Class implementing a stack of RObject*. More...

#include <NodeStack.hpp>

Classes
class	ElementProxy
	Proxy object for an element of a NodeStack. More...
class	Scope
	Object constraining lifetime of NodeStack entries. More...

Public Member Functions
	NodeStack (size_t initial_capacity)
	Constructor.
ElementProxy	operator[] (unsigned int index)
	Element access.
RObject *const	operator[] (unsigned int index) const
	Read-only element access.
void	eraseTopmost (RObject *node)
	Remove topmost cell with given contents.
ElementProxy	fromEnd (unsigned int count)
	Element access with respect to stack top.
void	pop (unsigned int count=1)
	Pop pointers from the NodeStack.
void	protectAll ()
	Ensure GC protection of all nodes.
unsigned int	push (RObject *node)
	Push a node pointer onto the NodeStack.
void	retarget (RObject *node, unsigned int index)
	Change the target of a pointer on the PPS.
void	resize (size_t new_size)
	Modify size of NodeStack.
size_t	size () const
	Current size of NodeStack.
RObject *	topnpop ()
	pop and return the top element of the stack.
void	visitRoots (GCNode::const_visitor *v)
	Conduct a const visitor via the NodeStack.

Detailed Description

Class implementing a stack of RObject*.

This class is not intended for general use. It is currently used in class ProtectStack and in the bytecode interpreter.

Note that it is necessary for GCNode::gclite() to call the protectAll() method of every NodeStack in existence before it starts to delete nodes with zero references counts.

Constructor & Destructor Documentation

NodeStack::NodeStack ( size_t initial_capacity )

Constructor.

Parameters:

initial_capacity The initial capacity of the NodeStack to be created. The capacity will be increased as necessary, so the value of this parameter is not critical.

Member Function Documentation

void NodeStack::eraseTopmost ( RObject * node )

Remove topmost cell with given contents.

Removes from the C pointer protection stack the uppermost stack cell containing a specified node address, and drops all the stack cells above it by one place.

If this function is executed within a NodeStack::Scope pertaining to this NodeStack, its execution counts as a 'pop', and must balance a push() previously executed within the innermost such scope. This is checked unless the class is compiled with NDEBUG.

Parameters:

node	Pointer value (possibly null) which must be contained in at least one cell within the NodeStack. This cell will be removed from the stack, and any cells above it dropped by one place.

Deprecated:: Used to implement the CR function UNPROTECT_PTR() (itself ghastly). Its use for any other purpose is strongly deprecated.

ElementProxy CXXR::NodeStack::fromEnd ( unsigned int count )

inline

Element access with respect to stack top.

Parameters:

count A value of 1 signifies the top value of the stack, 2 the element immediately below that, and so on. Must be strictly positive and smaller than the size of the stack (checked unless the class is compiled with NDEBUG).

Returns:: the specified element.

ElementProxy CXXR::NodeStack::operator[] ( unsigned int index )

inline

Element access.

Parameters:

index Index of required element (counting from zero). Bounds checking is applied unless the class is compiled with NDEBUG.

Returns:: Proxy for the specified element, via which the element can be examined or modified.

RObject* const CXXR::NodeStack::operator[] ( unsigned int index ) const

inline

Read-only element access.

Parameters:

index Index of required element (counting from zero). Bounds checking is applied unless the class is compiled with NDEBUG.

Returns:: the specified element.

void NodeStack::pop ( unsigned int count = 1 )

Pop pointers from the NodeStack.

If this function is executed within a NodeStack::Scope pertaining to this NodeStack, the number of elements popped must balance a corresponding number of push() operations previously executed within the innermost such scope. This is checked unless the class is compiled with NDEBUG.

Parameters:

count Number of cells to be popped. Must not be larger than the current size of the C pointer protection stack (checked unless compiled with NDEBUG).

void NodeStack::protectAll ( )

Ensure GC protection of all nodes.

This function ensures that all RObjects pointed to from the NodeStack are protected from garbage collection.

unsigned int CXXR::NodeStack::push ( RObject * node )

inline

Push a node pointer onto the NodeStack.

Parameters:

node	Pointer, possibly null, to the node to be pushed onto the NodeStack.

Returns:: Index of the stack cell thus created, counting from zero.

void CXXR::NodeStack::resize ( size_t new_size )

inline

Modify size of NodeStack.

Parameters:

new_size The required size. If larger than the current size, the added cells will contain null pointers. If smaller than the current size, then pointers are popped off the NodeStack to bring its size down to new_size.

void NodeStack::retarget	(	RObject *	node,
		unsigned int	index
	)

Change the target of a pointer on the PPS.

Change the node that a particular cell in the C pointer protection stack protects. As a consistency check, it is required that the retarget takes place within the same NodeStack::Scope as the corresponding protect.

Parameters:

node	Pointer to the node now to be protected from the garbage collector by the designated stack cell. (Not necessarily a different node from the one currently protected.)
index	Index (as returned by protect() ) of the stack cell to be retargeted to node. Must be less than the current size of the C pointer protection stack (checked).

size_t CXXR::NodeStack::size ( ) const

inline

Current size of NodeStack.

Returns:: the number of pointers currently on the NodeStack.

RObject* CXXR::NodeStack::topnpop ( )

inline

pop and return the top element of the stack.

The stack must not be empty; this is checked unless the class is compiled with NDEBUG.

Returns:: the pointer previously at the top of the stack.

void NodeStack::visitRoots ( GCNode::const_visitor * v )

Conduct a const visitor via the NodeStack.

Conduct a GCNode::const_visitor object to each RObject pointed to by the NodeStack.

Parameters:

v	Pointer to the const_visitor object.

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

Classes

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation