README
¶
Reed-Solomon ECC in Go
Implements error correcting codes using Russ Cox's rsc.io/qr/gf256 library.
It doesn't implement interleaved data, the data is assumed to be external to the content.
Documentation
¶
Overview ¶
Package rs implements Reed-Solomon error correcting codes.
The code was inspired by ZXing's Java implementation but was reduced to only support 256 values space. Source: https://github.com/zxing/zxing
Much credit is due to Sean Owen, William Rucklidge since portions of this code are an indirect port of their Java or C++ Reed-Solomon implementations.
Parts of ZXing's implementation have been replaced by Russ Cox's gf256 library https://rsc.io/qr/gf256.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var QRCodeField256 = NewField(0x11D, 2)
QRCodeField256 the Galois Field for QR codes. See http://research.swtch.com/field for more information.
x^8 + x^4 + x^3 + x^2 + 1
Functions ¶
This section is empty.
Types ¶
type Decoder ¶
type Decoder interface {
// Decodes given set of received codewords, which include both data and
// error-correction codewords. Really, this means it uses Reed-Solomon to
// detect and correct errors, in-place, in the input.
//
// Returns the number of errors corrected or an error if decoding failed.
Decode(data, ecc []byte) (int, error)
}
Decoder can error correct data with the corresponding ECC codes.
func NewDecoder ¶
NewDecoder creates a decoder in the defined field.
Example ¶
package main
import (
"fmt"
"github.com/maruel/rs"
)
func main() {
data := []byte("hello, wXrld")
ecc := []byte{171, 167}
fmt.Printf("Corrupted data: %s\n", data)
d := rs.NewDecoder(rs.QRCodeField256)
if nb, err := d.Decode(data, ecc); err != nil || nb != 1 {
fmt.Printf("Expected 1 fix, for %d. Error: %s\n", nb, err)
}
fmt.Printf("Fixed data: %s\n", data)
}
Output: Corrupted data: hello, wXrld Fixed data: hello, world
type Encoder ¶
type Encoder interface {
// Encode calculates the ECC code for data and writes it into ecc.
Encode(data []byte, ecc []byte)
}
Encoder can encode data into ecc codes.
func NewEncoder ¶
NewEncoder generates a Reed-Solomon encoder that can generate ECC codes.
Example ¶
package main
import (
"fmt"
"github.com/maruel/rs"
)
func main() {
data := []byte("hello, world")
fmt.Printf("Original data: %s\n", data)
ecc := make([]byte, 2)
e := rs.NewEncoder(rs.QRCodeField256, len(ecc))
e.Encode(data, ecc)
fmt.Printf("ECC bytes: %v\n", ecc)
}
Output: Original data: hello, world ECC bytes: [171 167]
Notes ¶
Bugs ¶
It's far from complete. It can't accept total buffer size of more than 255 bytes. So len(data)+len(ecc) must be under 256 bytes.
Source Files