ProtectStack.h File Reference

($Id: ProtectStack.h 1397 2013-08-16 18:25:59Z arr $)

Class CXXR::ProtectStack and associated C interface. More...

#include "CXXR/RObject.h"
#include "CXXR/NodeStack.hpp"

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Classes
class	CXXR::ProtectStack
	Class implementing CR's 'pointer protection stack'. More...
class	CXXR::ProtectStack::Scope
	Object constraining lifetime of ProtectStack entries. More...

Namespaces
namespace	CXXR
	Namespace for the CXXR project.

Typedefs
typedef unsigned int	PROTECT_INDEX

Functions
void	R_ProtectWithIndex (SEXP node, PROTECT_INDEX *iptr)
	Push a node pointer onto the C pointer protection stack.
void	R_Reprotect (SEXP node, PROTECT_INDEX index)
	Retarget a cell in the C pointer protection stack.
void	Rf_ppsRestoreSize (size_t new_size)
	Restore C pointer protection stack to a previous size.
size_t	Rf_ppsSize ()
	Current size of C pointer protection stack.
SEXP	Rf_protect (SEXP node)
	Push a node pointer onto the C pointer protection stack.
void	Rf_unprotect (int count)
	Pop cells from the C pointer protection stack.
void	Rf_unprotect_ptr (SEXP node)
	Remove entry from pointer protection stack.

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Detailed Description

Class CXXR::ProtectStack and associated C interface.

CXXR::ProtectStack encapsulates the functionality of the CR pointer protection stack.

See the paragraph 'Caller Protects' in the description of class CXXR::GCStackRoot for recommended coding policy.

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Function Documentation

void R_ProtectWithIndex ( SEXP  node, PROTECT_INDEX *  iptr  )

inline

Push a node pointer onto the C pointer protection stack.

Push a node pointer onto the C pointer protection stack, and record the index of the resulting stack cell (for subsequent use with R_Reprotect).

Parameters:

node	Pointer to the node to be protected from the garbage collector.
iptr	Pointer to a location in which the stack cell index is to be stored.

void R_Reprotect ( SEXP  node, PROTECT_INDEX  index  )

inline

Retarget a cell in the C pointer protection stack.

Change the node that a particular cell in the C pointer protection stack protects. As a consistency check, it is required that the reprotect takes place within the same ProtectStack::Scope as the original 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 R_ProtectWithIndex() ) of the stack cell to be retargeted to node. Must be less than the current size of the C pointer protection stack.

void Rf_ppsRestoreSize

(

size_t

new_size

)

Restore C pointer protection stack to a previous size.

Restore the C pointer protection stack to a previous size by popping elements off the top.

Parameters:

new_size

The size to which the stack is to be restored. Must not be greater than the current size.

Deprecated:

This is an interface for C code to call CXXR::ProtectStack::restoreSize(), which may cease to be available in future. In C++, use of the ProtectStack::Scope class is preferable.

size_t Rf_ppsSize

(

)

Current size of C pointer protection stack.

Returns:

the current size of the C pointer protection stack.

Deprecated:

This is an interface for C code to call CXXR::ProtectStack::size(), which may cease to be public in future.

SEXP Rf_protect ( SEXP  node )

inline

Push a node pointer onto the C pointer protection stack.

Parameters:

node	Pointer to the node to be protected from the garbage collector.

Returns:

a copy of node .

void Rf_unprotect ( int  count )

inline

Pop cells from the C pointer protection stack.

As a consistency check, it is required that the unprotect takes place within the same ProtectStack::Scope as the corresponding protects.

Parameters:

count

Number of cells to be popped. Must not be larger than the current size of the C pointer protection stack.

void Rf_unprotect_ptr ( SEXP  node )

inline

Remove entry from pointer protection stack.

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

Parameters:

node	Pointer to the node whose cell is to be removed from the C pointer protection stack.

Deprecated:

Utterly.