From cb845b9bc84dada9d03eb9d9cb9ccfa96c7ce06c Mon Sep 17 00:00:00 2001
From: obscuren <geffobscura@gmail.com>
Date: Fri, 10 Oct 2014 22:44:20 +0200
Subject: Implemented AR PoW

---
 pow/ar/rnd.go | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 pow/ar/rnd.go

(limited to 'pow/ar/rnd.go')

diff --git a/pow/ar/rnd.go b/pow/ar/rnd.go
new file mode 100644
index 000000000..4862d058d
--- /dev/null
+++ b/pow/ar/rnd.go
@@ -0,0 +1,66 @@
+package ar
+
+import (
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethcrypto"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+var b = big.NewInt
+
+type Node interface {
+	Big() *big.Int
+}
+
+type ByteNode []byte
+
+func (self ByteNode) Big() *big.Int {
+	return ethutil.BigD(ethutil.Encode([]byte(self)))
+}
+
+func Sha3(v interface{}) *big.Int {
+	if b, ok := v.(*big.Int); ok {
+		return ethutil.BigD(ethcrypto.Sha3(b.Bytes()))
+	} else if b, ok := v.([]interface{}); ok {
+		return ethutil.BigD(ethcrypto.Sha3(ethutil.Encode(b)))
+	} else if s, ok := v.([]*big.Int); ok {
+		v := make([]interface{}, len(s))
+		for i, b := range s {
+			v[i] = b
+		}
+
+		return ethutil.BigD(ethcrypto.Sha3(ethutil.Encode(v)))
+	}
+
+	return nil
+}
+
+type NumberGenerator interface {
+	rand(r *big.Int) *big.Int
+	rand64(r int64) *big.Int
+}
+
+type rnd struct {
+	seed *big.Int
+}
+
+func Rnd(s *big.Int) rnd {
+	return rnd{s}
+}
+
+func (self rnd) rand(r *big.Int) *big.Int {
+	o := b(0).Mod(self.seed, r)
+
+	self.seed.Div(self.seed, r)
+
+	if self.seed.Cmp(ethutil.BigPow(2, 64)) < 0 {
+		self.seed = Sha3(self.seed)
+	}
+
+	return o
+}
+
+func (self rnd) rand64(r int64) *big.Int {
+	return self.rand(b(r))
+}
-- 
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