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/*
* Copyright (c) 2015-2017, 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 Rose mask construction from NGHolder.
*/
#include "ng_fixed_width.h"
#include "grey.h"
#include "ng_holder.h"
#include "ng_util.h"
#include "rose/rose_build.h"
#include "util/container.h"
#include "ue2common.h"
#include <algorithm>
#include <iterator>
#include <set>
using namespace std;
namespace ue2 {
static
bool findMask(const NGHolder &g, vector<CharReach> *mask, bool *anchored,
flat_set<ReportID> *reports) {
DEBUG_PRINTF("looking for a mask pattern\n");
set<NFAVertex> s_succ;
insert(&s_succ, adjacent_vertices(g.start, g));
set<NFAVertex> sds_succ;
insert(&sds_succ, adjacent_vertices(g.startDs, g));
*anchored = sds_succ.size() == 1; /* sds itself */
bool floating = is_subset_of(s_succ, sds_succ);
DEBUG_PRINTF("sds %zu s %zu%s%s\n", sds_succ.size(), s_succ.size(),
*anchored ? " anchored" : "", floating ? " floating" : "");
if (!*anchored && !floating) {
DEBUG_PRINTF("semi-anchored\n");
return false;
}
set<NFAVertex> &succs = *anchored ? s_succ : sds_succ;
succs.erase(g.startDs);
if (succs.size() != 1) {
DEBUG_PRINTF("branchy root\n");
return false;
}
NFAVertex u = *anchored ? g.start : g.startDs;
NFAVertex v = *succs.begin();
while (true) {
DEBUG_PRINTF("validating vertex %zu\n", g[v].index);
assert(v != g.acceptEod);
// If we've reached an accept, we MAY have found a valid Rose pattern
if (v == g.accept) {
DEBUG_PRINTF("accept\n");
insert(reports, g[u].reports);
return true;
}
mask->push_back(g[v].char_reach);
if (out_degree(v, g) != 1) {
DEBUG_PRINTF("out_degree != 1\n");
return false; /* not a chain */
}
u = v;
v = *adjacent_vertices(v, g).first;
if (in_degree(v, g) != 1) {
DEBUG_PRINTF("blargh\n"); /* picks up cases where there is no path
* to case accept (large cycles),
* ensures term */
return false;
}
}
}
bool handleFixedWidth(RoseBuild &rose, const NGHolder &g, const Grey &grey) {
if (!grey.roseMasks) {
return false;
}
if (in_degree(g.acceptEod,g) != 1) {
DEBUG_PRINTF("EOD anchoring not supported\n");
return false;
}
flat_set<ReportID> reports;
bool anchored = false;
vector<CharReach> mask;
if (!findMask(g, &mask, &anchored, &reports)) {
return false;
}
DEBUG_PRINTF("%smasky masky\n", anchored ? "anchored " : "");
assert(!mask.empty());
assert(!reports.empty());
if (rose.add(anchored, mask, reports)) {
DEBUG_PRINTF("added as rose mask\n");
return true;
} else {
DEBUG_PRINTF("failed to add masky\n");
return false;
}
}
} // namespace ue2
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