projects / ceph.git / blame
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1 | [/ QuickBook Document version 1.5 ] |
| 2 | [section:clamp clamp] | |
| 3 | ||
| 4 | [/license | |
| 5 | ||
| 6 | Copyright (c) 2010-2012 Marshall Clow | |
| 7 | ||
| 8 | Distributed under the Boost Software License, Version 1.0. | |
| 9 | (See accompanying file LICENSE_1_0.txt or copy at | |
| 10 | http://www.boost.org/LICENSE_1_0.txt) | |
| 11 | ||
| 12 | ] | |
| 13 | ||
| 14 | ||
| 15 | The header file clamp.hpp contains two functions for "clamping" a value between a pair of boundary values. | |
| 16 | ||
| 17 | [heading clamp] | |
| 18 | ||
| 19 | The function `clamp (v, lo, hi)` returns: | |
| 20 | ||
| 21 | * lo if v < lo | |
| 22 | * hi if hi < v | |
| 23 | * otherwise, v | |
| 24 | ||
| 25 | Note: using `clamp` with floating point numbers may give unexpected results if one of the values is `NaN`. | |
| 26 | ||
| 27 | There is also a version that allows the caller to specify a comparison predicate to use instead of `operator <`. | |
| 28 | ||
| 29 | `` | |
| 30 | template<typename T> | |
| 31 | const T& clamp ( const T& val, const T& lo, const T& hi ); | |
| 32 | ||
| 33 | template<typename T, typename Pred> | |
| 34 | const T& clamp ( const T& val, const T& lo, const T& hi, Pred p ); | |
| 35 | `` | |
| 36 | ||
| 37 | The following code: `` | |
| 38 | int foo = 23; | |
| 39 | foo = clamp ( foo, 1, 10 ); | |
| 40 | `` | |
| 41 | will leave `foo` with a value of 10 | |
| 42 | ||
| 43 | Complexity: | |
| 44 | `clamp` will make either one or two calls to the comparison predicate before returning one of the three parameters. | |
| 45 | ||
| 46 | [heading clamp_range] | |
| 47 | There are also four range-based versions of clamp, that apply clamping to a series of values. You could write them yourself with std::transform and bind, like this: `std::transform ( first, last, out, bind ( clamp ( _1, lo, hi )))`, but they are provided here for your convenience. | |
| 48 | ||
| 49 | `` | |
| 50 | template<typename InputIterator, typename OutputIterator> | |
| 51 | OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out, | |
| 52 | typename std::iterator_traits<InputIterator>::value_type lo, | |
| 53 | typename std::iterator_traits<InputIterator>::value_type hi ); | |
| 54 | ||
| 55 | template<typename Range, typename OutputIterator> | |
| 56 | OutputIterator clamp_range ( const Range &r, OutputIterator out, | |
| 57 | typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, | |
| 58 | typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi ); | |
| 59 | ||
| 60 | template<typename InputIterator, typename OutputIterator, typename Pred> | |
| 61 | OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out, | |
| 62 | typename std::iterator_traits<InputIterator>::value_type lo, | |
| 63 | typename std::iterator_traits<InputIterator>::value_type hi, Pred p ); | |
| 64 | ||
| 65 | template<typename Range, typename OutputIterator, typename Pred> | |
| 66 | OutputIterator clamp_range ( const Range &r, OutputIterator out, | |
| 67 | typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, | |
| 68 | typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi, | |
| 69 | Pred p ); | |
| 70 | `` | |
| 71 | ||
| 72 | ||
| 73 | [endsect] |