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gitea/vendor/github.com/boombuler/barcode/utils/reedsolomon.go
Andrew 6dd096b7f0 Two factor authentication support (#630)
* Initial commit for 2FA support

Signed-off-by: Andrew <write@imaginarycode.com>

* Add vendored files

* Add missing depends

* A few clean ups

* Added improvements, proper encryption

* Better encryption key

* Simplify "key" generation

* Make 2FA enrollment page more robust

* Fix typo

* Rename twofa/2FA to TwoFactor

* UNIQUE INDEX -> UNIQUE
2017-01-16 10:14:29 +08:00

45 lines
1.1 KiB
Go
Vendored

package utils
import (
"sync"
)
type ReedSolomonEncoder struct {
gf *GaloisField
polynomes []*GFPoly
m *sync.Mutex
}
func NewReedSolomonEncoder(gf *GaloisField) *ReedSolomonEncoder {
return &ReedSolomonEncoder{
gf, []*GFPoly{NewGFPoly(gf, []int{1})}, new(sync.Mutex),
}
}
func (rs *ReedSolomonEncoder) getPolynomial(degree int) *GFPoly {
rs.m.Lock()
defer rs.m.Unlock()
if degree >= len(rs.polynomes) {
last := rs.polynomes[len(rs.polynomes)-1]
for d := len(rs.polynomes); d <= degree; d++ {
next := last.Multiply(NewGFPoly(rs.gf, []int{1, rs.gf.ALogTbl[d-1+rs.gf.Base]}))
rs.polynomes = append(rs.polynomes, next)
last = next
}
}
return rs.polynomes[degree]
}
func (rs *ReedSolomonEncoder) Encode(data []int, eccCount int) []int {
generator := rs.getPolynomial(eccCount)
info := NewGFPoly(rs.gf, data)
info = info.MultByMonominal(eccCount, 1)
_, remainder := info.Divide(generator)
result := make([]int, eccCount)
numZero := int(eccCount) - len(remainder.Coefficients)
copy(result[numZero:], remainder.Coefficients)
return result
}