tzhash/gf127/gf127x2.go
Evgenii Stratonikov 026731b260 gf127: use build tags for different implemenations
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
2022-03-21 12:30:08 +03:00

52 lines
1.3 KiB
Go

package gf127
import (
"encoding/binary"
"encoding/hex"
)
// GF127x2 represents a pair of elements of GF(2^127) stored together.
type GF127x2 [2]GF127
func mul10x2Generic(a, b *GF127x2) {
mul10Generic(&a[0], &b[0])
mul10Generic(&a[1], &b[1])
}
func mul11x2Generic(a, b *GF127x2) {
mul11Generic(&a[0], &b[0])
mul11Generic(&a[1], &b[1])
}
// Split returns 2 components of pair without additional allocations.
func Split(a *GF127x2) (*GF127, *GF127) {
return &a[0], &a[1]
}
// CombineTo 2 elements of GF(2^127) to the respective components of pair.
func CombineTo(a *GF127, b *GF127, c *GF127x2) {
c[0] = *a
c[1] = *b
}
// Equal checks if both elements of GF(2^127) pair are equal.
func (a *GF127x2) Equal(b *GF127x2) bool {
return a[0] == b[0] && a[1] == b[1]
}
// String returns hex-encoded representation, starting with MSB.
// Elements of pair are separated by comma.
func (a *GF127x2) String() string {
b := a.ByteArray()
return hex.EncodeToString(b[:16]) + " , " + hex.EncodeToString(b[16:])
}
// ByteArray represents element of GF(2^127) as byte array of length 32.
func (a *GF127x2) ByteArray() (buf []byte) {
buf = make([]byte, 32)
binary.BigEndian.PutUint64(buf, a[0][1])
binary.BigEndian.PutUint64(buf[8:], a[0][0])
binary.BigEndian.PutUint64(buf[16:], a[1][1])
binary.BigEndian.PutUint64(buf[24:], a[1][0])
return
}