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/*
* Copyright (c) 2015-2018, Intel Corporation
*
* 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 Intel Corporation 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.
*/
/** \file
* \brief Stop Alphabet calculation.
*/
#ifndef NG_STOP_H
#define NG_STOP_H
#include "ue2common.h"
#include "som/som.h"
#include <vector>
namespace ue2 {
struct CastleProto;
class CharReach;
class NGHolder;
/** Find the set of characters that are not present in the reachability of
* graph \p g after a certain depth (currently 8). If a character in this set
* is encountered, it means that the NFA is either dead or has not progressed
* more than 8 characters from its start states.
*
* This is only used to guide merging heuristics, use
* findLeftOffsetStopAlphabet for real uses.
*/
CharReach findStopAlphabet(const NGHolder &g, som_type som);
/** Calculate the stop alphabet for each depth from 0 to MAX_STOP_DEPTH. Then
* build an eight-bit mask per character C, with each bit representing the
* depth before the location of character C (if encountered) that the NFA would
* be in a predictable start state. */
std::vector<u8> findLeftOffsetStopAlphabet(const NGHolder &g, som_type som);
std::vector<u8> findLeftOffsetStopAlphabet(const CastleProto &c, som_type som);
} // namespace ue2
#endif
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