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package main
import (
_"math"
"math/big"
"fmt"
_"strconv"
_ "encoding/hex"
"strconv"
)
// Op codes
const (
oSTOP int = 0x00
oADD int = 0x01
oMUL int = 0x02
oSUB int = 0x03
oDIV int = 0x04
oSDIV int = 0x05
oMOD int = 0x06
oSMOD int = 0x07
oEXP int = 0x08
oNEG int = 0x09
oLT int = 0x0a
oLE int = 0x0b
oGT int = 0x0c
oGE int = 0x0d
oEQ int = 0x0e
oNOT int = 0x0f
oMYADDRESS int = 0x10
oTXSENDER int = 0x11
oPUSH int = 0x30
oPOP int = 0x31
oLOAD int = 0x36
)
type OpType int
const (
tNorm = iota
tData
tExtro
tCrypto
)
type TxCallback func(opType OpType) bool
// Simple push/pop stack mechanism
type Stack struct {
data []string
}
func NewStack() *Stack {
return &Stack{}
}
func (st *Stack) Pop() string {
s := len(st.data)
str := st.data[s-1]
st.data = st.data[:s-1]
return str
}
func (st *Stack) Popn() (*big.Int, *big.Int) {
s := len(st.data)
strs := st.data[s-2:]
st.data = st.data[:s-2]
return Big(strs[0]), Big(strs[1])
}
func (st *Stack) Push(d string) {
st.data = append(st.data, d)
}
func (st *Stack) Print() {
fmt.Println(st.data)
}
type Vm struct {
// Stack
stack *Stack
}
func NewVm() *Vm {
return &Vm{
stack: NewStack(),
}
}
func (vm *Vm) ProcContract(tx *Transaction, block *Block, cb TxCallback) {
// Instruction pointer
pc := 0
contract := block.GetContract(tx.Hash())
if contract == nil {
fmt.Println("Contract not found")
return
}
Pow256 := BigPow(2, 256)
fmt.Printf("# op arg\n")
out:
for {
// The base big int for all calculations. Use this for any results.
base := new(big.Int)
// XXX Should Instr return big int slice instead of string slice?
// Get the next instruction from the contract
//op, _, _ := Instr(contract.state.Get(string(Encode(uint32(pc)))))
op, _, _ := Instr(contract.state.Get(string(NumberToBytes(uint64(pc), 32))))
if !cb(0) { break }
if Debug {
fmt.Printf("%-3d %-4d\n", pc, op)
}
switch op {
case oADD:
x, y := vm.stack.Popn()
// (x + y) % 2 ** 256
base.Add(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oSUB:
x, y := vm.stack.Popn()
// (x - y) % 2 ** 256
base.Sub(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oMUL:
x, y := vm.stack.Popn()
// (x * y) % 2 ** 256
base.Mul(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oDIV:
x, y := vm.stack.Popn()
// floor(x / y)
base.Div(x, y)
// Pop result back on the stack
vm.stack.Push(base.String())
case oSDIV:
x, y := vm.stack.Popn()
// n > 2**255
if x.Cmp(Pow256) > 0 { x.Sub(Pow256, x) }
if y.Cmp(Pow256) > 0 { y.Sub(Pow256, y) }
z := new(big.Int)
z.Div(x, y)
if z.Cmp(Pow256) > 0 { z.Sub(Pow256, z) }
// Push result on to the stack
vm.stack.Push(z.String())
case oMOD:
x, y := vm.stack.Popn()
base.Mod(x, y)
vm.stack.Push(base.String())
case oSMOD:
x, y := vm.stack.Popn()
// n > 2**255
if x.Cmp(Pow256) > 0 { x.Sub(Pow256, x) }
if y.Cmp(Pow256) > 0 { y.Sub(Pow256, y) }
z := new(big.Int)
z.Mod(x, y)
if z.Cmp(Pow256) > 0 { z.Sub(Pow256, z) }
// Push result on to the stack
vm.stack.Push(z.String())
case oEXP:
x, y := vm.stack.Popn()
base.Exp(x, y, Pow256)
vm.stack.Push(base.String())
case oNEG:
base.Sub(Pow256, Big(vm.stack.Pop()))
vm.stack.Push(base.String())
case oLT:
x, y := vm.stack.Popn()
// x < y
if x.Cmp(y) < 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oLE:
x, y := vm.stack.Popn()
// x <= y
if x.Cmp(y) < 1 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oGT:
x, y := vm.stack.Popn()
// x > y
if x.Cmp(y) > 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oGE:
x, y := vm.stack.Popn()
// x >= y
if x.Cmp(y) > -1 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oNOT:
x, y := vm.stack.Popn()
// x != y
if x.Cmp(y) != 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oMYADDRESS:
vm.stack.Push(string(tx.Hash()))
case oTXSENDER:
vm.stack.Push(tx.sender)
case oPUSH:
// Get the next entry and pushes the value on the stack
pc++
vm.stack.Push(contract.state.Get(string(NumberToBytes(uint64(pc), 32))))
case oPOP:
// Pop current value of the stack
vm.stack.Pop()
case oLOAD:
// Load instruction X on the stack
i, _ := strconv.Atoi(vm.stack.Pop())
vm.stack.Push(contract.state.Get(string(NumberToBytes(uint64(i), 32))))
case oSTOP:
break out
}
pc++
}
vm.stack.Print()
}
|
