add a very simplistic and slow FNV-128a implementation

crypto/crypto_suite_test.go

@@ -0,0 +1,13 @@
+package crypto_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"testing"
+)
+
+func TestCrypto(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Crypto Suite")
+}

crypto/fnv.go

@@ -0,0 +1,64 @@
+package crypto
+
+// Taken and modified from https://golang.org/src/hash/fnv/fnv.go
+// TODO: This implementation uses big ints and is probably horrendously slow.
+
+// Implements FNV-1 and FNV-1a, non-cryptographic hash functions
+// created by Glenn Fowler, Landon Curt Noll, and Phong Vo.
+// See https://en.wikipedia.org/wiki/Fowler-Noll-Vo_hash_function.
+
+import (
+	"hash"
+	"math/big"
+)
+
+// Hash128 is the common interface implemented by all 128-bit hash functions.
+type Hash128 interface {
+	hash.Hash
+	Sum128() []byte
+}
+
+type sum128a struct {
+	*big.Int
+}
+
+var _ Hash128 = &sum128a{}
+
+var offset128 = &big.Int{}
+var prime128 = &big.Int{}
+
+func init() {
+	offset128.SetString("144066263297769815596495629667062367629", 0)
+	prime128.SetString("309485009821345068724781371", 0)
+}
+
+// New128a returns a new 128-bit FNV-1a hash.Hash.
+func New128a() Hash128 {
+	i := &big.Int{}
+	i.Set(offset128)
+	return &sum128a{i}
+}
+
+func (s *sum128a) Reset() { s.Set(offset128) }
+
+func (s *sum128a) Sum128() []byte { return s.Bytes() }
+
+func (s *sum128a) Write(data []byte) (int, error) {
+	for _, c := range data {
+		s.Xor(s.Int, big.NewInt(int64(c)))
+		s.Mul(s.Int, prime128)
+
+		// Truncate the bigint to 128 bits
+		s.SetBytes(s.Bytes()[len(s.Bytes())-16 : len(s.Bytes())])
+	}
+	return len(data), nil
+}
+
+func (s *sum128a) Size() int { return 16 }
+
+func (s *sum128a) BlockSize() int { return 1 }
+
+func (s *sum128a) Sum(in []byte) []byte {
+	b := s.Bytes()
+	return append(in, b[len(b)-s.Size():]...)
+}

crypto/fnv_test.go

@@ -0,0 +1,21 @@
+package crypto_test
+
+import (
+	"github.com/lucas-clemente/quic-go/crypto"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("FNV", func() {
+	It("gives proper null hash", func() {
+		h := crypto.New128a()
+		Expect(h.Sum128()).To(Equal([]byte{0x6c, 0x62, 0x27, 0x2e, 0x07, 0xbb, 0x01, 0x42, 0x62, 0xb8, 0x21, 0x75, 0x62, 0x95, 0xc5, 0x8d}))
+	})
+
+	It("gives hashes", func() {
+		h := crypto.New128a()
+		h.Write([]byte("foobar"))
+		Expect(h.Sum128()).To(Equal([]byte{0x34, 0x3e, 0x16, 0x62, 0x79, 0x3c, 0x64, 0xbf, 0x6f, 0xd, 0x35, 0x97, 0xba, 0x44, 0x6f, 0x18}))
+	})
+})