1 files changed, 64 insertions, 0 deletions
diff --git a/ethutil/bytes.go b/ethutil/bytes.go
new file mode 100644
index 000000000..40903a5f1
--- /dev/null
+++ b/ethutil/bytes.go
@@ -0,0 +1,64 @@
+package ethutil
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+func NumberToBytes(num interface{}, bits int) []byte {
+	buf := new(bytes.Buffer)
+	err := binary.Write(buf, binary.BigEndian, num)
+	if err != nil {
+		fmt.Println("NumberToBytes failed:", err)
+	}
+
+	return buf.Bytes()[buf.Len()-(bits/8):]
+}
+
+func BytesToNumber(b []byte) uint64 {
+	var number uint64
+
+	// Make sure the buffer is 64bits
+	data := make([]byte, 8)
+	data = append(data[:len(b)], b...)
+
+	buf := bytes.NewReader(data)
+	err := binary.Read(buf, binary.BigEndian, &number)
+	if err != nil {
+		fmt.Println("BytesToNumber failed:", err)
+	}
+
+	return number
+}
+
+// Read variable integer in big endian
+func ReadVarint(reader *bytes.Reader) (ret uint64) {
+	if reader.Len() == 8 {
+		var num uint64
+		binary.Read(reader, binary.BigEndian, &num)
+		ret = uint64(num)
+	} else if reader.Len() == 4 {
+		var num uint32
+		binary.Read(reader, binary.BigEndian, &num)
+		ret = uint64(num)
+	} else if reader.Len() == 2 {
+		var num uint16
+		binary.Read(reader, binary.BigEndian, &num)
+		ret = uint64(num)
+	} else {
+		var num uint8
+		binary.Read(reader, binary.BigEndian, &num)
+		ret = uint64(num)
+	}
+
+	return ret
+}
+
+func BinaryLength(num int) int {
+	if num == 0 {
+		return 0
+	}
+
+	return 1 + BinaryLength(num>>8)
+}