ladybird/Userland/Libraries/LibWeb/HTML/Numbers.cpp
2024-03-03 10:02:30 -05:00

103 lines
3.7 KiB
C++

/*
* Copyright (c) 2023, Jonatan Klemets <jonatan.r.klemets@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/GenericLexer.h>
#include <LibWeb/HTML/Numbers.h>
#include <LibWeb/Infra/CharacterTypes.h>
#include <math.h>
namespace Web::HTML {
// https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#rules-for-parsing-integers
Optional<i32> parse_integer(StringView string)
{
// 1. Let input be the string being parsed.
// 2. Let position be a pointer into input, initially pointing at the start of the string.
GenericLexer lexer { string };
// 3. Let sign have the value "positive".
// NOTE: Skipped, see comment on step 6.
// 4. Skip ASCII whitespace within input given position.
lexer.ignore_while(Web::Infra::is_ascii_whitespace);
// 5. If position is past the end of input, return an error.
if (lexer.is_eof()) {
return {};
}
// 6. If the character indicated by position (the first character) is a U+002D HYPHEN-MINUS character (-):
//
// If we parse a signed integer, then we include the sign character (if present) in the collect step
// (step 8) and lean on `AK::StringUtils::convert_to_int` to handle it for us.
size_t start_index = lexer.tell();
if (lexer.peek() == '-' || lexer.peek() == '+') {
lexer.consume();
}
// 7. If the character indicated by position is not an ASCII digit, then return an error.
if (!lexer.next_is(is_ascii_digit)) {
return {};
}
// 8. Collect a sequence of code points that are ASCII digits from input given position, and interpret the resulting sequence as a base-ten integer. Let value be that integer.
lexer.consume_while(is_ascii_digit);
size_t end_index = lexer.tell();
auto digits = lexer.input().substring_view(start_index, end_index - start_index);
auto optional_value = AK::StringUtils::convert_to_int<i32>(digits);
// 9. If sign is "positive", return value, otherwise return the result of subtracting value from zero.
// NOTE: Skipped, see comment on step 6.
return optional_value;
}
// https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#rules-for-parsing-non-negative-integers
Optional<u32> parse_non_negative_integer(StringView string)
{
// 1. Let input be the string being parsed.
// 2. Let value be the result of parsing input using the rules for parsing integers.
//
// NOTE: Because we call `parse_integer`, we parse all integers as signed. If we need the extra
// size that an unsigned integer offers, then this would need to be improved. That said,
// I don't think we need to support such large integers at the moment.
auto optional_value = parse_integer(string);
// 3. If value is an error, return an error.
if (!optional_value.has_value()) {
return {};
}
// 4. If value is less than zero, return an error.
if (optional_value.value() < 0) {
return {};
}
// 5. Return value.
return static_cast<u32>(optional_value.value());
}
// https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#rules-for-parsing-floating-point-number-values
Optional<double> parse_floating_point_number(StringView string)
{
// FIXME: Implement spec compliant floating point number parsing
auto maybe_double = string.to_number<double>(TrimWhitespace::Yes);
if (!maybe_double.has_value())
return {};
if (!isfinite(maybe_double.value()))
return {};
return maybe_double.value();
}
WebIDL::ExceptionOr<String> convert_non_negative_integer_to_string(JS::Realm& realm, WebIDL::Long value)
{
if (value < 0)
return WebIDL::IndexSizeError::create(realm, "The attribute is limited to only non-negative numbers"_fly_string);
return MUST(String::number(value));
}
}