1 /* 2 * Copyright (c) 2015-2018, Intel Corporation 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * * Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * * Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * * Neither the name of Intel Corporation nor the names of its contributors 13 * may be used to endorse or promote products derived from this software 14 * without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /** \file 30 * \brief Stop Alphabet calculation. 31 */ 32 33 #ifndef NG_STOP_H 34 #define NG_STOP_H 35 36 #include "ue2common.h" 37 #include "som/som.h" 38 39 #include <vector> 40 41 namespace ue2 { 42 43 struct CastleProto; 44 class CharReach; 45 class NGHolder; 46 47 /** Find the set of characters that are not present in the reachability of 48 * graph \p g after a certain depth (currently 8). If a character in this set 49 * is encountered, it means that the NFA is either dead or has not progressed 50 * more than 8 characters from its start states. 51 * 52 * This is only used to guide merging heuristics, use 53 * findLeftOffsetStopAlphabet for real uses. 54 */ 55 CharReach findStopAlphabet(const NGHolder &g, som_type som); 56 57 /** Calculate the stop alphabet for each depth from 0 to MAX_STOP_DEPTH. Then 58 * build an eight-bit mask per character C, with each bit representing the 59 * depth before the location of character C (if encountered) that the NFA would 60 * be in a predictable start state. */ 61 std::vector<u8> findLeftOffsetStopAlphabet(const NGHolder &g, som_type som); 62 std::vector<u8> findLeftOffsetStopAlphabet(const CastleProto &c, som_type som); 63 64 } // namespace ue2 65 66 #endif 67