Added a slightly faster IndexOf method

src/Core/StringExtensions.cs

@@ -34,5 +34,42 @@ namespace Nikse.SubtitleEdit.Core
         {
             return source.IndexOf(value, comparisonType) >= 0;
         }
+
+        // http://www.codeproject.com/Articles/43726/Optimizing-string-operations-in-C
+        public static int FastIndexOf(this string source, string pattern)
+        {
+            if (pattern == null) throw new ArgumentNullException();
+            if (pattern.Length == 0) return 0;
+            if (pattern.Length == 1) return source.IndexOf(pattern[0]);
+            int limit = source.Length - pattern.Length + 1;
+            if (limit < 1) return -1;
+            // Store the first 2 characters of "pattern"
+            char c0 = pattern[0];
+            char c1 = pattern[1];
+            // Find the first occurrence of the first character
+            int first = source.IndexOf(c0, 0, limit);
+            while (first != -1)
+            {
+                // Check if the following character is the same like
+                // the 2nd character of "pattern"
+                if (source[first + 1] != c1)
+                {
+                    first = source.IndexOf(c0, ++first, limit - first);
+                    continue;
+                }
+                // Check the rest of "pattern" (starting with the 3rd character)
+                bool found = true;
+                for (var j = 2; j < pattern.Length; j++)
+                    if (source[first + j] != pattern[j])
+                    {
+                        found = false;
+                        break;
+                    }
+                // If the whole word was found, return its index, otherwise try again
+                if (found) return first;
+                first = source.IndexOf(c0, ++first, limit - first);
+            }
+            return -1;
+        }
     }
 }

src/Logic/Dictionaries/OcrFixReplaceList.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Text;
 using System.Text.RegularExpressions;
@@ -140,7 +141,7 @@ namespace Nikse.SubtitleEdit.Logic.Dictionaries
 
             string newText = input;
             string pre = string.Empty;
-            if (newText.StartsWith("<i>"))
+            if (newText.StartsWith("<i>", StringComparison.Ordinal))
             {
                 pre += "<i>";
                 newText = newText.Remove(0, 3);
@@ -150,7 +151,7 @@ namespace Nikse.SubtitleEdit.Logic.Dictionaries
                 pre += newText[0];
                 newText = newText.Substring(1);
             }
-            if (newText.StartsWith("<i>"))
+            if (newText.StartsWith("<i>", StringComparison.Ordinal))
             {
                 pre += "<i>";
                 newText = newText.Remove(0, 3);
@@ -190,14 +191,15 @@ namespace Nikse.SubtitleEdit.Logic.Dictionaries
             newText = pre + newText;
 
             string post = string.Empty;
-            if (newText.EndsWith("</i>"))
+            if (newText.EndsWith("</i>", StringComparison.Ordinal))
             {
                 newText = newText.Remove(newText.Length - 4, 4);
                 post = "</i>";
             }
+
             foreach (string from in _endLineReplaceList.Keys)
             {
-                if (newText.EndsWith(from))
+                if (newText.EndsWith(from, StringComparison.Ordinal))
                 {
                     int position = (newText.Length - from.Length);
                     newText = newText.Remove(position).Insert(position, _endLineReplaceList[from]);
@@ -207,13 +209,13 @@ namespace Nikse.SubtitleEdit.Logic.Dictionaries
 
             foreach (string from in PartialLineWordBoundaryReplaceList.Keys)
             {
-                if (newText.Contains(from))
+                if (newText.FastIndexOf(from) >= 0)
                     newText = ReplaceWord(newText, from, PartialLineWordBoundaryReplaceList[from]);
             }
 
             foreach (string from in _partialLineAlwaysReplaceList.Keys)
             {
-                if (newText.Contains(from))
+                if (newText.FastIndexOf(from) >= 0)
                     newText = newText.Replace(from, _partialLineAlwaysReplaceList[from]);
             }
 
@@ -251,7 +253,7 @@ namespace Nikse.SubtitleEdit.Logic.Dictionaries
                 int i = 0;
                 while (s.Contains(letter) && i < 10)
                 {
-                    int index = s.IndexOf(letter, StringComparison.Ordinal);
+                    int index = s.FastIndexOf(letter);
                     s = AddToGuessList(list, s, index, letter, _partialWordReplaceList[letter]);
                     AddToGuessList(list, word, index, letter, _partialWordReplaceList[letter]);
                     i++;

src/Logic/OCR/OcrFixEngine.cs

@@ -968,7 +968,7 @@ namespace Nikse.SubtitleEdit.Logic.Ocr
 
             foreach (string name in _namesEtcMultiWordList)
             {
-                int start = tempLine.IndexOf(name, StringComparison.Ordinal);
+                int start = tempLine.FastIndexOf(name);
                 if (start >= 0)
                 {
                     if (start == 0 || (Environment.NewLine + @" ¡¿,.!?:;()[]{}+-$£""”“#&%…—♪").Contains(tempLine[start - 1]))

src/Logic/StripableText.cs

@@ -128,7 +128,7 @@ namespace Nikse.SubtitleEdit.Logic
 
             foreach (string name in namesEtc)
             {
-                int start = lower.IndexOf(name.ToLower(), StringComparison.Ordinal);
+                int start = lower.FastIndexOf(name.ToLower());
                 while (start >= 0 && start < lower.Length)
                 {
                     bool startOk = (start == 0) || (lower[start - 1] == ' ') || (lower[start - 1] == '-') ||