core-chain/ethutil/parsing.go

package ethutil

import (
	"errors"
	"fmt"
	"math/big"
	"strconv"
	"strings"
)

// Op codes
var OpCodes = map[string]string{
	"STOP":      "0",
	"ADD":       "1",
	"MUL":       "2",
	"SUB":       "3",
	"DIV":       "4",
	"SDIV":      "5",
	"MOD":       "6",
	"SMOD":      "7",
	"EXP":       "8",
	"NEG":       "9",
	"LT":        "10",
	"LE":        "11",
	"GT":        "12",
	"GE":        "13",
	"EQ":        "14",
	"NOT":       "15",
	"MYADDRESS": "16",
	"TXSENDER":  "17",

	"PUSH": "48",
	"POP":  "49",
	"LOAD": "54",
}

func CompileInstr(s string) (string, error) {
	tokens := strings.Split(s, " ")
	if OpCodes[tokens[0]] == "" {
		return s, errors.New(fmt.Sprintf("OP not found: %s", tokens[0]))
	}

	code := OpCodes[tokens[0]] // Replace op codes with the proper numerical equivalent
	op := new(big.Int)
	op.SetString(code, 0)

	args := make([]*big.Int, 6)
	for i, val := range tokens[1:len(tokens)] {
		num := new(big.Int)
		num.SetString(val, 0)
		args[i] = num
	}

	// Big int equation = op + x * 256 + y * 256**2 + z * 256**3 + a * 256**4 + b * 256**5 + c * 256**6
	base := new(big.Int)
	x := new(big.Int)
	y := new(big.Int)
	z := new(big.Int)
	a := new(big.Int)
	b := new(big.Int)
	c := new(big.Int)

	if args[0] != nil {
		x.Mul(args[0], big.NewInt(256))
	}
	if args[1] != nil {
		y.Mul(args[1], BigPow(256, 2))
	}
	if args[2] != nil {
		z.Mul(args[2], BigPow(256, 3))
	}
	if args[3] != nil {
		a.Mul(args[3], BigPow(256, 4))
	}
	if args[4] != nil {
		b.Mul(args[4], BigPow(256, 5))
	}
	if args[5] != nil {
		c.Mul(args[5], BigPow(256, 6))
	}

	base.Add(op, x)
	base.Add(base, y)
	base.Add(base, z)
	base.Add(base, a)
	base.Add(base, b)
	base.Add(base, c)

	return base.String(), nil
}

func Instr(instr string) (int, []string, error) {
	base := new(big.Int)
	base.SetString(instr, 0)

	args := make([]string, 7)
	for i := 0; i < 7; i++ {
		// int(int(val) / int(math.Pow(256,float64(i)))) % 256
		exp := BigPow(256, i)
		num := new(big.Int)
		num.Div(base, exp)

		args[i] = num.Mod(num, big.NewInt(256)).String()
	}
	op, _ := strconv.Atoi(args[0])

	return op, args[1:7], nil
}