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 "StepRange.h" 23 24#include "HTMLNames.h" 25#include "HTMLParserIdioms.h" 26#include <wtf/MathExtras.h> 27 28namespace WebCore { 29 30using namespace HTMLNames; 31 32StepRange::StepRange() 33 : m_maximum(100) 34 , m_minimum(0) 35 , m_step(1) 36 , m_stepBase(0) 37 , m_hasStep(false) 38{ 39} 40 41StepRange::StepRange(const StepRange& stepRange) 42 : m_maximum(stepRange.m_maximum) 43 , m_minimum(stepRange.m_minimum) 44 , m_step(stepRange.m_step) 45 , m_stepBase(stepRange.m_stepBase) 46 , m_stepDescription(stepRange.m_stepDescription) 47 , m_hasStep(stepRange.m_hasStep) 48{ 49} 50 51StepRange::StepRange(const Decimal& stepBase, const Decimal& minimum, const Decimal& maximum, const Decimal& step, const StepDescription& stepDescription) 52 : m_maximum(maximum) 53 , m_minimum(minimum) 54 , m_step(step.isFinite() ? step : 1) 55 , m_stepBase(stepBase.isFinite() ? stepBase : 1) 56 , m_stepDescription(stepDescription) 57 , m_hasStep(step.isFinite()) 58{ 59 ASSERT(m_maximum.isFinite()); 60 ASSERT(m_minimum.isFinite()); 61 ASSERT(m_step.isFinite()); 62 ASSERT(m_stepBase.isFinite()); 63} 64 65Decimal StepRange::acceptableError() const 66{ 67 // FIXME: We should use DBL_MANT_DIG instead of FLT_MANT_DIG regarding to HTML5 specification. 68 DEPRECATED_DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfFloatMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << FLT_MANT_DIG)); 69 return m_stepDescription.stepValueShouldBe == StepValueShouldBeReal ? m_step / twoPowerOfFloatMantissaBits : Decimal(0); 70} 71 72Decimal StepRange::alignValueForStep(const Decimal& currentValue, const Decimal& newValue) const 73{ 74 DEPRECATED_DEFINE_STATIC_LOCAL(const Decimal, tenPowerOf21, (Decimal::Positive, 21, 1)); 75 if (newValue >= tenPowerOf21) 76 return newValue; 77 78 return stepMismatch(currentValue) ? newValue : roundByStep(newValue, m_stepBase); 79} 80 81Decimal StepRange::clampValue(const Decimal& value) const 82{ 83 const Decimal inRangeValue = std::max(m_minimum, std::min(value, m_maximum)); 84 if (!m_hasStep) 85 return inRangeValue; 86 // Rounds inRangeValue to minimum + N * step. 87 const Decimal roundedValue = roundByStep(inRangeValue, m_minimum); 88 const Decimal clampedValue = roundedValue > m_maximum ? roundedValue - m_step : roundedValue; 89 ASSERT(clampedValue >= m_minimum); 90 ASSERT(clampedValue <= m_maximum); 91 return clampedValue; 92} 93 94Decimal StepRange::parseStep(AnyStepHandling anyStepHandling, const StepDescription& stepDescription, const String& stepString) 95{ 96 if (stepString.isEmpty()) 97 return stepDescription.defaultValue(); 98 99 if (equalIgnoringCase(stepString, "any")) { 100 switch (anyStepHandling) { 101 case RejectAny: 102 return Decimal::nan(); 103 case AnyIsDefaultStep: 104 return stepDescription.defaultValue(); 105 default: 106 ASSERT_NOT_REACHED(); 107 } 108 } 109 110 Decimal step = parseToDecimalForNumberType(stepString); 111 if (!step.isFinite() || step <= 0) 112 return stepDescription.defaultValue(); 113 114 switch (stepDescription.stepValueShouldBe) { 115 case StepValueShouldBeReal: 116 step *= stepDescription.stepScaleFactor; 117 break; 118 case ParsedStepValueShouldBeInteger: 119 // For date, month, and week, the parsed value should be an integer for some types. 120 step = std::max(step.round(), Decimal(1)); 121 step *= stepDescription.stepScaleFactor; 122 break; 123 case ScaledStepValueShouldBeInteger: 124 // For datetime, datetime-local, time, the result should be an integer. 125 step *= stepDescription.stepScaleFactor; 126 step = std::max(step.round(), Decimal(1)); 127 break; 128 default: 129 ASSERT_NOT_REACHED(); 130 } 131 132 ASSERT(step > 0); 133 return step; 134} 135 136Decimal StepRange::roundByStep(const Decimal& value, const Decimal& base) const 137{ 138 return base + ((value - base) / m_step).round() * m_step; 139} 140 141bool StepRange::stepMismatch(const Decimal& valueForCheck) const 142{ 143 if (!m_hasStep) 144 return false; 145 if (!valueForCheck.isFinite()) 146 return false; 147 const Decimal value = (valueForCheck - m_stepBase).abs(); 148 if (!value.isFinite()) 149 return false; 150 // Decimal's fractional part size is DBL_MAN_DIG-bit. If the current value 151 // is greater than step*2^DBL_MANT_DIG, the following computation for 152 // remainder makes no sense. 153 DEPRECATED_DEFINE_STATIC_LOCAL(const Decimal, twoPowerOfDoubleMantissaBits, (Decimal::Positive, 0, UINT64_C(1) << DBL_MANT_DIG)); 154 if (value / twoPowerOfDoubleMantissaBits > m_step) 155 return false; 156 // The computation follows HTML5 4.10.7.2.10 `The step attribute' : 157 // ... that number subtracted from the step base is not an integral multiple 158 // of the allowed value step, the element is suffering from a step mismatch. 159 const Decimal remainder = (value - m_step * (value / m_step).round()).abs(); 160 // Accepts erros in lower fractional part which IEEE 754 single-precision 161 // can't represent. 162 const Decimal computedAcceptableError = acceptableError(); 163 return computedAcceptableError < remainder && remainder < (m_step - computedAcceptableError); 164} 165 166} // namespace WebCore 167