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 |
74 | |