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https://github.com/RGBCube/serenity
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53 lines
1.5 KiB
C++
53 lines
1.5 KiB
C++
/*
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* Copyright (c) 2021, Luke Wilde <lukew@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/NumericLimits.h>
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#include <LibJS/Runtime/AbstractOperations.h>
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#include <LibJS/Runtime/PropertyKey.h>
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#include <LibWeb/Bindings/IDLAbstractOperations.h>
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namespace Web::Bindings::IDL {
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// https://webidl.spec.whatwg.org/#is-an-array-index
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bool is_an_array_index(JS::GlobalObject& global_object, JS::PropertyKey const& property_name)
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{
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// 1. If Type(P) is not String, then return false.
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if (!property_name.is_number())
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return false;
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// 2. Let index be ! CanonicalNumericIndexString(P).
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auto index = JS::canonical_numeric_index_string(global_object, property_name);
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// 3. If index is undefined, then return false.
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if (index.is_undefined())
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return false;
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// 4. If IsInteger(index) is false, then return false.
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// NOTE: IsInteger is the old name of IsIntegralNumber.
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if (!index.is_integral_number())
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return false;
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// 5. If index is −0, then return false.
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if (index.is_negative_zero())
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return false;
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// FIXME: I'm not sure if this is correct.
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auto index_as_double = index.as_double();
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// 6. If index < 0, then return false.
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if (index_as_double < 0)
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return false;
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// 7. If index ≥ 2 ** 32 − 1, then return false.
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// Note: 2 ** 32 − 1 is the maximum array length allowed by ECMAScript.
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if (index_as_double >= NumericLimits<u32>::max())
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return false;
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// 8. Return true.
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return true;
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}
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}
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