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authorJoshua Sjoding <joshua.sjoding@scjalliance.com>2016-02-25 10:13:13 -0800
committerJoshua Sjoding <joshua.sjoding@scjalliance.com>2016-02-25 10:13:13 -0800
commit397526522d8b81a1485671146acb0ed58a6bfa98 (patch)
tree3b96f28ce8196f290522dd8983a4965fdbd090f0
parent5bc563727ffa798caee3b007c366eb66c3d69caa (diff)
downloadgo-git-397526522d8b81a1485671146acb0ed58a6bfa98.tar.gz
Added Hasher for computing hashes of streamed objects
-rw-r--r--core/hash.go29
-rw-r--r--core/hash_test.go7
2 files changed, 29 insertions, 7 deletions
diff --git a/core/hash.go b/core/hash.go
index 9b30b6e..c50ffb2 100644
--- a/core/hash.go
+++ b/core/hash.go
@@ -3,6 +3,7 @@ package core
import (
"crypto/sha1"
"encoding/hex"
+ "hash"
"strconv"
)
@@ -14,13 +15,9 @@ var ZeroHash Hash
// ComputeHash compute the hash for a given ObjectType and content
func ComputeHash(t ObjectType, content []byte) Hash {
- h := t.Bytes()
- h = append(h, ' ')
- h = strconv.AppendInt(h, int64(len(content)), 10)
- h = append(h, 0)
- h = append(h, content...)
-
- return Hash(sha1.Sum(h))
+ h := NewHasher(t, int64(len(content)))
+ h.Write(content)
+ return h.Sum()
}
// NewHash return a new Hash from a hexadecimal hash representation
@@ -41,3 +38,21 @@ func (h Hash) IsZero() bool {
func (h Hash) String() string {
return hex.EncodeToString(h[:])
}
+
+type Hasher struct {
+ hash.Hash
+}
+
+func NewHasher(t ObjectType, size int64) Hasher {
+ h := Hasher{sha1.New()}
+ h.Write(t.Bytes())
+ h.Write([]byte(" "))
+ h.Write([]byte(strconv.FormatInt(size, 10)))
+ h.Write([]byte{0})
+ return h
+}
+
+func (h Hasher) Sum() (hash Hash) {
+ copy(hash[:], h.Hash.Sum(nil))
+ return
+}
diff --git a/core/hash_test.go b/core/hash_test.go
index 8c4ed67..782777e 100644
--- a/core/hash_test.go
+++ b/core/hash_test.go
@@ -33,3 +33,10 @@ func (s *HashSuite) TestIsZero(c *C) {
hash = NewHash("8ab686eafeb1f44702738c8b0f24f2567c36da6d")
c.Assert(hash.IsZero(), Equals, false)
}
+
+func (s *HashSuite) TestNewHasher(c *C) {
+ content := "hasher test sample"
+ hasher := NewHasher(BlobObject, int64(len(content)))
+ hasher.Write([]byte(content))
+ c.Assert(hasher.Sum().String(), Equals, "dc42c3cc80028d0ec61f0a6b24cadd1c195c4dfc")
+}