1 files changed, 87 insertions, 0 deletions
diff --git a/predicate-search-core/src/main/java/com/yahoo/search/predicate/optimization/PredicateOptions.java b/predicate-search-core/src/main/java/com/yahoo/search/predicate/optimization/PredicateOptions.java
new file mode 100644
index 00000000000..134d52dd3ab
--- /dev/null
+++ b/predicate-search-core/src/main/java/com/yahoo/search/predicate/optimization/PredicateOptions.java
@@ -0,0 +1,87 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.predicate.optimization;
+
+import java.util.OptionalLong;
+
+/**
+ * This class contains the configured options for predicate indexes.
+ * The adjusted bounds are extended to the nearest power of the arity (-1)
+ * and are used to generate more efficient indexes.
+ *
+ * @author magnarn
+ * @author bjorncs
+ */
+public class PredicateOptions {
+    public static final long DEFAULT_LOWER_BOUND = 0x8000000000000000L;
+    public static final long DEFAULT_UPPER_BOUND = 0x7fffffffffffffffL;
+
+    private final int arity;
+    private final long lowerBound;
+    private final long upperBound;
+    private OptionalLong adjustedLowerBound;
+    private OptionalLong adjustedUpperBound;
+
+    public PredicateOptions(int arity, Long lowerBound, Long upperBound) {
+        this.arity = arity;
+        this.lowerBound = lowerBound == null? DEFAULT_LOWER_BOUND : lowerBound;
+        this.upperBound = upperBound == null? DEFAULT_UPPER_BOUND : upperBound;
+        this.adjustedLowerBound = OptionalLong.empty();
+        this.adjustedUpperBound = OptionalLong.empty();
+    }
+
+    public PredicateOptions(int arity) {
+        this(arity, DEFAULT_LOWER_BOUND, DEFAULT_UPPER_BOUND);
+    }
+
+    public int getArity() {
+        return arity;
+    }
+
+    public long getLowerBound() {
+        return lowerBound;
+    }
+
+    public long getUpperBound() {
+        return upperBound;
+    }
+
+    public long getAdjustedLowerBound() {
+        if (!adjustedLowerBound.isPresent()) {
+            if (lowerBound == DEFAULT_LOWER_BOUND) {
+                adjustedLowerBound = OptionalLong.of(lowerBound);
+            } else if (lowerBound > 0) {
+                adjustedLowerBound = OptionalLong.of(0L);
+            } else {
+                adjustedLowerBound = OptionalLong.of(-adjustBound(arity, -lowerBound));
+            }
+        }
+        return adjustedLowerBound.getAsLong();
+    }
+
+    public long getAdjustedUpperBound() {
+        if (!adjustedUpperBound.isPresent()) {
+            if (upperBound == DEFAULT_UPPER_BOUND) {
+                adjustedUpperBound = OptionalLong.of(DEFAULT_UPPER_BOUND);
+            } else if (upperBound < 0) {
+                adjustedUpperBound = OptionalLong.of(-1L);  // 0 belongs to the positive range.
+            } else {
+                adjustedUpperBound = OptionalLong.of(adjustBound(arity, upperBound));
+            }
+        }
+        return adjustedUpperBound.getAsLong();
+    }
+
+    private static long adjustBound(int arity, long bound) {
+        long adjusted = arity;
+        long value = bound;
+        long max = Long.MAX_VALUE / arity;
+        while ((value/=arity) > 0) {
+            if (adjusted > max) {
+                return bound;
+            }
+            adjusted *= arity;
+        }
+        return adjusted - 1;
+    }
+}
+