source: src/Common/utility.h@ dc2334c

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// utility.h --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Andrew Beach
// Last Modified On : Thr Aug 17 11:38:00 2017
// Update Count     : 34
//

#pragma once

#include <cctype>
#include <algorithm>
#include <iostream>
#include <iterator>
#include <list>
#include <memory>
#include <sstream>
#include <string>
#include <type_traits>

#include <cassert>

template< typename T >
static inline T * maybeClone( const T *orig ) {
        if ( orig ) {
                return orig->clone();
        } else {
                return 0;
        } // if
}

template< typename T, typename U >
struct maybeBuild_t {
        static T * doit( const U *orig ) {
                if ( orig ) {
                        return orig->build();
                } else {
                        return 0;
                } // if
        }
};

template< typename T, typename U >
static inline T * maybeBuild( const U *orig ) {
        return maybeBuild_t<T,U>::doit(orig);
}

template< typename T, typename U >
static inline T * maybeMoveBuild( const U *orig ) {
        T* ret = maybeBuild<T>(orig);
        delete orig;
        return ret;
}

template< typename Input_iterator >
void printEnums( Input_iterator begin, Input_iterator end, const char * const *name_array, std::ostream &os ) {
        for ( Input_iterator i = begin; i != end; ++i ) {
                os << name_array[ *i ] << ' ';
        } // for
}

template< typename Container >
void deleteAll( Container &container ) {
        for ( typename Container::iterator i = container.begin(); i != container.end(); ++i ) {
                delete *i;
        } // for
}

template< typename Container >
void printAll( const Container &container, std::ostream &os, int indent = 0 ) {
        for ( typename Container::const_iterator i = container.begin(); i != container.end(); ++i ) {
                if ( *i ) {
                        os << std::string( indent,  ' ' );
                        (*i)->print( os, indent + 2 );
                        // need an endl after each element because it's not easy to know when each individual item should end
                        os << std::endl;
                } // if
        } // for
}

template< typename SrcContainer, typename DestContainer >
void cloneAll( const SrcContainer &src, DestContainer &dest ) {
        typename SrcContainer::const_iterator in = src.begin();
        std::back_insert_iterator< DestContainer > out( dest );
        while ( in != src.end() ) {
                *out++ = (*in++)->clone();
        } // while
}

template< typename Container >
void assertAll( const Container &container ) {
        int count = 0;
        for ( typename Container::const_iterator i = container.begin(); i != container.end(); ++i ) {
                if ( !(*i) ) {
                        std::cerr << count << " is null" << std::endl;
                } // if
        } // for
}

template < typename T >
std::list<T> tail( std::list<T> l ) {
        if ( ! l.empty() ) {
                std::list<T> ret(++(l.begin()), l.end());
                return ret;
        } // if
}

template < typename T >
std::list<T> flatten( std::list < std::list<T> > l) {
        typedef std::list <T> Ts;

        Ts ret;

        switch ( l.size() ) {
          case 0:
                return ret;
          case 1:
                return l.front();
          default:
                ret = flatten(tail(l));
                ret.insert(ret.begin(), l.front().begin(), l.front().end());
                return ret;
        } // switch
}

template < typename T >
void toString_single( std::ostream & os, const T & value ) {
        os << value;
}

template < typename T, typename... Params >
void toString_single( std::ostream & os, const T & value, const Params & ... params ) {
        os << value;
        toString_single( os, params ... );
}

template < typename ... Params >
std::string toString( const Params & ... params ) {
        std::ostringstream os;
        toString_single( os, params... );
        return os.str();
}

// replace element of list with all elements of another list
template< typename T >
void replace( std::list< T > &org, typename std::list< T >::iterator pos, std::list< T > &with ) {
        typename std::list< T >::iterator next = pos; advance( next, 1 );

        //if ( next != org.end() ) {
        org.erase( pos );
        org.splice( next, with );
        //}

        return;
}

// replace range of a list with a single element
template< typename T >
void replace( std::list< T > &org, typename std::list< T >::iterator begin, typename std::list< T >::iterator end, const T & with ) {
        org.insert( begin, with );
        org.erase( begin, end );
}

template< typename... Args >
auto filter(Args&&... args) -> decltype(std::copy_if(std::forward<Args>(args)...)) {
  return std::copy_if(std::forward<Args>(args)...);
}

template <typename E, typename UnaryPredicate, template< typename, typename...> class Container, typename... Args >
void filter( Container< E *, Args... > & container, UnaryPredicate pred, bool doDelete ) {
        auto i = begin( container );
        while ( i != end( container ) ) {
                auto it = next( i );
                if ( pred( *i ) ) {
                        if ( doDelete ) {
                                delete *i;
                        } // if
                        container.erase( i );
                } // if
                i = it;
        } // while
}

template< typename... Args >
auto zip(Args&&... args) -> decltype(zipWith(std::forward<Args>(args)..., std::make_pair)) {
  return zipWith(std::forward<Args>(args)..., std::make_pair);
}

template< class InputIterator1, class InputIterator2, class OutputIterator, class BinFunction >
void zipWith( InputIterator1 b1, InputIterator1 e1, InputIterator2 b2, InputIterator2 e2, OutputIterator out, BinFunction func ) {
        while ( b1 != e1 && b2 != e2 )
                *out++ = func(*b1++, *b2++);
}

// it's nice to actually be able to increment iterators by an arbitrary amount
template< class InputIt, class Distance >
InputIt operator+( InputIt it, Distance n ) {
        advance(it, n);
        return it;
}

template< typename T >
void warn_single( const T & arg ) {
        std::cerr << arg << std::endl;
}

template< typename T, typename... Params >
void warn_single(const T & arg, const Params & ... params ) {
        std::cerr << arg;
        warn_single( params... );
}

template< typename... Params >
void warn( const Params & ... params ) {
        std::cerr << "Warning: ";
        warn_single( params... );
}

/// determines if `pref` is a prefix of `str`
static inline bool isPrefix( const std::string & str, const std::string & pref ) {
        if ( pref.size() > str.size() ) return false;
        auto its = std::mismatch( pref.begin(), pref.end(), str.begin() );
        return its.first == pref.end();
}

// -----------------------------------------------------------------------------
// Ref Counted Singleton class
// Objects that inherit from this class will have at most one reference to it
// but if all references die, the object will be deleted.

template< typename ThisType >
class RefCountSingleton {
  public:
        static std::shared_ptr<ThisType> get() {
                if( global_instance.expired() ) {
                        std::shared_ptr<ThisType> new_instance = std::make_shared<ThisType>();
                        global_instance = new_instance;
                        return std::move(new_instance);
                }
                return global_instance.lock();
        }
  private:
        static std::weak_ptr<ThisType> global_instance;
};

template< typename ThisType >
std::weak_ptr<ThisType> RefCountSingleton<ThisType>::global_instance;

// -----------------------------------------------------------------------------
// RAII object to regulate "save and restore" behaviour, e.g.
// void Foo::bar() {
//   ValueGuard<int> guard(var); // var is a member of type Foo
//   var = ...;
// } // var's original value is restored
template< typename T >
struct ValueGuard {
        T old;
        T& ref;

        ValueGuard(T& inRef) : old(inRef), ref(inRef) {}
        ~ValueGuard() { ref = old; }
};

template< typename T >
struct ValueGuardPtr {
        T old;
        T* ref;

        ValueGuardPtr(T * inRef) : old( inRef ? *inRef : T() ), ref(inRef) {}
        ~ValueGuardPtr() { if( ref ) *ref = old; }
};

template< typename aT >
struct FuncGuard {
        aT m_after;

        template< typename bT >
        FuncGuard( bT before, aT after ) : m_after( after ) {
                before();
        }

        ~FuncGuard() {
                m_after();
        }
};

template< typename bT, typename aT >
FuncGuard<aT> makeFuncGuard( bT && before, aT && after ) {
        return FuncGuard<aT>( std::forward<bT>(before), std::forward<aT>(after) );
}

template< typename T >
struct ValueGuardPtr< std::list< T > > {
        std::list< T > old;
        std::list< T >* ref;

        ValueGuardPtr( std::list< T > * inRef) : old(), ref(inRef) {
                if( ref ) { swap( *ref, old ); }
        }
        ~ValueGuardPtr() { if( ref ) { swap( *ref, old ); } }
};

// -----------------------------------------------------------------------------
// Helper struct and function to support
// for ( val : reverseIterate( container ) ) {}
// syntax to have a for each that iterates backwards

template< typename T >
struct reverse_iterate_t {
        T& ref;

        reverse_iterate_t( T & ref ) : ref(ref) {}

        typedef typename T::reverse_iterator iterator;
        iterator begin() { return ref.rbegin(); }
        iterator end() { return ref.rend(); }
};

template< typename T >
reverse_iterate_t< T > reverseIterate( T & ref ) {
        return reverse_iterate_t< T >( ref );
}

template< typename OutType, typename Range, typename Functor >
OutType map_range( const Range& range, Functor&& functor ) {
        OutType out;

        std::transform(
                begin( range ),
                end( range ),
                std::back_inserter( out ),
                std::forward< Functor >( functor )
        );

        return out;
}

// -----------------------------------------------------------------------------
// Helper struct and function to support
// for ( val : group_iterate( container1, container2, ... ) ) {}
// syntax to have a for each that iterates multiple containers of the same length
// TODO: update to use variadic arguments

template< typename T1, typename T2 >
struct group_iterate_t {
        group_iterate_t( bool skipBoundsCheck, const T1 & v1, const T2 & v2 ) : args(v1, v2) {
                assertf(skipBoundsCheck || v1.size() == v2.size(), "group iteration requires containers of the same size: <%zd, %zd>.", v1.size(), v2.size());
        };

        struct iterator {
                typedef typename std::remove_reference<T1>::type T1val;
                typedef typename std::remove_reference<T2>::type T2val;
                typedef std::tuple<typename T1val::value_type &, typename T2val::value_type &> value_type;
                typedef typename T1val::iterator T1Iter;
                typedef typename T2val::iterator T2Iter;
                typedef std::tuple<T1Iter, T2Iter> IterTuple;
                IterTuple it;
                iterator( T1Iter i1, T2Iter i2 ) : it( i1, i2 ) {}
                iterator operator++() {
                        return iterator( ++std::get<0>(it), ++std::get<1>(it) );
                }
                bool operator!=( const iterator &other ) const { return it != other.it; }
                value_type operator*() const { return std::tie( *std::get<0>(it), *std::get<1>(it) ); }
        };
        iterator begin() { return iterator( std::get<0>(args).begin(), std::get<1>(args).begin() ); }
        iterator end() { return iterator( std::get<0>(args).end(), std::get<1>(args).end() ); }

private:
        std::tuple<T1, T2> args;
};

/// performs bounds check to ensure that all arguments are of the same length.
template< typename... Args >
group_iterate_t<Args...> group_iterate( Args &&... args ) {
        return group_iterate_t<Args...>(false, std::forward<Args>( args )...);
}

/// does not perform a bounds check - requires user to ensure that iteration terminates when appropriate.
template< typename... Args >
group_iterate_t<Args...> unsafe_group_iterate( Args &&... args ) {
        return group_iterate_t<Args...>(true, std::forward<Args>( args )...);
}

// -----------------------------------------------------------------------------
// Helper struct and function to support
// for ( val : lazy_map( container1, f ) ) {}
// syntax to have a for each that iterates a container, mapping each element by applying f
template< typename T, typename Func >
struct lambda_iterate_t {
        const T & ref;
        std::function<Func> f;

        struct iterator {
                typedef decltype(begin(ref)) Iter;
                Iter it;
                std::function<Func> f;
                iterator( Iter it, std::function<Func> f ) : it(it), f(f) {}
                iterator & operator++() {
                        ++it; return *this;
                }
                bool operator!=( const iterator &other ) const { return it != other.it; }
                auto operator*() const -> decltype(f(*it)) { return f(*it); }
        };

        lambda_iterate_t( const T & ref, std::function<Func> f ) : ref(ref), f(f) {}

        auto begin() const -> decltype(iterator(std::begin(ref), f)) { return iterator(std::begin(ref), f); }
        auto end() const   -> decltype(iterator(std::end(ref), f)) { return iterator(std::end(ref), f); }
};

template< typename... Args >
lambda_iterate_t<Args...> lazy_map( const Args &... args ) {
        return lambda_iterate_t<Args...>( args...);
}



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