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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.
*/
#ifndef ROSE_COUNTING_MIRACLE_H
#define ROSE_COUNTING_MIRACLE_H
#include "ue2common.h"
#include "runtime.h"
#include "rose_internal.h"
#include "nfa/nfa_api_queue.h"
#include "util/simd_utils.h"
/** \brief Maximum number of bytes to scan when looking for a "counting miracle"
* stop character. */
#define COUNTING_MIRACLE_LEN_MAX 256
static really_inline
char roseCountingMiracleScan(u8 c, const u8 *d, const u8 *d_end,
u32 target_count, u32 *count_inout,
const u8 **d_out) {
assert(d <= d_end);
u32 count = *count_inout;
m128 chars = set16x8(c);
for (; d + 16 <= d_end; d_end -= 16) {
m128 data = loadu128(d_end - 16);
u32 z1 = movemask128(eq128(chars, data));
count += popcount32(z1);
if (count >= target_count) {
*d_out = d_end - 16;
*count_inout = count;
return 1;
}
}
if (d != d_end) {
char temp[sizeof(m128)];
assert(d + sizeof(temp) > d_end);
memset(temp, c + 1, sizeof(temp));
memcpy(temp, d, d_end - d);
m128 data = loadu128(temp);
u32 z1 = movemask128(eq128(chars, data));
count += popcount32(z1);
if (count >= target_count) {
*d_out = d;
*count_inout = count;
return 1;
}
}
*count_inout = count;
return 0;
}
#define GET_LO_4(chars) and128(chars, low4bits)
#define GET_HI_4(chars) rshift64_m128(andnot128(low4bits, chars), 4)
static really_inline
u32 roseCountingMiracleScanShufti(m128 mask_lo, m128 mask_hi, u8 poison,
const u8 *d, const u8 *d_end,
u32 target_count, u32 *count_inout,
const u8 **d_out) {
assert(d <= d_end);
u32 count = *count_inout;
const m128 zeroes = zeroes128();
const m128 low4bits = _mm_set1_epi8(0xf);
for (; d + 16 <= d_end; d_end -= 16) {
m128 data = loadu128(d_end - 16);
m128 c_lo = pshufb_m128(mask_lo, GET_LO_4(data));
m128 c_hi = pshufb_m128(mask_hi, GET_HI_4(data));
m128 t = and128(c_lo, c_hi);
u32 z1 = movemask128(eq128(t, zeroes));
count += popcount32(z1 ^ 0xffff);
if (count >= target_count) {
*d_out = d_end - 16;
*count_inout = count;
return 1;
}
}
if (d != d_end) {
char temp[sizeof(m128)];
assert(d + sizeof(temp) > d_end);
memset(temp, poison, sizeof(temp));
memcpy(temp, d, d_end - d);
m128 data = loadu128(temp);
m128 c_lo = pshufb_m128(mask_lo, GET_LO_4(data));
m128 c_hi = pshufb_m128(mask_hi, GET_HI_4(data));
m128 t = and128(c_lo, c_hi);
u32 z1 = movemask128(eq128(t, zeroes));
count += popcount32(z1 ^ 0xffff);
if (count >= target_count) {
*d_out = d;
*count_inout = count;
return 1;
}
}
*count_inout = count;
return 0;
}
/**
* \brief "Counting Miracle" scan: If we see more than N instances of a
* particular character class we know that the engine must be dead.
*
* Scans the buffer/history between relative locations \a begin_loc and \a
* end_loc, and returns a miracle location (if any) that appears in the stream
* after \a begin_loc.
*
* Returns 1 if some bytes can be skipped and sets \a miracle_loc
* appropriately, 0 otherwise.
*/
static never_inline
int roseCountingMiracleOccurs(const struct RoseEngine *t,
const struct LeftNfaInfo *left,
const struct core_info *ci, s64a begin_loc,
const s64a end_loc, s64a *miracle_loc) {
if (!left->countingMiracleOffset) {
return 0;
}
const struct RoseCountingMiracle *cm
= (const void *)((const char *)t + left->countingMiracleOffset);
assert(!left->transient);
assert(cm->count > 1); /* should be a normal miracle then */
DEBUG_PRINTF("looking for counting miracle over [%lld,%lld], maxLag=%u\n",
begin_loc, end_loc, left->maxLag);
DEBUG_PRINTF("ci->len=%zu, ci->hlen=%zu\n", ci->len, ci->hlen);
assert(begin_loc <= end_loc);
assert(begin_loc >= -(s64a)ci->hlen);
assert(end_loc <= (s64a)ci->len);
const s64a scan_end_loc = end_loc - left->maxLag;
if (scan_end_loc <= begin_loc) {
DEBUG_PRINTF("nothing to scan\n");
return 0;
}
const s64a start = MAX(begin_loc, scan_end_loc - COUNTING_MIRACLE_LEN_MAX);
DEBUG_PRINTF("scan [%lld..%lld]\n", start, scan_end_loc);
u32 count = 0;
s64a m_loc = start;
if (!cm->shufti) {
u8 c = cm->c;
// Scan buffer.
const s64a buf_scan_start = MAX(0, start);
if (scan_end_loc > buf_scan_start) {
const u8 *buf = ci->buf;
const u8 *d = buf + scan_end_loc;
const u8 *d_start = buf + buf_scan_start;
const u8 *d_out;
if (roseCountingMiracleScan(c, d_start, d, cm->count, &count,
&d_out)) {
assert(d_out >= d_start);
m_loc = (d_out - d_start) + buf_scan_start;
goto success;
}
}
// Scan history.
if (start < 0) {
const u8 *hbuf_end = ci->hbuf + ci->hlen;
const u8 *d = hbuf_end + MIN(0, scan_end_loc);
const u8 *d_start = hbuf_end + start;
const u8 *d_out;
if (roseCountingMiracleScan(c, d_start, d, cm->count, &count,
&d_out)) {
assert(d_out >= d_start);
m_loc = (d_out - d_start) + start;
goto success;
}
}
} else {
m128 lo = cm->lo;
m128 hi = cm->hi;
u8 poison = cm->poison;
// Scan buffer.
const s64a buf_scan_start = MAX(0, start);
if (scan_end_loc > buf_scan_start) {
const u8 *buf = ci->buf;
const u8 *d = buf + scan_end_loc;
const u8 *d_start = buf + buf_scan_start;
const u8 *d_out;
if (roseCountingMiracleScanShufti(lo, hi, poison, d_start, d,
cm->count, &count, &d_out)) {
assert(d_out >= d_start);
m_loc = (d_out - d_start) + buf_scan_start;
goto success;
}
}
// Scan history.
if (start < 0) {
const u8 *hbuf_end = ci->hbuf + ci->hlen;
const u8 *d = hbuf_end + MIN(0, scan_end_loc);
const u8 *d_start = hbuf_end + start;
const u8 *d_out;
if (roseCountingMiracleScanShufti(lo, hi, poison, d_start, d,
cm->count, &count, &d_out)) {
assert(d_out >= d_start);
m_loc = (d_out - d_start) + start;
goto success;
}
}
}
DEBUG_PRINTF("found %u/%u\n", count, cm->count);
return 0;
success:
DEBUG_PRINTF("found %u/%u\n", count, cm->count);
assert(count >= cm->count);
assert(m_loc < scan_end_loc);
assert(m_loc >= start);
*miracle_loc = m_loc;
return 1;
}
#endif
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