forked from TrueCloudLab/tzhash
52 lines
1.3 KiB
Go
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
|
|
}
|