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1 | // Copyright (C) 2005-2006 The Trustees of Indiana University. |
2 | ||
3 | // Distributed under the Boost Software License, Version 1.0. | |
4 | // (See accompanying file LICENSE_1_0.txt or copy at | |
5 | // http://www.boost.org/LICENSE_1_0.txt) | |
6 | ||
7 | // Authors: Jeremiah Willcock | |
8 | // Douglas Gregor | |
9 | // Andrew Lumsdaine | |
10 | ||
11 | // Two bit per color property map | |
12 | ||
13 | #ifndef BOOST_TWO_BIT_COLOR_MAP_HPP | |
14 | #define BOOST_TWO_BIT_COLOR_MAP_HPP | |
15 | ||
16 | #include <boost/property_map/property_map.hpp> | |
17 | #include <boost/graph/properties.hpp> | |
18 | #include <boost/shared_array.hpp> | |
19 | #include <boost/config.hpp> | |
20 | #include <boost/assert.hpp> | |
21 | #include <algorithm> | |
22 | #include <limits> | |
23 | ||
24 | namespace boost { | |
25 | ||
26 | enum two_bit_color_type { | |
27 | two_bit_white = 0, | |
28 | two_bit_gray = 1, | |
29 | two_bit_green = 2, | |
30 | two_bit_black = 3 | |
31 | }; | |
32 | ||
33 | template <> | |
34 | struct color_traits<two_bit_color_type> | |
35 | { | |
36 | static two_bit_color_type white() { return two_bit_white; } | |
37 | static two_bit_color_type gray() { return two_bit_gray; } | |
38 | static two_bit_color_type green() { return two_bit_green; } | |
39 | static two_bit_color_type black() { return two_bit_black; } | |
40 | }; | |
41 | ||
42 | ||
43 | template<typename IndexMap = identity_property_map> | |
44 | struct two_bit_color_map | |
45 | { | |
46 | std::size_t n; | |
47 | IndexMap index; | |
48 | shared_array<unsigned char> data; | |
49 | ||
50 | BOOST_STATIC_CONSTANT(int, bits_per_char = std::numeric_limits<unsigned char>::digits); | |
51 | BOOST_STATIC_CONSTANT(int, elements_per_char = bits_per_char / 2); | |
52 | typedef typename property_traits<IndexMap>::key_type key_type; | |
53 | typedef two_bit_color_type value_type; | |
54 | typedef void reference; | |
55 | typedef read_write_property_map_tag category; | |
56 | ||
57 | explicit two_bit_color_map(std::size_t n, const IndexMap& index = IndexMap()) | |
58 | : n(n), index(index), data(new unsigned char[(n + elements_per_char - 1) / elements_per_char]) | |
59 | { | |
60 | // Fill to white | |
61 | std::fill(data.get(), data.get() + (n + elements_per_char - 1) / elements_per_char, 0); | |
62 | } | |
63 | }; | |
64 | ||
65 | template<typename IndexMap> | |
66 | inline two_bit_color_type | |
67 | get(const two_bit_color_map<IndexMap>& pm, | |
68 | typename property_traits<IndexMap>::key_type key) | |
69 | { | |
70 | BOOST_STATIC_CONSTANT(int, elements_per_char = two_bit_color_map<IndexMap>::elements_per_char); | |
71 | typename property_traits<IndexMap>::value_type i = get(pm.index, key); | |
72 | BOOST_ASSERT ((std::size_t)i < pm.n); | |
73 | std::size_t byte_num = i / elements_per_char; | |
74 | std::size_t bit_position = ((i % elements_per_char) * 2); | |
75 | return two_bit_color_type((pm.data.get()[byte_num] >> bit_position) & 3); | |
76 | } | |
77 | ||
78 | template<typename IndexMap> | |
79 | inline void | |
80 | put(const two_bit_color_map<IndexMap>& pm, | |
81 | typename property_traits<IndexMap>::key_type key, | |
82 | two_bit_color_type value) | |
83 | { | |
84 | BOOST_STATIC_CONSTANT(int, elements_per_char = two_bit_color_map<IndexMap>::elements_per_char); | |
85 | typename property_traits<IndexMap>::value_type i = get(pm.index, key); | |
86 | BOOST_ASSERT ((std::size_t)i < pm.n); | |
87 | BOOST_ASSERT (value >= 0 && value < 4); | |
88 | std::size_t byte_num = i / elements_per_char; | |
89 | std::size_t bit_position = ((i % elements_per_char) * 2); | |
90 | pm.data.get()[byte_num] = | |
91 | (unsigned char) | |
92 | ((pm.data.get()[byte_num] & ~(3 << bit_position)) | |
93 | | (value << bit_position)); | |
94 | } | |
95 | ||
96 | template<typename IndexMap> | |
97 | inline two_bit_color_map<IndexMap> | |
98 | make_two_bit_color_map(std::size_t n, const IndexMap& index_map) | |
99 | { | |
100 | return two_bit_color_map<IndexMap>(n, index_map); | |
101 | } | |
102 | ||
103 | } // end namespace boost | |
104 | ||
105 | #endif // BOOST_TWO_BIT_COLOR_MAP_HPP | |
106 | ||
107 | #ifdef BOOST_GRAPH_USE_MPI | |
108 | # include <boost/graph/distributed/two_bit_color_map.hpp> | |
109 | #endif |