From 2d7f50c858251bc6cab73994d0eac103d56b6545 Mon Sep 17 00:00:00 2001
From: Andrea Paatz <andrea@icsharpcode.net>
Date: Sun, 31 Jul 2005 16:18:41 +0000
Subject: [PATCH] tryed to implement a BoyerMoore algorithm, commented out,
 only copied from a web site

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@294 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61
---
 .../BoyerMooreSearchStrategy.cs               | 122 ++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 src/Main/Base/Project/Src/TextEditor/SearchAndReplace/Engine/SearchStrategy/BoyerMooreSearchStrategy.cs

diff --git a/src/Main/Base/Project/Src/TextEditor/SearchAndReplace/Engine/SearchStrategy/BoyerMooreSearchStrategy.cs b/src/Main/Base/Project/Src/TextEditor/SearchAndReplace/Engine/SearchStrategy/BoyerMooreSearchStrategy.cs
new file mode 100644
index 0000000000..d1192c6d2c
--- /dev/null
+++ b/src/Main/Base/Project/Src/TextEditor/SearchAndReplace/Engine/SearchStrategy/BoyerMooreSearchStrategy.cs
@@ -0,0 +1,122 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt">2002-2005 AlphaSierraPapa</copyright>
+//     <license see="prj:///doc/license.txt">GNU General Public License</license>
+//     <owner name="Mike Krüger" email="mike@icsharpcode.net"/>
+//     <version>$Revision: 230 $</version>
+// </file>
+/*
+using System;
+using System.Drawing;
+
+using ICSharpCode.Core;
+using ICSharpCode.SharpDevelop.Internal.Undo;
+
+namespace SearchAndReplace
+{
+	/// <summary>
+	/// This interface is the basic interface which all 
+	/// search algorithms must implement.
+	/// </summary>
+	public class BoyerMooreSearchStrategy
+	{
+		// Shift table for chars present in the pattern
+		Hashtable PatternCharShifts;
+		// Shifts for all other chars
+		int[] OtherCharShifts;
+		// the patern to search
+		string searchPattern;
+		// Length of the search pattern
+		int PatternLength;
+		
+		/// <remarks>
+		/// Only with a call to this method the search strategy must
+		/// update their pattern information. This method will be called 
+		/// before the FindNext function.
+		/// </remarks>
+		public void CompilePattern()
+		{
+			searchPattern = SearchOptions.MatchCase ? SearchOptions.FindPattern : SearchOptions.FindPattern.ToUpper();
+			PatternCharShifts = new Hashtable();
+			
+			// Building shift table
+			PatternLength = Pattern.Length;
+			int MaxShift = PatternLength;
+			// Constructing the table where number
+			// of columns is equal to PatternLength
+			// and number of rows is equal to the
+			// number of distinct chars in the pattern
+			for (int i = 0; i < PatternLength; ++i) {
+				if (!PatternCharShifts.ContainsKey(Pattern[i])) {
+					PatternCharShifts.Add(Pattern[i], new int[PatternLength]);
+				}
+			}
+			OtherCharShifts = new int[PatternLength];
+			// Filling the last column of the
+			// table with maximum shifts (pattern length)
+			foreach(DictionaryEntry Row in PatternCharShifts) {
+				((int[])Row.Value)[PatternLength - 1] = MaxShift;
+			}
+			OtherCharShifts[PatternLength - 1] = MaxShift;
+			// Calculating other shifts (filling each column
+			// from PatternLength - 2 to 0 (from right to left)
+			for (int i = PatternLength - 1; i >= 0; --i)
+			{
+				// Suffix string contains the characters
+				// right to the character being processsed
+				string Suffix = new String(Pattern.ToCharArray(),
+				                           i + 1,  PatternLength - i - 1);
+				// if Pattern begins with Suffix
+				// the maximum shift is equal to i + 1
+				if (Pattern.StartsWith(Suffix)) {
+					MaxShift = i + 1;
+				}
+				// Store shift for characters not present in the pattern
+				OtherCharShifts[i] = MaxShift;
+				// We shorten patter by one char in NewPattern.
+				string NewPattern = new string(Pattern.ToCharArray(),
+				                               0, Pattern.Length -1);
+				if ((NewPattern.LastIndexOf(Suffix) > 0) || (Suffix.Length == 0)) {
+					foreach(DictionaryEntry Row in PatternCharShifts)
+					{
+						string NewSuffix  = (char)Row.Key + Suffix;
+						// Calculate shifts:
+						//Check if there are other occurences
+						//of the new suffix in the pattern
+						// If several occurences exist, we need the rightmost one
+						int NewSuffixPos = NewPattern.LastIndexOf(NewSuffix);
+						if (NewSuffixPos >= 0) {
+							((int[])Row.Value)[i] = i - NewSuffixPos;
+						} else {
+							((int[])Row.Value)[i] = MaxShift;
+						}
+						// Storing 0 if characters
+						// in a row and a columnt are the same
+						if ((char)Row.Key == Pattern[i]) {
+							((int[])Row.Value)[i] = 0;
+						}
+					}
+				} else {
+					foreach(DictionaryEntry Row in PatternCharShifts)
+					{
+						// if Suffix doesn't occure in NewPattern
+						// we simply use previous shift value
+						((int[])Row.Value)[i] = MaxShift;
+						if ((char)Row.Key == Pattern[i]) {
+							((int[])Row.Value)[i] = 0;
+						}
+					}
+				}
+			}
+		}
+		
+		/// <remarks>
+		/// The find next method should search the next occurrence of the 
+		/// compiled pattern in the text using the textIterator and options.
+		/// </remarks>
+		public SearchResult FindNext(ITextIterator textIterator)
+		{
+			return null;
+		}
+	}
+}
+*/