From dcba2159eb65d0f08b5643c401b9f8d62eb31e67 Mon Sep 17 00:00:00 2001
From: dm4 <dm4@skymizer.com>
Date: Tue, 26 Mar 2019 18:21:43 +0800
Subject: core/vm/dvm: add random into eei of dvm

random in EEI is the same as opRand implemented in core/vm/evm/instructions.go
---
 core/vm/dvm/eei.go    | 31 +++++++++++++++++++++++++++++++
 core/vm/dvm/linker.go |  1 +
 2 files changed, 32 insertions(+)

(limited to 'core')

diff --git a/core/vm/dvm/eei.go b/core/vm/dvm/eei.go
index df97438b6..35074fa61 100644
--- a/core/vm/dvm/eei.go
+++ b/core/vm/dvm/eei.go
@@ -20,6 +20,7 @@
 package dvm
 
 import (
+	"encoding/binary"
 	"fmt"
 	"math/big"
 	"reflect"
@@ -68,6 +69,7 @@ const (
 	GasCostLogTopic       = 375
 	GasCostCopy           = 3
 	GasCostBlockHash      = 800
+	GasCostRandom         = 800
 )
 
 var eeiTypes = &wasm.SectionTypes{
@@ -351,6 +353,11 @@ func eeiFuncs(in *DVM) []wasm.Function {
 			Host: reflect.ValueOf(func(p *exec.Process) int64 { return getBlockTimestamp(p, in) }),
 			Body: &wasm.FunctionBody{},
 		},
+		{
+			Sig:  &eeiTypes.Entries[12],
+			Host: reflect.ValueOf(func(p *exec.Process) int64 { return random(p, in) }),
+			Body: &wasm.FunctionBody{},
+		},
 	}
 }
 
@@ -1005,3 +1012,27 @@ func getBlockTimestamp(p *exec.Process, in *DVM) int64 {
 	in.gasAccounting(GasCostBase)
 	return in.Time.Int64()
 }
+
+func random(p *exec.Process, in *DVM) int64 {
+	in.gasAccounting(GasCostRandom)
+
+	nonce := in.StateDB().GetNonce(in.Origin)
+	binaryOriginNonce := make([]byte, binary.MaxVarintLen64)
+	binary.PutUvarint(binaryOriginNonce, nonce)
+
+	binaryUsedIndex := make([]byte, binary.MaxVarintLen64)
+	binary.PutUvarint(binaryUsedIndex, in.RandCallIndex)
+
+	in.RandCallIndex += 1
+
+	hash := crypto.Keccak256(
+		in.Randomness,
+		in.Origin.Bytes(),
+		binaryOriginNonce,
+		binaryUsedIndex)
+
+	ret := big.NewInt(0)
+	ret.SetBytes(hash)
+
+	return ret.Int64()
+}
diff --git a/core/vm/dvm/linker.go b/core/vm/dvm/linker.go
index eb57f8b79..e22a982d2 100644
--- a/core/vm/dvm/linker.go
+++ b/core/vm/dvm/linker.go
@@ -56,6 +56,7 @@ var eeiFunctionList = []string{
 	"returnDataCopy",
 	"selfDestruct",
 	"getBlockTimestamp",
+	"random",
 }
 
 var debugFunctionList = []string{
-- 
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