X-Git-Url: http://secure.phpeclipse.com

diff --git a/net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/spelling/engine/DefaultPhoneticDistanceAlgorithm.java b/net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/spelling/engine/DefaultPhoneticDistanceAlgorithm.java
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+++ b/net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/spelling/engine/DefaultPhoneticDistanceAlgorithm.java
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+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+
+package net.sourceforge.phpdt.internal.ui.text.spelling.engine;
+
+/**
+ * Default phonetic distance algorithm for english words.
+ * <p>
+ * This algorithm implements the Levenshtein text edit distance.
+ * </p>
+ * 
+ * @since 3.0
+ */
+public final class DefaultPhoneticDistanceAlgorithm implements
+		IPhoneticDistanceAlgorithm {
+
+	/** The change case cost */
+	public static final int COST_CASE = 10;
+
+	/** The insert character cost */
+	public static final int COST_INSERT = 95;
+
+	/** The remove character cost */
+	public static final int COST_REMOVE = 95;
+
+	/** The substitute characters cost */
+	public static final int COST_SUBSTITUTE = 100;
+
+	/** The swap characters cost */
+	public static final int COST_SWAP = 90;
+
+	/*
+	 * @see org.eclipse.spelling.done.IPhoneticDistanceAlgorithm#getDistance(java.lang.String,java.lang.String)
+	 */
+	public final int getDistance(final String from, final String to) {
+
+		final char[] first = (" " + from).toCharArray(); //$NON-NLS-1$
+		final char[] second = (" " + to).toCharArray(); //$NON-NLS-1$
+
+		final int rows = first.length;
+		final int columns = second.length;
+
+		final int[][] metric = new int[rows][columns];
+		for (int column = 1; column < columns; column++)
+			metric[0][column] = metric[0][column - 1] + COST_REMOVE;
+
+		for (int row = 1; row < rows; row++)
+			metric[row][0] = metric[row - 1][0] + COST_INSERT;
+
+		char source, target;
+
+		int swap = Integer.MAX_VALUE;
+		int change = Integer.MAX_VALUE;
+
+		int minimum, diagonal, insert, remove;
+		for (int row = 1; row < rows; row++) {
+
+			source = first[row];
+			for (int column = 1; column < columns; column++) {
+
+				target = second[column];
+				diagonal = metric[row - 1][column - 1];
+
+				if (source == target) {
+					metric[row][column] = diagonal;
+					continue;
+				}
+
+				change = Integer.MAX_VALUE;
+				if (Character.toLowerCase(source) == Character
+						.toLowerCase(target))
+					change = COST_CASE + diagonal;
+
+				swap = Integer.MAX_VALUE;
+				if (row != 1 && column != 1 && source == second[column - 1]
+						&& first[row - 1] == target)
+					swap = COST_SWAP + metric[row - 2][column - 2];
+
+				minimum = COST_SUBSTITUTE + diagonal;
+				if (swap < minimum)
+					minimum = swap;
+
+				remove = metric[row][column - 1];
+				if (COST_REMOVE + remove < minimum)
+					minimum = COST_REMOVE + remove;
+
+				insert = metric[row - 1][column];
+				if (COST_INSERT + insert < minimum)
+					minimum = COST_INSERT + insert;
+				if (change < minimum)
+					minimum = change;
+
+				metric[row][column] = minimum;
+			}
+		}
+		return metric[rows - 1][columns - 1];
+	}
+}