org.bytedeco.arrow

Class MemoryMappedFile

java.lang.Object

org.bytedeco.javacpp.Pointer

org.bytedeco.arrow.RandomAccessFile

org.bytedeco.arrow.ReadWriteFileInterface

org.bytedeco.arrow.MemoryMappedFile

All Implemented Interfaces:

AutoCloseable

@Namespace(value="arrow::io")
 @NoOffset
 @Properties(inherit=arrow.class)
public class MemoryMappedFile
extends ReadWriteFileInterface

\brief A file interface that uses memory-mapped files for memory interactions This implementation supports zero-copy reads. The same class is used for both reading and writing. If opening a file in a writable mode, it is not truncated first as with FileOutputStream.

Nested Class Summary

Nested classes/interfaces inherited from class org.bytedeco.javacpp.Pointer

Pointer.CustomDeallocator, Pointer.Deallocator, Pointer.NativeDeallocator, Pointer.ReferenceCounter

Field Summary

Fields inherited from class org.bytedeco.javacpp.Pointer

address, capacity, limit, position

Constructor Summary

Constructors

Constructor and Description
MemoryMappedFile(Pointer p) Pointer cast constructor.

Method Summary

Modifier and Type	Method and Description
Status	Close()
boolean	closed()
static MemoryMappedFileResult	Create(BytePointer path, long size)
static MemoryMappedFileResult	Create(String path, long size) Create new file with indicated size, return in read/write mode
int	file_descriptor()
LongResult	GetSize() \brief Return the total file size in bytes.
static MemoryMappedFileResult	Open(BytePointer path, int mode)
static MemoryMappedFileResult	Open(BytePointer path, int mode, long offset, long length)
static MemoryMappedFileResult	Open(String path, FileMode.type mode)
static MemoryMappedFileResult	Open(String path, FileMode.type mode, long offset, long length)
BufferResult	Read(long nbytes)
LongResult	Read(long nbytes, Pointer out)
BufferResult	ReadAt(long _position, long nbytes) \brief Read data from given file position.
LongResult	ReadAt(long _position, long nbytes, Pointer out) \brief Read data from given file position.
Status	Resize(long new_size) \endcond
Status	Seek(long _position)
boolean	supports_zero_copy()
LongResult	Tell()
Status	WillNeed(ReadRange ranges) EXPERIMENTAL: Inform that the given ranges may be read soon.
Status	Write(Pointer data, long nbytes) Write data at the current position in the file.
Status	WriteAt(long _position, Pointer data, long nbytes) Write data at a particular position in the file.

Methods inherited from class org.bytedeco.arrow.ReadWriteFileInterface

asWritableFile, asWritableFile

Methods inherited from class org.bytedeco.arrow.RandomAccessFile

asInputStream, asInputStream, asSeekable, asSeekable, GetStream

Methods inherited from class org.bytedeco.javacpp.Pointer

address, asBuffer, asByteBuffer, availablePhysicalBytes, calloc, capacity, capacity, close, deallocate, deallocate, deallocateReferences, deallocator, deallocator, equals, fill, formatBytes, free, getPointer, getPointer, getPointer, getPointer, hashCode, isNull, isNull, limit, limit, malloc, maxBytes, maxPhysicalBytes, memchr, memcmp, memcpy, memmove, memset, offsetAddress, offsetof, offsetof, parseBytes, physicalBytes, position, position, put, realloc, referenceCount, releaseReference, retainReference, setNull, sizeof, sizeof, toString, totalBytes, totalCount, totalPhysicalBytes, withDeallocator, zero

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MemoryMappedFile

public MemoryMappedFile(Pointer p)

Pointer cast constructor. Invokes Pointer(Pointer).

Method Detail

Create

@ByVal
public static MemoryMappedFileResult Create(@StdString
                                                   String path,
                                                   @Cast(value="int64_t")
                                                   long size)

Create new file with indicated size, return in read/write mode

Create

@ByVal
public static MemoryMappedFileResult Create(@StdString
                                                   BytePointer path,
                                                   @Cast(value="int64_t")
                                                   long size)

Open

@ByVal
public static MemoryMappedFileResult Open(@StdString
                                                 String path,
                                                 FileMode.type mode)

Open

@ByVal
public static MemoryMappedFileResult Open(@StdString
                                                 BytePointer path,
                                                 @Cast(value="arrow::io::FileMode::type")
                                                 int mode)

Open

@ByVal
public static MemoryMappedFileResult Open(@StdString
                                                 String path,
                                                 FileMode.type mode,
                                                 @Cast(value="const int64_t")
                                                 long offset,
                                                 @Cast(value="const int64_t")
                                                 long length)

Open

@ByVal
public static MemoryMappedFileResult Open(@StdString
                                                 BytePointer path,
                                                 @Cast(value="arrow::io::FileMode::type")
                                                 int mode,
                                                 @Cast(value="const int64_t")
                                                 long offset,
                                                 @Cast(value="const int64_t")
                                                 long length)

Close

@ByVal
public Status Close()

closed

@Cast(value="bool")
public boolean closed()

Tell

@ByVal
public LongResult Tell()

Seek

@ByVal
public Status Seek(@Cast(value="int64_t")
                          long _position)

Read

@ByVal
public LongResult Read(@Cast(value="int64_t")
                              long nbytes,
                              Pointer out)

Read

@ByVal
public BufferResult Read(@Cast(value="int64_t")
                                long nbytes)

ReadAt

@ByVal
public BufferResult ReadAt(@Cast(value="int64_t")
                                  long _position,
                                  @Cast(value="int64_t")
                                  long nbytes)

Description copied from class: RandomAccessFile

\brief Read data from given file position. At most nbytes bytes are read, but it can be less if EOF is reached.

Overrides:

ReadAt in class RandomAccessFile

nbytes - [in] The number of bytes to read

Returns:

A buffer containing the bytes read, or an error

ReadAt

@ByVal
public LongResult ReadAt(@Cast(value="int64_t")
                                long _position,
                                @Cast(value="int64_t")
                                long nbytes,
                                Pointer out)

Description copied from class: RandomAccessFile

\brief Read data from given file position. At most nbytes bytes are read. The number of bytes read is returned (it can be less than nbytes if EOF is reached). This method can be safely called from multiple threads concurrently. It is unspecified whether this method updates the file position or not. The default RandomAccessFile-provided implementation uses Seek() and Read(), but subclasses may override it with a more efficient implementation that doesn't depend on implicit file positioning.

Overrides:

ReadAt in class RandomAccessFile

nbytes - [in] The number of bytes to read

out - [out] The buffer to read bytes into

Returns:

The number of bytes read, or an error

WillNeed

@ByVal
public Status WillNeed(@StdVector
                              ReadRange ranges)

Description copied from class: RandomAccessFile

EXPERIMENTAL: Inform that the given ranges may be read soon. Some implementations might arrange to prefetch some of the data. However, no guarantee is made and the default implementation does nothing. For robust prefetching, use ReadAt() or ReadAsync().

Overrides:

WillNeed in class RandomAccessFile

supports_zero_copy

@Cast(value="bool")
public boolean supports_zero_copy()

Write

@ByVal
public Status Write(@Const
                           Pointer data,
                           @Cast(value="int64_t")
                           long nbytes)

Write data at the current position in the file. Thread-safe

Resize

@ByVal
public Status Resize(@Cast(value="int64_t")
                            long new_size)

\endcond

Set the size of the map to new_size.

WriteAt

@ByVal
public Status WriteAt(@Cast(value="int64_t")
                             long _position,
                             @Const
                             Pointer data,
                             @Cast(value="int64_t")
                             long nbytes)

Write data at a particular position in the file. Thread-safe

GetSize

@ByVal
public LongResult GetSize()

Description copied from class: RandomAccessFile

\brief Return the total file size in bytes. This method does not read or move the current file position, so is safe to call concurrently with e.g. ReadAt().

Overrides:

GetSize in class RandomAccessFile

file_descriptor

public int file_descriptor()