Create and map a disk file into memory.
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#include <file.h>
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char * | fetch (off_t pos, size_t len) |
| Fetch and map a portion of a disk file to a logical memory block.
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char * | fetch (size_t offset=0) |
| Fetch a pointer to an offset within the memory mapped portion of the disk file.
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bool | lock (void) |
| Lock the currently mapped portion of a file.
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| MappedFile (const char *fname, Access mode) |
| Open a file for mapping.
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| MappedFile (const char *fname, Access mode, size_t size) |
| Create if not exists, and map a file of specified size into memory.
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| MappedFile (const char *fname, pos_t offset, size_t size, Access mode) |
| Map a portion or all of a specified file in the specified shared memory access mode.
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size_t | pageAligned (size_t size) |
| Compute map size to aligned page boundry.
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void | release (char *address, size_t len) |
| Release (unmap) a memory segment.
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void | sync (char *address, size_t len) |
| Synchronize a segment of memory mapped from a segment fetch.
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void | sync (void) |
| Synchronize the contents of the mapped portion of memory with the disk file and wait for completion.
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void | unlock (void) |
| Unlock a locked mapped portion of a file.
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void | update (char *address, size_t len) |
| Update a mapped region back to disk as specified by address and length.
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void | update (size_t offset=0, size_t len=0) |
| Map a portion of the memory mapped from the file back to the file and do not wait for completion.
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virtual | ~MappedFile () |
| Release a mapped section of memory associated with a file.
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off_t | getCapacity (void) |
| Get current file capacity.
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Error | getErrorNumber (void) const |
| Return current error id.
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char * | getErrorString (void) const |
| Return current error string.
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bool | initial (void) |
| This method should be called right after a RandomFile derived object has been created.
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| operator bool () const |
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bool | operator! (void) const |
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virtual Error | restart (void) |
| This method is commonly used to close and re-open an existing database.
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virtual | ~RandomFile () |
| Destroy a random access file or it's derived class.
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Error | error (char *err) |
| Post an extended string error message.
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Error | error (Error errid, char *errstr=NULL) |
| Post an error event.
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void | final (void) |
| Close the file.
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virtual Attr | initialize (void) |
| This method is used to initialize a newly created file as indicated by the "initial" flag.
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| RandomFile (const char *name=NULL) |
| Create an unopened random access file.
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| RandomFile (const RandomFile &rf) |
| Default copy constructor.
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Error | setCompletion (Complete mode) |
| Used to set file completion modes.
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void | setError (bool enable) |
| Used to enable or disable throwing of exceptions on errors.
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void | setTemporary (bool enable) |
| Used to set the temporary attribute for the file.
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Access | access |
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int | fd |
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struct { | |
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unsigned count: 16 | |
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bool immediate: 1 | |
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bool initial: 1 | |
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bool temp: 1 | |
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bool thrown: 1 | |
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} | flags | |
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char * | pathname |
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bool | canAccess (const char *path) |
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bool | canModify (const char *path) |
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bool | isDevice (const char *path) |
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bool | isDir (const char *path) |
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bool | isFile (const char *path) |
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time_t | lastAccessed (const char *path) |
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time_t | lastModified (const char *path) |
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Create and map a disk file into memory.
This portable class works under both Posix via mmap and under the win32 API. A mapped file can be referenced directly by it's memory segment. One can map and unmap portions of a file on demand, and update changed memory pages mapped from files immediately through sync().
- Author
- David Sugar dyfet.nosp@m.@ost.nosp@m.el.co.nosp@m.m
Map a named disk file into memory.
Definition at line 663 of file file.h.
◆ MappedFile() [1/3]
ost::MappedFile::MappedFile |
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const char * | fname, |
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Access | mode ) |
Open a file for mapping.
More than one segment of a file may be mapped into seperate regions of memory.
- Parameters
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fname | file name to access for mapping. |
mode | access mode to map file. |
◆ MappedFile() [2/3]
ost::MappedFile::MappedFile |
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const char * | fname, |
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Access | mode, |
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size_t | size ) |
Create if not exists, and map a file of specified size into memory.
- Parameters
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fname | file name to access for mapping. |
mode | access mode to map file. |
size | of file to map. |
◆ MappedFile() [3/3]
ost::MappedFile::MappedFile |
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const char * | fname, |
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pos_t | offset, |
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size_t | size, |
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Access | mode ) |
Map a portion or all of a specified file in the specified shared memory access mode.
Valid mapping modes include mappedRead, mappedWrite, and mappedReadWrite.
- Parameters
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fname | pathname of file to map into memory. |
offset | from start of file to begin mapping in bytes. |
size | of mapped area in bytes. |
mode | to map file. |
◆ ~MappedFile()
virtual ost::MappedFile::~MappedFile |
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virtual |
Release a mapped section of memory associated with a file.
The mapped area is updated back to disk.
◆ fetch() [1/2]
char * ost::MappedFile::fetch |
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off_t | pos, |
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size_t | len ) |
Fetch and map a portion of a disk file to a logical memory block.
- Returns
- pointer to memory segment.
- Parameters
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pos | offset of file segment to map. |
len | size of memory segment to map. |
◆ fetch() [2/2]
char * ost::MappedFile::fetch |
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size_t | offset = 0 | ) |
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inline |
Fetch a pointer to an offset within the memory mapped portion of the disk file.
This really is used for convience of matching operations between Update and Fetch, as one could simply have accessed the base pointer where the file was mapped directly.
- Parameters
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offset | from start of mapped memory. |
Definition at line 764 of file file.h.
◆ lock()
bool ost::MappedFile::lock |
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void | | ) |
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Lock the currently mapped portion of a file.
- Returns
- true if pages are locked.
◆ pageAligned()
size_t ost::MappedFile::pageAligned |
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size_t | size | ) |
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Compute map size to aligned page boundry.
- Parameters
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- Returns
- page aligned size.
◆ release()
void ost::MappedFile::release |
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char * | address, |
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size_t | len ) |
Release (unmap) a memory segment.
- Parameters
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address | address of memory segment to release. |
len | length of memory segment to release. |
◆ sync() [1/2]
void ost::MappedFile::sync |
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char * | address, |
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size_t | len ) |
Synchronize a segment of memory mapped from a segment fetch.
- Parameters
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address | memory address to update. |
len | size of segment. |
◆ sync() [2/2]
void ost::MappedFile::sync |
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void | | ) |
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Synchronize the contents of the mapped portion of memory with the disk file and wait for completion.
This assures the memory mapped from the file is written back.
◆ update() [1/2]
void ost::MappedFile::update |
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char * | address, |
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size_t | len ) |
Update a mapped region back to disk as specified by address and length.
- Parameters
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address | address of segment. |
len | length of segment. |
◆ update() [2/2]
void ost::MappedFile::update |
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size_t | offset = 0, |
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size_t | len = 0 ) |
Map a portion of the memory mapped from the file back to the file and do not wait for completion.
This is useful when mapping a database file and updating a single record.
- Parameters
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offset | offset into the mapped region of memory. |
len | length of partial region (example, record length). |
The documentation for this class was generated from the following file:
- /builddir/build/BUILD/ucommon-7.0.0-build/ucommon-7.0.0/inc/commoncpp/file.h