org.datavec.image.mnist

Class MnistDbFile

java.lang.Object

java.io.RandomAccessFile

org.datavec.image.mnist.MnistDbFile

All Implemented Interfaces:

java.io.Closeable, java.io.DataInput, java.io.DataOutput, java.lang.AutoCloseable

Direct Known Subclasses:

MnistImageFile, MnistLabelFile

public abstract class MnistDbFile
extends java.io.RandomAccessFile

MNIST database file containing entries that can represent image or label data. Extends the standard random access file with methods for navigating over the entries. The file format is basically idx with specific header information. This includes a magic number for determining the type of stored entries, count of entries.

Constructor Summary

Constructors

Constructor and Description
MnistDbFile(java.lang.String name, java.lang.String mode) Creates new instance and reads the header information.

Method Summary

Modifier and Type	Method and Description
int	getCount()
long	getCurrentIndex() The current entry index.
int	getEntryLength() Number of bytes for each entry.
int	getHeaderSize()
protected abstract int	getMagicNumber() MNIST DB files start with unique integer number.
void	next() Move to the next entry.
void	prev() Move to the previous entry.
void	setCurrentIndex(long curr) Set the required current entry index.

Methods inherited from class java.io.RandomAccessFile

close, getChannel, getFD, getFilePointer, length, read, read, read, readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, seek, setLength, skipBytes, write, write, write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MnistDbFile

public MnistDbFile(java.lang.String name,
                   java.lang.String mode)
            throws java.io.IOException

Creates new instance and reads the header information.

Parameters:

name - the system-dependent filename

mode - the access mode

Throws:

java.io.IOException

java.io.FileNotFoundException

See Also:

RandomAccessFile

Method Detail

getMagicNumber

protected abstract int getMagicNumber()

MNIST DB files start with unique integer number.

Returns:

integer number that should be found in the beginning of the file.

getCurrentIndex

public long getCurrentIndex()
                     throws java.io.IOException

The current entry index.

Returns:

long

Throws:

java.io.IOException

setCurrentIndex

public void setCurrentIndex(long curr)

Set the required current entry index.

Parameters:

curr - the entry index

getHeaderSize

public int getHeaderSize()

getEntryLength

public int getEntryLength()

Number of bytes for each entry. Defaults to 1.

Returns:

int

next

public void next()
          throws java.io.IOException

Move to the next entry.

Throws:

java.io.IOException

prev

public void prev()
          throws java.io.IOException

Move to the previous entry.

Throws:

java.io.IOException

getCount

public int getCount()