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