vectorscan/src/nfagraph/ng_restructuring.h
2015-10-20 09:13:35 +11:00

87 lines
3.1 KiB
C++

/*
* Copyright (c) 2015, 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 State numbering and late graph restructuring code.
*/
#ifndef NG_RESTRUCTURING_H
#define NG_RESTRUCTURING_H
#include "ng_holder.h"
#include "ue2common.h"
#include "util/ue2_containers.h"
#include <map>
#include <vector>
namespace ue2 {
class NGHolder;
/** Construct a reversed copy of an arbitrary NGHolder, mapping starts to
* accepts. */
void reverseHolder(const NGHolder &g, NGHolder &out);
/** Connect the start vertex to each of the vertices in \p tops. This is useful
* temporarily for when we need to run a graph algorithm that expects a single
* source vertex. */
void wireStartToTops(NGHolder &g, const std::map<u32, NFAVertex> &tops,
std::vector<NFAEdge> &topEdges);
/**
* \brief Special state index value meaning that the vertex will not
* participate in an (NFA/DFA/etc) implementation.
*/
static constexpr u32 NO_STATE = ~0;
/**
* \brief Gives each participating vertex in the graph a unique state index.
*/
ue2::unordered_map<NFAVertex, u32>
numberStates(NGHolder &h,
const std::map<u32, NFAVertex> &tops = std::map<u32, NFAVertex>{});
/**
* \brief Counts the number of states (vertices with state indices) in the
* graph.
*
* If addTops is true, also accounts for states that will be constructed for
* each unique top.
*/
u32 countStates(const NGHolder &g,
const ue2::unordered_map<NFAVertex, u32> &state_ids,
bool addTops = true);
/** Optimisation: drop unnecessary start states. */
void dropUnusedStarts(NGHolder &g, ue2::unordered_map<NFAVertex, u32> &states);
} // namespace ue2
#endif