org.iq80.snappy

Class SnappyFramedOutputStream

java.lang.Object

java.io.OutputStream

org.iq80.snappy.SnappyFramedOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public final class SnappyFramedOutputStream
extends OutputStream

Implements the x-snappy-framed as an OutputStream.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_BLOCK_SIZE
static double	DEFAULT_MIN_COMPRESSION_RATIO
static int	MAX_BLOCK_SIZE We place an additional restriction that the uncompressed data in a chunk must be no longer than 65536 bytes.

Constructor Summary

Constructors

Constructor and Description
SnappyFramedOutputStream(OutputStream out)
SnappyFramedOutputStream(OutputStream out, int blockSize, double minCompressionRatio)

Method Summary

Modifier and Type	Method and Description
protected int	calculateCRC32C(byte[] data, int offset, int length) Calculates a CRC32C checksum over the data.
void	close()
void	flush()
void	write(byte[] input, int offset, int length)
void	write(int b)
protected void	writeBlock(OutputStream out, byte[] data, int offset, int length, boolean compressed, int crc32c) Each chunk consists first a single byte of chunk identifier, then a three-byte little-endian length of the chunk in bytes (from 0 to 16777215, inclusive), and then the data if any.
protected void	writeHeader(OutputStream out) Writes the implementation specific header or "marker bytes" to out.

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

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

Field Detail

MAX_BLOCK_SIZE

public static final int MAX_BLOCK_SIZE

We place an additional restriction that the uncompressed data in a chunk must be no longer than 65536 bytes. This allows consumers to easily use small fixed-size buffers.

See Also:

Constant Field Values

DEFAULT_BLOCK_SIZE

public static final int DEFAULT_BLOCK_SIZE

See Also:

Constant Field Values

DEFAULT_MIN_COMPRESSION_RATIO

public static final double DEFAULT_MIN_COMPRESSION_RATIO

See Also:

Constant Field Values

Constructor Detail

SnappyFramedOutputStream

public SnappyFramedOutputStream(OutputStream out)
                         throws IOException

Throws:

IOException

SnappyFramedOutputStream

public SnappyFramedOutputStream(OutputStream out,
                                int blockSize,
                                double minCompressionRatio)
                         throws IOException

Throws:

IOException

Method Detail

writeHeader

protected void writeHeader(OutputStream out)
                    throws IOException

Writes the implementation specific header or "marker bytes" to out.

Parameters:

out - The underlying OutputStream.

Throws:

IOException

writeBlock

protected void writeBlock(OutputStream out,
                          byte[] data,
                          int offset,
                          int length,
                          boolean compressed,
                          int crc32c)
                   throws IOException

Each chunk consists first a single byte of chunk identifier, then a three-byte little-endian length of the chunk in bytes (from 0 to 16777215, inclusive), and then the data if any. The four bytes of chunk header is not counted in the data length.

Parameters:

out - The OutputStream to write to.

data - The data to write.

offset - The offset in data to start at.

length - The length of data to use.

compressed - Indicates if data is the compressed or raw content. This is based on whether the compression ratio desired is reached.

crc32c - The calculated checksum.

Throws:

IOException

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] input,
                  int offset,
                  int length)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

flush

public final void flush()
                 throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

close

public final void close()
                 throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class OutputStream

Throws:

IOException

calculateCRC32C

protected int calculateCRC32C(byte[] data,
                              int offset,
                              int length)

Calculates a CRC32C checksum over the data.

This can be overridden to provider alternative implementations (such as returning 0 if checksums are not desired).

Returns:

The CRC32 checksum.