Function readBits

crypto/secp256k1/curve.go:57–66

readBits encodes the absolute value of bigint as big-endian bytes. Callers must ensure that buf has enough space. If buf is too short the result will be incomplete.

(bigint *big.Int, buf []byte)

// must ensure that buf has enough space. If buf is too short the result will
// be incomplete.
func readBits(bigint *big.Int, buf []byte) {
	i := len(buf)
	for _, d := range bigint.Bits() {
		for j := 0; j < wordBytes && i > 0; j++ {
			i--
			buf[i] = byte(d)
			d >>= 8
		}
	}
}

// This code is from https://github.com/ThePiachu/GoBit and implements
// several Koblitz elliptic curves over prime fields.