celeritas::IdStack< T, Extent, S > Class Template Reference

Stack "view" that keeps the top element in a local scalar. More...

#include <IdStack.hh>

Public Types
using	value_type = T
using	size_type = S

Public Member Functions
	IdStack (Span< T, Extent > storage)
	Construct with underlying spill storage.
void	push (T element)
	Push an element onto the top of the stack.
void	pop ()
	Remove the top element.
T	top () const
	Get the top element.
bool	empty () const
	Whether there are any elements in the container.
size_type	size () const
	Get the number of elements.
constexpr size_type	capacity () const
	Get the number of elements that can fit in the allocated storage.

Static Public Attributes
static constexpr std::size_t	spill_extent = Extent
	Capacity (may be dynamic)

Detailed Description

template<class T, std::size_t Extent = dynamic_extent, class S = ::celeritas::size_type>
class celeritas::IdStack< T, Extent, S >

Stack "view" that keeps the top element in a local scalar.

Template Parameters

T	value type
E	extent for spill (dynamic or fixed)

This particular stack requires OpaqueId as its element type, because the default value must evaluate to "false" and is never a valid stack value. Without this restriction it would need an extra boolean in addition to the top item.

The most recently pushed value is always stored in top_. Older values are spilled into the underlying storage. This increases the effective stack capacity by one: for storage size N, the stack capacity is N + 1. The internal size_ tracks only the number of spilled elements in underlying storage. The logical size reported by size() is therefore size_ + !this->empty().

Example:

Array<int, 3> storage;
IdStack stack(Span{storage});
 
EXPECT_TRUE(stack.empty());
EXPECT_EQ(0, stack.size());
EXPECT_EQ(4, stack.capacity());
 
// Push  and pop
stack.push(42);
EXPECT_FALSE(stack.empty());
EXPECT_EQ(1, stack.size());
EXPECT_EQ(42, stack.top());
stack.pop();

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The documentation for this class was generated from the following file:

• IdStack.hh