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comparison: gfx/graphite2/src/inc/SegCacheEntry.h
gfx/graphite2/src/inc/SegCacheEntry.h
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| 1 /* GRAPHITE2 LICENSING | |
| 2 | |
| 3 Copyright 2010, SIL International | |
| 4 All rights reserved. | |
| 5 | |
| 6 This library is free software; you can redistribute it and/or modify | |
| 7 it under the terms of the GNU Lesser General Public License as published | |
| 8 by the Free Software Foundation; either version 2.1 of License, or | |
| 9 (at your option) any later version. | |
| 10 | |
| 11 This program is distributed in the hope that it will be useful, | |
| 12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 Lesser General Public License for more details. | |
| 15 | |
| 16 You should also have received a copy of the GNU Lesser General Public | |
| 17 License along with this library in the file named "LICENSE". | |
| 18 If not, write to the Free Software Foundation, 51 Franklin Street, | |
| 19 Suite 500, Boston, MA 02110-1335, USA or visit their web page on the | |
| 20 internet at http://www.fsf.org/licenses/lgpl.html. | |
| 21 | |
| 22 Alternatively, the contents of this file may be used under the terms of the | |
| 23 Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public | |
| 24 License, as published by the Free Software Foundation, either version 2 | |
| 25 of the License or (at your option) any later version. | |
| 26 */ | |
| 27 #pragma once | |
| 28 | |
| 29 #ifndef GRAPHITE2_NSEGCACHE | |
| 30 | |
| 31 #include "inc/Main.h" | |
| 32 #include "inc/Slot.h" | |
| 33 | |
| 34 namespace graphite2 { | |
| 35 | |
| 36 class Segment; | |
| 37 class Slot; | |
| 38 class SegCacheEntry; | |
| 39 class SegCachePrefixEntry; | |
| 40 | |
| 41 enum SegCacheParameters { | |
| 42 /** number of characters used in initial prefix tree */ | |
| 43 ePrefixLength = 2, | |
| 44 /** Segments more recent than maxSegmentCount() / eAgeFactor are kept */ | |
| 45 eAgeFactor = 4, | |
| 46 /** Segments are purged according to the formular: | |
| 47 * accessCount < (totalAccesses)/(ePurgeFactor * maxSegments) */ | |
| 48 ePurgeFactor = 5, | |
| 49 /** Maximum number of Segments to store which have the same | |
| 50 * prefix. Needed to prevent unique identifiers flooding the cache */ | |
| 51 eMaxSuffixCount = 15 | |
| 52 | |
| 53 }; | |
| 54 | |
| 55 class SegCacheCharInfo | |
| 56 { | |
| 57 public: | |
| 58 uint16 m_unicode; | |
| 59 uint16 m_before; | |
| 60 uint16 m_after; | |
| 61 }; | |
| 62 | |
| 63 /** | |
| 64 * SegCacheEntry stores the result of running the engine for specific unicode | |
| 65 * code points in the typical mid-line situation. | |
| 66 */ | |
| 67 class SegCacheEntry | |
| 68 { | |
| 69 // Prevent any implict copying; | |
| 70 SegCacheEntry(const SegCacheEntry &); | |
| 71 SegCacheEntry & operator = (const SegCacheEntry &); | |
| 72 | |
| 73 friend class SegCachePrefixEntry; | |
| 74 public: | |
| 75 SegCacheEntry() : | |
| 76 m_glyphLength(0), m_unicode(NULL), m_glyph(NULL), m_attr(NULL), m_justs(0), | |
| 77 m_accessCount(0), m_lastAccess(0) | |
| 78 {} | |
| 79 SegCacheEntry(const uint16 * cmapGlyphs, size_t length, Segment * seg, size_t charOffset, long long cacheTime); | |
| 80 ~SegCacheEntry() { clear(); }; | |
| 81 void clear(); | |
| 82 size_t glyphLength() const { return m_glyphLength; } | |
| 83 const Slot * first() const { return m_glyph; } | |
| 84 const Slot * last() const { return m_glyph + (m_glyphLength - 1); } | |
| 85 | |
| 86 /** Total number of times this entry has been accessed since creation */ | |
| 87 unsigned long long accessCount() const { return m_accessCount; } | |
| 88 /** "time" of last access where "time" is measured in accesses to the cache owning this entry */ | |
| 89 void accessed(unsigned long long cacheTime) const | |
| 90 { | |
| 91 m_lastAccess = cacheTime; ++m_accessCount; | |
| 92 }; | |
| 93 | |
| 94 int compareRank(const SegCacheEntry & entry) const | |
| 95 { | |
| 96 if (m_accessCount > entry.m_accessCount) return 1; | |
| 97 else if (m_accessCount < entry.m_accessCount) return 1; | |
| 98 else if (m_lastAccess > entry.m_lastAccess) return 1; | |
| 99 else if (m_lastAccess < entry.m_lastAccess) return -1; | |
| 100 return 0; | |
| 101 } | |
| 102 unsigned long long lastAccess() const { return m_lastAccess; }; | |
| 103 | |
| 104 CLASS_NEW_DELETE; | |
| 105 private: | |
| 106 | |
| 107 size_t m_glyphLength; | |
| 108 /** glyph ids resulting from cmap mapping from unicode to glyph before substitution | |
| 109 * the length of this array is determined by the position in the SegCachePrefixEntry */ | |
| 110 uint16 * m_unicode; | |
| 111 /** slots after shapping and positioning */ | |
| 112 Slot * m_glyph; | |
| 113 int16 * m_attr; | |
| 114 byte * m_justs; | |
| 115 mutable unsigned long long m_accessCount; | |
| 116 mutable unsigned long long m_lastAccess; | |
| 117 }; | |
| 118 | |
| 119 } // namespace graphite2 | |
| 120 | |
| 121 #endif |
