From 1c4f5e2506a935cbb11fc7f21e11b2a5e1a23c37 Mon Sep 17 00:00:00 2001
From: Jae Kwon <jkwon.work@gmail.com>
Date: Wed, 4 Jun 2014 01:39:50 -0700
Subject: [PATCH] refactor out binary

---
 binary/binary.go                    |  9 +++++++++
 merkle/binary.go => binary/codec.go |  2 +-
 {merkle => binary}/int.go           | 24 +++++++++++------------
 {merkle => binary}/string.go        |  6 +++---
 merkle/iavl.go                      | 30 +++++++++++++++--------------
 merkle/iavl_test.go                 |  1 +
 merkle/types.go                     | 10 ++--------
 merkle/util.go                      | 24 +++++++++++++++++++++++
 8 files changed, 68 insertions(+), 38 deletions(-)
 create mode 100644 binary/binary.go
 rename merkle/binary.go => binary/codec.go (99%)
 rename {merkle => binary}/int.go (91%)
 rename {merkle => binary}/string.go (93%)

diff --git a/binary/binary.go b/binary/binary.go
new file mode 100644
index 000000000..f13e38b12
--- /dev/null
+++ b/binary/binary.go
@@ -0,0 +1,9 @@
+package binary
+
+import "io"
+
+type Binary interface {
+    ByteSize()      int
+    WriteTo(io.Writer) (int64, error)
+    Equals(Binary)  bool
+}
diff --git a/merkle/binary.go b/binary/codec.go
similarity index 99%
rename from merkle/binary.go
rename to binary/codec.go
index bddb9ae68..96e73e248 100644
--- a/merkle/binary.go
+++ b/binary/codec.go
@@ -1,4 +1,4 @@
-package merkle
+package binary
 
 const (
     TYPE_NIL        = byte(0x00)
diff --git a/merkle/int.go b/binary/int.go
similarity index 91%
rename from merkle/int.go
rename to binary/int.go
index cf12326ea..f7de9cd4d 100644
--- a/merkle/int.go
+++ b/binary/int.go
@@ -1,4 +1,4 @@
-package merkle
+package binary
 
 import (
     "io"
@@ -24,7 +24,7 @@ func (self Byte) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Byte) Less(other Key) bool {
+func (self Byte) Less(other Binary) bool {
     if o, ok := other.(Byte); ok {
         return self < o
     } else {
@@ -52,7 +52,7 @@ func (self Int8) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Int8) Less(other Key) bool {
+func (self Int8) Less(other Binary) bool {
     if o, ok := other.(Int8); ok {
         return self < o
     } else {
@@ -80,7 +80,7 @@ func (self UInt8) Equals(other Binary) bool {
     return self == other
 }
 
-func (self UInt8) Less(other Key) bool {
+func (self UInt8) Less(other Binary) bool {
     if o, ok := other.(UInt8); ok {
         return self < o
     } else {
@@ -108,7 +108,7 @@ func (self Int16) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Int16) Less(other Key) bool {
+func (self Int16) Less(other Binary) bool {
     if o, ok := other.(Int16); ok {
         return self < o
     } else {
@@ -136,7 +136,7 @@ func (self UInt16) Equals(other Binary) bool {
     return self == other
 }
 
-func (self UInt16) Less(other Key) bool {
+func (self UInt16) Less(other Binary) bool {
     if o, ok := other.(UInt16); ok {
         return self < o
     } else {
@@ -164,7 +164,7 @@ func (self Int32) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Int32) Less(other Key) bool {
+func (self Int32) Less(other Binary) bool {
     if o, ok := other.(Int32); ok {
         return self < o
     } else {
@@ -192,7 +192,7 @@ func (self UInt32) Equals(other Binary) bool {
     return self == other
 }
 
-func (self UInt32) Less(other Key) bool {
+func (self UInt32) Less(other Binary) bool {
     if o, ok := other.(UInt32); ok {
         return self < o
     } else {
@@ -220,7 +220,7 @@ func (self Int64) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Int64) Less(other Key) bool {
+func (self Int64) Less(other Binary) bool {
     if o, ok := other.(Int64); ok {
         return self < o
     } else {
@@ -248,7 +248,7 @@ func (self UInt64) Equals(other Binary) bool {
     return self == other
 }
 
-func (self UInt64) Less(other Key) bool {
+func (self UInt64) Less(other Binary) bool {
     if o, ok := other.(UInt64); ok {
         return self < o
     } else {
@@ -276,7 +276,7 @@ func (self Int) Equals(other Binary) bool {
     return self == other
 }
 
-func (self Int) Less(other Key) bool {
+func (self Int) Less(other Binary) bool {
     if o, ok := other.(Int); ok {
         return self < o
     } else {
@@ -303,7 +303,7 @@ func (self UInt) Equals(other Binary) bool {
     return self == other
 }
 
-func (self UInt) Less(other Key) bool {
+func (self UInt) Less(other Binary) bool {
     if o, ok := other.(UInt); ok {
         return self < o
     } else {
diff --git a/merkle/string.go b/binary/string.go
similarity index 93%
rename from merkle/string.go
rename to binary/string.go
index a7dc35092..3dd91cbe0 100644
--- a/merkle/string.go
+++ b/binary/string.go
@@ -1,4 +1,4 @@
-package merkle
+package binary
 
 import "io"
 import "bytes"
@@ -12,7 +12,7 @@ func (self String) Equals(other Binary) bool {
     return self == other
 }
 
-func (self String) Less(other Key) bool {
+func (self String) Less(other Binary) bool {
     if o, ok := other.(String); ok {
         return self < o
     } else {
@@ -49,7 +49,7 @@ func (self ByteSlice) Equals(other Binary) bool {
     }
 }
 
-func (self ByteSlice) Less(other Key) bool {
+func (self ByteSlice) Less(other Binary) bool {
     if o, ok := other.(ByteSlice); ok {
         return bytes.Compare(self, o) < 0 // -1 if a < b
     } else {
diff --git a/merkle/iavl.go b/merkle/iavl.go
index 008383b51..44680df0d 100644
--- a/merkle/iavl.go
+++ b/merkle/iavl.go
@@ -1,7 +1,7 @@
 package merkle
 
 import (
-    //"fmt"
+    . "github.com/tendermint/tendermint/binary"
     "bytes"
     "io"
     "crypto/sha256"
@@ -195,7 +195,7 @@ func (self *IAVLNode) Hash() (ByteSlice, uint64) {
     }
 
     hasher := sha256.New()
-    _, hashCount, err := self.saveToCountHashes(hasher)
+    _, hashCount, err := self.saveToCountHashes(hasher, false)
     if err != nil { panic(err) }
     self.hash = hasher.Sum(nil)
 
@@ -325,24 +325,26 @@ func (self *IAVLNode) ByteSize() int {
 }
 
 func (self *IAVLNode) WriteTo(w io.Writer) (n int64, err error) {
-    n, _, err = self.saveToCountHashes(w)
+    n, _, err = self.saveToCountHashes(w, true)
     return
 }
 
-func (self *IAVLNode) saveToCountHashes(w io.Writer) (n int64, hashCount uint64, err error) {
+func (self *IAVLNode) saveToCountHashes(w io.Writer, meta bool) (n int64, hashCount uint64, err error) {
     var _n int64
 
-    // height & size
-    _n, err = UInt8(self.height).WriteTo(w)
-    if err != nil { return } else { n += _n }
-    _n, err = UInt64(self.size).WriteTo(w)
-    if err != nil { return } else { n += _n }
+    if meta {
+        // height & size
+        _n, err = UInt8(self.height).WriteTo(w)
+        if err != nil { return } else { n += _n }
+        _n, err = UInt64(self.size).WriteTo(w)
+        if err != nil { return } else { n += _n }
 
-    // key
-    _n, err = Byte(GetBinaryType(self.key)).WriteTo(w)
-    if err != nil { return } else { n += _n }
-    _n, err = self.key.WriteTo(w)
-    if err != nil { return } else { n += _n }
+        // key
+        _n, err = Byte(GetBinaryType(self.key)).WriteTo(w)
+        if err != nil { return } else { n += _n }
+        _n, err = self.key.WriteTo(w)
+        if err != nil { return } else { n += _n }
+    }
 
     if self.height == 0 {
         // value
diff --git a/merkle/iavl_test.go b/merkle/iavl_test.go
index 9a6c11bed..c81f7298b 100644
--- a/merkle/iavl_test.go
+++ b/merkle/iavl_test.go
@@ -1,6 +1,7 @@
 package merkle
 
 import (
+    . "github.com/tendermint/tendermint/binary"
     "testing"
     "fmt"
     "os"
diff --git a/merkle/types.go b/merkle/types.go
index 3e2fbaa92..b379adba2 100644
--- a/merkle/types.go
+++ b/merkle/types.go
@@ -1,23 +1,17 @@
 package merkle
 
 import (
-    "io"
+    . "github.com/tendermint/tendermint/binary"
     "fmt"
 )
 
-type Binary interface {
-    ByteSize()      int
-    WriteTo(io.Writer) (int64, error)
-    Equals(Binary)  bool
-}
-
 type Value interface {
     Binary
 }
 
 type Key interface {
     Binary
-    Less(b Key)     bool
+    Less(b Binary)  bool
 }
 
 type Db interface {
diff --git a/merkle/util.go b/merkle/util.go
index f2183d913..0b5b7ebcf 100644
--- a/merkle/util.go
+++ b/merkle/util.go
@@ -1,10 +1,34 @@
 package merkle
 
 import (
+    . "github.com/tendermint/tendermint/binary"
     "os"
     "fmt"
+    "crypto/sha256"
 )
 
+/*
+Compute a deterministic merkle hash from a list of byteslices.
+*/
+func HashFromBinarySlice(items []Binary) ByteSlice {
+    switch len(items) {
+    case 0:
+        panic("Cannot compute hash of empty slice")
+    case 1:
+        hasher := sha256.New()
+        _, err := items[0].WriteTo(hasher)
+        if err != nil { panic(err) }
+        return ByteSlice(hasher.Sum(nil))
+    default:
+        hasher := sha256.New()
+        _, err := HashFromBinarySlice(items[0:len(items)/2]).WriteTo(hasher)
+        if err != nil { panic(err) }
+        _, err = HashFromBinarySlice(items[len(items)/2:]).WriteTo(hasher)
+        if err != nil { panic(err) }
+        return ByteSlice(hasher.Sum(nil))
+    }
+}
+
 func PrintIAVLNode(node *IAVLNode) {
     fmt.Println("==== NODE")
     if node != nil {