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1 | /* boost random/random_number_generator.hpp header file |
2 | * | |
3 | * Copyright Jens Maurer 2000-2001 | |
4 | * Distributed under the Boost Software License, Version 1.0. (See | |
5 | * accompanying file LICENSE_1_0.txt or copy at | |
6 | * http://www.boost.org/LICENSE_1_0.txt) | |
7 | * | |
8 | * See http://www.boost.org for most recent version including documentation. | |
9 | * | |
10 | * $Id$ | |
11 | * | |
12 | * Revision history | |
13 | * 2001-02-18 moved to individual header files | |
14 | */ | |
15 | ||
16 | #ifndef BOOST_RANDOM_RANDOM_NUMBER_GENERATOR_HPP | |
17 | #define BOOST_RANDOM_RANDOM_NUMBER_GENERATOR_HPP | |
18 | ||
19 | #include <boost/assert.hpp> | |
20 | #include <boost/random/uniform_int_distribution.hpp> | |
21 | ||
22 | #include <boost/random/detail/disable_warnings.hpp> | |
23 | ||
24 | namespace boost { | |
25 | namespace random { | |
26 | ||
27 | /** | |
28 | * Instantiations of class template random_number_generator model a | |
29 | * RandomNumberGenerator (std:25.2.11 [lib.alg.random.shuffle]). On | |
30 | * each invocation, it returns a uniformly distributed integer in | |
31 | * the range [0..n). | |
32 | * | |
33 | * The template parameter IntType shall denote some integer-like value type. | |
34 | */ | |
35 | template<class URNG, class IntType = long> | |
36 | class random_number_generator | |
37 | { | |
38 | public: | |
39 | typedef URNG base_type; | |
40 | typedef IntType argument_type; | |
41 | typedef IntType result_type; | |
42 | /** | |
43 | * Constructs a random_number_generator functor with the given | |
44 | * \uniform_random_number_generator as the underlying source of | |
45 | * random numbers. | |
46 | */ | |
47 | random_number_generator(base_type& rng) : _rng(rng) {} | |
48 | ||
49 | // compiler-generated copy ctor is fine | |
50 | // assignment is disallowed because there is a reference member | |
51 | ||
52 | /** | |
53 | * Returns a value in the range [0, n) | |
54 | */ | |
55 | result_type operator()(argument_type n) | |
56 | { | |
57 | BOOST_ASSERT(n > 0); | |
58 | return uniform_int_distribution<IntType>(0, n-1)(_rng); | |
59 | } | |
60 | ||
61 | private: | |
62 | base_type& _rng; | |
63 | }; | |
64 | ||
65 | } // namespace random | |
66 | ||
67 | using random::random_number_generator; | |
68 | ||
69 | } // namespace boost | |
70 | ||
71 | #include <boost/random/detail/enable_warnings.hpp> | |
72 | ||
73 | #endif // BOOST_RANDOM_RANDOM_NUMBER_GENERATOR_HPP |