Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
The header file clamp.hpp contains two functions for "clamping" a value between a pair of boundary values.
The function clamp (v, lo, hi)
returns:
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.
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 );