1 | /* |
2 | * Copyright (c) 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 | * \file |
31 | * \brief Hashing utility functions. |
32 | */ |
33 | |
34 | #ifndef UTIL_HASH_DYNAMIC_BITSET_H |
35 | #define UTIL_HASH_DYNAMIC_BITSET_H |
36 | |
37 | #include "hash.h" |
38 | |
39 | #include <boost/dynamic_bitset.hpp> |
40 | |
41 | #include <iterator> |
42 | |
43 | namespace ue2 { |
44 | |
45 | /** |
46 | * \brief An output iterator which calculates the combined hash of all elements |
47 | * written to it. |
48 | * |
49 | * The location to output the hash is provided to the constructor and should |
50 | * already be zero initialised. |
51 | */ |
52 | struct hash_output_it { |
53 | using value_type = void; |
54 | using difference_type = ptrdiff_t; |
55 | using pointer = void *; |
56 | using reference = void; |
57 | using iterator_category = std::output_iterator_tag; |
58 | |
59 | hash_output_it(size_t *hash_out = nullptr) : out(hash_out) {} |
60 | hash_output_it &operator++() { |
61 | return *this; |
62 | } |
63 | hash_output_it &operator++(int) { |
64 | return *this; |
65 | } |
66 | |
67 | struct deref_proxy { |
68 | deref_proxy(size_t *hash_out) : out(hash_out) {} |
69 | |
70 | template<typename T> |
71 | void operator=(const T &val) const { |
72 | hash_combine(*out, val); |
73 | } |
74 | |
75 | private: |
76 | size_t *out; /* output location of the owning iterator */ |
77 | }; |
78 | |
79 | deref_proxy operator*() { return {out}; } |
80 | |
81 | private: |
82 | size_t *out; /* location to output the hashes to */ |
83 | }; |
84 | |
85 | /* Function object for hashing a dynamic bitset */ |
86 | struct hash_dynamic_bitset { |
87 | size_t operator()(const boost::dynamic_bitset<> &bs) const { |
88 | size_t rv = 0; |
89 | to_block_range(bs, hash_output_it(&rv)); |
90 | return rv; |
91 | } |
92 | }; |
93 | |
94 | } // namespace ue2 |
95 | |
96 | #endif |
97 | |