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// Copyright (C) 2008-2018 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0 (see accompanying
// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
//[meyer97_stack4
// File: stack4.hpp
#ifndef STACK4_HPP_
#define STACK4_HPP_
#include <boost/contract.hpp>
// Dispenser with LIFO access policy and fixed max capacity.
template<typename T>
class stack4
#define BASES private boost::contract::constructor_precondition<stack4<T> >
: BASES
{
friend boost::contract::access;
typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types;
#undef BASES
void invariant() const {
BOOST_CONTRACT_ASSERT(count() >= 0); // Count non-negative.
BOOST_CONTRACT_ASSERT(count() <= capacity()); // Count bounded.
BOOST_CONTRACT_ASSERT(empty() == (count() == 0)); // Empty if no elem.
}
public:
/* Initialization */
// Allocate static from a maximum of n elements.
explicit stack4(int n) :
boost::contract::constructor_precondition<stack4>([&] {
BOOST_CONTRACT_ASSERT(n >= 0); // Non-negative capacity.
})
{
boost::contract::check c = boost::contract::constructor(this)
.postcondition([&] {
BOOST_CONTRACT_ASSERT(capacity() == n); // Capacity set.
})
;
capacity_ = n;
count_ = 0;
array_ = new T[n];
}
// Deep copy via constructor.
/* implicit */ stack4(stack4 const& other) {
boost::contract::check c = boost::contract::constructor(this)
.postcondition([&] {
BOOST_CONTRACT_ASSERT(capacity() == other.capacity());
BOOST_CONTRACT_ASSERT(count() == other.count());
BOOST_CONTRACT_ASSERT_AXIOM(*this == other);
})
;
capacity_ = other.capacity_;
count_ = other.count_;
array_ = new T[other.capacity_];
for(int i = 0; i < other.count_; ++i) array_[i] = other.array_[i];
}
// Deep copy via assignment.
stack4& operator=(stack4 const& other) {
boost::contract::check c = boost::contract::public_function(this)
.postcondition([&] {
BOOST_CONTRACT_ASSERT(capacity() == other.capacity());
BOOST_CONTRACT_ASSERT(count() == other.count());
BOOST_CONTRACT_ASSERT_AXIOM(*this == other);
})
;
delete[] array_;
capacity_ = other.capacity_;
count_ = other.count_;
array_ = new T[other.capacity_];
for(int i = 0; i < other.count_; ++i) array_[i] = other.array_[i];
return *this;
}
// Destroy this stack.
virtual ~stack4() {
// Check invariants.
boost::contract::check c = boost::contract::destructor(this);
delete[] array_;
}
/* Access */
// Max number of stack elements.
int capacity() const {
// Check invariants.
boost::contract::check c = boost::contract::public_function(this);
return capacity_;
}
// Number of stack elements.
int count() const {
// Check invariants.
boost::contract::check c = boost::contract::public_function(this);
return count_;
}
// Top element.
T const& item() const {
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
BOOST_CONTRACT_ASSERT(!empty()); // Not empty (i.e., count > 0).
})
;
return array_[count_ - 1];
}
/* Status Report */
// Is stack empty?
bool empty() const {
bool result;
boost::contract::check c = boost::contract::public_function(this)
.postcondition([&] {
// Empty definition.
BOOST_CONTRACT_ASSERT(result == (count() == 0));
})
;
return result = (count_ == 0);
}
// Is stack full?
bool full() const {
bool result;
boost::contract::check c = boost::contract::public_function(this)
.postcondition([&] {
BOOST_CONTRACT_ASSERT( // Full definition.
result == (count() == capacity()));
})
;
return result = (count_ == capacity_);
}
/* Element Change */
// Add x on top.
void put(T const& x) {
boost::contract::old_ptr<int> old_count = BOOST_CONTRACT_OLDOF(count());
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
BOOST_CONTRACT_ASSERT(!full()); // Not full.
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(!empty()); // Not empty.
BOOST_CONTRACT_ASSERT(item() == x); // Added to top.
BOOST_CONTRACT_ASSERT(count() == *old_count + 1); // One more.
})
;
array_[count_++] = x;
}
// Remove top element.
void remove() {
boost::contract::old_ptr<int> old_count = BOOST_CONTRACT_OLDOF(count());
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
BOOST_CONTRACT_ASSERT(!empty()); // Not empty (i.e., count > 0).
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(!full()); // Not full.
BOOST_CONTRACT_ASSERT(count() == *old_count - 1); // One less.
})
;
--count_;
}
/* Friend Helpers */
friend bool operator==(stack4 const& left, stack4 const& right) {
boost::contract::check inv1 = boost::contract::public_function(&left);
boost::contract::check inv2 = boost::contract::public_function(&right);
if(left.count_ != right.count_) return false;
for(int i = 0; i < left.count_; ++i) {
if(left.array_[i] != right.array_[i]) return false;
}
return true;
}
private:
int capacity_;
int count_;
T* array_; // Internally use C-style array.
};
#endif // #include guard
//]
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