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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 Reverse acceleration analysis.
*/
#include "ng_revacc.h"
#include "grey.h"
#include "ng_holder.h"
#include "ue2common.h"
#include "nfa/accel.h"
#include "nfa/nfa_internal.h"
#include "util/bitutils.h"
#include "util/charreach.h"
#include "util/graph_range.h"
#include <set>
using namespace std;
namespace ue2 {
static
bool isPseudoNoCaseChar(const CharReach &cr) {
return cr.count() == 2 && !(cr.find_first() & 32)
&& cr.test(cr.find_first() | 32);
}
static
bool lookForEodSchemes(const RevAccInfo &rev_info, const u32 minWidth,
NFA *nfa) {
DEBUG_PRINTF("pure eod triggered pattern\n");
/* 2 char */
for (u8 nocase = 0; nocase < 2; nocase++) {
for (u8 i = 1; i < MAX_RACCEL_OFFSET; i++) {
const CharReach &cr = rev_info.acceptEodReach[i];
const CharReach &cr2 = rev_info.acceptEodReach[i - 1];
if (!nocase && cr.count() == 1 && cr2.count() == 1) {
assert(i < minWidth);
if (i >= minWidth) {
goto single;
}
nfa->rAccelType = ACCEL_RDEOD;
nfa->rAccelData.array[0] = (u8)cr.find_first();
nfa->rAccelData.array[1] = (u8)cr2.find_first();
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel eod x2 %u %04hx\n",
nfa->rAccelOffset, nfa->rAccelData.dc);
return true;
} else if (nocase && (cr.count() == 1 || isPseudoNoCaseChar(cr))
&& (cr2.count() == 1 || isPseudoNoCaseChar(cr2))) {
assert(i < minWidth);
if (i >= minWidth) {
goto single;
}
nfa->rAccelType = ACCEL_RDEOD_NOCASE;
nfa->rAccelData.array[0] = (u8)cr.find_first() & CASE_CLEAR; /* uppercase */
nfa->rAccelData.array[1] = (u8)cr2.find_first() & CASE_CLEAR;
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel nc eod x2 %u %04hx\n",
nfa->rAccelOffset, nfa->rAccelData.dc);
return true;
}
}
}
single:
/* 1 char */
for (u8 nocase = 0; nocase < 2; nocase++) {
for (u8 i = 0; i < MAX_RACCEL_OFFSET; i++) {
const CharReach &cr = rev_info.acceptEodReach[i];
if (!nocase && cr.count() == 1) {
assert(i < minWidth);
if (i >= minWidth) {
return false;
}
nfa->rAccelType = ACCEL_REOD;
nfa->rAccelData.c = (u8) cr.find_first();
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel eod %u %02hhx\n",
nfa->rAccelOffset, nfa->rAccelData.c);
return true;
} else if (nocase && isPseudoNoCaseChar(cr)) {
assert(i < minWidth);
if (i >= minWidth) {
return false;
}
nfa->rAccelType = ACCEL_REOD_NOCASE;
nfa->rAccelData.c = (u8)cr.find_first(); /* uppercase */
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel nc eod %u %02hhx\n",
nfa->rAccelOffset, nfa->rAccelData.c);
return true;
}
}
}
return false;
}
static
bool lookForFloatingSchemes(const RevAccInfo &rev_info,
const u32 minWidth, NFA *nfa) {
/* 2 char */
for (u8 nocase = 0; nocase < 2; nocase++) {
for (u8 i = 1; i < MAX_RACCEL_OFFSET; i++) {
CharReach cr = rev_info.acceptEodReach[i] | rev_info.acceptReach[i];
CharReach cr2 = rev_info.acceptEodReach[i - 1]
| rev_info.acceptReach[i - 1];
if (!nocase && cr.count() == 1 && cr2.count() == 1) {
assert((u8)(i - 1) < minWidth);
if (i > minWidth) {
goto single;
}
nfa->rAccelType = ACCEL_RDVERM;
nfa->rAccelData.array[0] = (u8)cr.find_first();
nfa->rAccelData.array[1] = (u8)cr2.find_first();
nfa->rAccelOffset = i;
DEBUG_PRINTF("raccel dverm %u %02hhx%02hhx\n",
nfa->rAccelOffset, nfa->rAccelData.array[0],
nfa->rAccelData.array[1]);
return true;
} else if (nocase && (cr.count() == 1 || isPseudoNoCaseChar(cr))
&& (cr2.count() == 1 || isPseudoNoCaseChar(cr2))) {
assert((u8)(i - 1) < minWidth);
if (i > minWidth) {
goto single;
}
nfa->rAccelType = ACCEL_RDVERM_NOCASE;
nfa->rAccelData.array[0] = (u8)cr.find_first() & CASE_CLEAR;
nfa->rAccelData.array[1] = (u8)cr2.find_first() & CASE_CLEAR;
nfa->rAccelOffset = i;
DEBUG_PRINTF("raccel dverm %u %02hhx%02hhx nc\n",
nfa->rAccelOffset, nfa->rAccelData.array[0],
nfa->rAccelData.array[1]);
return true;
}
}
}
single:
/* 1 char */
for (u8 nocase = 0; nocase < 2; nocase++) {
for (u8 i = 0; i < MAX_RACCEL_OFFSET; i++) {
CharReach cr = rev_info.acceptEodReach[i] | rev_info.acceptReach[i];
if (!nocase && cr.count() == 1) {
assert(i < minWidth);
if (i >= minWidth) {
return false;
}
nfa->rAccelType = ACCEL_RVERM;
nfa->rAccelData.c = (u8)cr.find_first();
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel verm %u %02hhx\n", nfa->rAccelOffset,
nfa->rAccelData.c);
return true;
} else if (nocase && isPseudoNoCaseChar(cr)) {
assert(i < minWidth);
if (i >= minWidth) {
return false;
}
nfa->rAccelType = ACCEL_RVERM_NOCASE;
nfa->rAccelData.c = (u8)cr.find_first(); /* 'uppercase' char */
nfa->rAccelOffset = i + 1;
DEBUG_PRINTF("raccel nc verm %u %02hhx\n", nfa->rAccelOffset,
nfa->rAccelData.c);
return true;
}
}
}
return false;
}
void buildReverseAcceleration(NFA *nfa, const RevAccInfo &rev_info,
u32 min_width, bool eod_only) {
assert(nfa);
if (!rev_info.valid) {
return;
}
nfa->rAccelOffset = 1;
assert(rev_info.acceptReach[0].any() || rev_info.acceptEodReach[0].any());
if (rev_info.acceptReach[0].none() && rev_info.acceptEodReach[0].none()) {
DEBUG_PRINTF("expected path to accept\n");
return;
}
if (rev_info.acceptReach[0].none()) {
/* eod only */
if (lookForEodSchemes(rev_info, min_width, nfa)) {
assert(nfa->rAccelOffset <= min_width);
return;
}
}
if (eod_only) {
return;
}
if (!lookForFloatingSchemes(rev_info, min_width, nfa)) {
DEBUG_PRINTF("failed to accelerate\n");
}
}
static
void populateRevAccelInfo(const NGHolder &g, NFAVertex terminal,
vector<CharReach> *reach) {
set<NFAVertex> vset;
for (auto v : inv_adjacent_vertices_range(terminal, g)) {
if (!is_special(v, g)) {
vset.insert(v);
}
}
for (u8 offset = 0; offset < MAX_RACCEL_OFFSET; offset++) {
set<NFAVertex> next;
for (auto v : vset) {
const CharReach &cr = g[v].char_reach;
(*reach)[offset] |= cr;
DEBUG_PRINTF("off %u adding %zu to %zu\n", offset, cr.count(),
(*reach)[offset].count());
for (auto u : inv_adjacent_vertices_range(v, g)) {
if (u == g.start || u == g.startDs) {
/* kill all subsequent offsets by setting to dot, setting
* to dot is in someways not accurate as there may be no
* data at all but neither case can be accelerated */
for (u8 i = offset + 1; i < MAX_RACCEL_OFFSET; i++) {
(*reach)[i].setall();
}
break;
} else if (!is_special(u, g)) {
next.insert(u);
}
}
}
swap(vset, next);
}
}
void populateReverseAccelerationInfo(RevAccInfo &rai, const NGHolder &g) {
DEBUG_PRINTF("pop rev info\n");
populateRevAccelInfo(g, g.accept, &rai.acceptReach);
populateRevAccelInfo(g, g.acceptEod, &rai.acceptEodReach);
rai.valid = true;
}
void mergeReverseAccelerationInfo(RevAccInfo &dest, const RevAccInfo &vic) {
DEBUG_PRINTF("merging ra\n");
dest.valid &= vic.valid;
for (u8 i = 0; i < MAX_RACCEL_OFFSET; i++) {
dest.acceptReach[i] |= vic.acceptReach[i];
dest.acceptEodReach[i] |= vic.acceptEodReach[i];
}
}
RevAccInfo::RevAccInfo(void)
: valid(false), acceptReach(MAX_RACCEL_OFFSET),
acceptEodReach(MAX_RACCEL_OFFSET) {}
} // namespace ue2
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