1 package utils
2
3 import (
4 "sync"
5 )
6
7 type ReedSolomonEncoder struct {
8 gf *GaloisField
9 polynomes []*GFPoly
10 m *sync.Mutex
11 }
12
13 func NewReedSolomonEncoder(gf *GaloisField) *ReedSolomonEncoder {
14 return &ReedSolomonEncoder{
15 gf, []*GFPoly{NewGFPoly(gf, []int{1})}, new(sync.Mutex),
16 }
17 }
18
19 func (rs *ReedSolomonEncoder) getPolynomial(degree int) *GFPoly {
20 rs.m.Lock()
21 defer rs.m.Unlock()
22
23 if degree >= len(rs.polynomes) {
24 last := rs.polynomes[len(rs.polynomes)-1]
25 for d := len(rs.polynomes); d <= degree; d++ {
26 next := last.Multiply(NewGFPoly(rs.gf, []int{1, rs.gf.ALogTbl[d-1+rs.gf.Base]}))
27 rs.polynomes = append(rs.polynomes, next)
28 last = next
29 }
30 }
31 return rs.polynomes[degree]
32 }
33
34 func (rs *ReedSolomonEncoder) Encode(data []int, eccCount int) []int {
35 generator := rs.getPolynomial(eccCount)
36 info := NewGFPoly(rs.gf, data)
37 info = info.MultByMonominal(eccCount, 1)
38 _, remainder := info.Divide(generator)
39
40 result := make([]int, eccCount)
41 numZero := int(eccCount) - len(remainder.Coefficients)
42 copy(result[numZero:], remainder.Coefficients)
43 return result
44 }
45
View as plain text