org.terrier.compression.bit

Interface BitInSeekable

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

BitFile, BitFileBuffered, BitFileInMemory, BitFileInMemoryLarge

public interface BitInSeekable
extends Closeable

Interface for reading a bit compressed file in a random access manner. Each method returns a BitIn implementation that allows access to the encoded integers. Several implementations exist:

• BitFileBuffered - buffers an amount of data starting that the specified offset.
• BitFile - buffers the pre-specified amount starting and ending as specified. This implementation can also be used for reading. This class is deprecated.
• BitFileInMemory - reads the entire file into memory. File must be less than Integer.MAX_VALUE (2GB).
• BitFileInMemoryLarge - reads the entire file into memory. File size only constrained by available memory.

Since:

2.0

Author:

Craig Macdonald

See Also:

BitFileBuffered, BitOut, BitIn

Method Summary

Methods

Modifier and Type	Method and Description
BitIn	readReset(long startByteOffset, byte startBitOffset) Reads from the file a specific number of bytes and after this call, a sequence of read calls may follow.
BitIn	readReset(long startByteOffset, byte startBitOffset, long endByteOffset, byte endBitOffset) Reads from the file a specific number of bytes and after this call, a sequence of read calls may follow.

Methods inherited from interface java.io.Closeable

close

Method Detail

readReset

BitIn readReset(long startByteOffset,
              byte startBitOffset,
              long endByteOffset,
              byte endBitOffset)
                throws IOException

Reads from the file a specific number of bytes and after this call, a sequence of read calls may follow. The offsets given as arguments are inclusive. For example, if we call this method with arguments 0, 2, 1, 7, it will read in a buffer the contents of the underlying file from the third bit of the first byte to the last bit of the second byte.

Parameters:

startByteOffset - the starting byte to read from

startBitOffset - the bit offset in the starting byte

endByteOffset - the ending byte

endBitOffset - the bit offset in the ending byte. This bit is the last bit of this entry.

Returns:

Returns the BitIn object to use to read that data

Throws:

IOException

readReset

BitIn readReset(long startByteOffset,
              byte startBitOffset)
                throws IOException

Reads from the file a specific number of bytes and after this call, a sequence of read calls may follow. The offsets given as arguments are inclusive. For example, if we call this method with arguments 0, 2, 1, 7, it will read in a buffer the contents of the underlying file from the third bit of the first byte to the last bit of the second byte.

Parameters:

startByteOffset - the starting byte to read from

startBitOffset - the bit offset in the starting byte

Returns:

Returns the BitIn object to use to read that data

Throws:

IOException