5db38d7ba1
Three standalone Cell creation functions remain in the JS namespace: - js_bigint() - js_string() - js_symbol() All of them are leftovers from early iterations when LibJS still took inspiration from JSC, which itself has jsString(). Nowadays, we pretty much exclusively use static create() functions to construct types allocated on the JS heap, and there's no reason to not do the same for these. Also change the return type from BigInt* to NonnullGCPtr<BigInt> while we're here. This is patch 1/3, replacement of js_string() and js_symbol() follow.
105 lines
3.8 KiB
C++
105 lines
3.8 KiB
C++
/*
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* Copyright (c) 2020-2022, 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/DeprecatedString.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(realm.vm().names.BigInt.as_string(), *realm.intrinsics().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.intrinsics().bigint_prototype(), 0);
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u8 attr = Attribute::Writable | Attribute::Configurable;
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define_native_function(realm, vm.names.asIntN, as_int_n, 2, attr);
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define_native_function(realm, 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 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(vm, 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(vm, primitive));
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// 4. Otherwise, return ? ToBigInt(prim).
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return TRY(primitive.to_bigint(vm));
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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>(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(vm));
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// 2. Set bigint to ? ToBigInt(bigint).
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auto* bigint = TRY(vm.argument(1).to_bigint(vm));
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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 BigInt::create(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 BigInt::create(vm, mod.minus(bits_shift_left));
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return BigInt::create(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(vm));
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// 2. Set bigint to ? ToBigInt(bigint).
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auto* bigint = TRY(vm.argument(1).to_bigint(vm));
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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 BigInt::create(vm, modulo(bigint->big_integer(), BIGINT_ONE.shift_left(bits)));
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}
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}
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