utility class factored out and covered by test

...a stack which can be Lumiera-iterated
This commit is contained in:
Fischlurch 2012-06-04 01:08:58 +02:00
parent da4a343e9e
commit d14b37a71d
4 changed files with 239 additions and 5 deletions

View file

@ -303,21 +303,21 @@ namespace lib {
reference
operator*() const
{
_maybe_throw();
__throw_if_empty();
return yield (core_); // extension point: yield
}
pointer
operator->() const
{
_maybe_throw();
__throw_if_empty();
return & yield(core_); // extension point: yield
}
IterStateWrapper&
operator++()
{
_maybe_throw();
__throw_if_empty();
iterNext (core_); // extension point: iterNext
return *this;
}
@ -334,10 +334,18 @@ namespace lib {
return !isValid();
}
private:
protected:
/** allow derived classes to
* access state representation */
ST &
stateCore()
{
return core_;
}
void
_maybe_throw() const
__throw_if_empty() const
{
if (!isValid())
_throwIterExhausted();

111
src/lib/iter-stack.hpp Normal file
View file

@ -0,0 +1,111 @@
/*
ITER-STACK.hpp - a stack which can be popped by iterating
Copyright (C) Lumiera.org
2012, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef LIB_ITER_STACK_H
#define LIB_ITER_STACK_H
#include "lib/error.hpp"
#include "lib/iter-adapter.hpp"
#include "lib/util.hpp"
#include <stack>
namespace lib {
namespace {
using util::unConst;
/**
* Wrapper to mark a std::stack instance for use
* as "state core" within lib::IterStateWrapper
*/
template<class TY>
struct IterStackStorage
: std::stack<TY>
{
/* === Iteration control API for IterStateWrapper == */
friend bool
checkPoint (IterStackStorage const& elements)
{
return !elements.empty();
}
friend TY &
yield (IterStackStorage const& elements)
{
return unConst(elements).top();
}
friend void
iterNext (IterStackStorage & elements)
{
REQUIRE (!elements.empty());
elements.pop();
}
};
}//(End) Wrapper/Helper
/**
* A Stack which can be popped by iterating.
* This is a simple helper built on top of std::stack.
* Thus, each instance holds the full state, which is
* actually kept in heap allocated storage. Pushing of
* new elements and iterator use may be mixed.
*
* Contrary to just using std::stack
* - the iteration is compliant to the Lumiera Forward Iterator concept
* - there is a simplified #pop() function which removes and returns at once
*/
template<class TY>
struct IterStack
: IterStateWrapper<TY, IterStackStorage<TY> >
{
// using default create and copy operations
void
push (TY const& elm)
{
this->stateCore().push (elm);
}
TY
pop()
{
this->__throw_if_empty();
TY frontElement (this->stateCore().top());
this->stateCore().pop();
return frontElement;
}
};
} // namespace lib
#endif

View file

@ -508,6 +508,10 @@ out: values_4_key(::[0-9]{1,2})+
END
TEST "Stack-like iterator" IterStack_test
END
TEST "Iterable type detection" IterableClassification_test <<END
out: can_STL_ForEach<LongVector> : Yes
out: can_STL_ForEach<TimeSet> : Yes

View file

@ -0,0 +1,111 @@
/*
IterStack(Test) - verify stack-like iterator
Copyright (C) Lumiera.org
2012, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* *****************************************************/
#include "lib/test/run.hpp"
#include "lib/test/test-helper.hpp"
#include "lib/util.hpp"
#include "lib/iter-stack.hpp"
namespace lib {
namespace test{
using ::Test;
using util::isnil;
using lumiera::error::LUMIERA_ERROR_ITER_EXHAUST;
typedef IterStack<int> IStack;
/*********************************************************************
* @test cover behaviour of a convenience class built by using a
* std::stack as "state core" of an Lumiera IterStateWrapper.
* - iterable according to the Lumiera Forward Iterator concept
* - can push and pop values repeatedly
* - iterating and push / pop can be mixed
* - empty state detected consistently
*
* @see IterExplorer
* @see IterAdapter
*/
class IterStack_test : public Test
{
virtual void
run (Arg)
{
IStack stack;
CHECK (isnil (stack));
VERIFY_ERROR (ITER_EXHAUST, *stack );
VERIFY_ERROR (ITER_EXHAUST, ++stack );
stack.push (1);
stack.push (3);
stack.push (5);
stack.push (7);
stack.push (9);
CHECK (!isnil (stack));
CHECK (9 == *stack);
++stack;
CHECK (7 == *stack);
CHECK (7 == stack.pop());
CHECK (5 == *stack);
++++stack;
CHECK (1 == *stack);
CHECK (1 == stack.pop());
CHECK (isnil (stack));
VERIFY_ERROR (ITER_EXHAUST, *stack );
VERIFY_ERROR (ITER_EXHAUST, ++stack );
VERIFY_ERROR (ITER_EXHAUST, stack.pop() );
stack.push(23);
CHECK (23 == *stack);
int i = stack.pop();
CHECK (i == 23);
VERIFY_ERROR (ITER_EXHAUST, *stack );
CHECK (isnil (stack));
}
};
LAUNCHER (IterStack_test, "unit common");
}} // namespace lib::test