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