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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 "third_party/blink/renderer/core/html/forms/step_range.h"
#include <float.h>
#include "third_party/blink/renderer/core/html/parser/html_parser_idioms.h"
#include "third_party/blink/renderer/core/html_names.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
namespace blink {
StepRange::StepRange()
: maximum_(100),
minimum_(0),
step_(1),
step_base_(0),
has_step_(false),
has_range_limitations_(false),
supports_reversed_range_(false) {}
StepRange::StepRange(const StepRange& step_range) = default;
StepRange::StepRange(const Decimal& step_base,
const Decimal& minimum,
const Decimal& maximum,
bool has_range_limitations,
bool supports_reversed_range,
const Decimal& step,
const StepDescription& step_description)
: maximum_(maximum),
minimum_(minimum),
step_(step.IsFinite() ? step : 1),
step_base_(step_base.IsFinite() ? step_base : 1),
step_description_(step_description),
has_step_(step.IsFinite()),
has_range_limitations_(has_range_limitations),
supports_reversed_range_(supports_reversed_range) {
DCHECK(maximum_.IsFinite());
DCHECK(minimum_.IsFinite());
DCHECK(step_.IsFinite());
DCHECK(step_base_.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, two_power_of_float_mantissa_bits,
(Decimal::kPositive, 0, UINT64_C(1) << FLT_MANT_DIG));
return step_description_.step_value_should_be == kStepValueShouldBeReal
? step_ / two_power_of_float_mantissa_bits
: Decimal(0);
}
Decimal StepRange::AlignValueForStep(const Decimal& current_value,
const Decimal& new_value) const {
DEFINE_STATIC_LOCAL(const Decimal, ten_power_of21,
(Decimal::kPositive, 21, 1));
if (new_value >= ten_power_of21)
return new_value;
return StepMismatch(current_value) ? new_value
: RoundByStep(new_value, step_base_);
}
Decimal StepRange::ClampValue(const Decimal& value) const {
const Decimal in_range_value = std::max(minimum_, std::min(value, maximum_));
if (!has_step_)
return in_range_value;
// Rounds inRangeValue to stepBase + N * step.
const Decimal rounded_value = RoundByStep(in_range_value, step_base_);
const Decimal clamped_value =
rounded_value > maximum_
? rounded_value - step_
: (rounded_value < minimum_ ? rounded_value + step_ : rounded_value);
// clamped_value can be outside of [minimum_, maximum_] if step_ is huge.
if (clamped_value < minimum_ || clamped_value > maximum_)
return in_range_value;
return clamped_value;
}
Decimal StepRange::ParseStep(AnyStepHandling any_step_handling,
const StepDescription& step_description,
const String& step_string) {
if (step_string.IsEmpty())
return step_description.DefaultValue();
if (EqualIgnoringASCIICase(step_string, "any")) {
switch (any_step_handling) {
case kRejectAny:
return Decimal::Nan();
case kAnyIsDefaultStep:
return step_description.DefaultValue();
default:
NOTREACHED();
}
}
Decimal step = ParseToDecimalForNumberType(step_string);
if (!step.IsFinite() || step <= 0)
return step_description.DefaultValue();
switch (step_description.step_value_should_be) {
case kStepValueShouldBeReal:
step *= step_description.step_scale_factor;
break;
case kParsedStepValueShouldBeInteger:
// For date, month, and week, the parsed value should be an integer for
// some types.
step = std::max(step.Round(), Decimal(1));
step *= step_description.step_scale_factor;
break;
case kScaledStepValueShouldBeInteger:
// For datetime, datetime-local, time, the result should be an integer.
step *= step_description.step_scale_factor;
step = std::max(step.Round(), Decimal(1));
break;
default:
NOTREACHED();
}
DCHECK_GT(step, 0);
return step;
}
Decimal StepRange::RoundByStep(const Decimal& value,
const Decimal& base) const {
return base + ((value - base) / step_).Round() * step_;
}
bool StepRange::StepMismatch(const Decimal& value_for_check) const {
if (!has_step_)
return false;
if (!value_for_check.IsFinite())
return false;
const Decimal value = (value_for_check - step_base_).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, two_power_of_double_mantissa_bits,
(Decimal::kPositive, 0, UINT64_C(1) << DBL_MANT_DIG));
if (value / two_power_of_double_mantissa_bits > 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 - step_ * (value / step_).Round()).Abs();
// Accepts errors in lower fractional part which IEEE 754 single-precision
// can't represent.
const Decimal computed_acceptable_error = AcceptableError();
return computed_acceptable_error < remainder &&
remainder < (step_ - computed_acceptable_error);
}
Decimal StepRange::StepSnappedMaximum() const {
Decimal base = StepBase();
Decimal step = Step();
if (base - step == base || !(base / step).IsFinite())
return Decimal::Nan();
Decimal aligned_maximum = base + ((Maximum() - base) / step).Floor() * step;
if (aligned_maximum > Maximum())
aligned_maximum -= step;
DCHECK_LE(aligned_maximum, Maximum());
if (aligned_maximum < Minimum())
return Decimal::Nan();
return aligned_maximum;
}
// https://html.spec.whatwg.org/C/#has-a-reversed-range
bool StepRange::HasReversedRange() const {
return supports_reversed_range_ && Maximum() < Minimum();
}
} // namespace blink
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