Package com.drew.lang

Class SequentialReader

java.lang.Object

com.drew.lang.SequentialReader

Direct Known Subclasses:

SequentialByteArrayReader, StreamReader

public abstract class SequentialReader
extends Object

Author:

Drew Noakes https://drewnoakes.com

Constructor Summary

Constructors

Constructor	Description
SequentialReader()

Method Summary

Modifier and Type	Method	Description
abstract int	available()	Returns an estimate of the number of bytes that can be read (or skipped over) from this SequentialReader without blocking by the next invocation of a method for this input stream.
abstract byte	getByte()	Gets the next byte in the sequence.
abstract void	getBytes(byte[] buffer, int offset, int count)	Retrieves bytes, writing them into a caller-provided buffer.
abstract byte[]	getBytes(int count)	Returns the required number of bytes from the sequence.
double	getDouble64()
float	getFloat32()
short	getInt16()	Returns a signed 16-bit int calculated from two bytes of data (MSB, LSB).
int	getInt32()	Returns a signed 32-bit integer from four bytes of data.
long	getInt64()	Get a signed 64-bit integer from the buffer.
byte	getInt8()	Returns a signed 8-bit int calculated from the next byte the sequence.
byte[]	getNullTerminatedBytes(int maxLengthBytes)	Returns the sequence of bytes punctuated by a \0 value.
String	getNullTerminatedString(int maxLengthBytes, Charset charset)	Creates a String from the stream, ending where byte=='\0' or where length==maxLength.
StringValue	getNullTerminatedStringValue(int maxLengthBytes, Charset charset)	Creates a String from the stream, ending where byte=='\0' or where length==maxLength.
abstract long	getPosition()
float	getS15Fixed16()	Gets a s15.16 fixed point float from the buffer.
String	getString(int bytesRequested)
String	getString(int bytesRequested, String charset)
String	getString(int bytesRequested, Charset charset)
StringValue	getStringValue(int bytesRequested, Charset charset)
int	getUInt16()	Returns an unsigned 16-bit int calculated from the next two bytes of the sequence.
long	getUInt32()	Get a 32-bit unsigned integer from the buffer, returning it as a long.
short	getUInt8()	Returns an unsigned 8-bit int calculated from the next byte of the sequence.
boolean	isMotorolaByteOrder()	Gets the endianness of this reader.
void	setMotorolaByteOrder(boolean motorolaByteOrder)	Sets the endianness of this reader.
abstract void	skip(long n)	Skips forward in the sequence.
abstract boolean	trySkip(long n)	Skips forward in the sequence, returning a boolean indicating whether the skip succeeded, or whether the sequence ended.

Methods inherited from class java.lang.Object

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

Constructor Details

SequentialReader

public SequentialReader()

Method Details

getPosition

public abstract long getPosition()
                          throws IOException

Throws:

IOException

getByte

public abstract byte getByte()
                      throws IOException

Gets the next byte in the sequence.

Returns:

The read byte value

Throws:

IOException

getBytes

public abstract byte[] getBytes(int count)
                         throws IOException

Returns the required number of bytes from the sequence.

Parameters:

count - The number of bytes to be returned

Returns:

The requested bytes

Throws:

IOException

getBytes

public abstract void getBytes(byte[] buffer,
 int offset,
 int count)
                       throws IOException

Retrieves bytes, writing them into a caller-provided buffer.

Parameters:

buffer - The array to write bytes to.

offset - The starting position within buffer to write to.

count - The number of bytes to be written.

Throws:

IOException

skip

public abstract void skip(long n)
                   throws IOException

Skips forward in the sequence. If the sequence ends, an EOFException is thrown.

Parameters:

n - the number of byte to skip. Must be zero or greater.

Throws:

EOFException - the end of the sequence is reached.

IOException - an error occurred reading from the underlying source.

trySkip

public abstract boolean trySkip(long n)
                         throws IOException

Skips forward in the sequence, returning a boolean indicating whether the skip succeeded, or whether the sequence ended.

Parameters:

n - the number of byte to skip. Must be zero or greater.

Returns:

a boolean indicating whether the skip succeeded, or whether the sequence ended.

Throws:

IOException - an error occurred reading from the underlying source.

available

public abstract int available()

Returns an estimate of the number of bytes that can be read (or skipped over) from this SequentialReader without blocking by the next invocation of a method for this input stream. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Note that while some implementations of SequentialReader like SequentialByteArrayReader will return the total remaining number of bytes in the stream, others will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream.

Returns:

an estimate of the number of bytes that can be read (or skipped over) from this SequentialReader without blocking or 0 when it reaches the end of the input stream.

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.

getUInt8

public short getUInt8()
               throws IOException

Returns an unsigned 8-bit int calculated from the next byte of the sequence.

Returns:

the 8 bit int value, between 0 and 255

Throws:

IOException

getInt8

public byte getInt8()
             throws IOException

Returns a signed 8-bit int calculated from the next byte the sequence.

Returns:

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

Throws:

IOException

getUInt16

public int getUInt16()
              throws IOException

Returns an unsigned 16-bit int calculated from the next two bytes of the sequence.

Returns:

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

Throws:

IOException

getInt16

public short getInt16()
               throws IOException

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

Returns:

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

Throws:

IOException - the buffer does not contain enough bytes to service the request

getUInt32

public long getUInt32()
               throws IOException

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

Returns:

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

Throws:

IOException - the buffer does not contain enough bytes to service the request

getInt32

public int getInt32()
             throws IOException

Returns a signed 32-bit integer from four bytes of data.

Returns:

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

Throws:

IOException - the buffer does not contain enough bytes to service the request

getInt64

public long getInt64()
              throws IOException

Get a signed 64-bit integer from the buffer.

Returns:

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

Throws:

IOException - the buffer does not contain enough bytes to service the request

getS15Fixed16

public float getS15Fixed16()
                    throws 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:

IOException - the buffer does not contain enough bytes to service the request

getFloat32

public float getFloat32()
                 throws IOException

Throws:

IOException

getDouble64

public double getDouble64()
                   throws IOException

Throws:

IOException

getString

public String getString(int bytesRequested)
                 throws IOException

Throws:

IOException

getString

public String getString(int bytesRequested,
 String charset)
                 throws IOException

Throws:

IOException

getString

public String getString(int bytesRequested,
 Charset charset)
                 throws IOException

Throws:

IOException

getStringValue

public StringValue getStringValue(int bytesRequested,
 Charset charset)
                           throws IOException

Throws:

IOException

getNullTerminatedString

public String getNullTerminatedString(int maxLengthBytes,
 Charset charset)
                               throws IOException

Creates a String from the stream, ending where byte=='\0' or where length==maxLength.

Parameters:

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:

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

getNullTerminatedStringValue

public StringValue getNullTerminatedStringValue(int maxLengthBytes,
 Charset charset)
                                         throws IOException

Creates a String from the stream, ending where byte=='\0' or where length==maxLength.

Parameters:

maxLengthBytes - The maximum number of bytes to read. If a \0 byte is not reached within this limit, reading will stop and the string will be truncated to this length.

charset - The Charset to register with the returned StringValue, or null if the encoding is unknown

Returns:

The read string.

Throws:

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

getNullTerminatedBytes

public byte[] getNullTerminatedBytes(int maxLengthBytes)
                              throws IOException

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

Parameters:

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:

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