decoder

Documentation

Index

• type Decoder
  • func NewGaussElimRLNCDecoder(pieceCount uint) Decoder
• type GaussElimDecoderState
  • func NewGaussElimDecoderState(gf *galoisfield.GF, coeffs, coded matrix.Matrix) *GaussElimDecoderState
  • func NewGaussElimDecoderStateWithPieceCount(gf *galoisfield.GF, pieceCount uint) *GaussElimDecoderState
  • func (d *GaussElimDecoderState) AddPiece(codedPiece *coder.CodedPiece)
  • func (d *GaussElimDecoderState) CodedPieceMatrix() matrix.Matrix
  • func (d *GaussElimDecoderState) CoefficientMatrix() matrix.Matrix
  • func (d *GaussElimDecoderState) GetPiece(idx uint) (coder.Piece, error)
  • func (d *GaussElimDecoderState) IsLinearIndependent(vector coder.CodingVector) bool
  • func (d *GaussElimDecoderState) Rank() uint
  • func (d *GaussElimDecoderState) Rref()
• type GaussElimRLNCDecoder
  • func (d *GaussElimRLNCDecoder) AddPiece(piece *coder.CodedPiece) error
  • func (d *GaussElimRLNCDecoder) GetPiece(i uint) (coder.Piece, error)
  • func (d *GaussElimRLNCDecoder) GetPieces() ([]coder.Piece, error)
  • func (d *GaussElimRLNCDecoder) IsDecoded() bool
  • func (d *GaussElimRLNCDecoder) PieceLength() uint
  • func (d *GaussElimRLNCDecoder) ProcessRate() float64
  • func (d *GaussElimRLNCDecoder) Required() uint

Types

type Decoder

type Decoder interface {
	PieceLength() uint
	IsDecoded() bool
	Required() uint
	ProcessRate() float64
	AddPiece(piece *coder.CodedPiece) error
	GetPiece(index uint) (coder.Piece, error)
	GetPieces() ([]coder.Piece, error)
}

func NewGaussElimRLNCDecoder

func NewGaussElimRLNCDecoder(pieceCount uint) Decoder

If minimum #-of linearly independent coded pieces required for decoding coded pieces --- is provided with, it returns a decoder, which keeps applying full RLNC decoding step on received coded pieces

As soon as minimum #-of linearly independent pieces are obtained which is generally equal to original #-of pieces, decoded pieces can be read back

type GaussElimDecoderState

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

func NewGaussElimDecoderState

func NewGaussElimDecoderState(gf *galoisfield.GF, coeffs, coded matrix.Matrix) *GaussElimDecoderState

func NewGaussElimDecoderStateWithPieceCount

func NewGaussElimDecoderStateWithPieceCount(gf *galoisfield.GF, pieceCount uint) *GaussElimDecoderState

func (*GaussElimDecoderState) AddPiece

func (d *GaussElimDecoderState) AddPiece(codedPiece *coder.CodedPiece)

Adds a new coded piece to decoder state, which will hopefully help in decoding pieces, if linearly independent with other rows i.e. read pieces

func (*GaussElimDecoderState) CodedPieceMatrix

func (d *GaussElimDecoderState) CodedPieceMatrix() matrix.Matrix

Current state of coded piece matrix, which is updated along side coding coefficient matrix ( during rref )

func (*GaussElimDecoderState) CoefficientMatrix

func (d *GaussElimDecoderState) CoefficientMatrix() matrix.Matrix

Current state of coding coefficient matrix

func (*GaussElimDecoderState) GetPiece

func (d *GaussElimDecoderState) GetPiece(idx uint) (coder.Piece, error)

Request decoded piece by index ( 0 based, definitely )

If piece not yet decoded/ requested index is >= #-of pieces coded together, returns error message indicating so

Otherwise piece is returned, without any error

Note: This method will copy decoded piece into newly allocated memory when whole decoding hasn't yet happened, to prevent any chance that user mistakenly modifies slice returned ( read piece ) & that affects next round of decoding ( when new piece is received )

func (*GaussElimDecoderState) IsLinearIndependent

func (d *GaussElimDecoderState) IsLinearIndependent(vector coder.CodingVector) bool

func (*GaussElimDecoderState) Rank

func (d *GaussElimDecoderState) Rank() uint

Expected to be invoked after RREF-ed, in other words it won't rref matrix first to calculate rank, rather that needs to first invoked

func (*GaussElimDecoderState) Rref

func (d *GaussElimDecoderState) Rref()

Calculates Reduced Row Echelon Form of coefficient matrix, while also modifying coded piece matrix First it forward, backward cleans up matrix i.e. cells other than pivots are zeroed, later it checks if some rows of coefficient matrix are linearly dependent or not, if yes it removes those, while respective rows of coded piece matrix is also removed --- considered to be `not useful piece`

Note: All operations are in-place, no more memory allocations are performed

type GaussElimRLNCDecoder

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

func (*GaussElimRLNCDecoder) AddPiece

func (d *GaussElimRLNCDecoder) AddPiece(piece *coder.CodedPiece) error

AddPiece - Adds a new received coded piece along with coding vector. After every new coded piece reception augmented matrix ( coding vector + coded piece ) is rref-ed, to keep it as ready as possible for consuming decoded pieces

Note: As soon as all pieces are decoded, no more calls to this method does anything useful --- so better check for error & proceed !

func (*GaussElimRLNCDecoder) GetPiece

func (d *GaussElimRLNCDecoder) GetPiece(i uint) (coder.Piece, error)

GetPiece - Get a decoded piece by index, may ( not ) succeed !

Note: It's not necessary that full decoding needs to happen for this method to return something useful

If M-many pieces are received among N-many expected ( read M <= N ) then pieces with index in [0..M] ( remember upper bound exclusive ) can be attempted to be consumed, given algebric structure has revealed requested piece at index `i`

func (*GaussElimRLNCDecoder) GetPieces

func (d *GaussElimRLNCDecoder) GetPieces() ([]coder.Piece, error)

GetPieces - Get a list of all decoded pieces, given full decoding has happened

func (*GaussElimRLNCDecoder) IsDecoded

func (d *GaussElimRLNCDecoder) IsDecoded() bool

IsDecoded - Use it for checking whether more piece collection is required or not

If it returns false, denotes more linearly independent pieces need to be collected, only then decoding can be completed

func (*GaussElimRLNCDecoder) PieceLength

func (d *GaussElimRLNCDecoder) PieceLength() uint

PieceLength - Returns piece length in bytes

If no pieces are yet added to decoder state, then returns 0, denoting **unknown**

func (*GaussElimRLNCDecoder) ProcessRate

func (d *GaussElimRLNCDecoder) ProcessRate() float64

ProcessRate - How many pieces are received so far ? Returns a value in range [0..1]

func (*GaussElimRLNCDecoder) Required

func (d *GaussElimRLNCDecoder) Required() uint

Required - How many more linearly independent pieces are required for successfully decoding pieces ?