AnsCompression

java.lang.Object
- org.h2.dev.util.AnsCompression

```
public class AnsCompression
extends java.lang.Object
```
An ANS (Asymmetric Numeral Systems) compression tool. It uses the range variant.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`countFrequencies(int[] freq, byte[] data)`	Count the frequencies of codes in the data, and increment the target frequency table.
`static byte[]`	`decode(int[] freq, byte[] data, int length)`	Decode the data.
`static byte[]`	`encode(int[] freq, byte[] data)`	Encode the data.
`static void`	`scaleFrequencies(int[] freq, int total)`	Scale the frequencies to a new total.

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

- Method Detail
  - countFrequencies
```
public static void countFrequencies(int[] freq,
                                    byte[] data)
```
    Count the frequencies of codes in the data, and increment the target frequency table.
    
    Parameters:
    
    freq - the target frequency table
    
    data - the data
  - scaleFrequencies
```
public static void scaleFrequencies(int[] freq,
                                    int total)
```
    Scale the frequencies to a new total. Frequencies of 0 are kept as 0; larger frequencies result in at least 1.
    
    Parameters:
    
    freq - the (source and target) frequency table
    
    total - the target total (sum of all frequencies)
  - encode
```
public static byte[] encode(int[] freq,
                            byte[] data)
```
    Encode the data.
    
    Parameters:
    
    freq - the frequency table (will be scaled)
    
    data - the source data (uncompressed)
    
    Returns:
    
    the compressed data
  - decode
```
public static byte[] decode(int[] freq,
                            byte[] data,
                            int length)
```
    Decode the data.
    
    Parameters:
    
    freq - the frequency table (will be scaled)
    
    data - the compressed data
    
    length - the target length
    
    Returns:
    
    the uncompressed result