mirror of
https://github.com/RGBCube/serenity
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5dd5896588
This is a continuation of the previous commit. Calling initialize() is the first thing that's done after allocating a cell on the JS heap - and in the common case of allocating an object, that's where properties are assigned and intrinsics occasionally accessed. Since those are supposed to live on the realm eventually, this is another step into that direction.
106 lines
3.9 KiB
C++
106 lines
3.9 KiB
C++
/*
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* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/String.h>
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#include <LibJS/Runtime/AbstractOperations.h>
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#include <LibJS/Runtime/BigInt.h>
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#include <LibJS/Runtime/BigIntConstructor.h>
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#include <LibJS/Runtime/BigIntObject.h>
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#include <LibJS/Runtime/Error.h>
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#include <LibJS/Runtime/GlobalObject.h>
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#include <LibJS/Runtime/VM.h>
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namespace JS {
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static const Crypto::SignedBigInteger BIGINT_ONE { 1 };
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BigIntConstructor::BigIntConstructor(Realm& realm)
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: NativeFunction(vm().names.BigInt.as_string(), *realm.global_object().function_prototype())
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{
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}
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void BigIntConstructor::initialize(Realm& realm)
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{
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auto& vm = this->vm();
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NativeFunction::initialize(realm);
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// 21.2.2.3 BigInt.prototype, https://tc39.es/ecma262/#sec-bigint.prototype
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define_direct_property(vm.names.prototype, realm.global_object().bigint_prototype(), 0);
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u8 attr = Attribute::Writable | Attribute::Configurable;
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define_native_function(vm.names.asIntN, as_int_n, 2, attr);
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define_native_function(vm.names.asUintN, as_uint_n, 2, attr);
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define_direct_property(vm.names.length, Value(1), Attribute::Configurable);
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}
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// 21.2.1.1 BigInt ( value ), https://tc39.es/ecma262/#sec-bigint-constructor-number-value
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ThrowCompletionOr<Value> BigIntConstructor::call()
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{
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auto& vm = this->vm();
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auto& global_object = this->global_object();
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auto value = vm.argument(0);
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// 2. Let prim be ? ToPrimitive(value, number).
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auto primitive = TRY(value.to_primitive(global_object, Value::PreferredType::Number));
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// 3. If Type(prim) is Number, return ? NumberToBigInt(prim).
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if (primitive.is_number())
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return TRY(number_to_bigint(global_object, primitive));
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// 4. Otherwise, return ? ToBigInt(prim).
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return TRY(primitive.to_bigint(global_object));
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}
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// 21.2.1.1 BigInt ( value ), https://tc39.es/ecma262/#sec-bigint-constructor-number-value
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ThrowCompletionOr<Object*> BigIntConstructor::construct(FunctionObject&)
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{
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return vm().throw_completion<TypeError>(global_object(), ErrorType::NotAConstructor, "BigInt");
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}
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// 21.2.2.1 BigInt.asIntN ( bits, bigint ), https://tc39.es/ecma262/#sec-bigint.asintn
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JS_DEFINE_NATIVE_FUNCTION(BigIntConstructor::as_int_n)
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{
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// 1. Set bits to ? ToIndex(bits).
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auto bits = TRY(vm.argument(0).to_index(global_object));
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// 2. Set bigint to ? ToBigInt(bigint).
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auto* bigint = TRY(vm.argument(1).to_bigint(global_object));
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// 3. Let mod be ℝ(bigint) modulo 2^bits.
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// FIXME: For large values of `bits`, this can likely be improved with a SignedBigInteger API to
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// drop the most significant bits.
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auto bits_shift_left = BIGINT_ONE.shift_left(bits);
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auto mod = modulo(bigint->big_integer(), bits_shift_left);
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// 4. If mod ≥ 2^(bits-1), return ℤ(mod - 2^bits); otherwise, return ℤ(mod).
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// NOTE: Some of the below conditionals are non-standard, but are to protect SignedBigInteger from
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// allocating an absurd amount of memory if `bits - 1` overflows to NumericLimits<size_t>::max.
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if ((bits == 0) && (mod >= BIGINT_ONE))
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return js_bigint(vm, mod.minus(bits_shift_left));
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if ((bits > 0) && (mod >= BIGINT_ONE.shift_left(bits - 1)))
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return js_bigint(vm, mod.minus(bits_shift_left));
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return js_bigint(vm, mod);
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}
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// 21.2.2.2 BigInt.asUintN ( bits, bigint ), https://tc39.es/ecma262/#sec-bigint.asuintn
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JS_DEFINE_NATIVE_FUNCTION(BigIntConstructor::as_uint_n)
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{
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// 1. Set bits to ? ToIndex(bits).
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auto bits = TRY(vm.argument(0).to_index(global_object));
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// 2. Set bigint to ? ToBigInt(bigint).
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auto* bigint = TRY(vm.argument(1).to_bigint(global_object));
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// 3. Return the BigInt value that represents ℝ(bigint) modulo 2bits.
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// FIXME: For large values of `bits`, this can likely be improved with a SignedBigInteger API to
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// drop the most significant bits.
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return js_bigint(vm, modulo(bigint->big_integer(), BIGINT_ONE.shift_left(bits)));
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}
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}
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