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Diffstat (limited to 'src/base/sched_list.hh')
-rw-r--r-- | src/base/sched_list.hh | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/base/sched_list.hh b/src/base/sched_list.hh new file mode 100644 index 000000000..56ee2f8ec --- /dev/null +++ b/src/base/sched_list.hh @@ -0,0 +1,180 @@ +/* + * Copyright (c) 2002-2005 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * 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; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 COPYRIGHT + * OWNER OR CONTRIBUTORS 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. + * + * Authors: Steve Raasch + */ + +#ifndef SCHED_LIST_HH +#define SCHED_LIST_HH + +#include <list> +#include "base/intmath.hh" +#include "base/misc.hh" + + +// Any types you use this class for must be covered here... +namespace { + void ClearEntry(int &i) { i = 0; }; + void ClearEntry(unsigned &i) { i = 0; }; + void ClearEntry(double &i) { i = 0; }; + template <class T> void ClearEntry(std::list<T> &l) { l.clear(); }; +}; + + +// +// this is a special list type that allows the user to insert elements at a +// specified positive offset from the "current" element, but only allow them +// be extracted from the "current" element +// + + +template <class T> +class SchedList +{ + T *data_array; + unsigned position; + unsigned size; + unsigned mask; + + public: + SchedList(unsigned size); + SchedList(void); + + void init(unsigned size); + + T &operator[](unsigned offset); + + void advance(void); + + void clear(void); +}; + + + +// +// Constructor +// +template<class T> +SchedList<T>::SchedList(unsigned _size) +{ + size = _size; + + // size must be a power of two + if (!isPowerOf2(size)) { + panic("SchedList: size must be a power of two"); + } + + if (size < 2) { + panic("SchedList: you don't want a list that small"); + } + + // calculate the bit mask for the modulo operation + mask = size - 1; + + data_array = new T[size]; + + if (!data_array) { + panic("SchedList: could not allocate memory"); + } + + clear(); +} + +template<class T> +SchedList<T>::SchedList(void) +{ + data_array = 0; + size = 0; +} + + +template<class T> void +SchedList<T>::init(unsigned _size) +{ + size = _size; + + if (!data_array) { + // size must be a power of two + if (size & (size-1)) { + panic("SchedList: size must be a power of two"); + } + + if (size < 2) { + panic("SchedList: you don't want a list that small"); + } + + // calculate the bit mask for the modulo operation + mask = size - 1; + + data_array = new T[size]; + + if (!data_array) { + panic("SchedList: could not allocate memory"); + } + + clear(); + } +} + + +template<class T> void +SchedList<T>::advance(void) +{ + ClearEntry(data_array[position]); + + // position = (++position % size); + position = ++position & mask; +} + + +template<class T> void +SchedList<T>::clear(void) +{ + for (unsigned i=0; i<size; ++i) { + ClearEntry(data_array[i]); + } + + position = 0; +} + + +template<class T> T& +SchedList<T>::operator[](unsigned offset) +{ + if (offset >= size) { + panic("SchedList: can't access element beyond current pointer"); + } + + // unsigned p = (position + offset) % size; + unsigned p = (position + offset) & mask; + + return data_array[p]; +} + + + +#endif |