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1 | // Copyright (c) 2001 Daniel C. Nuffer |
2 | // Copyright (c) 2001-2011 Hartmut Kaiser | |
3 | // | |
4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | ||
7 | #if !defined(BOOST_SPIRIT_ITERATOR_REF_COUNTED_POLICY_MAR_16_2007_1108AM) | |
8 | #define BOOST_SPIRIT_ITERATOR_REF_COUNTED_POLICY_MAR_16_2007_1108AM | |
9 | ||
10 | #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp> | |
11 | #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp> | |
12 | #if defined(BOOST_HAS_THREADS) | |
13 | #include <boost/detail/atomic_count.hpp> | |
14 | #endif | |
15 | #include <cstdlib> | |
16 | ||
17 | namespace boost { namespace spirit { namespace iterator_policies | |
18 | { | |
19 | /////////////////////////////////////////////////////////////////////////// | |
20 | // class ref_counted | |
21 | // Implementation of an OwnershipPolicy used by multi_pass. | |
22 | // | |
23 | // Implementation modified from RefCounted class from the Loki library by | |
24 | // Andrei Alexandrescu. | |
25 | /////////////////////////////////////////////////////////////////////////// | |
26 | struct ref_counted | |
27 | { | |
28 | /////////////////////////////////////////////////////////////////////// | |
29 | struct unique // : detail::default_ownership_policy | |
30 | { | |
31 | void swap(unique&) {} | |
32 | ||
33 | // clone is called when a copy of the iterator is made, so | |
34 | // increment the ref-count. | |
35 | template <typename MultiPass> | |
36 | static void clone(MultiPass& mp) | |
37 | { | |
38 | if (0 != mp.shared()) | |
39 | ++mp.shared()->count; | |
40 | } | |
41 | ||
42 | // called when a copy is deleted. Decrement the ref-count. Return | |
43 | // value of true indicates that the last copy has been released. | |
44 | template <typename MultiPass> | |
45 | static bool release(MultiPass& mp) | |
46 | { | |
47 | return 0 != mp.shared() && 0 == --mp.shared()->count; | |
48 | } | |
49 | ||
50 | // returns true if there is only one iterator in existence. | |
51 | // std_deque StoragePolicy will free it's buffered data if this | |
52 | // returns true. | |
53 | template <typename MultiPass> | |
54 | static bool is_unique(MultiPass const& mp) | |
55 | { | |
56 | return 0 == mp.shared() || 1 == mp.shared()->count; | |
57 | } | |
58 | ||
59 | template <typename MultiPass> | |
60 | static void destroy(MultiPass&) {} | |
61 | }; | |
62 | ||
63 | //////////////////////////////////////////////////////////////////////// | |
64 | struct shared | |
65 | { | |
66 | shared() : count(1) {} | |
67 | ||
68 | #if defined(BOOST_HAS_THREADS) | |
69 | boost::detail::atomic_count count; | |
70 | #else | |
71 | std::size_t count; | |
72 | #endif | |
73 | }; | |
74 | ||
75 | }; | |
76 | ||
77 | }}} | |
78 | ||
79 | #endif |