/*
* [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> */
[CLSCompliant( false )]
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();
}
}
}