compressor

Documentation

Overview

Package rollsum implements rolling checksums similar to apenwarr's bup, which is similar to librsync.

The bup project is at https://github.com/apenwarr/bup and its splitting in particular is at https://github.com/apenwarr/bup/blob/master/lib/bup/bupsplit.c

Index

• Constants
• func ZstdCompressor(r io.Writer, metadata map[string]string, level *int) (io.WriteCloser, error)
• type RollSum
  • func NewRollSum() *RollSum
  • func (rs *RollSum) Bits() int
  • func (rs *RollSum) Digest() uint32
  • func (rs *RollSum) OnSplit() bool
  • func (rs *RollSum) OnSplitWithBits(n uint32) bool
  • func (rs *RollSum) Roll(ch byte)

Constants

const RollsumBits = 16

Functions

func ZstdCompressor

func ZstdCompressor(r io.Writer, metadata map[string]string, level *int) (io.WriteCloser, error)

ZstdCompressor is a CompressorFunc for the zstd compression algorithm.

Types

type RollSum

type RollSum struct {
	// contains filtered or unexported fields
}

func NewRollSum

func NewRollSum() *RollSum

func (*RollSum) Bits

func (rs *RollSum) Bits() int

func (*RollSum) Digest

func (rs *RollSum) Digest() uint32

func (*RollSum) OnSplit

func (rs *RollSum) OnSplit() bool

OnSplit reports whether at least 13 consecutive trailing bits of the current checksum are set the same way.

func (*RollSum) OnSplitWithBits

func (rs *RollSum) OnSplitWithBits(n uint32) bool

OnSplitWithBits reports whether at least n consecutive trailing bits of the current checksum are set the same way.

func (*RollSum) Roll

func (rs *RollSum) Roll(ch byte)

Roll adds ch to the rolling sum.