1 /* 2 * Copyright (C) 2013 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * 3. Neither the name of Google Inc. nor the names of its contributors 15 * may be used to endorse or promote products derived from this 16 * software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef FontCacheKey_h 32 #define FontCacheKey_h 33 34 #include "wtf/HashMap.h" 35 #include "wtf/HashTableDeletedValueType.h" 36 #include "wtf/text/AtomicStringHash.h" 37 #include "wtf/text/StringHash.h" 38 39 namespace WebCore { 40 41 // Multiplying the floating point size by 100 gives two decimal point 42 // precision which should be sufficient. 43 static const unsigned s_fontSizePrecisionMultiplier = 100; 44 45 struct FontCacheKey { 46 WTF_MAKE_FAST_ALLOCATED; 47 public: FontCacheKeyFontCacheKey48 FontCacheKey() 49 : m_familyName() 50 , m_fontSize(0) 51 , m_options(0) { } FontCacheKeyFontCacheKey52 FontCacheKey(AtomicString familyName, float fontSize, unsigned options) 53 : m_familyName(familyName) 54 , m_fontSize(fontSize * s_fontSizePrecisionMultiplier) 55 , m_options(options) { } FontCacheKeyFontCacheKey56 FontCacheKey(WTF::HashTableDeletedValueType) 57 : m_fontSize(hashTableDeletedSize()) { } 58 hashFontCacheKey59 unsigned hash() const 60 { 61 unsigned hashCodes[3] = { 62 CaseFoldingHash::hash(m_familyName), 63 m_fontSize, 64 m_options 65 }; 66 return StringHasher::hashMemory<sizeof(hashCodes)>(hashCodes); 67 } 68 69 bool operator==(const FontCacheKey& other) const 70 { 71 return equalIgnoringCase(m_familyName, other.m_familyName) 72 && m_fontSize == other.m_fontSize 73 && m_options == other.m_options; 74 } 75 isHashTableDeletedValueFontCacheKey76 bool isHashTableDeletedValue() const 77 { 78 return m_fontSize == hashTableDeletedSize(); 79 } 80 precisionMultiplierFontCacheKey81 static unsigned precisionMultiplier() 82 { 83 return s_fontSizePrecisionMultiplier; 84 } 85 86 private: hashTableDeletedSizeFontCacheKey87 static unsigned hashTableDeletedSize() 88 { 89 return 0xFFFFFFFFU; 90 } 91 92 AtomicString m_familyName; 93 unsigned m_fontSize; 94 unsigned m_options; 95 }; 96 97 struct FontCacheKeyHash { hashFontCacheKeyHash98 static unsigned hash(const FontCacheKey& key) 99 { 100 return key.hash(); 101 } 102 equalFontCacheKeyHash103 static bool equal(const FontCacheKey& a, const FontCacheKey& b) 104 { 105 return a == b; 106 } 107 108 static const bool safeToCompareToEmptyOrDeleted = true; 109 }; 110 111 struct FontCacheKeyTraits : WTF::SimpleClassHashTraits<FontCacheKey> { }; 112 113 } 114 115 #endif // FontCacheKey_h 116