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/*
* [The "BSD licence"]
* Copyright (c) 2005-2008 Terence Parr
* All rights reserved.
*
* Conversion to C#:
* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
* 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.
*/
namespace Antlr.Runtime {
using System.Collections.Generic;
using Array = System.Array;
using CLSCompliant = System.CLSCompliantAttribute;
using ICloneable = System.ICloneable;
using Math = System.Math;
using StringBuilder = System.Text.StringBuilder;
/** <summary>
* A stripped-down version of org.antlr.misc.BitSet that is just
* good enough to handle runtime requirements such as FOLLOW sets
* for automatic error recovery.
* </summary>
*/
[System.Serializable]
public sealed class BitSet : ICloneable {
private const int BITS = 64; // number of bits / long
private const int LOG_BITS = 6; // 2^6 == 64
/** <summary>
* We will often need to do a mod operator (i mod nbits). Its
* turns out that, for powers of two, this mod operation is
* same as (i & (nbits-1)). Since mod is slow, we use a
* precomputed mod mask to do the mod instead.
* </summary>
*/
private const int MOD_MASK = BITS - 1;
/** <summary>The actual data bits</summary> */
ulong[] _bits;
/** <summary>Construct a bitset of size one word (64 bits)</summary> */
public BitSet()
: this(BITS) {
}
/** <summary>Construction from a static array of longs</summary> */
public BitSet(ulong[] bits) {
_bits = bits;
}
/** <summary>Construction from a list of integers</summary> */
public BitSet(IEnumerable<int> items)
: this() {
foreach (int i in items)
Add(i);
}
/** <summary>Construct a bitset given the size</summary>
* <param name="nbits">The size of the bitset in bits</param>
*/
public BitSet(int nbits) {
_bits = new ulong[((nbits - 1) >> LOG_BITS) + 1];
}
public static BitSet Of(int el) {
BitSet s = new BitSet(el + 1);
s.Add(el);
return s;
}
public static BitSet Of(int a, int b) {
BitSet s = new BitSet(Math.Max(a, b) + 1);
s.Add(a);
s.Add(b);
return s;
}
public static BitSet Of(int a, int b, int c) {
BitSet s = new BitSet();
s.Add(a);
s.Add(b);
s.Add(c);
return s;
}
public static BitSet Of(int a, int b, int c, int d) {
BitSet s = new BitSet();
s.Add(a);
s.Add(b);
s.Add(c);
s.Add(d);
return s;
}
/** <summary>return this | a in a new set</summary> */
public BitSet Or(BitSet a) {
if (a == null) {
return this;
}
BitSet s = (BitSet)this.Clone();
s.OrInPlace(a);
return s;
}
/** <summary>or this element into this set (grow as necessary to accommodate)</summary> */
public void Add(int el) {
int n = WordNumber(el);
if (n >= _bits.Length) {
GrowToInclude(el);
}
_bits[n] |= BitMask(el);
}
/** <summary>Grows the set to a larger number of bits.</summary>
* <param name="bit">element that must fit in set</param>
*/
public void GrowToInclude(int bit) {
int newSize = Math.Max(_bits.Length << 1, NumWordsToHold(bit));
SetSize(newSize);
}
public void OrInPlace(BitSet a) {
if (a == null) {
return;
}
// If this is smaller than a, grow this first
if (a._bits.Length > _bits.Length) {
SetSize(a._bits.Length);
}
int min = Math.Min(_bits.Length, a._bits.Length);
for (int i = min - 1; i >= 0; i--) {
_bits[i] |= a._bits[i];
}
}
/** <summary>Sets the size of a set.</summary>
* <param name="nwords">how many words the new set should be</param>
*/
private void SetSize(int nwords) {
Array.Resize(ref _bits, nwords);
}
private static ulong BitMask(int bitNumber) {
int bitPosition = bitNumber & MOD_MASK; // bitNumber mod BITS
return 1UL << bitPosition;
}
public object Clone() {
return new BitSet((ulong[])_bits.Clone());
}
public int Size() {
int deg = 0;
for (int i = _bits.Length - 1; i >= 0; i--) {
ulong word = _bits[i];
if (word != 0L) {
for (int bit = BITS - 1; bit >= 0; bit--) {
if ((word & (1UL << bit)) != 0) {
deg++;
}
}
}
}
return deg;
}
public override int GetHashCode() {
throw new System.NotImplementedException();
}
public override bool Equals(object other) {
if (other == null || !(other is BitSet)) {
return false;
}
BitSet otherSet = (BitSet)other;
int n = Math.Min(this._bits.Length, otherSet._bits.Length);
// for any bits in common, compare
for (int i = 0; i < n; i++) {
if (this._bits[i] != otherSet._bits[i]) {
return false;
}
}
// make sure any extra bits are off
if (this._bits.Length > n) {
for (int i = n + 1; i < this._bits.Length; i++) {
if (this._bits[i] != 0) {
return false;
}
}
} else if (otherSet._bits.Length > n) {
for (int i = n + 1; i < otherSet._bits.Length; i++) {
if (otherSet._bits[i] != 0) {
return false;
}
}
}
return true;
}
public bool Member(int el) {
if (el < 0) {
return false;
}
int n = WordNumber(el);
if (n >= _bits.Length)
return false;
return (_bits[n] & BitMask(el)) != 0;
}
// remove this element from this set
public void Remove(int el) {
int n = WordNumber(el);
if (n < _bits.Length) {
_bits[n] &= ~BitMask(el);
}
}
public bool IsNil() {
for (int i = _bits.Length - 1; i >= 0; i--) {
if (_bits[i] != 0)
return false;
}
return true;
}
private static int NumWordsToHold(int el) {
return (el >> LOG_BITS) + 1;
}
public int NumBits() {
return _bits.Length << LOG_BITS; // num words * bits per word
}
/** <summary>return how much space is being used by the bits array not how many actually have member bits on.</summary> */
public int LengthInLongWords() {
return _bits.Length;
}
/**Is this contained within a? */
/*
public boolean subset(BitSet a) {
if (a == null || !(a instanceof BitSet)) return false;
return this.and(a).equals(this);
}
*/
public int[] ToArray() {
int[] elems = new int[Size()];
int en = 0;
for (int i = 0; i < (_bits.Length << LOG_BITS); i++) {
if (Member(i)) {
elems[en++] = i;
}
}
return elems;
}
private static int WordNumber(int bit) {
return bit >> LOG_BITS; // bit / BITS
}
public override string ToString() {
return ToString(null);
}
public string ToString(string[] tokenNames) {
StringBuilder buf = new StringBuilder();
string separator = ",";
bool havePrintedAnElement = false;
buf.Append('{');
for (int i = 0; i < (_bits.Length << LOG_BITS); i++) {
if (Member(i)) {
if (i > 0 && havePrintedAnElement) {
buf.Append(separator);
}
if (tokenNames != null) {
buf.Append(tokenNames[i]);
} else {
buf.Append(i);
}
havePrintedAnElement = true;
}
}
buf.Append('}');
return buf.ToString();
}
}
}