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/*
* Copyright (C) 2018-2021 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/CheckedArithmetic.h>
#include <wtf/text/ParsingUtilities.h>
#include <wtf/text/StringView.h>
namespace WTF {
// The parseInteger function template may allow leading and trailing spaces as defined by isUnicodeCompatibleASCIIWhitespace, and, after the leading spaces, allows a single leading "+".
// The parseIntegerAllowingTrailingJunk function template is like parseInteger, but allows any characters after the integer.
// FIXME: Should we add a version that does not allow "+"?
// FIXME: Should we add a version that allows other definitions of spaces, like isASCIIWhitespace or isASCIIWhitespaceWithoutFF?
enum class ParseIntegerWhitespacePolicy : bool { Disallow, Allow };
template<typename IntegralType> std::optional<IntegralType> parseInteger(StringView, uint8_t base = 10, ParseIntegerWhitespacePolicy = ParseIntegerWhitespacePolicy::Allow);
template<typename IntegralType> std::optional<IntegralType> parseIntegerAllowingTrailingJunk(StringView, uint8_t base = 10);
enum class TrailingJunkPolicy : bool { Disallow, Allow };
template<typename IntegralType, typename CharacterType> std::optional<IntegralType> parseInteger(std::span<const CharacterType> data, uint8_t base, TrailingJunkPolicy policy, ParseIntegerWhitespacePolicy whitespacePolicy = ParseIntegerWhitespacePolicy::Allow)
{
if (!data.data())
return std::nullopt;
if (whitespacePolicy == ParseIntegerWhitespacePolicy::Allow)
skipWhile<isUnicodeCompatibleASCIIWhitespace>(data);
bool isNegative = false;
if (std::is_signed_v<IntegralType> && skipExactly(data, '-'))
isNegative = true;
else
skipExactly(data, '+');
auto isCharacterAllowedInBase = [] (auto character, auto base) {
if (isASCIIDigit(character))
return character - '0' < base;
return toASCIILowerUnchecked(character) >= 'a' && toASCIILowerUnchecked(character) < 'a' + std::min(base - 10, 26);
};
if (!(!data.empty() && isCharacterAllowedInBase(data.front(), base)))
return std::nullopt;
Checked<IntegralType, RecordOverflow> value;
do {
auto c = consume(data);
IntegralType digitValue = isASCIIDigit(c) ? c - '0' : toASCIILowerUnchecked(c) - 'a' + 10;
value *= static_cast<IntegralType>(base);
if (isNegative)
value -= digitValue;
else
value += digitValue;
} while (!data.empty() && isCharacterAllowedInBase(data.front(), base));
if (UNLIKELY(value.hasOverflowed()))
return std::nullopt;
if (policy == TrailingJunkPolicy::Disallow) {
if (whitespacePolicy == ParseIntegerWhitespacePolicy::Allow)
skipWhile<isUnicodeCompatibleASCIIWhitespace>(data);
if (!data.empty())
return std::nullopt;
}
return value.value();
}
template<typename IntegralType> std::optional<IntegralType> parseInteger(StringView string, uint8_t base, ParseIntegerWhitespacePolicy whitespacePolicy)
{
if (string.is8Bit())
return parseInteger<IntegralType>(string.span8(), base, TrailingJunkPolicy::Disallow, whitespacePolicy);
return parseInteger<IntegralType>(string.span16(), base, TrailingJunkPolicy::Disallow, whitespacePolicy);
}
template<typename IntegralType> std::optional<IntegralType> parseIntegerAllowingTrailingJunk(StringView string, uint8_t base)
{
if (string.is8Bit())
return parseInteger<IntegralType>(string.span8(), base, TrailingJunkPolicy::Allow);
return parseInteger<IntegralType>(string.span16(), base, TrailingJunkPolicy::Allow);
}
}
using WTF::parseInteger;
using WTF::parseIntegerAllowingTrailingJunk;
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