Package com.drew.lang

Class RandomAccessStreamReader

java.lang.Object

com.drew.lang.RandomAccessReader

com.drew.lang.RandomAccessStreamReader

public class RandomAccessStreamReader
extends RandomAccessReader

Field Summary

Fields

Modifier and Type	Field	Description
private final int	_chunkLength
private final ArrayList<byte[]>	_chunks
private boolean	_isStreamFinished
private final InputStream	_stream
private long	_streamLength
static final int	DEFAULT_CHUNK_LENGTH

Constructor Summary

Constructors

Constructor	Description
RandomAccessStreamReader(InputStream stream)
RandomAccessStreamReader(InputStream stream, int chunkLength)
RandomAccessStreamReader(InputStream stream, int chunkLength, long streamLength)

Method Summary

Modifier and Type	Method	Description
byte	getByte(int index)	Gets the byte value at the specified byte index.
byte[]	getBytes(int index, int count)	Returns the required number of bytes from the specified index from the underlying source.
long	getLength()	Reads to the end of the stream, in order to determine the total number of bytes.
protected boolean	isValidIndex(int index, int bytesRequested)
int	toUnshiftedOffset(int localOffset)
protected void	validateIndex(int index, int bytesRequested)	Ensures that the buffered bytes extend to cover the specified index.

Methods inherited from class com.drew.lang.RandomAccessReader

getBit, getDouble64, getFloat32, getInt16, getInt24, getInt32, getInt64, getInt8, getNullTerminatedBytes, getNullTerminatedString, getNullTerminatedStringValue, getS15Fixed16, getString, getString, getStringValue, getUInt16, getUInt32, getUInt8, isMotorolaByteOrder, setMotorolaByteOrder

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_CHUNK_LENGTH

public static final int DEFAULT_CHUNK_LENGTH

See Also:

• Constant Field Values

_stream

private final InputStream _stream

_chunkLength

private final int _chunkLength

_chunks

private final ArrayList<byte[]> _chunks

_isStreamFinished

private boolean _isStreamFinished

_streamLength

private long _streamLength

Constructor Details

RandomAccessStreamReader

public RandomAccessStreamReader(InputStream stream)

RandomAccessStreamReader

public RandomAccessStreamReader(InputStream stream,
 int chunkLength)

RandomAccessStreamReader

public RandomAccessStreamReader(InputStream stream,
 int chunkLength,
 long streamLength)

Method Details

getLength

public long getLength()
               throws IOException

Reads to the end of the stream, in order to determine the total number of bytes. In general, this is not a good idea for this implementation of RandomAccessReader.

Specified by:

getLength in class RandomAccessReader

Returns:

the length of the data source, in bytes.

Throws:

IOException

validateIndex

protected void validateIndex(int index,
 int bytesRequested)
                      throws IOException

Ensures that the buffered bytes extend to cover the specified index. If not, an attempt is made to read to that point.

If the stream ends before the point is reached, a BufferBoundsException is raised.

Specified by:

validateIndex in class RandomAccessReader

Parameters:

index - the index from which the required bytes start

bytesRequested - the number of bytes which are required

Throws:

BufferBoundsException - if the stream ends before the required number of bytes are acquired

IOException - if the stream ends before the required number of bytes are acquired

isValidIndex

protected boolean isValidIndex(int index,
 int bytesRequested)
                        throws IOException

Specified by:

isValidIndex in class RandomAccessReader

Throws:

IOException

toUnshiftedOffset

public int toUnshiftedOffset(int localOffset)

Specified by:

toUnshiftedOffset in class RandomAccessReader

getByte

public byte getByte(int index)
             throws IOException

Description copied from class: RandomAccessReader

Gets the byte value at the specified byte index.

Implementations should not perform any bounds checking in this method. That should be performed in validateIndex and isValidIndex.

Specified by:

getByte in class RandomAccessReader

Parameters:

index - The index from which to read the byte

Returns:

The read byte value

Throws:

BufferBoundsException - if the requested byte is beyond the end of the underlying data source

IOException - if the byte is unable to be read

getBytes

public byte[] getBytes(int index,
 int count)
                throws IOException

Description copied from class: RandomAccessReader

Returns the required number of bytes from the specified index from the underlying source.

Specified by:

getBytes in class RandomAccessReader

Parameters:

index - The index from which the bytes begins in the underlying source

count - The number of bytes to be returned

Returns:

The requested bytes

Throws:

BufferBoundsException - if the requested bytes extend beyond the end of the underlying data source

IOException - if the byte is unable to be read