third_party/boost/algorithm/doc/clamp-hpp.qbk

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[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 );
``


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