internal

Documentation

Overview

Package internal is a collection of common compression algorithms.

For performance reasons, these packages lack strong error checking and require that the caller to ensure that strict invariants are kept.

Index

• Constants
• Variables
• func ReverseUint32(v uint32) (x uint32)
• func ReverseUint32N(v uint32, n uint) (x uint32)
• func ReverseUint64(v uint64) (x uint64)
• func ReverseUint64N(v uint64, n uint) (x uint64)
• type MoveToFront
  • func (m *MoveToFront) Decode(idxs []uint8)
  • func (m *MoveToFront) Encode(vals []uint8)

Constants

const Debug = false

Debug indicates whether the debug build tag was set.

If set, programs may choose to print with more human-readable debug information and also perform sanity checks that would otherwise be too expensive to run in a release build.

const GoFuzz = false

GoFuzz indicates whether the gofuzz build tag was set.

If set, programs may choose to disable certain checks (like checksums) that would be nearly impossible for gofuzz to properly get right. If GoFuzz is set, it implies that Debug is set as well.

Variables

var (
	// IdentityLUT returns the input key itself.
	IdentityLUT = func() (lut [256]byte) {
		for i := range lut {
			lut[i] = uint8(i)
		}
		return lut
	}()

	// ReverseLUT returns the input key with its bits reversed.
	ReverseLUT = func() (lut [256]byte) {
		for i := range lut {
			b := uint8(i)
			b = (b&0xaa)>>1 | (b&0x55)<<1
			b = (b&0xcc)>>2 | (b&0x33)<<2
			b = (b&0xf0)>>4 | (b&0x0f)<<4
			lut[i] = b
		}
		return lut
	}()
)

Functions

func ReverseUint32

func ReverseUint32(v uint32) (x uint32)

ReverseUint32 reverses all bits of v.

func ReverseUint32N

func ReverseUint32N(v uint32, n uint) (x uint32)

ReverseUint32N reverses the lower n bits of v.

func ReverseUint64

func ReverseUint64(v uint64) (x uint64)

ReverseUint64 reverses all bits of v.

func ReverseUint64N

func ReverseUint64N(v uint64, n uint) (x uint64)

ReverseUint64N reverses the lower n bits of v.

Types

type MoveToFront

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

MoveToFront is a data structure that allows for more efficient move-to-front transformations. This specific implementation assumes that the alphabet is densely packed within 0..255.

func (*MoveToFront) Decode

func (m *MoveToFront) Decode(idxs []uint8)

func (*MoveToFront) Encode

func (m *MoveToFront) Encode(vals []uint8)