1 | /* |
2 | * Copyright (c) 2015-2019, 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 | /** \file |
30 | * \brief Hamster Wheel Literal Matcher: literal representation at build time. |
31 | */ |
32 | #include "hwlm_literal.h" |
33 | #include "util/bitutils.h" // for CASE_BIT |
34 | #include "util/compare.h" // for ourisalpha |
35 | #include "util/ue2string.h" // for escapeString |
36 | |
37 | #include <algorithm> |
38 | #include <iomanip> |
39 | #include <sstream> |
40 | |
41 | using namespace std; |
42 | |
43 | namespace ue2 { |
44 | |
45 | #ifdef DEBUG |
46 | static UNUSED |
47 | std::string dumpMask(const vector<u8> &v) { |
48 | ostringstream oss; |
49 | vector<u8>::const_iterator it, ite; |
50 | for (it = v.begin(), ite = v.end(); it != ite; ++it) { |
51 | oss << setfill('0') << setw(2) << hex << (unsigned int)*it; |
52 | } |
53 | return oss.str(); |
54 | } |
55 | #endif |
56 | |
57 | bool maskIsConsistent(const std::string &s, bool nocase, const vector<u8> &msk, |
58 | const vector<u8> &cmp) { |
59 | string::const_reverse_iterator si = s.rbegin(); |
60 | vector<u8>::const_reverse_iterator mi = msk.rbegin(), ci = cmp.rbegin(); |
61 | |
62 | for (; si != s.rend() && mi != msk.rend(); ++si, ++mi, ++ci) { |
63 | u8 c = *si, m = *mi, v = *ci; |
64 | if (nocase && ourisalpha(c)) { |
65 | m &= ~CASE_BIT; |
66 | v &= ~CASE_BIT; |
67 | } |
68 | |
69 | assert(ci != cmp.rend()); |
70 | if ((c & m) != v) { |
71 | DEBUG_PRINTF("c = %02hhx; *ci = %02hhx m =%02hhx\n" , c, *ci, m); |
72 | DEBUG_PRINTF("s = %s; dist = %zd\n" , s.c_str(), si - s.rbegin()); |
73 | return false; |
74 | } |
75 | } |
76 | |
77 | return true; |
78 | } |
79 | |
80 | /** \brief Complete constructor, takes group information and msk/cmp. |
81 | * |
82 | * This constructor takes a msk/cmp pair. Both must be vectors of length <= |
83 | * \ref HWLM_MASKLEN. */ |
84 | hwlmLiteral::hwlmLiteral(const std::string &s_in, bool nocase_in, |
85 | bool noruns_in, u32 id_in, hwlm_group_t groups_in, |
86 | const vector<u8> &msk_in, const vector<u8> &cmp_in, |
87 | bool pure_in) |
88 | : s(s_in), id(id_in), nocase(nocase_in), noruns(noruns_in), |
89 | groups(groups_in), msk(msk_in), cmp(cmp_in), pure(pure_in) { |
90 | assert(s.size() <= HWLM_LITERAL_MAX_LEN); |
91 | assert(msk.size() <= HWLM_MASKLEN); |
92 | assert(msk.size() == cmp.size()); |
93 | |
94 | // If we've been handled a nocase literal, all letter characters must be |
95 | // upper-case. |
96 | if (nocase) { |
97 | upperString(s); |
98 | } |
99 | |
100 | DEBUG_PRINTF("literal '%s'%s, msk=%s, cmp=%s\n" , escapeString(s).c_str(), |
101 | nocase ? " (nocase)" : "" , dumpMask(msk).c_str(), |
102 | dumpMask(cmp).c_str()); |
103 | |
104 | |
105 | // Mask and compare vectors MUST be the same size. |
106 | assert(msk.size() == cmp.size()); |
107 | |
108 | // We must have been passed a msk/cmp that can be applied to s. |
109 | assert(maskIsConsistent(s, nocase, msk, cmp)); |
110 | |
111 | // In the name of good hygiene, zap msk/cmp if msk is all zeroes. |
112 | if (all_of(begin(msk), end(msk), [](u8 val) { return val == 0; })) { |
113 | msk.clear(); |
114 | cmp.clear(); |
115 | } |
116 | } |
117 | |
118 | } // namespace ue2 |
119 | |