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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 Code for discovering properties of an NFA graph used by
* hs_expression_info().
*/
#include "ng_expr_info.h"
#include "hs_internal.h"
#include "ng.h"
#include "ng_asserts.h"
#include "ng_depth.h"
#include "ng_edge_redundancy.h"
#include "ng_extparam.h"
#include "ng_fuzzy.h"
#include "ng_holder.h"
#include "ng_prune.h"
#include "ng_reports.h"
#include "ng_util.h"
#include "ue2common.h"
#include "compiler/expression_info.h"
#include "parser/position.h" // for POS flags
#include "util/boundary_reports.h"
#include "util/compile_context.h"
#include "util/depth.h"
#include "util/graph.h"
#include "util/graph_range.h"
#include "util/report_manager.h"
#include <limits.h>
#include <set>
using namespace std;
namespace ue2 {
/* get rid of leading \b and multiline ^ vertices */
static
void removeLeadingVirtualVerticesFromRoot(NGHolder &g, NFAVertex root) {
vector<NFAVertex> victims;
for (auto v : adjacent_vertices_range(root, g)) {
if (g[v].assert_flags & POS_FLAG_VIRTUAL_START) {
DEBUG_PRINTF("(?m)^ vertex or leading \\[bB] vertex\n");
victims.push_back(v);
}
}
for (auto u : victims) {
for (auto v : adjacent_vertices_range(u, g)) {
add_edge_if_not_present(root, v, g);
}
}
remove_vertices(victims, g);
}
static
void checkVertex(const ReportManager &rm, const NGHolder &g, NFAVertex v,
const vector<DepthMinMax> &depths, DepthMinMax &info) {
if (is_any_accept(v, g)) {
return;
}
if (is_any_start(v, g)) {
info.min = depth(0);
info.max = max(info.max, depth(0));
return;
}
u32 idx = g[v].index;
assert(idx < depths.size());
const DepthMinMax &d = depths.at(idx);
for (ReportID report_id : g[v].reports) {
const Report &report = rm.getReport(report_id);
assert(report.type == EXTERNAL_CALLBACK);
DepthMinMax rd = d;
// Compute graph width to this report, taking any offset adjustment
// into account.
rd.min += report.offsetAdjust;
rd.max += report.offsetAdjust;
// A min_length param is a lower bound for match width.
if (report.minLength && report.minLength <= depth::max_value()) {
depth min_len((u32)report.minLength);
rd.min = max(rd.min, min_len);
rd.max = max(rd.max, min_len);
}
// A max_offset param is an upper bound for match width.
if (report.maxOffset && report.maxOffset <= depth::max_value()) {
depth max_offset((u32)report.maxOffset);
rd.min = min(rd.min, max_offset);
rd.max = min(rd.max, max_offset);
}
DEBUG_PRINTF("vertex %zu report %u: %s\n", g[v].index, report_id,
rd.str().c_str());
info = unionDepthMinMax(info, rd);
}
}
static
bool hasOffsetAdjust(const ReportManager &rm, const NGHolder &g) {
for (const auto &report_id : all_reports(g)) {
if (rm.getReport(report_id).offsetAdjust) {
return true;
}
}
return false;
}
void fillExpressionInfo(ReportManager &rm, const CompileContext &cc,
NGHolder &g, ExpressionInfo &expr,
hs_expr_info *info) {
assert(info);
// remove reports that aren't on vertices connected to accept.
clearReports(g);
assert(allMatchStatesHaveReports(g));
/*
* Note: the following set of analysis passes / transformations should
* match those in NG::addGraph().
*/
/* ensure utf8 starts at cp boundary */
ensureCodePointStart(rm, g, expr);
if (can_never_match(g)) {
throw CompileError(expr.index, "Pattern can never match.");
}
bool hamming = expr.hamm_distance > 0;
u32 e_dist = hamming ? expr.hamm_distance : expr.edit_distance;
// validate graph's suitability for fuzzing
validate_fuzzy_compile(g, e_dist, hamming, expr.utf8, cc.grey);
resolveAsserts(rm, g, expr);
assert(allMatchStatesHaveReports(g));
// fuzz graph - this must happen before any transformations are made
make_fuzzy(g, e_dist, hamming, cc.grey);
pruneUseless(g);
pruneEmptyVertices(g);
if (can_never_match(g)) {
throw CompileError(expr.index, "Pattern can never match.");
}
optimiseVirtualStarts(g);
propagateExtendedParams(g, expr, rm);
removeLeadingVirtualVerticesFromRoot(g, g.start);
removeLeadingVirtualVerticesFromRoot(g, g.startDs);
auto depths = calcDepthsFrom(g, g.start);
DepthMinMax d;
for (auto u : inv_adjacent_vertices_range(g.accept, g)) {
checkVertex(rm, g, u, depths, d);
}
for (auto u : inv_adjacent_vertices_range(g.acceptEod, g)) {
checkVertex(rm, g, u, depths, d);
}
if (d.max.is_finite()) {
info->max_width = d.max;
} else {
info->max_width = UINT_MAX;
}
if (d.min.is_finite()) {
info->min_width = d.min;
} else {
info->min_width = UINT_MAX;
}
info->unordered_matches = hasOffsetAdjust(rm, g);
info->matches_at_eod = can_match_at_eod(g);
info->matches_only_at_eod = can_only_match_at_eod(g);
}
} // namespace ue2
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