package bcrypt

func newFromPasswordAndSalt(password, unencodedSalt []byte, cost int) (*hashed, error) {
	if cost < MinCost {
		cost = DefaultCost
	}
	p := new(hashed)
	p.major = majorVersion
	p.minor = minorVersion

	err := checkCost(cost)
	if err != nil {
		return nil, err
	}
	p.cost = cost

	p.salt = unencodedSalt
	hash, err := bcrypt(password, p.cost, p.salt)
	if err != nil {
		return nil, err
	}
	p.hash = hash
	return p, err
}

/*
This function is necessary because mbcrypt needs to control the salt (like you can with other KDFs).
All other bcrypt source remains unmodified from the original x/crypto/bcrypt.
*/
func GenerateFromPasswordAndSalt(password, rawSalt []byte, cost int) ([]byte, error) {
	p, err := newFromPasswordAndSalt(password, rawSalt, cost)
	if err != nil {
		return nil, err
	}
	return p.Hash(), nil
}