ucommon::MappedMemory Class Reference

Construct or access a named section of memory. More...

#include <mapped.h>

Inheritance diagram for ucommon::MappedMemory:

Inheritance graph
[legend]

Public Member Functions

caddr_t addr (void)
 Get starting address of mapped segment.
bool copy (size_t offset, void *buffer, size_t size)
 Copy memory from specific offset within the mapped memory segment.
size_t len (void)
 Get size of mapped segment.
 MappedMemory (char *name)
 Provide read-only mapped access to an existing named shared memory segment.
 MappedMemory (char *name, size_t size)
 Construct a read/write access mapped shared segment of memory of a known size.
void * offset (size_t offset)
 Get memory from a specific offset within the mapped memory segment.
 operator bool ()
 Test if map active.
bool operator! ()
 Test if map is inactive.
void release (void)
 Unmap memory segment.
void * sbrk (size_t size)
 Extend size of managed heap on shared memory segment.
virtual ~MappedMemory ()
 Unmap memory segment.

Static Public Member Functions

static void disable (void)
 An API that allows "disabling" of publishing shared memory maps.
static void remove (char *name)
 Destroy a previously existing memory segment under the specified name.

Protected Member Functions

void create (char *name, size_t size=(size_t) 0)
 Supporting function to construct a new or access an existing shared memory segment.
virtual void fault (void)
 Handler for failure to map (allocate) memory.
virtual void * invalid (void)
 Handler to invoke in derived class when accessing outside the shared memory segment boundary.

Protected Attributes

bool erase
char idname [65]
size_t size
size_t used

Detailed Description

Construct or access a named section of memory.

A logical name is used which might map to something that is invoked from a call like shm_open or a named w32 mapped swap segment. This is meant to support mapping a vector onto shared memory and is often used as a supporting class for our shared memory access templates.

Author:
David Sugar <dyfet@gnutelephony.org>

Definition at line 58 of file mapped.h.


Constructor & Destructor Documentation

ucommon::MappedMemory::MappedMemory ( char *  name,
size_t  size 
)

Construct a read/write access mapped shared segment of memory of a known size.

This constructs a new memory segment.

Parameters:
name of segment.
size of segment.

ucommon::MappedMemory::MappedMemory ( char *  name  ) 

Provide read-only mapped access to an existing named shared memory segment.

The size of the map is found by the size of the already existing segment.

Parameters:
name of existing segment.


Member Function Documentation

caddr_t ucommon::MappedMemory::addr ( void   )  [inline]

Get starting address of mapped segment.

Returns:
starting address of mapped segment.

Definition at line 177 of file mapped.h.

bool ucommon::MappedMemory::copy ( size_t  offset,
void *  buffer,
size_t  size 
)

Copy memory from specific offset within the mapped memory segment.

This function assures the copy is not in the middle of being modified.

Parameters:
offset from start of segment.
buffer to copy into.
size of object to copy.
Returns:
true on success.

void ucommon::MappedMemory::create ( char *  name,
size_t  size = (size_t) 0 
) [protected]

Supporting function to construct a new or access an existing shared memory segment.

Used by primary constructors.

Parameters:
name of segment to create or access.
size of segment if creating new. Use 0 for read-only access.

static void ucommon::MappedMemory::disable ( void   )  [static]

An API that allows "disabling" of publishing shared memory maps.

This may be useful when an app doesn't want to use shared memory as a runtime or build option, but does not want to have to be "recoded" explicitly for non-shared memory either. Basically it substitutes a dummy map running on the local heap.

size_t ucommon::MappedMemory::len ( void   )  [inline]

Get size of mapped segment.

Returns:
size of mapped segment.

Definition at line 170 of file mapped.h.

void* ucommon::MappedMemory::offset ( size_t  offset  ) 

Get memory from a specific offset within the mapped memory segment.

Parameters:
offset from start of segment. Will fault if past end.
Returns:
address of offset.

ucommon::MappedMemory::operator bool (  )  [inline]

Test if map active.

Returns:
true if active map.

Reimplemented in ucommon::mapped_reuse< T >.

Definition at line 130 of file mapped.h.

bool ucommon::MappedMemory::operator! (  )  [inline]

Test if map is inactive.

Returns:
true if map inactive.

Reimplemented in ucommon::mapped_reuse< T >.

Definition at line 137 of file mapped.h.

static void ucommon::MappedMemory::remove ( char *  name  )  [static]

Destroy a previously existing memory segment under the specified name.

This is used both before creating a new one, and after a publishing process unmaps the segment it created.

Parameters:
name of segment to remove.

void* ucommon::MappedMemory::sbrk ( size_t  size  ) 

Extend size of managed heap on shared memory segment.

This does not change the size of the mapped segment in any way, only that of any heap space that is being allocated and used from the mapped segment.

Returns:
start of space from map.
Parameters:
size of space requested. Will fault if past end of segment.


The documentation for this class was generated from the following file:
Generated on 14 Aug 2013 for UCommon by  doxygen 1.4.7