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/* 
 * 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 Short Exhaustible Passthroughs. 
 * 
 * Analysis code for determining whether a graph should be treated specially 
 * because it is short and contains exhaustible reports; typically we turn 
 * these into outfixes rather than risk them becoming Rose literals. 
 * 
 * For example, the pattern: 
 * 
 *     /[a-f]/H 
 * 
 * ... is far better suited to becoming a small outfix that generates one match 
 * and goes dead than being split into six one-byte Rose literals that end up 
 * in the literal matcher. 
 */ 
#include "ng_sep.h" 
 
#include "grey.h" 
#include "ng_holder.h" 
#include "ng_reports.h" 
#include "ng_util.h" 
#include "ue2common.h" 
#include "util/graph_range.h" 
 
using namespace std; 
 
namespace ue2 { 
 
static 
bool checkFromVertex(const NGHolder &g, NFAVertex start) { 
    for (auto v : adjacent_vertices_range(start, g)) { 
        if (v == g.startDs) { 
            continue; 
        } 
 
        assert(!is_special(v, g)); /* should not be vacuous */ 
 
        if (!edge(g.startDs, v, g).second) { /* only floating starts */ 
            return false; 
        } else if (out_degree(v, g) == 1 
                   && edge(v, g.accept, g).second) { /* only floating end */ 
            ; /* possible sep */ 
        } else { 
            return false; 
        } 
    } 
    return true; 
} 
 
bool isSEP(const NGHolder &g, const ReportManager &rm, const Grey &grey) { 
    if (!grey.mergeSEP || !can_exhaust(g, rm)) { 
        return false; 
    } 
 
    if (!checkFromVertex(g, g.start) || !checkFromVertex(g, g.startDs)) { 
        return false; 
    } 
 
    assert(out_degree(g.start, g) || proper_out_degree(g.startDs, g)); 
 
    DEBUG_PRINTF("graph is an SEP\n"); 
    return true; 
} 
 
} // namespace ue2