144 lines
2.9 KiB
COBOL
144 lines
2.9 KiB
COBOL
// This may look like C code, but it is really -*- C++ -*-
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/*
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Copyright (C) 1988 Free Software Foundation
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written by Doug Lea (dl@rocky.oswego.edu)
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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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#ifdef __GNUG__
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#pragma implementation
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#endif
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#include "<T>.XPPQ.h"
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int <T>XPPQ::OK()
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{
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int v = p.OK();
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v &= p.low() == 1;
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v &= count == p.length();
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if (!v) error("invariant failure");
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return v;
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}
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Pix <T>XPPQ::seek(<T&> item)
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{
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for (int i = p.low(); i < p.fence(); p.next(i))
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if (<T>EQ(p[i],item)) return p.index_to_Pix(i);
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return 0;
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}
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// standard 2-ary heap ops
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// pointers are used a lot to avoid thrashing across chunks with plexes
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Pix <T>XPPQ::enq(<T&> item)
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{
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p.add_high(item);
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<T>* pk = &(p.high_element());
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int par = ++count >> 1;
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while (par != 0)
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{
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<T>* ppar = &(p[par]);
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if (!(<T>LE(*ppar, item)))
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{
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*pk = *ppar;
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pk = ppar;
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par >>= 1;
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}
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else
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break;
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}
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*pk = item;
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return Pix(pk);
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}
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void <T>XPPQ::del_front()
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{
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if (count == 0) error("empty PQ");
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--count;
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<T>* pk = &(p.low_element());
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<T>* ph = &(p.high_element());
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int child = 2;
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while (child <= count)
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{
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<T>* pchild = &(p[child]);
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if (child < count)
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{
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<T>* prchild = &(p[child+1]);
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if (!(<T>LE(*pchild, *prchild)))
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{
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pchild = prchild;
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++child;
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}
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}
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if (!(<T>LE(*ph, *pchild)))
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{
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*pk = *pchild;
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pk = pchild;
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child <<= 1;
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}
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else
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break;
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}
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*pk = *ph;
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p.del_high();
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}
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void <T>XPPQ::del(Pix i)
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{
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if (i == 0) error("null Pix");
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--count;
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int k = p.Pix_to_index(i);
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<T>* pk = &(p[k]);
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<T>* ph = &(p.high_element());
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int child = k << 1;
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while (child <= count)
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{
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<T>* pchild = &(p[child]);
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if (child < count)
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{
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<T>* prchild = &(p[child+1]);
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if (!(<T>LE(*pchild, *prchild)))
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{
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pchild = prchild;
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++child;
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}
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}
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if (!(<T>LE(*ph, *pchild)))
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{
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*pk = *pchild;
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pk = pchild;
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child <<= 1;
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}
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else
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break;
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}
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int par = child >> 2;
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while (par != 0)
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{
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<T>* ppar = &(p[par]);
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if (!(<T>LE(*ppar, *ph)))
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{
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*pk = *ppar;
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pk = ppar;
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par >>= 1;
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}
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else
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break;
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}
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*pk = *ph;
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p.del_high();
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}
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