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https://github.com/VectorCamp/vectorscan.git
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94 lines
3.2 KiB
C++
94 lines
3.2 KiB
C++
/*
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* Copyright (c) 2015, Intel Corporation
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Intel Corporation nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* \brief Short Exhaustible Passthroughs.
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*
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* Analysis code for determining whether a graph should be treated specially
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* because it is short and contains exhaustible reports; typically we turn
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* these into outfixes rather than risk them becoming Rose literals.
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*
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* For example, the pattern:
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*
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* /[a-f]/H
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*
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* ... is far better suited to becoming a small outfix that generates one match
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* and goes dead than being split into six one-byte Rose literals that end up
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* in the literal matcher.
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*/
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#include "ng_sep.h"
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#include "grey.h"
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#include "ng_holder.h"
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#include "ng_reports.h"
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#include "ng_util.h"
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#include "ue2common.h"
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#include "util/graph_range.h"
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using namespace std;
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namespace ue2 {
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static
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bool checkFromVertex(const NGHolder &g, NFAVertex start) {
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for (auto v : adjacent_vertices_range(start, g)) {
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if (v == g.startDs) {
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continue;
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}
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assert(!is_special(v, g)); /* should not be vacuous */
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if (!edge(g.startDs, v, g).second) { /* only floating starts */
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return false;
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} else if (out_degree(v, g) == 1
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&& edge(v, g.accept, g).second) { /* only floating end */
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; /* possible sep */
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} else {
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return false;
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}
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}
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return true;
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}
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bool isSEP(const NGHolder &g, const ReportManager &rm, const Grey &grey) {
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if (!grey.mergeSEP || !can_exhaust(g, rm)) {
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return false;
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}
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if (!checkFromVertex(g, g.start) || !checkFromVertex(g, g.startDs)) {
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return false;
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}
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assert(out_degree(g.start, g) || proper_out_degree(g.startDs, g));
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DEBUG_PRINTF("graph is an SEP\n");
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return true;
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}
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} // namespace ue2
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