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[/ QuickBook Document version 1.5 ]
[section:clamp clamp]
[/license
Copyright (c) 2010-2012 Marshall Clow
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or copy at
http://www.boost.org/LICENSE_1_0.txt)
]
The header file clamp.hpp contains two functions for "clamping" a value between a pair of boundary values.
[heading clamp]
The function `clamp (v, lo, hi)` returns:
* lo if v < lo
* hi if hi < v
* otherwise, v
Note: using `clamp` with floating point numbers may give unexpected results if one of the values is `NaN`.
There is also a version that allows the caller to specify a comparison predicate to use instead of `operator <`.
``
template<typename T>
const T& clamp ( const T& val, const T& lo, const T& hi );
template<typename T, typename Pred>
const T& clamp ( const T& val, const T& lo, const T& hi, Pred p );
``
The following code: ``
int foo = 23;
foo = clamp ( foo, 1, 10 );
``
will leave `foo` with a value of 10
Complexity:
`clamp` will make either one or two calls to the comparison predicate before returning one of the three parameters.
[heading clamp_range]
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.
``
template<typename InputIterator, typename OutputIterator>
OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
typename std::iterator_traits<InputIterator>::value_type lo,
typename std::iterator_traits<InputIterator>::value_type hi );
template<typename Range, typename OutputIterator>
OutputIterator clamp_range ( const Range &r, OutputIterator out,
typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo,
typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi );
template<typename InputIterator, typename OutputIterator, typename Pred>
OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
typename std::iterator_traits<InputIterator>::value_type lo,
typename std::iterator_traits<InputIterator>::value_type hi, Pred p );
template<typename Range, typename OutputIterator, typename Pred>
OutputIterator clamp_range ( const Range &r, OutputIterator out,
typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo,
typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi,
Pred p );
``
[endsect]
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