Package gov.nih.mipav.model.file

Class MetadataExtractor.RandomAccessReader

java.lang.Object

gov.nih.mipav.model.file.MetadataExtractor.RandomAccessReader

Direct Known Subclasses:

MetadataExtractor.ByteArrayReader, MetadataExtractor.RandomAccessFileReader, MetadataExtractor.RandomAccessStreamReader

Enclosing class:

MetadataExtractor

public abstract class MetadataExtractor.RandomAccessReader
extends java.lang.Object

Base class for random access data reading operations of common data types.

By default, the reader operates with Motorola byte order (big endianness). This can be changed by calling com.drew.lang.RandomAccessReader#setMotorolaByteOrder(boolean).

Concrete implementations include:

• MetadataExtractor.ByteArrayReader
• MetadataExtractor.RandomAccessStreamReader

Author:

Drew Noakes https://drewnoakes.com

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	_isMotorolaByteOrder

Constructor Summary

Constructors

Constructor	Description
RandomAccessReader()

Method Summary

Modifier and Type	Method	Description
boolean	getBit(int index)	Gets whether a bit at a specific index is set or not.
abstract byte	getByte(int index)	Gets the byte value at the specified byte index.
abstract byte[]	getBytes(int index, int count)	Returns the required number of bytes from the specified index from the underlying source.
double	getDouble64(int index)
float	getFloat32(int index)
short	getInt16(int index)	Returns a signed 16-bit int calculated from two bytes of data at the specified index (MSB, LSB).
int	getInt24(int index)	Get a 24-bit unsigned integer from the buffer, returning it as an int.
int	getInt32(int index)	Returns a signed 32-bit integer from four bytes of data at the specified index the buffer.
long	getInt64(int index)	Get a signed 64-bit integer from the buffer.
byte	getInt8(int index)	Returns a signed 8-bit int calculated from one byte of data at the specified index.
abstract long	getLength()	Returns the length of the data source in bytes.
byte[]	getNullTerminatedBytes(int index, int maxLengthBytes)	Returns the sequence of bytes punctuated by a \0 value.
java.lang.String	getNullTerminatedString(int index, int maxLengthBytes, java.nio.charset.Charset charset)	Creates a String from the _data buffer starting at the specified index, and ending where byte=='\0' or where length==maxLength.
MetadataExtractor.StringValue	getNullTerminatedStringValue(int index, int maxLengthBytes, java.nio.charset.Charset charset)
float	getS15Fixed16(int index)	Gets a s15.16 fixed point float from the buffer.
java.lang.String	getString(int index, int bytesRequested, java.lang.String charset)
java.lang.String	getString(int index, int bytesRequested, java.nio.charset.Charset charset)
MetadataExtractor.StringValue	getStringValue(int index, int bytesRequested, java.nio.charset.Charset charset)
int	getUInt16(int index)	Returns an unsigned 16-bit int calculated from two bytes of data at the specified index.
long	getUInt32(int index)	Get a 32-bit unsigned integer from the buffer, returning it as a long.
short	getUInt8(int index)	Returns an unsigned 8-bit int calculated from one byte of data at the specified index.
boolean	isMotorolaByteOrder()	Gets the endianness of this reader.
protected abstract boolean	isValidIndex(int index, int bytesRequested)
void	setMotorolaByteOrder(boolean motorolaByteOrder)	Sets the endianness of this reader.
abstract int	toUnshiftedOffset(int localOffset)
protected abstract void	validateIndex(int index, int bytesRequested)	Ensures that the buffered bytes extend to cover the specified index.

Methods inherited from class java.lang.Object

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

Field Detail

_isMotorolaByteOrder

private boolean _isMotorolaByteOrder

Constructor Detail

RandomAccessReader

public RandomAccessReader()

Method Detail

toUnshiftedOffset

public abstract int toUnshiftedOffset(int localOffset)

getByte

public abstract byte getByte(int index)
                      throws java.io.IOException

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.

Parameters:

index - The index from which to read the byte

Returns:

The read byte value

Throws:

java.lang.IllegalArgumentException - index is negative

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

java.io.IOException - if the byte is unable to be read

getBytes

public abstract byte[] getBytes(int index,
                                int count)
                         throws java.io.IOException

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

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:

java.lang.IllegalArgumentException - index or count are negative

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

java.io.IOException - if the byte is unable to be read

validateIndex

protected abstract void validateIndex(int index,
                                      int bytesRequested)
                               throws java.io.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 MetadataExtractor.BufferBoundsException is raised.

Parameters:

index - the index from which the required bytes start

bytesRequested - the number of bytes which are required

Throws:

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

isValidIndex

protected abstract boolean isValidIndex(int index,
                                        int bytesRequested)
                                 throws java.io.IOException

Throws:

java.io.IOException

getLength

public abstract long getLength()
                        throws java.io.IOException

Returns the length of the data source in bytes.

This is a simple operation for implementations (such as MetadataExtractor.RandomAccessFileReader and MetadataExtractor.ByteArrayReader) that have the entire data source available.

Users of this method must be aware that sequentially accessed implementations such as MetadataExtractor.RandomAccessStreamReader will have to read and buffer the entire data source in order to determine the length.

Returns:

the length of the data source, in bytes.

Throws:

java.io.IOException

setMotorolaByteOrder

public void setMotorolaByteOrder(boolean motorolaByteOrder)

Sets the endianness of this reader.

• true for Motorola (or big) endianness (also known as network byte order), with MSB before LSB.
• false for Intel (or little) endianness, with LSB before MSB.

Parameters:

motorolaByteOrder - true for Motorola/big endian, false for Intel/little endian

isMotorolaByteOrder

public boolean isMotorolaByteOrder()

Gets the endianness of this reader.

• true for Motorola (or big) endianness (also known as network byte order), with MSB before LSB.
• false for Intel (or little) endianness, with LSB before MSB.

getBit

public boolean getBit(int index)
               throws java.io.IOException

Gets whether a bit at a specific index is set or not.

Parameters:

index - the number of bits at which to test

Returns:

true if the bit is set, otherwise false

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getUInt8

public short getUInt8(int index)
               throws java.io.IOException

Returns an unsigned 8-bit int calculated from one byte of data at the specified index.

Parameters:

index - position within the data buffer to read byte

Returns:

the 8 bit int value, between 0 and 255

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getInt8

public byte getInt8(int index)
             throws java.io.IOException

Returns a signed 8-bit int calculated from one byte of data at the specified index.

Parameters:

index - position within the data buffer to read byte

Returns:

the 8 bit int value, between 0x00 and 0xFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getUInt16

public int getUInt16(int index)
              throws java.io.IOException

Returns an unsigned 16-bit int calculated from two bytes of data at the specified index.

Parameters:

index - position within the data buffer to read first byte

Returns:

the 16 bit int value, between 0x0000 and 0xFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getInt16

public short getInt16(int index)
               throws java.io.IOException

Returns a signed 16-bit int calculated from two bytes of data at the specified index (MSB, LSB).

Parameters:

index - position within the data buffer to read first byte

Returns:

the 16 bit int value, between 0x0000 and 0xFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getInt24

public int getInt24(int index)
             throws java.io.IOException

Get a 24-bit unsigned integer from the buffer, returning it as an int.

Parameters:

index - position within the data buffer to read first byte

Returns:

the unsigned 24-bit int value as a long, between 0x00000000 and 0x00FFFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getUInt32

public long getUInt32(int index)
               throws java.io.IOException

Get a 32-bit unsigned integer from the buffer, returning it as a long.

Parameters:

index - position within the data buffer to read first byte

Returns:

the unsigned 32-bit int value as a long, between 0x00000000 and 0xFFFFFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getInt32

public int getInt32(int index)
             throws java.io.IOException

Returns a signed 32-bit integer from four bytes of data at the specified index the buffer.

Parameters:

index - position within the data buffer to read first byte

Returns:

the signed 32 bit int value, between 0x00000000 and 0xFFFFFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getInt64

public long getInt64(int index)
              throws java.io.IOException

Get a signed 64-bit integer from the buffer.

Parameters:

index - position within the data buffer to read first byte

Returns:

the 64 bit int value, between 0x0000000000000000 and 0xFFFFFFFFFFFFFFFF

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getS15Fixed16

public float getS15Fixed16(int index)
                    throws java.io.IOException

Gets a s15.16 fixed point float from the buffer.

This particular fixed point encoding has one sign bit, 15 numerator bits and 16 denominator bits.

Returns:

the floating point value

Throws:

java.io.IOException - the buffer does not contain enough bytes to service the request, or index is negative

getFloat32

public float getFloat32(int index)
                 throws java.io.IOException

Throws:

java.io.IOException

getDouble64

public double getDouble64(int index)
                   throws java.io.IOException

Throws:

java.io.IOException

getStringValue

public MetadataExtractor.StringValue getStringValue(int index,
                                                    int bytesRequested,
                                                    java.nio.charset.Charset charset)
                                             throws java.io.IOException

Throws:

java.io.IOException

getString

public java.lang.String getString(int index,
                                  int bytesRequested,
                                  java.nio.charset.Charset charset)
                           throws java.io.IOException

Throws:

java.io.IOException

getString

public java.lang.String getString(int index,
                                  int bytesRequested,
                                  java.lang.String charset)
                           throws java.io.IOException

Throws:

java.io.IOException

getNullTerminatedString

public java.lang.String getNullTerminatedString(int index,
                                                int maxLengthBytes,
                                                java.nio.charset.Charset charset)
                                         throws java.io.IOException

Creates a String from the _data buffer starting at the specified index, and ending where byte=='\0' or where length==maxLength.

Parameters:

index - The index within the buffer at which to start reading the string.

maxLengthBytes - The maximum number of bytes to read. If a zero-byte is not reached within this limit, reading will stop and the string will be truncated to this length.

Returns:

The read string.

Throws:

java.io.IOException - The buffer does not contain enough bytes to satisfy this request.

getNullTerminatedStringValue

public MetadataExtractor.StringValue getNullTerminatedStringValue(int index,
                                                                  int maxLengthBytes,
                                                                  java.nio.charset.Charset charset)
                                                           throws java.io.IOException

Throws:

java.io.IOException

getNullTerminatedBytes

public byte[] getNullTerminatedBytes(int index,
                                     int maxLengthBytes)
                              throws java.io.IOException

Returns the sequence of bytes punctuated by a \0 value.

Parameters:

index - The index within the buffer at which to start reading the string.

maxLengthBytes - The maximum number of bytes to read. If a \0 byte is not reached within this limit, the returned array will be maxLengthBytes long.

Returns:

The read byte array, excluding the null terminator.

Throws:

java.io.IOException - The buffer does not contain enough bytes to satisfy this request.