==null || vocabulary.isNil() ) {
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return null; // nothing in common with null set
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}
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IntervalSet vocabularyIS = ((IntervalSet)vocabulary);
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int maxElement = vocabularyIS.getMaxElement();
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IntervalSet compl = new IntervalSet();
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int n = intervals.size();
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if ( n ==0 ) {
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return compl;
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IntervalSet vocabularyIS;
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if (vocabulary instanceof IntervalSet) {
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vocabularyIS = (IntervalSet)vocabulary;
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}
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Interval first = intervals.get(0);
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// add a range from 0 to first.a constrained to vocab
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if ( first.a > 0 ) {
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int minKnownElement = KNOWN_NEGATIVE_ELEMENTS.getMinElement();
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IntervalSet s = IntervalSet.of(minKnownElement, first.a-1);
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IntervalSet a = s.and(vocabularyIS);
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compl.addAll(a);
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else {
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vocabularyIS = new IntervalSet();
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vocabularyIS.addAll(vocabulary);
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}
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for (int i=1; i<n; i++) { // from 2nd interval .. nth
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Interval previous = intervals.get(i-1);
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Interval current = intervals.get(i);
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IntervalSet s = IntervalSet.of(previous.b+1, current.a-1);
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IntervalSet a = s.and(vocabularyIS);
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compl.addAll(a);
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}
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Interval last = intervals.get(n -1);
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// add a range from last.b to maxElement constrained to vocab
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if ( last.b < maxElement ) {
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IntervalSet s = IntervalSet.of(last.b+1, maxElement);
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IntervalSet a = s.and(vocabularyIS);
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compl.addAll(a);
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}
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return compl;
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return vocabularyIS.subtract(this);
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}
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/** Compute this-other via this&~other.
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* Return a new set containing all elements in this but not in other.
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* other is assumed to be a subset of this;
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* anything that is in other but not in this will be ignored.
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*/
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@Override
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public IntervalSet subtract(IntSet other) {
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// assume the whole unicode range here for the complement
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// because it doesn't matter. Anything beyond the max of this' set
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// will be ignored since we are doing this & ~other. The intersection
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// will be empty. The only problem would be when this' set max value
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// goes beyond MAX_CHAR_VALUE, but hopefully the constant MAX_CHAR_VALUE
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// will prevent this.
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return this.and(((IntervalSet)other).complement(COMPLETE_SET));
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public IntervalSet subtract(IntSet a) {
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if (a == null || a.isNil()) {
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return new IntervalSet(this);
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}
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if (a instanceof IntervalSet) {
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return subtract(this, (IntervalSet)a);
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}
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IntervalSet other = new IntervalSet();
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other.addAll(a);
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return subtract(this, other);
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}
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/**
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* Compute the set difference between two interval sets. The specific
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* operation is {@code left - right}. If either of the input sets is
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* {@code null}, it is treated as though it was an empty set.
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*/
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@NotNull
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public static IntervalSet subtract(@Nullable IntervalSet left, @Nullable IntervalSet right) {
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if (left == null || left.isNil()) {
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return new IntervalSet();
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}
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IntervalSet result = new IntervalSet(left);
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if (right == null || right.isNil()) {
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// right set has no elements; just return the copy of the current set
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return result;
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}
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int resultI = 0;
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int rightI = 0;
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while (resultI < result.intervals.size() && rightI < right.intervals.size()) {
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Interval resultInterval = result.intervals.get(resultI);
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Interval rightInterval = right.intervals.get(rightI);
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// operation: (resultInterval - rightInterval) and update indexes
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if (rightInterval.b < resultInterval.a) {
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rightI++;
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continue;
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}
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if (rightInterval.a > resultInterval.b) {
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resultI++;
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continue;
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}
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Interval beforeCurrent = null;
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Interval afterCurrent = null;
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if (rightInterval.a > resultInterval.a) {
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beforeCurrent = new Interval(resultInterval.a, rightInterval.a - 1);
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}
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if (rightInterval.b < resultInterval.b) {
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afterCurrent = new Interval(rightInterval.b + 1, resultInterval.b);
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}
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if (beforeCurrent != null) {
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if (afterCurrent != null) {
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// split the current interval into two
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result.intervals.set(resultI, beforeCurrent);
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result.intervals.add(resultI + 1, afterCurrent);
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resultI++;
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rightI++;
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continue;
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}
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else {
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// replace the current interval
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result.intervals.set(resultI, beforeCurrent);
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resultI++;
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continue;
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}
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}
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else {
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if (afterCurrent != null) {
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// replace the current interval
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result.intervals.set(resultI, afterCurrent);
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rightI++;
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continue;
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}
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else {
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// remove the current interval (thus no need to increment resultI)
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result.intervals.remove(resultI);
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continue;
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}
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}
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}
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// If rightI reached right.intervals.size(), no more intervals to subtract from result.
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// If resultI reached result.intervals.size(), we would be subtracting from an empty set.
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// Either way, we are done.
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return result;
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}
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@Override
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@ -279,11 +332,7 @@ public class IntervalSet implements IntSet {
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return o;
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}
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/** Return a new set with the intersection of this set with other. Because
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* the intervals are sorted, we can use an iterator for each list and
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* just walk them together. This is roughly O(min(n,m)) for interval
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* list lengths n and m.
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*/
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/** {@inheritDoc} */
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@Override
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public IntervalSet and(IntSet other) {
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if ( other==null ) { //|| !(other instanceof IntervalSet) ) {
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@ -353,7 +402,7 @@ public class IntervalSet implements IntSet {
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return intersection;
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}
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/** Is el in any range of this set? */
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/** {@inheritDoc} */
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@Override
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public boolean contains(int el) {
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int n = intervals.size();
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|
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@ -383,13 +432,13 @@ public class IntervalSet implements IntSet {
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*/
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}
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/** return true if this set has no members */
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/** {@inheritDoc} */
|
||||
@Override
|
||||
public boolean isNil() {
|
||||
return intervals==null || intervals.isEmpty();
|
||||
}
|
||||
|
||||
/** If this set is a single integer, return it otherwise Token.INVALID_TYPE */
|
||||
/** {@inheritDoc} */
|
||||
@Override
|
||||
public int getSingleElement() {
|
||||
if ( intervals!=null && intervals.size()==1 ) {
|
||||
|
|
@ -401,6 +450,12 @@ public class IntervalSet implements IntSet {
|
|||
return Token.INVALID_TYPE;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the maximum value contained in the set.
|
||||
*
|
||||
* @return the maximum value contained in the set. If the set is empty, this
|
||||
* method returns {@link Token#INVALID_TYPE}.
|
||||
*/
|
||||
public int getMaxElement() {
|
||||
if ( isNil() ) {
|
||||
return Token.INVALID_TYPE;
|
||||
|
|
@ -409,7 +464,12 @@ public class IntervalSet implements IntSet {
|
|||
return last.b;
|
||||
}
|
||||
|
||||
/** Return minimum element */
|
||||
/**
|
||||
* Returns the minimum value contained in the set.
|
||||
*
|
||||
* @return the minimum value contained in the set. If the set is empty, this
|
||||
* method returns {@link Token#INVALID_TYPE}.
|
||||
*/
|
||||
public int getMinElement() {
|
||||
if ( isNil() ) {
|
||||
return Token.INVALID_TYPE;
|
||||
|
|
@ -644,6 +704,7 @@ public class IntervalSet implements IntSet {
|
|||
}
|
||||
|
||||
public void setReadonly(boolean readonly) {
|
||||
if ( this.readonly && !readonly ) throw new IllegalStateException("can't alter readonly IntervalSet");
|
||||
this.readonly = readonly;
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -35,7 +35,9 @@ import org.antlr.v4.runtime.Token;
|
|||
import org.antlr.v4.runtime.misc.IntervalSet;
|
||||
import org.junit.Test;
|
||||
|
||||
import static org.junit.Assert.*;
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertFalse;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
|
||||
public class TestIntervalSet extends BaseTest {
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue