// UnaryOp returns the result of the unary expression op y.
// The operation must be defined for the operand.
// If size >= 0 it specifies the ^ (xor) result size in bytes.
// If y is Unknown, the result is Unknown.
//
func UnaryOp(op token.Token, y Value, size int) Value {
switch op {
case token.ADD:
switch y.(type) {
case unknownVal, int64Val, intVal, floatVal, complexVal:
return y
}
case token.SUB:
switch y := y.(type) {
case unknownVal:
return y
case int64Val:
if z := -y; z != y {
return z // no overflow
}
return normInt(new(big.Int).Neg(big.NewInt(int64(y))))
case intVal:
return normInt(new(big.Int).Neg(y.val))
case floatVal:
return normFloat(new(big.Rat).Neg(y.val))
case complexVal:
return normComplex(new(big.Rat).Neg(y.re), new(big.Rat).Neg(y.im))
}
case token.XOR:
var z big.Int
switch y := y.(type) {
case unknownVal:
return y
case int64Val:
z.Not(big.NewInt(int64(y)))
case intVal:
z.Not(y.val)
default:
goto Error
}
// For unsigned types, the result will be negative and
// thus "too large": We must limit the result size to
// the type's size.
if size >= 0 {
s := uint(size) * 8
z.AndNot(&z, new(big.Int).Lsh(big.NewInt(-1), s)) // z &^= (-1)<<s
}
return normInt(&z)
case token.NOT:
switch y := y.(type) {
case unknownVal:
return y
case boolVal:
return !y
}
}
Error:
panic(fmt.Sprintf("invalid unary operation %s%v", op, y))
}
// unaryOpConst returns the result of the constant evaluation op x where x is of the given type.
func unaryOpConst(x interface{}, op token.Token, typ *Basic) interface{} {
switch op {
case token.ADD:
return x // nothing to do
case token.SUB:
switch x := x.(type) {
case int64:
if z := -x; z != x {
return z // no overflow
}
// overflow - need to convert to big.Int
return normalizeIntConst(new(big.Int).Neg(big.NewInt(x)))
case *big.Int:
return normalizeIntConst(new(big.Int).Neg(x))
case *big.Rat:
return normalizeRatConst(new(big.Rat).Neg(x))
case complex:
return newComplex(new(big.Rat).Neg(x.re), new(big.Rat).Neg(x.im))
}
case token.XOR:
var z big.Int
switch x := x.(type) {
case int64:
z.Not(big.NewInt(x))
case *big.Int:
z.Not(x)
default:
unreachable()
}
// For unsigned types, the result will be negative and
// thus "too large": We must limit the result size to
// the type's size.
if typ.Info&IsUnsigned != 0 {
s := uint(typ.Size) * 8
if s == 0 {
// platform-specific type
// TODO(gri) this needs to be factored out
switch typ.Kind {
case Uint:
s = intBits
case Uintptr:
s = ptrBits
default:
unreachable()
}
}
// z &^= (-1)<<s
z.AndNot(&z, new(big.Int).Lsh(big.NewInt(-1), s))
}
return normalizeIntConst(&z)
case token.NOT:
return !x.(bool)
}
unreachable()
return nil
}
func binaryIntOp(x *big.Int, op token.Token, y *big.Int) interface{} {
var z big.Int
switch op {
case token.ADD:
return z.Add(x, y)
case token.SUB:
return z.Sub(x, y)
case token.MUL:
return z.Mul(x, y)
case token.QUO:
return z.Quo(x, y)
case token.REM:
return z.Rem(x, y)
case token.AND:
return z.And(x, y)
case token.OR:
return z.Or(x, y)
case token.XOR:
return z.Xor(x, y)
case token.AND_NOT:
return z.AndNot(x, y)
case token.SHL:
// The shift length must be uint, or untyped int and
// convertible to uint.
// TODO 32/64bit
if y.BitLen() > 32 {
panic("Excessive shift length")
}
return z.Lsh(x, uint(y.Int64()))
case token.SHR:
if y.BitLen() > 32 {
panic("Excessive shift length")
}
return z.Rsh(x, uint(y.Int64()))
case token.EQL:
return x.Cmp(y) == 0
case token.NEQ:
return x.Cmp(y) != 0
case token.LSS:
return x.Cmp(y) < 0
case token.LEQ:
return x.Cmp(y) <= 0
case token.GTR:
return x.Cmp(y) > 0
case token.GEQ:
return x.Cmp(y) >= 0
}
panic("unreachable")
}
func bigIntAndNot(oldValues [][]byte, newValues [][]byte, w float64) (result [][]byte) {
var sum *big.Int
if oldValues != nil {
sum = new(big.Int).SetBytes(oldValues[0])
for _, b := range newValues {
sum.AndNot(sum, new(big.Int).Mul(common.DecodeBigInt(b), big.NewInt(int64(w))))
}
} else {
sum = new(big.Int).Mul(new(big.Int).SetBytes(newValues[0]), big.NewInt(int64(w)))
for _, b := range newValues[1:] {
sum.AndNot(sum, new(big.Int).Mul(common.DecodeBigInt(b), big.NewInt(int64(w))))
}
}
return [][]byte{sum.Bytes()}
}
// unaryOpConst returns the result of the constant evaluation op x where x is of the given type.
func unaryOpConst(x interface{}, ctxt *Context, op token.Token, typ *Basic) interface{} {
switch op {
case token.ADD:
return x // nothing to do
case token.SUB:
switch x := x.(type) {
case int64:
if z := -x; z != x {
return z // no overflow
}
// overflow - need to convert to big.Int
return normalizeIntConst(new(big.Int).Neg(big.NewInt(x)))
case *big.Int:
return normalizeIntConst(new(big.Int).Neg(x))
case *big.Rat:
return normalizeRatConst(new(big.Rat).Neg(x))
case Complex:
return newComplex(new(big.Rat).Neg(x.Re), new(big.Rat).Neg(x.Im))
}
case token.XOR:
var z big.Int
switch x := x.(type) {
case int64:
z.Not(big.NewInt(x))
case *big.Int:
z.Not(x)
default:
unreachable()
}
// For unsigned types, the result will be negative and
// thus "too large": We must limit the result size to
// the type's size.
if typ.Info&IsUnsigned != 0 {
s := uint(ctxt.sizeof(typ)) * 8
z.AndNot(&z, new(big.Int).Lsh(big.NewInt(-1), s)) // z &^= (-1)<<s
}
return normalizeIntConst(&z)
case token.NOT:
return !x.(bool)
}
unreachable()
return nil
}
func binaryIntOp(x *big.Int, op token.Token, y *big.Int) interface{} {
var z big.Int
switch op {
case token.ADD:
return z.Add(x, y)
case token.SUB:
return z.Sub(x, y)
case token.MUL:
return z.Mul(x, y)
case token.QUO:
return z.Quo(x, y)
case token.REM:
return z.Rem(x, y)
case token.AND:
return z.And(x, y)
case token.OR:
return z.Or(x, y)
case token.XOR:
return z.Xor(x, y)
case token.AND_NOT:
return z.AndNot(x, y)
case token.SHL:
panic("unimplemented")
case token.SHR:
panic("unimplemented")
case token.EQL:
return x.Cmp(y) == 0
case token.NEQ:
return x.Cmp(y) != 0
case token.LSS:
return x.Cmp(y) < 0
case token.LEQ:
return x.Cmp(y) <= 0
case token.GTR:
return x.Cmp(y) > 0
case token.GEQ:
return x.Cmp(y) >= 0
}
panic("unreachable")
}
// binaryOpConst returns the result of the constant evaluation x op y;
// both operands must be of the same "kind" (boolean, numeric, or string).
// If intDiv is true, division (op == token.QUO) is using integer division
// (and the result is guaranteed to be integer) rather than floating-point
// division. Division by zero leads to a run-time panic.
//
func binaryOpConst(x, y interface{}, op token.Token, intDiv bool) interface{} {
x, y = matchConst(x, y)
switch x := x.(type) {
case bool:
y := y.(bool)
switch op {
case token.LAND:
return x && y
case token.LOR:
return x || y
default:
unreachable()
}
case int64:
y := y.(int64)
switch op {
case token.ADD:
// TODO(gri) can do better than this
if is63bit(x) && is63bit(y) {
return x + y
}
return normalizeIntConst(new(big.Int).Add(big.NewInt(x), big.NewInt(y)))
case token.SUB:
// TODO(gri) can do better than this
if is63bit(x) && is63bit(y) {
return x - y
}
return normalizeIntConst(new(big.Int).Sub(big.NewInt(x), big.NewInt(y)))
case token.MUL:
// TODO(gri) can do better than this
if is32bit(x) && is32bit(y) {
return x * y
}
return normalizeIntConst(new(big.Int).Mul(big.NewInt(x), big.NewInt(y)))
case token.REM:
return x % y
case token.QUO:
if intDiv {
return x / y
}
return normalizeRatConst(new(big.Rat).SetFrac(big.NewInt(x), big.NewInt(y)))
case token.AND:
return x & y
case token.OR:
return x | y
case token.XOR:
return x ^ y
case token.AND_NOT:
return x &^ y
default:
unreachable()
}
case *big.Int:
y := y.(*big.Int)
var z big.Int
switch op {
case token.ADD:
z.Add(x, y)
case token.SUB:
z.Sub(x, y)
case token.MUL:
z.Mul(x, y)
case token.REM:
z.Rem(x, y)
case token.QUO:
if intDiv {
z.Quo(x, y)
} else {
return normalizeRatConst(new(big.Rat).SetFrac(x, y))
}
case token.AND:
z.And(x, y)
case token.OR:
z.Or(x, y)
case token.XOR:
z.Xor(x, y)
case token.AND_NOT:
z.AndNot(x, y)
default:
unreachable()
}
return normalizeIntConst(&z)
case *big.Rat:
y := y.(*big.Rat)
var z big.Rat
switch op {
case token.ADD:
z.Add(x, y)
case token.SUB:
z.Sub(x, y)
case token.MUL:
z.Mul(x, y)
case token.QUO:
z.Quo(x, y)
default:
unreachable()
}
return normalizeRatConst(&z)
case complex:
y := y.(complex)
a, b := x.re, x.im
c, d := y.re, y.im
var re, im big.Rat
switch op {
case token.ADD:
// (a+c) + i(b+d)
re.Add(a, c)
im.Add(b, d)
case token.SUB:
// (a-c) + i(b-d)
re.Sub(a, c)
im.Sub(b, d)
case token.MUL:
// (ac-bd) + i(bc+ad)
var ac, bd, bc, ad big.Rat
ac.Mul(a, c)
bd.Mul(b, d)
bc.Mul(b, c)
ad.Mul(a, d)
re.Sub(&ac, &bd)
im.Add(&bc, &ad)
case token.QUO:
// (ac+bd)/s + i(bc-ad)/s, with s = cc + dd
var ac, bd, bc, ad, s big.Rat
ac.Mul(a, c)
bd.Mul(b, d)
bc.Mul(b, c)
ad.Mul(a, d)
s.Add(c.Mul(c, c), d.Mul(d, d))
re.Add(&ac, &bd)
re.Quo(&re, &s)
im.Sub(&bc, &ad)
im.Quo(&im, &s)
default:
unreachable()
}
return normalizeComplexConst(complex{&re, &im})
case string:
if op == token.ADD {
return x + y.(string)
}
}
unreachable()
return nil
}
// Post-order traversal, equivalent to postfix notation.
func Eval(node interface{}) (*big.Int, error) {
switch nn := node.(type) {
case *ast.BinaryExpr:
z := new(big.Int)
x, xerr := Eval(nn.X)
if xerr != nil {
return nil, xerr
}
y, yerr := Eval(nn.Y)
if yerr != nil {
return nil, yerr
}
switch nn.Op {
case token.ADD:
return z.Add(x, y), nil
case token.SUB:
return z.Sub(x, y), nil
case token.MUL:
return z.Mul(x, y), nil
case token.QUO:
if y.Sign() == 0 { // 0 denominator
return nil, DivideByZero
}
return z.Quo(x, y), nil
case token.REM:
if y.Sign() == 0 {
return nil, DivideByZero
}
return z.Rem(x, y), nil
case token.AND:
return z.And(x, y), nil
case token.OR:
return z.Or(x, y), nil
case token.XOR:
return z.Xor(x, y), nil
case token.SHL:
if y.Sign() < 0 { // negative shift
return nil, NegativeShift
}
return z.Lsh(x, uint(y.Int64())), nil
case token.SHR:
if y.Sign() < 0 {
return nil, NegativeShift
}
return z.Rsh(x, uint(y.Int64())), nil
case token.AND_NOT:
return z.AndNot(x, y), nil
default:
return nil, UnknownOpErr
}
case *ast.UnaryExpr:
var z *big.Int
var err error
if z, err = Eval(nn.X); err != nil {
return nil, err
}
switch nn.Op {
case token.SUB: // -x
return z.Neg(z), nil
case token.XOR: // ^x
return z.Not(z), nil
case token.ADD: // +x (useless)
return z, nil
}
case *ast.BasicLit:
z := new(big.Int)
switch nn.Kind {
case token.INT:
z.SetString(nn.Value, 0)
return z, nil
default:
return nil, UnknownLitErr
}
case *ast.ParenExpr:
z, err := Eval(nn.X)
if err != nil {
return nil, err
}
return z, nil
case *ast.CallExpr:
ident, ok := nn.Fun.(*ast.Ident)
if !ok {
return nil, UnknownTokenErr // quarter to four am; dunno correct error
}
var f Func
f, ok = FuncMap[ident.Name]
if !ok {
return nil, UnknownFuncErr
}
var aerr error
args := make([]*big.Int, len(nn.Args))
for i, a := range nn.Args {
if args[i], aerr = Eval(a); aerr != nil {
return nil, aerr
}
}
x, xerr := f(args...)
if xerr != nil {
return nil, xerr
}
return x, nil
}
return nil, UnknownTokenErr
}