java.lang.Object
- elki.utilities.io.ByteArrayUtil

```
public final class ByteArrayUtil
extends java.lang.Object
```
Class with various utilities for manipulating byte arrays.
If you find a reusable copy of this in the Java API, please tell me. Using a ByteArrayOutputStream and DataInputStream doesn't seem appropriate.
C.f. DataOutputStream and ByteArrayOutputStream

Since:

0.2

Author:

Erich Schubert

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ByteArrayUtil.ByteSerializer`	Serializer for byte objects.
`static class`	`ByteArrayUtil.DoubleSerializer`	Serializer for double objects.
`static class`	`ByteArrayUtil.FloatSerializer`	Serializer for float objects.
`static class`	`ByteArrayUtil.IntegerSerializer`	Serializer for integer objects.
`static class`	`ByteArrayUtil.LongSerializer`	Serializer for long objects.
`static class`	`ByteArrayUtil.ShortSerializer`	Serializer for short objects.
`static class`	`ByteArrayUtil.StringSerializer`	Serializer for String objects.
`static class`	`ByteArrayUtil.VarintSerializer`	Serializer for Integer objects using a variable size encoding.

Field Summary

Fields
Modifier and Type	Field	Description
`static ByteArrayUtil.ByteSerializer`	`BYTE_SERIALIZER`	Static instance.
`static ByteArrayUtil.DoubleSerializer`	`DOUBLE_SERIALIZER`	Static instance.
`static ByteArrayUtil.FloatSerializer`	`FLOAT_SERIALIZER`	Static instance.
`static ByteArrayUtil.IntegerSerializer`	`INT_SERIALIZER`	Static instance.
`static ByteArrayUtil.LongSerializer`	`LONG_SERIALIZER`	Static instance.
`static ByteArrayUtil.ShortSerializer`	`SHORT_SERIALIZER`	Static instance.
`static int`	`SIZE_BYTE`	Size of a byte in bytes.
`static int`	`SIZE_DOUBLE`	Size of a double in bytes.
`static int`	`SIZE_FLOAT`	Size of a float in bytes.
`static int`	`SIZE_INT`	Size of an integer in bytes.
`static int`	`SIZE_LONG`	Size of a long in bytes.
`static int`	`SIZE_SHORT`	Size of a short in bytes.
`static ByteArrayUtil.StringSerializer`	`STRING_SERIALIZER`	Static instance.
`static ByteArrayUtil.VarintSerializer`	`VARINT_SERIALIZER`	Static instance.

Constructor Summary

Constructors
Modifier Constructor Description

private ByteArrayUtil()
Fake constructor.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static int`	`getSignedVarintLongSize(long val)`	Compute the size of the varint encoding for this signed integer.
`static int`	`getSignedVarintSize(int val)`	Compute the size of the varint encoding for this signed integer.
`static int`	`getStringSize(java.lang.String s)`	Compute the size of the string after encoding.
`static int`	`getUnsignedVarintLongSize(long obj)`	Compute the size of the varint encoding for this unsigned integer.
`static int`	`getUnsignedVarintSize(int obj)`	Compute the size of the varint encoding for this unsigned integer.
`static double`	`readDouble(byte[] array, int offset)`	Read a double from the byte array at the given offset.
`static float`	`readFloat(byte[] array, int offset)`	Read a float from the byte array at the given offset.
`static int`	`readInt(byte[] array, int offset)`	Read an integer from the byte array at the given offset.
`static long`	`readLong(byte[] array, int offset)`	Read a long from the byte array at the given offset.
`static short`	`readShort(byte[] array, int offset)`	Read a short from the byte array at the given offset.
`static int`	`readSignedVarint(java.nio.ByteBuffer buffer)`	Read a signed integer.
`static long`	`readSignedVarintLong(java.nio.ByteBuffer buffer)`	Read a signed long.
`static java.lang.String`	`readString(java.nio.ByteBuffer buffer)`	Read a string from the buffer.
`static int`	`readUnsignedShort(byte[] array, int offset)`	Read an unsigned short from the byte array at the given offset.
`static int`	`readUnsignedVarint(java.nio.ByteBuffer buffer)`	Read an unsigned integer.
`static long`	`readUnsignedVarintLong(java.nio.ByteBuffer buffer)`	Read an unsigned long.
`static int`	`writeDouble(byte[] array, int offset, double v)`	Write a double to the byte array at the given offset.
`static int`	`writeFloat(byte[] array, int offset, float v)`	Write a float to the byte array at the given offset.
`static int`	`writeInt(byte[] array, int offset, int v)`	Write an integer to the byte array at the given offset.
`static int`	`writeLong(byte[] array, int offset, long v)`	Write a long to the byte array at the given offset.
`static int`	`writeShort(byte[] array, int offset, int v)`	Write a short to the byte array at the given offset.
`static void`	`writeSignedVarint(java.nio.ByteBuffer buffer, int val)`	Write an signed integer using a variable-length encoding.
`static void`	`writeSignedVarintLong(java.nio.ByteBuffer buffer, long val)`	Write a signed long using a variable-length encoding.
`static void`	`writeString(java.nio.ByteBuffer buffer, java.lang.String s)`	Write a string to the buffer.
`static void`	`writeUnsignedVarint(java.nio.ByteBuffer buffer, int val)`	Write an unsigned integer using a variable-length encoding.
`static void`	`writeUnsignedVarintLong(java.nio.ByteBuffer buffer, long val)`	Write an unsigned long using a variable-length encoding.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - SIZE_BYTE
```
public static final int SIZE_BYTE
```
    Size of a byte in bytes.
    
    See Also:
    
    Constant Field Values
  - SIZE_SHORT
```
public static final int SIZE_SHORT
```
    Size of a short in bytes.
    
    See Also:
    
    Constant Field Values
  - SIZE_INT
```
public static final int SIZE_INT
```
    Size of an integer in bytes.
    
    See Also:
    
    Constant Field Values
  - SIZE_LONG
```
public static final int SIZE_LONG
```
    Size of a long in bytes.
    
    See Also:
    
    Constant Field Values
  - SIZE_FLOAT
```
public static final int SIZE_FLOAT
```
    Size of a float in bytes.
    
    See Also:
    
    Constant Field Values
  - SIZE_DOUBLE
```
public static final int SIZE_DOUBLE
```
    Size of a double in bytes.
    
    See Also:
    
    Constant Field Values
  - BYTE_SERIALIZER
```
public static final ByteArrayUtil.ByteSerializer BYTE_SERIALIZER
```
    Static instance.
  - SHORT_SERIALIZER
```
public static final ByteArrayUtil.ShortSerializer SHORT_SERIALIZER
```
    Static instance.
  - INT_SERIALIZER
```
public static final ByteArrayUtil.IntegerSerializer INT_SERIALIZER
```
    Static instance.
  - LONG_SERIALIZER
```
public static final ByteArrayUtil.LongSerializer LONG_SERIALIZER
```
    Static instance.
  - FLOAT_SERIALIZER
```
public static final ByteArrayUtil.FloatSerializer FLOAT_SERIALIZER
```
    Static instance.
  - DOUBLE_SERIALIZER
```
public static final ByteArrayUtil.DoubleSerializer DOUBLE_SERIALIZER
```
    Static instance.
  - STRING_SERIALIZER
```
public static final ByteArrayUtil.StringSerializer STRING_SERIALIZER
```
    Static instance.
  - VARINT_SERIALIZER
```
public static final ByteArrayUtil.VarintSerializer VARINT_SERIALIZER
```
    Static instance.
- Constructor Detail
  - ByteArrayUtil
```
private ByteArrayUtil()
```
    Fake constructor.
- Method Detail
  - writeShort
```
public static int writeShort(byte[] array,
                             int offset,
                             int v)
```
    Write a short to the byte array at the given offset.
    
    Parameters:
    
    array - Array to write to
    
    offset - Offset to write to
    
    v - data
    
    Returns:
    
    number of bytes written
  - writeInt
```
public static int writeInt(byte[] array,
                           int offset,
                           int v)
```
    Write an integer to the byte array at the given offset.
    
    Parameters:
    
    array - Array to write to
    
    offset - Offset to write to
    
    v - data
    
    Returns:
    
    number of bytes written
  - writeLong
```
public static int writeLong(byte[] array,
                            int offset,
                            long v)
```
    Write a long to the byte array at the given offset.
    
    Parameters:
    
    array - Array to write to
    
    offset - Offset to write to
    
    v - data
    
    Returns:
    
    number of bytes written
  - writeFloat
```
public static int writeFloat(byte[] array,
                             int offset,
                             float v)
```
    Write a float to the byte array at the given offset.
    
    Parameters:
    
    array - Array to write to
    
    offset - Offset to write to
    
    v - data
    
    Returns:
    
    number of bytes written
  - writeDouble
```
public static int writeDouble(byte[] array,
                              int offset,
                              double v)
```
    Write a double to the byte array at the given offset.
    
    Parameters:
    
    array - Array to write to
    
    offset - Offset to write to
    
    v - data
    
    Returns:
    
    number of bytes written
  - readShort
```
public static short readShort(byte[] array,
                              int offset)
```
    Read a short from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    (signed) short
  - readUnsignedShort
```
public static int readUnsignedShort(byte[] array,
                                    int offset)
```
    Read an unsigned short from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    short
  - readInt
```
public static int readInt(byte[] array,
                          int offset)
```
    Read an integer from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    data
  - readLong
```
public static long readLong(byte[] array,
                            int offset)
```
    Read a long from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    data
  - readFloat
```
public static float readFloat(byte[] array,
                              int offset)
```
    Read a float from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    data
  - readDouble
```
public static double readDouble(byte[] array,
                                int offset)
```
    Read a double from the byte array at the given offset.
    
    Parameters:
    
    array - Array to read from
    
    offset - Offset to read at
    
    Returns:
    
    data
  - writeSignedVarint
```
public static void writeSignedVarint(java.nio.ByteBuffer buffer,
                                     int val)
```
    Write an signed integer using a variable-length encoding.
    The sign bit is moved to bit 0.
    Data is always written in 7-bit little-endian, where the 8th bit is the continuation flag.
    
    Parameters:
    
    buffer - Buffer to write to
    
    val - number to write
  - writeSignedVarintLong
```
public static void writeSignedVarintLong(java.nio.ByteBuffer buffer,
                                         long val)
```
    Write a signed long using a variable-length encoding.
    The sign bit is moved to bit 0.
    Data is always written in 7-bit little-endian, where the 8th bit is the continuation flag.
    
    Parameters:
    
    buffer - Buffer to write to
    
    val - number to write
  - writeUnsignedVarint
```
public static void writeUnsignedVarint(java.nio.ByteBuffer buffer,
                                       int val)
```
    Write an unsigned integer using a variable-length encoding.
    Data is always written in 7-bit little-endian, where the 8th bit is the continuation flag.
    
    Parameters:
    
    buffer - Buffer to write to
    
    val - number to write
  - writeUnsignedVarintLong
```
public static void writeUnsignedVarintLong(java.nio.ByteBuffer buffer,
                                           long val)
```
    Write an unsigned long using a variable-length encoding.
    Data is always written in 7-bit little-endian, where the 8th bit is the continuation flag.
    Note that for integers, this will result in the same encoding as writeUnsignedVarint(java.nio.ByteBuffer, int)
    
    Parameters:
    
    buffer - Buffer to write to
    
    val - number to write
  - writeString
```
public static void writeString(java.nio.ByteBuffer buffer,
                               java.lang.String s)
                        throws java.io.IOException
```
    Write a string to the buffer.
    See ByteArrayUtil.StringSerializer for details.
    
    Parameters:
    
    buffer - Buffer to write to
    
    s - String to write
    
    Throws:
    
    java.io.IOException
  - getSignedVarintSize
```
public static int getSignedVarintSize(int val)
```
    Compute the size of the varint encoding for this signed integer.
    
    Parameters:
    
    val - integer to write
    
    Returns:
    
    Encoding size of this integer
  - getUnsignedVarintSize
```
public static int getUnsignedVarintSize(int obj)
```
    Compute the size of the varint encoding for this unsigned integer.
    
    Parameters:
    
    obj - integer to write
    
    Returns:
    
    Encoding size of this integer
  - getSignedVarintLongSize
```
public static int getSignedVarintLongSize(long val)
```
    Compute the size of the varint encoding for this signed integer.
    
    Parameters:
    
    val - integer to write
    
    Returns:
    
    Encoding size of this integer
  - getUnsignedVarintLongSize
```
public static int getUnsignedVarintLongSize(long obj)
```
    Compute the size of the varint encoding for this unsigned integer.
    
    Parameters:
    
    obj - integer to write
    
    Returns:
    
    Encoding size of this integer
  - getStringSize
```
public static int getStringSize(java.lang.String s)
                         throws java.io.IOException
```
    Compute the size of the string after encoding.
    
    Parameters:
    
    s - String to encode
    
    Returns:
    
    Byte size
    
    Throws:
    
    java.io.IOException
  - readSignedVarint
```
public static int readSignedVarint(java.nio.ByteBuffer buffer)
                            throws java.io.IOException
```
    Read a signed integer.
    
    Parameters:
    
    buffer - Buffer to read from
    
    Returns:
    
    Integer value
    
    Throws:
    
    java.io.IOException
  - readUnsignedVarint
```
public static int readUnsignedVarint(java.nio.ByteBuffer buffer)
                              throws java.io.IOException
```
    Read an unsigned integer.
    
    Parameters:
    
    buffer - Buffer to read from
    
    Returns:
    
    Integer value
    
    Throws:
    
    java.io.IOException
  - readSignedVarintLong
```
public static long readSignedVarintLong(java.nio.ByteBuffer buffer)
                                 throws java.io.IOException
```
    Read a signed long.
    
    Parameters:
    
    buffer - Buffer to read from
    
    Returns:
    
    long value
    
    Throws:
    
    java.io.IOException
  - readUnsignedVarintLong
```
public static long readUnsignedVarintLong(java.nio.ByteBuffer buffer)
                                   throws java.io.IOException
```
    Read an unsigned long.
    
    Parameters:
    
    buffer - Buffer to read from
    
    Returns:
    
    long value
    
    Throws:
    
    java.io.IOException
  - readString
```
public static java.lang.String readString(java.nio.ByteBuffer buffer)
                                   throws java.io.IOException
```
    Read a string from the buffer.
    Note: this is not 100% symmetric to writeString, as a null value and the empty string are encoded the same way.
    
    Parameters:
    
    buffer - Buffer to read from.
    
    Returns:
    
    Deserialized string
    
    Throws:
    
    java.io.IOException

Class ByteArrayUtil

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

SIZE_BYTE

SIZE_SHORT

SIZE_INT

SIZE_LONG

SIZE_FLOAT

SIZE_DOUBLE

BYTE_SERIALIZER

SHORT_SERIALIZER

INT_SERIALIZER

LONG_SERIALIZER

FLOAT_SERIALIZER

DOUBLE_SERIALIZER

STRING_SERIALIZER

VARINT_SERIALIZER

Constructor Detail

ByteArrayUtil

Method Detail

writeShort

writeInt

writeLong

writeFloat

writeDouble

readShort

readUnsignedShort

readInt

readLong

readFloat

readDouble

writeSignedVarint

writeSignedVarintLong

writeUnsignedVarint

writeUnsignedVarintLong

writeString

getSignedVarintSize

getUnsignedVarintSize

getSignedVarintLongSize

getUnsignedVarintLongSize

getStringSize

readSignedVarint

readUnsignedVarint

readSignedVarintLong

readUnsignedVarintLong

readString