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LibJS: Port the TrimString AO to String

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This also adds spec comments to parseFloat to make it clear that we are
now deviating a bit from the spec (the TrimString invocation should be
infallible, but we want to propagate OOM errors).
This commit is contained in:
Timothy Flynn 2023-01-14 23:11:50 -05:00 • committed by Linus Groh
parent 4235c59397
commit 0d47c4e7a0
3 changed files with 37 additions and 19 deletions
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48
Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
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@ -223,26 +223,41 @@ JS_DEFINE_NATIVE_FUNCTION(GlobalObject::is_finite)
// 19.2.4 parseFloat ( string ), https://tc39.es/ecma262/#sec-parsefloat-string
JS_DEFINE_NATIVE_FUNCTION(GlobalObject::parse_float)
{
// OPTIMIZATION: We can skip the number-to-string-to-number round trip when the value is already a number.
if (vm.argument(0).is_number())
return vm.argument(0);
// 1. Let inputString be ? ToString(string).
auto input_string = TRY(vm.argument(0).to_deprecated_string(vm));
auto trimmed_string = MUST(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
// 2. Let trimmedString be ! TrimString(inputString, start).
// NOTE: We TRY this operation only to propagate OOM errors.
auto trimmed_string = TRY(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
if (trimmed_string.is_empty())
return js_nan();
auto result = parse_first_floating_point<double>(trimmed_string.characters(), trimmed_string.characters() + trimmed_string.length());
if (result.parsed_value())
return result.value;
// 3. If neither trimmedString nor any prefix of trimmedString satisfies the syntax of a StrDecimalLiteral (see 7.1.4.1), return NaN.
// 4. Let numberString be the longest prefix of trimmedString, which might be trimmedString itself, that satisfies the syntax of a StrDecimalLiteral.
// 5. Let parsedNumber be ParseText(StringToCodePoints(numberString), StrDecimalLiteral).
// 6. Assert: parsedNumber is a Parse Node.
// 7. Return StringNumericValue of parsedNumber.
auto trimmed_string_view = trimmed_string.bytes_as_string_view();
auto const* begin = trimmed_string_view.characters_without_null_termination();
auto const* end = begin + trimmed_string_view.length();
bool starts_with_sign = trimmed_string[0] == '-' || trimmed_string[0] == '+';
auto signless_view = starts_with_sign ? trimmed_string.substring_view(1) : trimmed_string.view();
if (signless_view.starts_with("Infinity"sv, AK::CaseSensitivity::CaseSensitive)) {
auto parsed_number = parse_first_floating_point<double>(begin, end);
if (parsed_number.parsed_value())
return parsed_number.value;
auto first_code_point = *trimmed_string.code_points().begin();
if (first_code_point == '-' || first_code_point == '+')
trimmed_string_view = trimmed_string_view.substring_view(1);
if (trimmed_string_view.starts_with("Infinity"sv, AK::CaseSensitivity::CaseSensitive)) {
// Only an immediate - means we should return negative infinity
if (trimmed_string[0] == '-')
return js_negative_infinity();
return js_infinity();
return first_code_point == '-' ? js_negative_infinity() : js_infinity();
}
return js_nan();
}
@ -253,17 +268,20 @@ JS_DEFINE_NATIVE_FUNCTION(GlobalObject::parse_int)
auto input_string = TRY(vm.argument(0).to_deprecated_string(vm));
// 2. Let S be ! TrimString(inputString, start).
auto string = MUST(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
// NOTE: We TRY this operation only to propagate OOM errors.
auto string = TRY(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
// 3. Let sign be 1.
auto sign = 1;
// 4. If S is not empty and the first code unit of S is the code unit 0x002D (HYPHEN-MINUS), set sign to -1.
if (!string.is_empty() && string[0] == 0x2D)
auto first_code_point = string.is_empty() ? OptionalNone {} : Optional<u32> { *string.code_points().begin() };
if (first_code_point == 0x2Du)
sign = -1;
// 5. If S is not empty and the first code unit of S is the code unit 0x002B (PLUS SIGN) or the code unit 0x002D (HYPHEN-MINUS), remove the first code unit from S.
auto trimmed_view = string.view();
if (!string.is_empty() && (string[0] == 0x2B || string[0] == 0x2D))
auto trimmed_view = string.bytes_as_string_view();
if (first_code_point == 0x2Bu || first_code_point == 0x2Du)
trimmed_view = trimmed_view.substring_view(1);
// 6. Let R be ℝ(? ToInt32(radix)).