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/*
* Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "StepRange.h"
#include "HTMLNames.h"
#include "HTMLParserIdioms.h"
#include <wtf/MathExtras.h>
#include <wtf/text/WTFString.h>
using namespace std;
namespace WebCore {
using namespace HTMLNames;
StepRange::StepRange()
: m_maximum(100)
, m_minimum(0)
, m_step(1)
, m_stepBase(0)
, m_hasStep(false)
{
}
StepRange::StepRange(const StepRange& stepRange)
: m_maximum(stepRange.m_maximum)
, m_minimum(stepRange.m_minimum)
, m_step(stepRange.m_step)
, m_stepBase(stepRange.m_stepBase)
, m_stepDescription(stepRange.m_stepDescription)
, m_hasStep(stepRange.m_hasStep)
{
}
StepRange::StepRange(const Decimal& stepBase, const Decimal& minimum, const Decimal& maximum, const Decimal& step, const StepDescription& stepDescription)
: m_maximum(maximum)
, m_minimum(minimum)
, m_step(step.isFinite() ? step : 1)
, m_stepBase(stepBase.isFinite() ? stepBase : 1)
, m_stepDescription(stepDescription)
, m_hasStep(step.isFinite())
{
ASSERT(m_maximum.isFinite());
ASSERT(m_minimum.isFinite());
ASSERT(m_step.isFinite());
ASSERT(m_stepBase.isFinite());
}
Decimal StepRange::acceptableError() const
{
// FIXME: We should use DBL_MANT_DIG instead of FLT_MANT_DIG regarding to HTML5 specification.
DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfFloatMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << FLT_MANT_DIG));
return m_stepDescription.stepValueShouldBe == StepValueShouldBeReal ? m_step / twoPowerOfFloatMantissaBits : Decimal(0);
}
Decimal StepRange::alignValueForStep(const Decimal& currentValue, const Decimal& newValue) const
{
DEFINE_STATIC_LOCAL(const Decimal, tenPowerOf21, (Decimal::Positive, 21, 1));
if (newValue >= tenPowerOf21)
return newValue;
return stepMismatch(currentValue) ? newValue : roundByStep(newValue, m_stepBase);
}
Decimal StepRange::clampValue(const Decimal& value) const
{
const Decimal inRangeValue = max(m_minimum, min(value, m_maximum));
if (!m_hasStep)
return inRangeValue;
// Rounds inRangeValue to minimum + N * step.
const Decimal roundedValue = roundByStep(inRangeValue, m_minimum);
const Decimal clampedValue = roundedValue > m_maximum ? roundedValue - m_step : roundedValue;
ASSERT(clampedValue >= m_minimum);
ASSERT(clampedValue <= m_maximum);
return clampedValue;
}
Decimal StepRange::parseStep(AnyStepHandling anyStepHandling, const StepDescription& stepDescription, const String& stepString)
{
if (stepString.isEmpty())
return stepDescription.defaultValue();
if (equalIgnoringCase(stepString, "any")) {
switch (anyStepHandling) {
case RejectAny:
return Decimal::nan();
case AnyIsDefaultStep:
return stepDescription.defaultValue();
default:
ASSERT_NOT_REACHED();
}
}
Decimal step = parseToDecimalForNumberType(stepString);
if (!step.isFinite() || step <= 0)
return stepDescription.defaultValue();
switch (stepDescription.stepValueShouldBe) {
case StepValueShouldBeReal:
step *= stepDescription.stepScaleFactor;
break;
case ParsedStepValueShouldBeInteger:
// For date, month, and week, the parsed value should be an integer for some types.
step = max(step.round(), Decimal(1));
step *= stepDescription.stepScaleFactor;
break;
case ScaledStepValueShouldBeInteger:
// For datetime, datetime-local, time, the result should be an integer.
step *= stepDescription.stepScaleFactor;
step = max(step.round(), Decimal(1));
break;
default:
ASSERT_NOT_REACHED();
}
ASSERT(step > 0);
return step;
}
Decimal StepRange::roundByStep(const Decimal& value, const Decimal& base) const
{
return base + ((value - base) / m_step).round() * m_step;
}
bool StepRange::stepMismatch(const Decimal& valueForCheck) const
{
if (!m_hasStep)
return false;
if (!valueForCheck.isFinite())
return false;
const Decimal value = (valueForCheck - m_stepBase).abs();
if (!value.isFinite())
return false;
// Decimal's fractional part size is DBL_MAN_DIG-bit. If the current value
// is greater than step*2^DBL_MANT_DIG, the following computation for
// remainder makes no sense.
DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfDoubleMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << DBL_MANT_DIG));
if (value / twoPowerOfDoubleMantissaBits > m_step)
return false;
// The computation follows HTML5 4.10.7.2.10 `The step attribute' :
// ... that number subtracted from the step base is not an integral multiple
// of the allowed value step, the element is suffering from a step mismatch.
const Decimal remainder = (value - m_step * (value / m_step).round()).abs();
// Accepts erros in lower fractional part which IEEE 754 single-precision
// can't represent.
const Decimal computedAcceptableError = acceptableError();
return computedAcceptableError < remainder && remainder < (m_step - computedAcceptableError);
}
} // namespace WebCore
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