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 "FontFaceCreationParams.h" 35 #include "wtf/HashMap.h" 36 #include "wtf/HashTableDeletedValueType.h" 37 #include "wtf/text/AtomicStringHash.h" 38 #include "wtf/text/StringHash.h" 39 40 namespace blink { 41 42 // Multiplying the floating point size by 100 gives two decimal point 43 // precision which should be sufficient. 44 static const unsigned s_fontSizePrecisionMultiplier = 100; 45 46 struct FontCacheKey { 47 WTF_MAKE_FAST_ALLOCATED; 48 public: FontCacheKeyFontCacheKey49 FontCacheKey() 50 : m_creationParams() 51 , m_fontSize(0) 52 , m_options(0) { } FontCacheKeyFontCacheKey53 FontCacheKey(FontFaceCreationParams creationParams, float fontSize, unsigned options) 54 : m_creationParams(creationParams) 55 , m_fontSize(fontSize * s_fontSizePrecisionMultiplier) 56 , m_options(options) { } FontCacheKeyFontCacheKey57 FontCacheKey(WTF::HashTableDeletedValueType) 58 : m_fontSize(hashTableDeletedSize()) { } 59 hashFontCacheKey60 unsigned hash() const 61 { 62 unsigned hashCodes[3] = { 63 m_creationParams.hash(), 64 m_fontSize, 65 m_options 66 }; 67 return StringHasher::hashMemory<sizeof(hashCodes)>(hashCodes); 68 } 69 70 bool operator==(const FontCacheKey& other) const 71 { 72 return m_creationParams == other.m_creationParams 73 && m_fontSize == other.m_fontSize 74 && m_options == other.m_options; 75 } 76 isHashTableDeletedValueFontCacheKey77 bool isHashTableDeletedValue() const 78 { 79 return m_fontSize == hashTableDeletedSize(); 80 } 81 precisionMultiplierFontCacheKey82 static unsigned precisionMultiplier() 83 { 84 return s_fontSizePrecisionMultiplier; 85 } 86 87 private: hashTableDeletedSizeFontCacheKey88 static unsigned hashTableDeletedSize() 89 { 90 return 0xFFFFFFFFU; 91 } 92 93 FontFaceCreationParams m_creationParams; 94 unsigned m_fontSize; 95 unsigned m_options; 96 }; 97 98 struct FontCacheKeyHash { hashFontCacheKeyHash99 static unsigned hash(const FontCacheKey& key) 100 { 101 return key.hash(); 102 } 103 equalFontCacheKeyHash104 static bool equal(const FontCacheKey& a, const FontCacheKey& b) 105 { 106 return a == b; 107 } 108 109 static const bool safeToCompareToEmptyOrDeleted = true; 110 }; 111 112 struct FontCacheKeyTraits : WTF::SimpleClassHashTraits<FontCacheKey> { }; 113 114 } // namespace blink 115 116 #endif // FontCacheKey_h 117