add missing files

new files are
	oath_test
	totp code

totp.go

@@ -0,0 +1,151 @@
+package twofactor
+
+import (
+	"crypto"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/base32"
+	"hash"
+	"io"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+type TOTP struct {
+	*oath
+	step uint64
+}
+
+func (otp *TOTP) Type() Type {
+	return OATH_TOTP
+}
+
+func (otp *TOTP) otp(counter uint64) string {
+	return otp.oath.OTP(counter)
+}
+
+func (otp *TOTP) OTP() string {
+	return otp.otp(otp.OTPCounter())
+}
+
+func (otp *TOTP) URL(label string) string {
+	return otp.oath.URL(otp.Type(), label)
+}
+
+func (otp *TOTP) SetProvider(provider string) {
+	otp.provider = provider
+}
+
+func (otp *TOTP) otpCounter(t uint64) uint64 {
+	return (t - otp.counter) / otp.step
+}
+
+func (otp *TOTP) OTPCounter() uint64 {
+	return otp.otpCounter(uint64(time.Now().Unix()))
+}
+
+func NewTOTP(key []byte, start uint64, step uint64, digits int, algo crypto.Hash) *TOTP {
+	h := hashFromAlgo(algo)
+	if h == nil {
+		return nil
+	}
+
+	return &TOTP{
+		oath: &oath{
+			key:     key,
+			counter: start,
+			size:    digits,
+			hash:    h,
+			algo:    algo,
+		},
+		step: step,
+	}
+
+}
+
+func NewTOTPSHA1(key []byte, start uint64, step uint64, digits int) *TOTP {
+	return NewTOTP(key, start, step, digits, crypto.SHA1)
+}
+
+func NewTOTPSHA256(key []byte, start uint64, step uint64, digits int) *TOTP {
+	return NewTOTP(key, start, step, digits, crypto.SHA256)
+}
+
+func NewTOTPSHA512(key []byte, start uint64, step uint64, digits int) *TOTP {
+	return NewTOTP(key, start, step, digits, crypto.SHA512)
+}
+
+func hashFromAlgo(algo crypto.Hash) func() hash.Hash {
+	switch algo {
+	case crypto.SHA1:
+		return sha1.New
+	case crypto.SHA256:
+		return sha256.New
+	case crypto.SHA512:
+		return sha512.New
+	}
+	return nil
+}
+
+// GenerateGoogleTOTP produces a new TOTP token with the defaults expected by
+// Google Authenticator.
+func GenerateGoogleTOTP() *TOTP {
+	key := make([]byte, sha1.Size)
+	if _, err := io.ReadFull(PRNG, key); err != nil {
+		return nil
+	}
+	return NewTOTP(key, 0, 30, 6, crypto.SHA1)
+}
+
+func totpFromURL(u *url.URL) (*TOTP, string, error) {
+	label := u.Path[1:]
+	v := u.Query()
+
+	secret := v.Get("secret")
+	if secret == "" {
+		return nil, "", ErrInvalidURL
+	}
+
+	var algo = crypto.SHA1
+	if algorithm := v.Get("algorithm"); algorithm != "" {
+		switch {
+		case algorithm == "SHA256":
+			algo = crypto.SHA256
+		case algorithm == "SHA512":
+			algo = crypto.SHA512
+		case algorithm != "SHA1":
+			return nil, "", ErrInvalidAlgo
+		}
+	}
+
+	var digits = 6
+	if sdigit := v.Get("digits"); sdigit != "" {
+		tmpDigits, err := strconv.ParseInt(sdigit, 10, 8)
+		if err != nil {
+			return nil, "", err
+		}
+		digits = int(tmpDigits)
+	}
+
+	var period uint64 = 30
+	if speriod := v.Get("period"); speriod != "" {
+		var err error
+		period, err = strconv.ParseUint(speriod, 10, 64)
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
+	key, err := base32.StdEncoding.DecodeString(secret)
+	if err != nil {
+		return nil, "", err
+	}
+	otp := NewTOTP(key, 0, period, digits, algo)
+	return otp, label, nil
+}
+
+func (otp *TOTP) QR(label string) ([]byte, error) {
+	return otp.oath.QR(otp.Type(), label)
+}