1/*
2 * Copyright (c) 2016-2017, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * * Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Intel Corporation nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * In order to use this macro, the following things need to be defined:
31 *
32 * - SHENG_IMPL (name of the Sheng implementation function)
33 * - DEAD_FUNC (name of the function checking for dead states)
34 * - ACCEPT_FUNC (name of the function checking for accept state)
35 * - STOP_AT_MATCH (can be 1 or 0, enable or disable stop at match)
36 */
37
38/* byte-by-byte version. we don't do byte-by-byte death checking as it's
39 * pretty pointless to do it over a buffer that's at most 3 bytes long */
40static really_inline
41char SHENG_IMPL(u8 *state, NfaCallback cb, void *ctxt, const struct sheng *s,
42 u8 *const cached_accept_state, ReportID *const cached_accept_id,
43 u8 single, u64a base_offset, const u8 *buf, const u8 *start,
44 const u8 *end, const u8 **scan_end) {
45 DEBUG_PRINTF("Starting DFA execution in state %u\n",
46 *state & SHENG_STATE_MASK);
47 const u8 *cur_buf = start;
48 if (DEAD_FUNC(*state)) {
49 DEBUG_PRINTF("Dead on arrival\n");
50 *scan_end = end;
51 return MO_CONTINUE_MATCHING;
52 }
53 DEBUG_PRINTF("Scanning %lli bytes\n", (s64a)(end - start));
54
55 m128 cur_state = set16x8(*state);
56 const m128 *masks = s->shuffle_masks;
57
58 while (likely(cur_buf != end)) {
59 const u8 c = *cur_buf;
60 const m128 shuffle_mask = masks[c];
61 cur_state = pshufb_m128(shuffle_mask, cur_state);
62 const u8 tmp = movd(cur_state);
63
64 DEBUG_PRINTF("c: %02hhx '%c'\n", c, ourisprint(c) ? c : '?');
65 DEBUG_PRINTF("s: %u (hi: %u lo: %u)\n", tmp, (tmp & 0xF0) >> 4,
66 tmp & 0xF);
67
68 if (unlikely(ACCEPT_FUNC(tmp))) {
69 DEBUG_PRINTF("Accept state %u reached\n", tmp & SHENG_STATE_MASK);
70 u64a match_offset = base_offset + (cur_buf - buf) + 1;
71 DEBUG_PRINTF("Match @ %llu\n", match_offset);
72 if (STOP_AT_MATCH) {
73 DEBUG_PRINTF("Stopping at match @ %lli\n",
74 (u64a)(cur_buf - start));
75 *state = tmp;
76 *scan_end = cur_buf;
77 return MO_MATCHES_PENDING;
78 }
79 if (single) {
80 if (fireSingleReport(cb, ctxt, s->report, match_offset) ==
81 MO_HALT_MATCHING) {
82 return MO_HALT_MATCHING;
83 }
84 } else {
85 if (fireReports(s, cb, ctxt, tmp, match_offset,
86 cached_accept_state, cached_accept_id,
87 0) == MO_HALT_MATCHING) {
88 return MO_HALT_MATCHING;
89 }
90 }
91 }
92 cur_buf++;
93 }
94 *state = movd(cur_state);
95 *scan_end = cur_buf;
96 return MO_CONTINUE_MATCHING;
97}
98