source: src/Common/utility.h@ fbdfcd8

//
// 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 Feb 16 12:35:00 2023
// Update Count     : 52
//

#pragma once

#include <cassert>
#include <cctype>
#include <algorithm>
#include <functional>
#include <iostream>
#include <iterator>
#include <list>
#include <memory>
#include <sstream>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
#include <cstring>                                                                              // memcmp

#include "Common/Indenter.h"

class Expression;

/// bring std::move into global scope
using std::move;

/// partner to move that copies any copyable type
template<typename T>
T copy( const T & x ) { return x; }

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

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( const Container &container ) {
        for ( const auto &i : container ) {
                delete i;
        } // for
}

template< typename Container >
void printAll( const Container &container, std::ostream &os, Indenter indent = {} ) {
        for ( typename Container::const_iterator i = container.begin(); i != container.end(); ++i ) {
                if ( *i ) {
                        os << indent;
                        (*i)->print( os, indent );
                        // 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 SrcContainer, typename DestContainer, typename Predicate >
void cloneAll_if( const SrcContainer &src, DestContainer &dest, Predicate pred ) {
        std::back_insert_iterator< DestContainer > out( dest );
        for ( auto x : src ) {
                if ( pred(x) ) {
                        *out++ = x->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
}

/// Splice src onto the end of dst, clearing src
template< typename T >
void splice( std::vector< T > & dst, std::vector< T > & src ) {
        dst.reserve( dst.size() + src.size() );
        for ( T & x : src ) { dst.emplace_back( std::move( x ) ); }
        src.clear();
}

/// Splice src onto the begining of dst, clearing src
template< typename T >
void spliceBegin( std::vector< T > & dst, std::vector< T > & src ) {
        splice( src, dst );
        dst.swap( src );
}

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();
}

#define toCString( ... ) toString( __VA_ARGS__ ).c_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 Container, typename Pred>
void erase_if( Container & cont, Pred && pred ) {
        auto keep_end = std::remove_if( cont.begin(), cont.end(), pred );
        cont.erase( keep_end, cont.end() );
}

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, unsigned int start = 0 ) {
        if ( pref.size() > str.size() ) return false;
    return 0 == memcmp( str.c_str() + start, pref.c_str(), pref.size() );
        // return prefix == full.substr(0, prefix.size()); // for future, requires c++17
}

// -----------------------------------------------------------------------------
// 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(const ValueGuardPtr& other) = delete;
        ValueGuardPtr(ValueGuardPtr&& other) : old(other.old), ref(other.ref) { other.ref = nullptr; }
        ~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) {}

        // this does NOT work on const T!!!
        // typedef typename T::reverse_iterator iterator;
        auto begin() { return ref.rbegin(); }
        auto end() { return ref.rend(); }
};

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

template< typename T >
struct enumerate_t {
        template<typename val_t>
        struct value_t {
                val_t & val;
                size_t idx;
        };

        template< typename iter_t, typename val_t >
        struct iterator_t {
                iter_t it;
                size_t idx;

                iterator_t( iter_t _it, size_t _idx ) : it(_it), idx(_idx) {}

                value_t<val_t> operator*() const { return value_t<val_t>{ *it, idx }; }

                bool operator==(const iterator_t & o) const { return o.it == it; }
                bool operator!=(const iterator_t & o) const { return o.it != it; }

                iterator_t & operator++() {
                        it++;
                        idx++;
                        return *this;
                }

                using difference_type   = typename std::iterator_traits< iter_t >::difference_type;
                using value_type        = value_t<val_t>;
                using pointer           = value_t<val_t> *;
                using reference         = value_t<val_t> &;
                using iterator_category = std::forward_iterator_tag;
        };

        T & ref;

        using iterator = iterator_t< typename T::iterator, typename T::value_type >;
        using const_iterator = iterator_t< typename T::const_iterator, const typename T::value_type >;

        iterator begin() { return iterator( ref.begin(), 0 ); }
        iterator end()   { return iterator( ref.end(), ref.size() ); }

        const_iterator begin() const { return const_iterator( ref.cbegin(), 0 ); }
        const_iterator end()   const { return const_iterator( ref.cend(), ref.size() ); }

        const_iterator cbegin() const { return const_iterator( ref.cbegin(), 0 ); }
        const_iterator cend()   const { return const_iterator( ref.cend(), ref.size() ); }
};

template< typename T >
enumerate_t<T> enumerate( T & ref ) {
        return enumerate_t< T >{ ref };
}

template< typename T >
const enumerate_t< const T > enumerate( const T & ref ) {
        return enumerate_t< const 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 ( auto val : group_iterate( container1, container2, ... ) ) { ... }
// This iteraters through multiple containers of the same size.

template<typename... Args>
class group_iterate_t {
        using Iterables = std::tuple<Args...>;
        Iterables iterables;

        // Getting the iterator and value types this way preserves const.
        template<size_t I> using Iter = decltype(std::get<I>(iterables).begin());
        template<size_t I> using Data = decltype(*std::get<I>(iterables).begin());
        template<typename> struct base_iterator;

        // This inner template puts the sequence of `0, 1, ... sizeof...(Args)-1`
        // into a pack. These are the indexes into the tuples, so unpacking can
        // go over each element of the tuple.
        // The std::integer_sequence is just used to build that sequence.
        // A library reference will probably explain it better than I can.
        template<std::size_t... Indices>
        struct base_iterator<std::integer_sequence<std::size_t, Indices...>> {
                using value_type = std::tuple< Data<Indices>... >;
                std::tuple<Iter<Indices>...> iterators;

                base_iterator( Iter<Indices>... is ) : iterators( is... ) {}
                base_iterator operator++() {
                        return base_iterator( ++std::get<Indices>( iterators )... );
                }
                bool operator!=( const base_iterator& other ) const {
                        return iterators != other.iterators;
                }
                value_type operator*() const {
                        return std::tie( *std::get<Indices>( iterators )... );
                }

                static base_iterator make_begin( Iterables & data ) {
                        return base_iterator( std::get<Indices>( data ).begin()... );
                }
                static base_iterator make_end( Iterables & data ) {
                        return base_iterator( std::get<Indices>( data ).end()... );
                }
        };

public:
        group_iterate_t( const Args &... args ) : iterables( args... ) {}

        using iterator = base_iterator<decltype(
                std::make_integer_sequence<std::size_t, sizeof...(Args)>())>;

        iterator begin() { return iterator::make_begin( iterables ); }
        iterator end() { return iterator::make_end( iterables ); }
};

// Helpers for the bounds checks (the non-varatic part of group_iterate):
static inline void runGroupBoundsCheck(size_t size0, size_t size1) {
        assertf( size0 == size1,
                "group iteration requires containers of the same size: <%zd, %zd>.",
                size0, size1 );
}

static inline void runGroupBoundsCheck(size_t size0, size_t size1, size_t size2) {
        assertf( size0 == size1 && size1 == size2,
                "group iteration requires containers of the same size: <%zd, %zd, %zd>.",
                size0, size1, size2 );
}

/// Performs bounds check to ensure that all arguments are of the same length.
template< typename... Args >
group_iterate_t<Args...> group_iterate( Args &&... args ) {
        runGroupBoundsCheck( args.size()... );
        return group_iterate_t<Args...>( 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...>( 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...);
}

// -----------------------------------------------------------------------------
// O(1) polymorphic integer ilog2, using clz, which returns the number of leading 0-bits, starting at the most
// significant bit (single instruction on x86)

template<typename T>
inline
#if defined(__GNUC__) && __GNUC__ > 4
constexpr
#endif
T ilog2(const T & t) {
        if(std::is_integral<T>::value) {
                const constexpr int r = sizeof(t) * __CHAR_BIT__ - 1;
                if( sizeof(T) == sizeof(unsigned       int) ) return r - __builtin_clz  ( t );
                if( sizeof(T) == sizeof(unsigned      long) ) return r - __builtin_clzl ( t );
                if( sizeof(T) == sizeof(unsigned long long) ) return r - __builtin_clzll( t );
        }
        assert(false);
        return -1;
} // ilog2

// -----------------------------------------------------------------------------
/// evaluates expr as a long long int. If second is false, expr could not be evaluated
std::pair<long long int, bool> eval(const Expression * expr);

namespace ast {
        class Expr;
}

std::pair<long long int, bool> eval(const ast::Expr * expr);

// -----------------------------------------------------------------------------
/// Reorders the input range in-place so that the minimal-value elements according to the
/// comparator are in front;
/// returns the iterator after the last minimal-value element.
template<typename Iter, typename Compare>
Iter sort_mins( Iter begin, Iter end, Compare& lt ) {
        if ( begin == end ) return end;

        Iter min_pos = begin;
        for ( Iter i = begin + 1; i != end; ++i ) {
                if ( lt( *i, *min_pos ) ) {
                        // new minimum cost; swap into first position
                        min_pos = begin;
                        std::iter_swap( min_pos, i );
                } else if ( ! lt( *min_pos, *i ) ) {
                        // duplicate minimum cost; swap into next minimum position
                        ++min_pos;
                        std::iter_swap( min_pos, i );
                }
        }
        return ++min_pos;
}

template<typename Iter, typename Compare>
inline Iter sort_mins( Iter begin, Iter end, Compare&& lt ) {
        return sort_mins( begin, end, lt );
}

/// sort_mins defaulted to use std::less
template<typename Iter>
inline Iter sort_mins( Iter begin, Iter end ) {
        return sort_mins( begin, end, std::less<typename std::iterator_traits<Iter>::value_type>{} );
}

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //