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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/usr/diag/prdf/common/util/UtilFunct.H $ */
/* */
/* IBM CONFIDENTIAL */
/* */
/* COPYRIGHT International Business Machines Corp. 2005,2013 */
/* */
/* p1 */
/* */
/* Object Code Only (OCO) source materials */
/* Licensed Internal Code Source Materials */
/* IBM HostBoot Licensed Internal Code */
/* */
/* The source code for this program is not published or otherwise */
/* divested of its trade secrets, irrespective of what has been */
/* deposited with the U.S. Copyright Office. */
/* */
/* Origin: 30 */
/* */
/* IBM_PROLOG_END_TAG */
/** @file UtilFunct.H
* Utility template classes for doing functional-style programming across
* iterators.
*/
#ifndef __UTIL_UTILFUNCT_H
#define __UTIL_UTILFUNCT_H
#include <functional>
namespace PRDF
{
namespace Util
{
/**
* @class unary_input
* Functor that will read a value from a stream; useful for "generate"
* algorithms such as std::generate_n.
*/
template <typename Type,
typename Stream>
struct unary_input :
public std::unary_function<void, Type>
{
Stream & stream;
/**
* @fn unary_input(Stream & i)
* Constructor
*
* @param i : The stream to read from.
*/
unary_input(Stream & i) : stream(i) {};
/**
* @fn operator()
* Read instance of 'Type' from stream.
*
* Overloaded () operator to implement the functor-style behavior.
*/
Type operator() ()
{
Type t;
stream >> t;
return t;
};
};
/**
* @class unary_compose
* Functor that will compose two functors as in: 'f(g(x))'.
*
* This template is an SGI extension to the STL, not currently in the C++
* standard. Since it is currently an extension, define it in our Util
* namespace for portability.
*
* Note: This is a clean implementation of the template, not a copy of the
* SGI code, based on the SGI::STL documentation.
*/
template <typename Unary1,
typename Unary2>
struct unary_compose :
public std::unary_function<typename Unary2::argument_type,
typename Unary1::result_type>
{
Unary1 u1;
Unary2 u2;
/**
* @fn unary_compose(Unary1 & i1, Unary2 & i2)
* Constructor
*
* @param i1 : f functor in f(g(x)).
* @param i2 : g functor in f(g(x)).
*/
unary_compose(const Unary1 & i1,
const Unary2 & i2) : u1(i1), u2(i2) {};
/**
* @fn operator()
* Execute f(g(x)).
*
* Overloaded () operator to implement the functor-style behavior.
*/
typename Unary1::result_type
operator() (typename Unary2::argument_type x)
{
return u1(u2(x));
};
};
/**
* @fn unary_compose
* Utility template function to automatically create a composition functor.
*/
template <typename Unary1,
typename Unary2>
inline
unary_compose<Unary1, Unary2> compose1(const Unary1 & i1,
const Unary2 & i2)
{
return unary_compose<Unary1, Unary2>(i1, i2);
};
/**
* @class unary_null.
* Functor that will do nothing.
*
* Useful in combination with compose for dropping a return from another
* functor.
*/
template <typename Type>
struct unary_null :
public std::unary_function<Type, void>
{
unary_null() {};
void operator() (Type i) {};
};
};
} // end namespace PRDF
#endif
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