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/* This may look like C code, but it is really -*- C++ -*- */
/* Simple lookup table abstraction implemented as an Iteration Number Array.
Copyright (C) 1989-1998, 2002 Free Software Foundation, Inc.
Written by Douglas C. Schmidt <schmidt@ics.uci.edu>
and Bruno Haible <bruno@clisp.org>.
This file is part of GNU GPERF.
GNU GPERF is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU GPERF is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#ifndef bool_array_h
#define bool_array_h 1
/* A Bool_Array instance is a bit array of fixed size, optimized for being
filled sparsely and cleared frequently. For example, when processing
tests/chill.gperf, the array will be:
- of size 15391,
- clear will be called 3509 times,
- set_bit will be called 300394 times.
With a conventional bit array implementation, clear would be too slow.
With a tree/hash based bit array implementation, set_bit would be slower. */
class Bool_Array
{
public:
/* Initializes the bit array with room for SIZE bits, numbered from
0 to SIZE-1. */
Bool_Array (unsigned int size);
/* Frees this object. */
~Bool_Array ();
/* Resets all bits to zero. */
void clear ();
/* Sets the specified bit to true.
Returns its previous value (false or true). */
bool set_bit (unsigned int index);
private:
/* Size of array. */
unsigned int const _size;
/* Current iteration number. Always nonzero. Starts out as 1, and is
incremented each time clear() is called. */
unsigned int _iteration_number;
/* For each index, we store in storage_array[index] the iteration_number at
the time set_bit(index) was last called. */
unsigned int * const _storage_array;
};
#ifdef __OPTIMIZE__ /* efficiency hack! */
#include <stdio.h>
#include <string.h>
#include "options.h"
#define INLINE inline
#include "bool-array.icc"
#undef INLINE
#endif
#endif
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