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+/* GRAPHITE2 LICENSING
+
+ Copyright 2010, SIL International
+ All rights reserved.
+
+ This library is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 2.1 of License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should also have received a copy of the GNU Lesser General Public
+ License along with this library in the file named "LICENSE".
+ If not, write to the Free Software Foundation, 51 Franklin Street,
+ Suite 500, Boston, MA 02110-1335, USA or visit their web page on the
+ internet at http://www.fsf.org/licenses/lgpl.html.
+
+Alternatively, the contents of this file may be used under the terms of the
+Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public
+License, as published by the Free Software Foundation, either version 2
+of the License or (at your option) any later version.
+*/
+#pragma once
+
+#ifndef GRAPHITE2_NSEGCACHE
+
+#include "inc/Main.h"
+#include "inc/Slot.h"
+
+namespace graphite2 {
+
+class Segment;
+class Slot;
+class SegCacheEntry;
+class SegCachePrefixEntry;
+
+enum SegCacheParameters {
+ /** number of characters used in initial prefix tree */
+ ePrefixLength = 2,
+ /** Segments more recent than maxSegmentCount() / eAgeFactor are kept */
+ eAgeFactor = 4,
+ /** Segments are purged according to the formular:
+ * accessCount < (totalAccesses)/(ePurgeFactor * maxSegments) */
+ ePurgeFactor = 5,
+ /** Maximum number of Segments to store which have the same
+ * prefix. Needed to prevent unique identifiers flooding the cache */
+ eMaxSuffixCount = 15
+
+};
+
+class SegCacheCharInfo
+{
+public:
+ uint16 m_unicode;
+ uint16 m_before;
+ uint16 m_after;
+};
+
+/**
+ * SegCacheEntry stores the result of running the engine for specific unicode
+ * code points in the typical mid-line situation.
+ */
+class SegCacheEntry
+{
+ // Prevent any implict copying;
+ SegCacheEntry(const SegCacheEntry &);
+ SegCacheEntry & operator = (const SegCacheEntry &);
+
+ friend class SegCachePrefixEntry;
+public:
+ SegCacheEntry() :
+ m_glyphLength(0), m_unicode(NULL), m_glyph(NULL), m_attr(NULL), m_justs(0),
+ m_accessCount(0), m_lastAccess(0)
+ {}
+ SegCacheEntry(const uint16 * cmapGlyphs, size_t length, Segment * seg, size_t charOffset, long long cacheTime);
+ ~SegCacheEntry() { clear(); };
+ void clear();
+ size_t glyphLength() const { return m_glyphLength; }
+ const Slot * first() const { return m_glyph; }
+ const Slot * last() const { return m_glyph + (m_glyphLength - 1); }
+
+ /** Total number of times this entry has been accessed since creation */
+ unsigned long long accessCount() const { return m_accessCount; }
+ /** "time" of last access where "time" is measured in accesses to the cache owning this entry */
+ void accessed(unsigned long long cacheTime) const
+ {
+ m_lastAccess = cacheTime; ++m_accessCount;
+ };
+
+ int compareRank(const SegCacheEntry & entry) const
+ {
+ if (m_accessCount > entry.m_accessCount) return 1;
+ else if (m_accessCount < entry.m_accessCount) return 1;
+ else if (m_lastAccess > entry.m_lastAccess) return 1;
+ else if (m_lastAccess < entry.m_lastAccess) return -1;
+ return 0;
+ }
+ unsigned long long lastAccess() const { return m_lastAccess; };
+
+ CLASS_NEW_DELETE;
+private:
+
+ size_t m_glyphLength;
+ /** glyph ids resulting from cmap mapping from unicode to glyph before substitution
+ * the length of this array is determined by the position in the SegCachePrefixEntry */
+ uint16 * m_unicode;
+ /** slots after shapping and positioning */
+ Slot * m_glyph;
+ int16 * m_attr;
+ byte * m_justs;
+ mutable unsigned long long m_accessCount;
+ mutable unsigned long long m_lastAccess;
+};
+
+} // namespace graphite2
+
+#endif