172 lines
3.8 KiB
C++
172 lines
3.8 KiB
C++
// This may look like C code, but it is really -*- C++ -*-
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/*
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Copyright (C) 1991 Free Software Foundation
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This file is part of the GNU C++ Library. This library is free
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software; you can redistribute it and/or modify it under the terms of
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the GNU Library General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version. This library is distributed in the hope
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that it will be useful, but WITHOUT ANY WARRANTY; without even the
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implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the GNU Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/*
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* Bags implemented via William Pugh SkipList algorithms.
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* CACM, June 1990, p 668-676.
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*
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*/
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#ifndef _<T>SkipBag_h
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#ifdef __GNUG__
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#pragma interface
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#endif
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#define _<T>SkipBag_h 1
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#include "<T>.Bag.h"
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#include <limits.h>
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#include <MLCG.h>
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class <T>SkipBag;
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class <T>RealSkipBagNode;
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class <T>SkipBagNode
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{
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friend class <T>SkipBag;
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private:
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<T>RealSkipBagNode * * forward;
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<T>SkipBagNode(int size);
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};
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class <T>RealSkipBagNode : public <T>SkipBagNode
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{
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friend class <T>SkipBag;
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private:
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<T> item;
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<T>RealSkipBagNode(<T&> h, int size);
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};
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typedef <T>RealSkipBagNode* <T>SkipBagNodePtr;
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inline <T>SkipBagNode::<T>SkipBagNode(int size)
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: forward(new <T>SkipBagNodePtr[size+1])
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{
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}
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inline <T>RealSkipBagNode::<T>RealSkipBagNode(<T&> h, int size)
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: item(h),
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<T>SkipBagNode(size)
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{
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}
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class <T>SkipBag : public <T>Bag
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{
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friend class <T>SkipBaginit;
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protected:
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<T>SkipBagNode* header;
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int level;
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int max_levels;
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int randoms_left;
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long random_bits;
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static MLCG* gen;
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int random_level(void);
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<T>SkipBagNodePtr leftmost(void);
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<T>SkipBagNodePtr rightmost(void);
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<T>SkipBagNodePtr pred(<T>SkipBagNodePtr t);
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<T>SkipBagNodePtr succ(<T>SkipBagNodePtr t);
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void _kill(void);
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private:
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enum { BITS_IN_RANDOM = LONGBITS-1 };
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public:
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<T>SkipBag(long size=DEFAULT_INITIAL_CAPACITY);
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<T>SkipBag(<T>SkipBag& a);
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~<T>SkipBag(void);
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Pix add(<T&> i);
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void del(<T&> i);
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void remove(<T&>i);
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int nof(<T&> i);
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int contains(<T&> i);
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void clear(void);
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Pix first(void);
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void next(Pix& i);
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<T>& operator () (Pix i);
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Pix seek(<T&> i, Pix from = 0);
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Pix last(void);
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void prev(Pix& i);
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int OK(void);
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};
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inline <T>SkipBagNodePtr <T>SkipBag::leftmost(void)
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{
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return header->forward[0];
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}
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inline <T>SkipBagNodePtr <T>SkipBag::succ(<T>SkipBagNodePtr t)
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{
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<T>SkipBagNodePtr result = 0;
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if (t->forward[0]!=header) result = t->forward[0];
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return result;
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}
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inline Pix <T>SkipBag::first(void)
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{
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return Pix(leftmost());
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}
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inline Pix <T>SkipBag::last(void)
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{
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return Pix(rightmost());
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}
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inline void <T>SkipBag::next(Pix& i)
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{
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if (i != 0) i = Pix(succ((<T>SkipBagNodePtr)i));
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}
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inline <T>& <T>SkipBag::operator () (Pix i)
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{
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if (i == 0) error("null Pix");
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return ((<T>SkipBagNodePtr)i)->item;
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}
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inline void <T>SkipBag::prev(Pix& i)
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{
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if (i != 0) i = Pix(pred((<T>SkipBagNodePtr)i));
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}
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inline int <T>SkipBag::contains(<T&> key)
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{
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return seek(key) != 0;
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}
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inline <T>SkipBag::~<T>SkipBag()
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{
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_kill();
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delete header;
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}
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static class <T>SkipBaginit
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{
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public:
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<T>SkipBaginit();
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~<T>SkipBaginit();
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private:
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static int count;
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} <T>skipBaginit;
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#endif
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