package FlexibleEncoding.Parquet;
/*
* adapt from parquet
*
*/
/**
* Packs and unpacks into bytes
*
* packing unpacking treats:
* - n values at a time (with n % 8 == 0)
* - bitWidth * (n/8) bytes at a time.
*
* @author Julien Le Dem
*
*/
public abstract class BytePacker {
private final int bitWidth;
protected BytePacker(int bitWidth) {
this.bitWidth = bitWidth;
}
/**
* @return the width in bits used for encoding, also how many bytes are packed/unpacked at a time by pack8Values/unpack8Values
*/
public final int getBitWidth() {
return bitWidth;
}
/**
* pack 8 values from input at inPos into bitWidth bytes in output at outPos.
* nextPosition: inPos += 8; outPos += getBitWidth()
* @param input the input values
* @param inPos where to read from in input
* @param output the output bytes
* @param outPos where to write to in output
*/
public abstract void pack8Values(final int[] input, final int inPos, final byte[] output, final int outPos);
/**
* pack 32 values from input at inPos into bitWidth * 4 bytes in output at outPos.
* nextPosition: inPos += 32; outPos += getBitWidth() * 4
* @param input the input values
* @param inPos where to read from in input
* @param output the output bytes
* @param outPos where to write to in output
*/
public abstract void pack32Values(int[] input, int inPos, byte[] output, int outPos);
/**
* unpack bitWidth bytes from input at inPos into 8 values in output at outPos.
* nextPosition: inPos += getBitWidth(); outPos += 8
* @param input the input bytes
* @param inPos where to read from in input
* @param output the output values
* @param outPos where to write to in output
*/
public abstract void unpack8Values(final byte[] input, final int inPos, final int[] output, final int outPos);
/**
* unpack bitWidth * 4 bytes from input at inPos into 32 values in output at outPos.
* nextPosition: inPos += getBitWidth() * 4; outPos += 32
* @param input the input bytes
* @param inPos where to read from in input
* @param output the output values
* @param outPos where to write to in output
*/
public abstract void unpack32Values(byte[] input, int inPos, int[] output, int outPos);
}