Implemented BigInt (#597)

Closes #556

builtin_bigint.go

@@ -0,0 +1,369 @@
+package goja
+
+import (
+	"fmt"
+	"hash/maphash"
+	"math"
+	"math/big"
+	"reflect"
+	"strconv"
+	"sync"
+
+	"github.com/dop251/goja/unistring"
+)
+
+type valueBigInt big.Int
+
+func (v *valueBigInt) ToInteger() int64 {
+	v.ToNumber()
+	return 0
+}
+
+func (v *valueBigInt) toString() String {
+	return asciiString((*big.Int)(v).String())
+}
+
+func (v *valueBigInt) string() unistring.String {
+	return unistring.String(v.String())
+}
+
+func (v *valueBigInt) ToString() Value {
+	return v
+}
+
+func (v *valueBigInt) String() string {
+	return (*big.Int)(v).String()
+}
+
+func (v *valueBigInt) ToFloat() float64 {
+	v.ToNumber()
+	return 0
+}
+
+func (v *valueBigInt) ToNumber() Value {
+	panic(typeError("Cannot convert a BigInt value to a number"))
+}
+
+func (v *valueBigInt) ToBoolean() bool {
+	return (*big.Int)(v).Sign() != 0
+}
+
+func (v *valueBigInt) ToObject(r *Runtime) *Object {
+	return r.newPrimitiveObject(v, r.getBigIntPrototype(), classObject)
+}
+
+func (v *valueBigInt) SameAs(other Value) bool {
+	if o, ok := other.(*valueBigInt); ok {
+		return (*big.Int)(v).Cmp((*big.Int)(o)) == 0
+	}
+	return false
+}
+
+func (v *valueBigInt) Equals(other Value) bool {
+	switch o := other.(type) {
+	case *valueBigInt:
+		return (*big.Int)(v).Cmp((*big.Int)(o)) == 0
+	case valueInt:
+		return (*big.Int)(v).Cmp(big.NewInt(int64(o))) == 0
+	case valueFloat:
+		if IsInfinity(o) || math.IsNaN(float64(o)) {
+			return false
+		}
+		if f := big.NewFloat(float64(o)); f.IsInt() {
+			i, _ := f.Int(nil)
+			return (*big.Int)(v).Cmp(i) == 0
+		}
+		return false
+	case String:
+		bigInt, err := stringToBigInt(o.toTrimmedUTF8())
+		if err != nil {
+			return false
+		}
+		return bigInt.Cmp((*big.Int)(v)) == 0
+	case valueBool:
+		return (*big.Int)(v).Int64() == o.ToInteger()
+	case *Object:
+		return v.Equals(o.toPrimitiveNumber())
+	}
+	return false
+}
+
+func (v *valueBigInt) StrictEquals(other Value) bool {
+	o, ok := other.(*valueBigInt)
+	if ok {
+		return (*big.Int)(v).Cmp((*big.Int)(o)) == 0
+	}
+	return false
+}
+
+func (v *valueBigInt) Export() interface{} {
+	return new(big.Int).Set((*big.Int)(v))
+}
+
+func (v *valueBigInt) ExportType() reflect.Type {
+	return typeBigInt
+}
+
+func (v *valueBigInt) baseObject(rt *Runtime) *Object {
+	return rt.getBigIntPrototype()
+}
+
+func (v *valueBigInt) hash(hash *maphash.Hash) uint64 {
+	var sign byte
+	if (*big.Int)(v).Sign() < 0 {
+		sign = 0x01
+	} else {
+		sign = 0x00
+	}
+	_ = hash.WriteByte(sign)
+	_, _ = hash.Write((*big.Int)(v).Bytes())
+	h := hash.Sum64()
+	hash.Reset()
+	return h
+}
+
+func toBigInt(value Value) *valueBigInt {
+	// Undefined	Throw a TypeError exception.
+	// Null			Throw a TypeError exception.
+	// Boolean		Return 1n if prim is true and 0n if prim is false.
+	// BigInt		Return prim.
+	// Number		Throw a TypeError exception.
+	// String		1. Let n be StringToBigInt(prim).
+	//				2. If n is undefined, throw a SyntaxError exception.
+	//				3. Return n.
+	// Symbol		Throw a TypeError exception.
+	switch prim := value.(type) {
+	case *valueBigInt:
+		return prim
+	case String:
+		bigInt, err := stringToBigInt(prim.toTrimmedUTF8())
+		if err != nil {
+			panic(syntaxError(fmt.Sprintf("Cannot convert %s to a BigInt", prim)))
+		}
+		return (*valueBigInt)(bigInt)
+	case valueBool:
+		return (*valueBigInt)(big.NewInt(prim.ToInteger()))
+	case *Symbol:
+		panic(typeError("Cannot convert Symbol to a BigInt"))
+	case *Object:
+		return toBigInt(prim.toPrimitiveNumber())
+	default:
+		panic(typeError(fmt.Sprintf("Cannot convert %s to a BigInt", prim)))
+	}
+}
+
+func numberToBigInt(v Value) *valueBigInt {
+	switch v := toNumeric(v).(type) {
+	case *valueBigInt:
+		return v
+	case valueInt:
+		return (*valueBigInt)(big.NewInt(v.ToInteger()))
+	case valueFloat:
+		if IsInfinity(v) || math.IsNaN(float64(v)) {
+			panic(rangeError(fmt.Sprintf("Cannot convert %s to a BigInt", v)))
+		}
+		if f := big.NewFloat(float64(v)); f.IsInt() {
+			n, _ := f.Int(nil)
+			return (*valueBigInt)(n)
+		}
+		panic(rangeError(fmt.Sprintf("Cannot convert %s to a BigInt", v)))
+	case *Object:
+		prim := v.toPrimitiveNumber()
+		switch prim.(type) {
+		case valueInt, valueFloat:
+			return numberToBigInt(prim)
+		default:
+			return toBigInt(prim)
+		}
+	default:
+		panic(newTypeError("Cannot convert %s to a BigInt", v))
+	}
+}
+
+func stringToBigInt(str string) (*big.Int, error) {
+	var bigint big.Int
+	n, err := stringToInt(str)
+	if err != nil {
+		switch {
+		case isRangeErr(err):
+			bigint.SetString(str, 0)
+		case err == strconv.ErrSyntax:
+		default:
+			return nil, strconv.ErrSyntax
+		}
+	} else {
+		bigint.SetInt64(n)
+	}
+	return &bigint, nil
+}
+
+func (r *Runtime) thisBigIntValue(value Value) Value {
+	switch t := value.(type) {
+	case *valueBigInt:
+		return t
+	case *Object:
+		switch t := t.self.(type) {
+		case *primitiveValueObject:
+			return r.thisBigIntValue(t.pValue)
+		case *objectGoReflect:
+			if t.exportType() == typeBigInt && t.valueOf != nil {
+				return t.valueOf()
+			}
+		}
+	}
+	panic(r.NewTypeError("requires that 'this' be a BigInt"))
+}
+
+func (r *Runtime) bigintproto_valueOf(call FunctionCall) Value {
+	return r.thisBigIntValue(call.This)
+}
+
+func (r *Runtime) bigintproto_toString(call FunctionCall) Value {
+	x := (*big.Int)(r.thisBigIntValue(call.This).(*valueBigInt))
+	radix := call.Argument(0)
+	var radixMV int
+
+	if radix == _undefined {
+		radixMV = 10
+	} else {
+		radixMV = int(radix.ToInteger())
+		if radixMV < 2 || radixMV > 36 {
+			panic(r.newError(r.getRangeError(), "radix must be an integer between 2 and 36"))
+		}
+	}
+
+	return asciiString(x.Text(radixMV))
+}
+
+func (r *Runtime) bigint_asIntN(call FunctionCall) Value {
+	if len(call.Arguments) < 2 {
+		panic(r.NewTypeError("Cannot convert undefined to a BigInt"))
+	}
+	bits := r.toIndex(call.Argument(0).ToNumber())
+	if bits < 0 {
+		panic(r.NewTypeError("Invalid value: not (convertible to) a safe integer"))
+	}
+	bigint := toBigInt(call.Argument(1))
+
+	twoToBits := new(big.Int).Lsh(big.NewInt(1), uint(bits))
+	mod := new(big.Int).Mod((*big.Int)(bigint), twoToBits)
+	if bits > 0 && mod.Cmp(new(big.Int).Lsh(big.NewInt(1), uint(bits-1))) >= 0 {
+		return (*valueBigInt)(mod.Sub(mod, twoToBits))
+	} else {
+		return (*valueBigInt)(mod)
+	}
+}
+
+func (r *Runtime) bigint_asUintN(call FunctionCall) Value {
+	if len(call.Arguments) < 2 {
+		panic(r.NewTypeError("Cannot convert undefined to a BigInt"))
+	}
+	bits := r.toIndex(call.Argument(0).ToNumber())
+	if bits < 0 {
+		panic(r.NewTypeError("Invalid value: not (convertible to) a safe integer"))
+	}
+	bigint := (*big.Int)(toBigInt(call.Argument(1)))
+	ret := new(big.Int).Mod(bigint, new(big.Int).Lsh(big.NewInt(1), uint(bits)))
+	return (*valueBigInt)(ret)
+}
+
+var bigintTemplate *objectTemplate
+var bigintTemplateOnce sync.Once
+
+func getBigIntTemplate() *objectTemplate {
+	bigintTemplateOnce.Do(func() {
+		bigintTemplate = createBigIntTemplate()
+	})
+	return bigintTemplate
+}
+
+func createBigIntTemplate() *objectTemplate {
+	t := newObjectTemplate()
+	t.protoFactory = func(r *Runtime) *Object {
+		return r.getFunctionPrototype()
+	}
+
+	t.putStr("name", func(r *Runtime) Value { return valueProp(asciiString("BigInt"), false, false, true) })
+	t.putStr("length", func(r *Runtime) Value { return valueProp(intToValue(1), false, false, true) })
+	t.putStr("prototype", func(r *Runtime) Value { return valueProp(r.getBigIntPrototype(), false, false, false) })
+
+	t.putStr("asIntN", func(r *Runtime) Value { return r.methodProp(r.bigint_asIntN, "asIntN", 2) })
+	t.putStr("asUintN", func(r *Runtime) Value { return r.methodProp(r.bigint_asUintN, "asUintN", 2) })
+
+	return t
+}
+
+func (r *Runtime) builtin_BigInt(call FunctionCall) Value {
+	if len(call.Arguments) > 0 {
+		switch v := call.Argument(0).(type) {
+		case *valueBigInt, valueInt, valueFloat, *Object:
+			return numberToBigInt(v)
+		default:
+			return toBigInt(v)
+		}
+	}
+	return (*valueBigInt)(big.NewInt(0))
+}
+
+func (r *Runtime) builtin_newBigInt(args []Value, newTarget *Object) *Object {
+	if newTarget != nil {
+		panic(r.NewTypeError("BigInt is not a constructor"))
+	}
+	var v Value
+	if len(args) > 0 {
+		v = numberToBigInt(args[0])
+	} else {
+		v = (*valueBigInt)(big.NewInt(0))
+	}
+	return r.newPrimitiveObject(v, newTarget, classObject)
+}
+
+func (r *Runtime) getBigInt() *Object {
+	ret := r.global.BigInt
+	if ret == nil {
+		ret = &Object{runtime: r}
+		r.global.BigInt = ret
+		r.newTemplatedFuncObject(getBigIntTemplate(), ret, r.builtin_BigInt,
+			r.wrapNativeConstruct(r.builtin_newBigInt, ret, r.getBigIntPrototype()))
+	}
+	return ret
+}
+
+func createBigIntProtoTemplate() *objectTemplate {
+	t := newObjectTemplate()
+	t.protoFactory = func(r *Runtime) *Object {
+		return r.global.ObjectPrototype
+	}
+
+	t.putStr("length", func(r *Runtime) Value { return valueProp(intToValue(0), false, false, true) })
+	t.putStr("name", func(r *Runtime) Value { return valueProp(asciiString("BigInt"), false, false, true) })
+	t.putStr("constructor", func(r *Runtime) Value { return valueProp(r.getBigInt(), true, false, true) })
+
+	t.putStr("toLocaleString", func(r *Runtime) Value { return r.methodProp(r.bigintproto_toString, "toLocaleString", 0) })
+	t.putStr("toString", func(r *Runtime) Value { return r.methodProp(r.bigintproto_toString, "toString", 0) })
+	t.putStr("valueOf", func(r *Runtime) Value { return r.methodProp(r.bigintproto_valueOf, "valueOf", 0) })
+	t.putSym(SymToStringTag, func(r *Runtime) Value { return valueProp(asciiString("BigInt"), false, false, true) })
+
+	return t
+}
+
+var bigintProtoTemplate *objectTemplate
+var bigintProtoTemplateOnce sync.Once
+
+func getBigIntProtoTemplate() *objectTemplate {
+	bigintProtoTemplateOnce.Do(func() {
+		bigintProtoTemplate = createBigIntProtoTemplate()
+	})
+	return bigintProtoTemplate
+}
+
+func (r *Runtime) getBigIntPrototype() *Object {
+	ret := r.global.BigIntPrototype
+	if ret == nil {
+		ret = &Object{runtime: r}
+		r.global.BigIntPrototype = ret
+		o := r.newTemplatedObject(getBigIntProtoTemplate(), ret)
+		o.class = classObject
+	}
+	return ret
+}