From da80ee18611b399accc445411a699f9b174719fa Mon Sep 17 00:00:00 2001
From: mappu <mappu04@gmail.com>
Date: Sat, 25 Nov 2017 13:45:26 +1300
Subject: [PATCH] add tth package and test cases (currently non-functional)

--HG--
branch : adc
---
 tth.go      | 40 ++++++++++++++++++++++++++++++++++++++++
 tth_test.go | 25 +++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 tth.go
 create mode 100644 tth_test.go

diff --git a/tth.go b/tth.go
new file mode 100644
index 0000000..b7c3892
--- /dev/null
+++ b/tth.go
@@ -0,0 +1,40 @@
+package libnmdc
+
+import (
+	"encoding/base32"
+	"errors"
+
+	"github.com/cxmcc/tiger"
+)
+
+func tth(input []byte) (string, error) {
+	if len(input) > 1024 {
+		return "", errors.New("TTH content exceeded 1024 bytes")
+	}
+
+	leafHash := tiger.New()
+
+	//buff := make([]byte, 1024)
+	//leafHash.Write([]byte("\x00"))
+	//copy(buff[1:], []byte(input))
+	//leafHash.Write(buff)
+	//fmt.Printf("%#v\n", buff)
+
+	leafHash.Write([]byte("\x00" + string(input)))
+	leafHashBytes := leafHash.Sum(nil)
+
+	rootHash := tiger.New()
+	//rootHash.Write([]byte("\x01"))
+	//rootHash.Write(leafHashBytes)
+	rootHash.Write([]byte("\x01" + string(leafHashBytes)))
+	rootHashBytes := rootHash.Sum(nil)
+
+	/*
+	   * The Tiger Hash function, modified to prepend the specified byte to the input
+	    * data. This is useful for the THEX algorithm which prepends a 0x00 to leaf
+	    * nodes and 0x01 to the hash nodes.
+	    **/
+
+	// Definitely StdEncoding
+	return base32.StdEncoding.EncodeToString(rootHashBytes), nil
+}
diff --git a/tth_test.go b/tth_test.go
new file mode 100644
index 0000000..e4be70c
--- /dev/null
+++ b/tth_test.go
@@ -0,0 +1,25 @@
+package libnmdc
+
+import (
+	"testing"
+)
+
+func TestTTH(t *testing.T) {
+
+	// echo -n 'hello world' | tthsum
+	testCases := [][2]string{
+		[2]string{"hello world", "ZIIVRZDR2FD3W4KKNMNYUU3765LPPK7BWY64CHI"},
+		[2]string{"", "LWPNACQDBZRYXW3VHJVCJ64QBZNGHOHHHZWCLNQ"},
+	}
+
+	for _, testCase := range testCases {
+		input, expected := testCase[0], testCase[1]
+		result, err := tth([]byte(input))
+		if err != nil {
+			t.Fatalf("Error getting TTH for '%s': %s", input, err.Error())
+		}
+		if result != expected {
+			t.Fatalf("Wrong TTH for '%s' (got '%s' expected '%s')", input, result, expected)
+		}
+	}
+}