Change directory structure.

[dvibrowser/dvi2epub.git] / src / main / java / jp / sourceforge / dvibrowser / dvicore / render / GammaCorrectorCache.java

diff --git a/src/main/java/jp/sourceforge/dvibrowser/dvicore/render/GammaCorrectorCache.java b/src/main/java/jp/sourceforge/dvibrowser/dvicore/render/GammaCorrectorCache.java
new file mode 100644 (file)
index 0000000..7dbe436
--- /dev/null
+++ b/src/main/java/jp/sourceforge/dvibrowser/dvicore/render/GammaCorrectorCache.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2009, Takeyuki Nagao
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the
+ * following conditions are met:
+ * 
+ *  * Redistributions of source code must retain the above
+ *    copyright notice, this list of conditions and the
+ *    following disclaimer.
+ *  * Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the
+ *    following disclaimer in the documentation and/or other
+ *    materials provided with the distribution.
+ *    
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ */
+
+package jp.sourceforge.dvibrowser.dvicore.render;
+
+import jp.sourceforge.dvibrowser.dvicore.api.GammaCorrector;
+import jp.sourceforge.dvibrowser.dvicore.util.DviCache;
+
+public class GammaCorrectorCache
+implements GammaCorrector
+{
+  private static final int MAX_LOOKUP_TABLE_SIZE = 65536;
+  private int maxval;
+  private LookupTable table;
+  private boolean canLookUp;
+  private final GammaCorrector gammaCorrector;
+  
+  private static class LookupTable
+  {
+    private final int[] data;
+
+    public LookupTable(int maxval)
+    {
+      this.data = new int [maxval+1];
+    }
+  }
+  
+  private static final DviCache<String, LookupTable>
+    cache = new DviCache<String, LookupTable>(10);
+ 
+  public static GammaCorrector wrap(GammaCorrector gammaCorrector)
+  {
+    return new GammaCorrectorCache(gammaCorrector);
+  }
+  
+  private GammaCorrectorCache(GammaCorrector gammaCorrector)
+  {
+    this.gammaCorrector = gammaCorrector;
+  }
+  
+  public void setMaxValue(int maxval)
+  {
+    this.maxval = maxval;
+    if (maxval < MAX_LOOKUP_TABLE_SIZE) {
+      String key = gammaCorrector.getCacheKey() + "--" + maxval;
+      LookupTable table = cache.get(key);
+      if (table == null) {
+        table = new LookupTable(maxval);
+        for (int i=0; i<=maxval; i++) {
+          table.data[i] = doCorrectGamma(i, maxval);
+        }
+        cache.put(key, table);
+      }
+      this.table = table;
+      canLookUp = true;
+    } else {
+      canLookUp = false;
+    }
+  }
+
+  public int correctGamma(int c, int maxval)
+  {
+    if (c < 0) throw new IllegalArgumentException("c is negative");
+    if (maxval < 0) throw new IllegalArgumentException("maxval is negative");
+    
+    if (gammaCorrector == null) return 0;
+    if (maxval != this.maxval) setMaxValue(maxval);
+    if (canLookUp && c <= maxval) {
+      return table.data[c];
+    }
+    return doCorrectGamma(c, maxval);
+  }
+  
+  private int doCorrectGamma(int c, int maxval)
+  {
+    return gammaCorrector.correctGamma(c, maxval);
+  }
+
+  public GammaCorrector getGammaCorrector()
+  {
+    return gammaCorrector;
+  }
+
+  public String getCacheKey() {
+    return null;
+  }
+}