public final class InterpolativeCoding extends Object
Interpolative coding is a sophisticated compression technique that can be applied to increasing sequences of integers. It is based on the idea that, for instance, when compressing the sequence 2 5 6 we already know that between 2 and 6 there are only 3 integers, so if we already know that the middle integer is between 2 and 6 we can use a small index to denote 5 among 3, 4, and 5.
The main limitation of interpolative coding is that it needs to code and decode the entire sequence in an array. This, however, makes it very suitable to code the positions of the occurrences of a term in a document, in particular in short documents.
Modifier and Type  Method and Description 

static void 
read(InputBitStream in,
int[] data,
int offset,
int len,
int lo,
int hi)
Reads from a bit stream an increasing sequence of integers coded using interpolative coding.

static int 
write(OutputBitStream out,
int[] data,
int offset,
int len,
int lo,
int hi)
Writes to a bit stream a increasing sequence of integers using interpolative coding.

public static int write(OutputBitStream out, int[] data, int offset, int len, int lo, int hi) throws IOException
Note that the length of the sequence and the arguments
lo
and hi
must be known at decoding
time.
out
 the output bit stream.data
 the vector containing the integer sequence.offset
 the offset into data
where the sequence starts.len
 the number of integers to code.lo
 a lower bound (must be smaller than or equal to the first integer in the sequence).hi
 an upper bound (must be greater than or equal to the last integer in the sequence).IOException
public static void read(InputBitStream in, int[] data, int offset, int len, int lo, int hi) throws IOException
in
 the input bit stream.data
 the vector that will store the sequence; it may be
null
, in which case the integers are discarded.offset
 the offset into data
where to store the result.len
 the number of integers to decode.lo
 a lower bound (the same as the one given to write()
).hi
 an upper bound (the same as the one given to write()
).IOException