java.lang.Object
- kala.compress.harmony.pack200.Codec

Direct Known Subclasses:

BHSDCodec, PopulationCodec, RunCodec
```
public abstract class Codec
extends java.lang.Object
```
A Codec allows a sequence of bytes to be decoded into integer values (or vice versa).
There are a number of standard Codecs (UDELTA5, UNSIGNED5, BYTE1, CHAR3) that are used in the implementation of many bands; but there are a variety of other ones, and indeed the specification assumes that other combinations of values can result in more specific and efficient formats. There are also a sequence of canonical encodings defined by the Pack200 specification, which allow a Codec to be referred to by canonical number. CodecEncoding.getCodec(int, InputStream, Codec))

Field Summary

Fields
Modifier and Type	Field	Description
`static BHSDCodec`	`BCI5`	BCI5 = (5,4): Used for storing branching information in bytecode.
`static BHSDCodec`	`BRANCH5`	BRANCH5 = (5,4,2): Used for storing branching information in bytecode.
`static BHSDCodec`	`BYTE1`	BYTE1 = (1,256): Used for storing plain bytes.
`static BHSDCodec`	`CHAR3`	CHAR3 = (3,128): Used for storing text (UTF-8) strings.
`static BHSDCodec`	`DELTA5`	DELTA5 = (5,64,1,1): Used for the majority of numerical codings where there is a correlated sequence of signed values.
`int`	`lastBandLength`
`static BHSDCodec`	`MDELTA5`	MDELTA5 = (5,64,2,1): Used for the majority of numerical codings where there is a correlated sequence of signed values, but where most of them are expected to be non-negative.
`static BHSDCodec`	`SIGNED5`	SIGNED5 = (5,64,1): Used for small signed values.
`static BHSDCodec`	`UDELTA5`	UDELTA5 = (5,64,0,1): Used for the majority of numerical codings where there is a correlated sequence of unsigned values.
`static BHSDCodec`	`UNSIGNED5`	UNSIGNED5 = (5,64): Used for small unsigned values.

Constructor Summary

Constructors
Constructor Description

Codec()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`(package private) int`	`check(int n, java.io.InputStream in)`
`abstract int`	`decode(java.io.InputStream in)`	Decodes a sequence of bytes from the given input stream, returning the value as a long.
`abstract int`	`decode(java.io.InputStream in, long last)`	Decodes a sequence of bytes from the given input stream, returning the value as a long.
`int[]`	`decodeInts(int n, java.io.InputStream in)`	Decodes a sequence of `n` values from `in`.
`int[]`	`decodeInts(int n, java.io.InputStream in, int firstValue)`	Decodes a sequence of `n` values from `in`.
`abstract byte[]`	`encode(int value)`	Encodes a single value into a sequence of bytes.
`byte[]`	`encode(int[] ints)`	Encodes a sequence of integers into a byte array
`abstract byte[]`	`encode(int value, int last)`	Encodes a single value into a sequence of bytes.

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

- Field Detail
  - BCI5
```
public static final BHSDCodec BCI5
```
    BCI5 = (5,4): Used for storing branching information in bytecode.
  - BRANCH5
```
public static final BHSDCodec BRANCH5
```
    BRANCH5 = (5,4,2): Used for storing branching information in bytecode.
  - BYTE1
```
public static final BHSDCodec BYTE1
```
    BYTE1 = (1,256): Used for storing plain bytes.
  - CHAR3
```
public static final BHSDCodec CHAR3
```
    CHAR3 = (3,128): Used for storing text (UTF-8) strings. This isn't quite the same as UTF-8, but has similar properties; ASCII characters < 127 are stored in a single byte.
  - DELTA5
```
public static final BHSDCodec DELTA5
```
    DELTA5 = (5,64,1,1): Used for the majority of numerical codings where there is a correlated sequence of signed values.
  - MDELTA5
```
public static final BHSDCodec MDELTA5
```
    MDELTA5 = (5,64,2,1): Used for the majority of numerical codings where there is a correlated sequence of signed values, but where most of them are expected to be non-negative.
  - SIGNED5
```
public static final BHSDCodec SIGNED5
```
    SIGNED5 = (5,64,1): Used for small signed values.
  - UDELTA5
```
public static final BHSDCodec UDELTA5
```
    UDELTA5 = (5,64,0,1): Used for the majority of numerical codings where there is a correlated sequence of unsigned values.
  - UNSIGNED5
```
public static final BHSDCodec UNSIGNED5
```
    UNSIGNED5 = (5,64): Used for small unsigned values.
  - lastBandLength
```
public int lastBandLength
```
- Constructor Detail
  - Codec
```
public Codec()
```
- Method Detail
  - check
```
int check(int n,
          java.io.InputStream in)
   throws Pack200Exception
```
    Throws:
    
    Pack200Exception
  - decode
```
public abstract int decode(java.io.InputStream in)
                    throws java.io.IOException,
                           Pack200Exception
```
    Decodes a sequence of bytes from the given input stream, returning the value as a long. Note that this method can only be applied for non-delta encodings.
    
    Parameters:
    
    in - the input stream to read from
    
    Returns:
    
    the value as a long
    
    Throws:
    
    java.io.IOException - if there is a problem reading from the underlying input stream
    
    Pack200Exception - if the encoding is a delta encoding
  - decode
```
public abstract int decode(java.io.InputStream in,
                           long last)
                    throws java.io.IOException,
                           Pack200Exception
```
    Decodes a sequence of bytes from the given input stream, returning the value as a long. If this encoding is a delta encoding (d=1) then the previous value must be passed in as a parameter. If it is a non-delta encoding, then it does not matter what value is passed in, so it makes sense for the value to be passed in by default using code similar to:
    long last = 0; while (condition) { last = codec.decode(in, last); // do something with last }
    Parameters:
    
    in - the input stream to read from
    
    last - the previous value read, which must be supplied if the codec is a delta encoding
    
    Returns:
    
    the value as a long
    
    Throws:
    
    java.io.IOException - if there is a problem reading from the underlying input stream
    
    Pack200Exception - if there is a problem decoding the value or that the value is invalid
  - decodeInts
```
public int[] decodeInts(int n,
                        java.io.InputStream in)
                 throws java.io.IOException,
                        Pack200Exception
```
    Decodes a sequence of n values from in. This should probably be used in most cases, since some codecs (such as PopulationCodec) only work when the number of values to be read is known.
    
    Parameters:
    
    n - the number of values to decode
    
    in - the input stream to read from
    
    Returns:
    
    an array of int values corresponding to values decoded
    
    Throws:
    
    java.io.IOException - if there is a problem reading from the underlying input stream
    
    Pack200Exception - if there is a problem decoding the value or that the value is invalid
  - decodeInts
```
public int[] decodeInts(int n,
                        java.io.InputStream in,
                        int firstValue)
                 throws java.io.IOException,
                        Pack200Exception
```
    Decodes a sequence of n values from in.
    
    Parameters:
    
    n - the number of values to decode
    
    in - the input stream to read from
    
    firstValue - the first value in the band if it has already been read
    
    Returns:
    
    an array of int values corresponding to values decoded, with firstValue as the first value in the array.
    
    Throws:
    
    java.io.IOException - if there is a problem reading from the underlying input stream
    
    Pack200Exception - if there is a problem decoding the value or that the value is invalid
  - encode
```
public abstract byte[] encode(int value)
                       throws Pack200Exception
```
    Encodes a single value into a sequence of bytes. Note that this method can only be used for non-delta encodings.
    
    Parameters:
    
    value - the value to encode
    
    Returns:
    
    the encoded bytes
    
    Throws:
    
    Pack200Exception - TODO
  - encode
```
public abstract byte[] encode(int value,
                              int last)
                       throws Pack200Exception
```
    Encodes a single value into a sequence of bytes.
    
    Parameters:
    
    value - the value to encode
    
    last - the previous value encoded (for delta encodings)
    
    Returns:
    
    the encoded bytes
    
    Throws:
    
    Pack200Exception - TODO
  - encode
```
public byte[] encode(int[] ints)
              throws Pack200Exception
```
    Encodes a sequence of integers into a byte array
    
    Parameters:
    
    ints - the values to encode
    
    Returns:
    
    byte[] encoded bytes
    
    Throws:
    
    Pack200Exception - if there is a problem encoding any of the values

Class Codec

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

BCI5

BRANCH5

BYTE1

CHAR3

DELTA5

MDELTA5

SIGNED5

UDELTA5

UNSIGNED5

lastBandLength

Constructor Detail

Codec

Method Detail

check

decode

decode

decodeInts

decodeInts

encode

encode

encode