1 /*
2 * Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB. If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 *
19 */
20
21 #include "config.h"
22 #include "core/html/forms/StepRange.h"
23
24 #include "HTMLNames.h"
25 #include "core/html/parser/HTMLParserIdioms.h"
26 #include "wtf/MathExtras.h"
27 #include "wtf/text/WTFString.h"
28 #include <float.h>
29
30 using namespace std;
31
32 namespace WebCore {
33
34 using namespace HTMLNames;
35
StepRange()36 StepRange::StepRange()
37 : m_maximum(100)
38 , m_minimum(0)
39 , m_step(1)
40 , m_stepBase(0)
41 , m_hasStep(false)
42 {
43 }
44
StepRange(const StepRange & stepRange)45 StepRange::StepRange(const StepRange& stepRange)
46 : m_maximum(stepRange.m_maximum)
47 , m_minimum(stepRange.m_minimum)
48 , m_step(stepRange.m_step)
49 , m_stepBase(stepRange.m_stepBase)
50 , m_stepDescription(stepRange.m_stepDescription)
51 , m_hasStep(stepRange.m_hasStep)
52 {
53 }
54
StepRange(const Decimal & stepBase,const Decimal & minimum,const Decimal & maximum,const Decimal & step,const StepDescription & stepDescription)55 StepRange::StepRange(const Decimal& stepBase, const Decimal& minimum, const Decimal& maximum, const Decimal& step, const StepDescription& stepDescription)
56 : m_maximum(maximum)
57 , m_minimum(minimum)
58 , m_step(step.isFinite() ? step : 1)
59 , m_stepBase(stepBase.isFinite() ? stepBase : 1)
60 , m_stepDescription(stepDescription)
61 , m_hasStep(step.isFinite())
62 {
63 ASSERT(m_maximum.isFinite());
64 ASSERT(m_minimum.isFinite());
65 ASSERT(m_step.isFinite());
66 ASSERT(m_stepBase.isFinite());
67 }
68
acceptableError() const69 Decimal StepRange::acceptableError() const
70 {
71 // FIXME: We should use DBL_MANT_DIG instead of FLT_MANT_DIG regarding to HTML5 specification.
72 DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfFloatMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << FLT_MANT_DIG));
73 return m_stepDescription.stepValueShouldBe == StepValueShouldBeReal ? m_step / twoPowerOfFloatMantissaBits : Decimal(0);
74 }
75
alignValueForStep(const Decimal & currentValue,const Decimal & newValue) const76 Decimal StepRange::alignValueForStep(const Decimal& currentValue, const Decimal& newValue) const
77 {
78 DEFINE_STATIC_LOCAL(const Decimal, tenPowerOf21, (Decimal::Positive, 21, 1));
79 if (newValue >= tenPowerOf21)
80 return newValue;
81
82 return stepMismatch(currentValue) ? newValue : roundByStep(newValue, m_stepBase);
83 }
84
clampValue(const Decimal & value) const85 Decimal StepRange::clampValue(const Decimal& value) const
86 {
87 const Decimal inRangeValue = max(m_minimum, min(value, m_maximum));
88 if (!m_hasStep)
89 return inRangeValue;
90 // Rounds inRangeValue to minimum + N * step.
91 const Decimal roundedValue = roundByStep(inRangeValue, m_minimum);
92 const Decimal clampedValue = roundedValue > m_maximum ? roundedValue - m_step : roundedValue;
93 ASSERT(clampedValue >= m_minimum);
94 ASSERT(clampedValue <= m_maximum);
95 return clampedValue;
96 }
97
parseStep(AnyStepHandling anyStepHandling,const StepDescription & stepDescription,const String & stepString)98 Decimal StepRange::parseStep(AnyStepHandling anyStepHandling, const StepDescription& stepDescription, const String& stepString)
99 {
100 if (stepString.isEmpty())
101 return stepDescription.defaultValue();
102
103 if (equalIgnoringCase(stepString, "any")) {
104 switch (anyStepHandling) {
105 case RejectAny:
106 return Decimal::nan();
107 case AnyIsDefaultStep:
108 return stepDescription.defaultValue();
109 default:
110 ASSERT_NOT_REACHED();
111 }
112 }
113
114 Decimal step = parseToDecimalForNumberType(stepString);
115 if (!step.isFinite() || step <= 0)
116 return stepDescription.defaultValue();
117
118 switch (stepDescription.stepValueShouldBe) {
119 case StepValueShouldBeReal:
120 step *= stepDescription.stepScaleFactor;
121 break;
122 case ParsedStepValueShouldBeInteger:
123 // For date, month, and week, the parsed value should be an integer for some types.
124 step = max(step.round(), Decimal(1));
125 step *= stepDescription.stepScaleFactor;
126 break;
127 case ScaledStepValueShouldBeInteger:
128 // For datetime, datetime-local, time, the result should be an integer.
129 step *= stepDescription.stepScaleFactor;
130 step = max(step.round(), Decimal(1));
131 break;
132 default:
133 ASSERT_NOT_REACHED();
134 }
135
136 ASSERT(step > 0);
137 return step;
138 }
139
roundByStep(const Decimal & value,const Decimal & base) const140 Decimal StepRange::roundByStep(const Decimal& value, const Decimal& base) const
141 {
142 return base + ((value - base) / m_step).round() * m_step;
143 }
144
stepMismatch(const Decimal & valueForCheck) const145 bool StepRange::stepMismatch(const Decimal& valueForCheck) const
146 {
147 if (!m_hasStep)
148 return false;
149 if (!valueForCheck.isFinite())
150 return false;
151 const Decimal value = (valueForCheck - m_stepBase).abs();
152 if (!value.isFinite())
153 return false;
154 // Decimal's fractional part size is DBL_MAN_DIG-bit. If the current value
155 // is greater than step*2^DBL_MANT_DIG, the following computation for
156 // remainder makes no sense.
157 DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfDoubleMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << DBL_MANT_DIG));
158 if (value / twoPowerOfDoubleMantissaBits > m_step)
159 return false;
160 // The computation follows HTML5 4.10.7.2.10 `The step attribute' :
161 // ... that number subtracted from the step base is not an integral multiple
162 // of the allowed value step, the element is suffering from a step mismatch.
163 const Decimal remainder = (value - m_step * (value / m_step).round()).abs();
164 // Accepts erros in lower fractional part which IEEE 754 single-precision
165 // can't represent.
166 const Decimal computedAcceptableError = acceptableError();
167 return computedAcceptableError < remainder && remainder < (m_step - computedAcceptableError);
168 }
169
170 } // namespace WebCore
171