1 files changed, 55 insertions, 0 deletions
diff --git a/bundles/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/rangedifferencer/IRangeComparator.java b/bundles/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/rangedifferencer/IRangeComparator.java
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index 000000000..2a7ca6643
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+++ b/bundles/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/rangedifferencer/IRangeComparator.java
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+/*
+ * Licensed Materials - Property of IBM,
+ * WebSphere Studio Workbench
+ * (c) Copyright IBM Corp 2000, 2001
+ */
+package org.eclipse.compare.rangedifferencer;
+
+/**
+ * For breaking an object to compare into a sequence of comparable entities.
+ * <p>
+ * It is used by <code>RangeDifferencer</code> to find longest sequences of
+ * matching and non-matching ranges.
+ * <p>
+ * For example, to compare two text documents and find longest common sequences
+ * of matching and non-matching lines, the implementation must break the document
+ * into lines. <code>getRangeCount</code> would return the number of lines in the 
+ * document, and <code>rangesEqual</code> would compare a specified line given 
+ * with one in another <code>IRangeComparator</code>.
+ * </p>
+ * <p>
+ * Clients should implement this interface; there is no standard implementation.
+ * </p>
+ */
+public interface IRangeComparator {
+
+	/**
+	 * Returns the number of comparable entities.
+	 *
+	 * @return the number of comparable entities 
+	 */
+	int getRangeCount();
+
+	/**
+	 * Returns whether the comparable entity given by the first index
+	 * matches an entity specified by the other <code>IRangeComparator</code> and index.
+	 *
+	 * @param thisIndex the index of the comparable entity within this <code>IRangeComparator</code>
+	 * @param other the IRangeComparator to compare this with
+	 * @param otherIndex the index of the comparable entity within the other <code>IRangeComparator</code>
+	 * @return <code>true</code> if the comparable entities are equal
+	 */
+	boolean rangesEqual(int thisIndex, IRangeComparator other, int otherIndex);
+
+	/**
+	 * Returns whether a comparison should be skipped because it would be too costly (or lengthy).
+	 * 
+	 * @param length a number on which to base the decision whether to return
+	 * 	<code>true</code> or <code>false</code>
+	 * @param maxLength another number on which to base the decision whether to return
+	 *	<code>true</code> or <code>false</code>
+	 * @param other the other <code>IRangeComparator</code> to compare with
+	 * @return <code>true</code> to avoid a too lengthy range comparison
+	 */
+	boolean skipRangeComparison(int length, int maxLength, IRangeComparator other);
+}