/mcs/class/corlib/System/String.cs

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//
// System.String.cs
//
// Authors:
//   Patrik Torstensson
//   Jeffrey Stedfast (fejj@ximian.com)
//   Dan Lewis (dihlewis@yahoo.co.uk)
//   Sebastien Pouliot  <sebastien@ximian.com>
//   Marek Safar (marek.safar@seznam.cz)
//   Andreas Nahr (Classdevelopment@A-SoftTech.com)
//
// (C) 2001 Ximian, Inc.  http://www.ximian.com
// Copyright (C) 2004-2005 Novell (http://www.novell.com)
// Copyright (c) 2012 Xamarin, Inc (http://www.xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//
//
// This class contains all implementation for culture-insensitive methods.
// Culture-sensitive methods are implemented in the System.Globalization or
// Mono.Globalization namespace.
//
// Ensure that argument checks on methods don't overflow
//

using System.Text;
using System.Collections;
using System.Globalization;
using System.Runtime.CompilerServices;

using System.Collections.Generic;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using Mono.Globalization.Unicode;


namespace System
{
	[Serializable]
	[ComVisible (true)]
	[StructLayout (LayoutKind.Sequential)]
	public sealed class String : IConvertible, ICloneable, IEnumerable, IComparable, IComparable<String>, IEquatable <String>, IEnumerable<char>
	{
		[NonSerialized] private int length;
		[NonSerialized] private char start_char;

		public static readonly String Empty = "";

		internal static readonly int LOS_limit = GetLOSLimit ();

		public static unsafe bool Equals (string a, string b)
		{
			if ((a as object) == (b as object))
				return true;

			if (a == null || b == null)
				return false;

			int len = a.length;

			if (len != b.length)
				return false;

			fixed (char* s1 = &a.start_char, s2 = &b.start_char) {
				char* s1_ptr = s1;
				char* s2_ptr = s2;

				while (len >= 8) {
					if (((int*)s1_ptr)[0] != ((int*)s2_ptr)[0] ||
						((int*)s1_ptr)[1] != ((int*)s2_ptr)[1] ||
						((int*)s1_ptr)[2] != ((int*)s2_ptr)[2] ||
						((int*)s1_ptr)[3] != ((int*)s2_ptr)[3])
						return false;

					s1_ptr += 8;
					s2_ptr += 8;
					len -= 8;
				}

				if (len >= 4) {
					if (((int*)s1_ptr)[0] != ((int*)s2_ptr)[0] ||
						((int*)s1_ptr)[1] != ((int*)s2_ptr)[1])
						return false;

					s1_ptr += 4;
					s2_ptr += 4;
					len -= 4;
				}

				if (len > 1) {
					if (((int*)s1_ptr)[0] != ((int*)s2_ptr)[0])
						return false;

					s1_ptr += 2;
					s2_ptr += 2;
					len -= 2;
				}

				return len == 0 || *s1_ptr == *s2_ptr;
			}
		}

		public static bool operator == (String a, String b)
		{
			return Equals (a, b);
		}

		public static bool operator != (String a, String b)
		{
			return !Equals (a, b);
		}

		[ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.MayFail)]
		public override bool Equals (Object obj)
		{
			return Equals (this, obj as String);
		}

		[ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.MayFail)]
		public bool Equals (String value)
		{
			return Equals (this, value);
		}

		[IndexerName ("Chars")]
		public unsafe char this [int index] {
			get {
				if (index < 0 || index >= length)
					throw new IndexOutOfRangeException ();
				fixed (char* c = &start_char)
					return c[index];
			}
		}

		public Object Clone ()
		{
			return this;
		}

		public TypeCode GetTypeCode ()
		{
			return TypeCode.String;
		}

		public unsafe void CopyTo (int sourceIndex, char[] destination, int destinationIndex, int count)
		{
			if (destination == null)
				throw new ArgumentNullException ("destination");
			if (sourceIndex < 0)
				throw new ArgumentOutOfRangeException ("sourceIndex", "Cannot be negative");
			if (destinationIndex < 0)
				throw new ArgumentOutOfRangeException ("destinationIndex", "Cannot be negative.");
			if (count < 0)
				throw new ArgumentOutOfRangeException ("count", "Cannot be negative.");
			if (sourceIndex > Length - count)
				throw new ArgumentOutOfRangeException ("sourceIndex", "sourceIndex + count > Length");
			if (destinationIndex > destination.Length - count)
				throw new ArgumentOutOfRangeException ("destinationIndex", "destinationIndex + count > destination.Length");

			fixed (char* dest = destination, src = this)
				CharCopy (dest + destinationIndex, src + sourceIndex, count);
		}

		public char[] ToCharArray ()
		{
			return ToCharArray (0, length);
		}

		public unsafe char[] ToCharArray (int startIndex, int length)
		{
			if (startIndex < 0)
				throw new ArgumentOutOfRangeException ("startIndex", "< 0"); 
			if (length < 0)
				throw new ArgumentOutOfRangeException ("length", "< 0"); 
			if (startIndex > this.length - length)
				throw new ArgumentOutOfRangeException ("startIndex", "Must be greater than the length of the string.");

			char[] tmp = new char [length];
			fixed (char* dest = tmp, src = this)
				CharCopy (dest, src + startIndex, length);
			return tmp;
		}

		public String [] Split (params char [] separator)
		{
			return Split (separator, int.MaxValue, 0);
		}

		public String[] Split (char[] separator, int count)
		{
			return Split (separator, count, 0);
		}

		[ComVisible (false)]
		public String[] Split (char[] separator, StringSplitOptions options)
		{
			return Split (separator, Int32.MaxValue, options);
		}

		[ComVisible (false)]
		public String[] Split (char[] separator, int count, StringSplitOptions options)
		{
			if (count < 0)
				throw new ArgumentOutOfRangeException ("count", "Count cannot be less than zero.");
			if ((options != StringSplitOptions.None) && (options != StringSplitOptions.RemoveEmptyEntries))
				throw new ArgumentException ("Illegal enum value: " + options + ".");

			if (Length == 0 && (options & StringSplitOptions.RemoveEmptyEntries) != 0)
				return EmptyArray<string>.Value;

			if (count <= 1) {
				return count == 0 ?
					EmptyArray<string>.Value :
					new String[1] { this };
			}

			return SplitByCharacters (separator, count, options != 0);
		}

		[ComVisible (false)]
		public String[] Split (string[] separator, StringSplitOptions options)
		{
			return Split (separator, Int32.MaxValue, options);
		}

		[ComVisible (false)]
		public String[] Split (string[] separator, int count, StringSplitOptions options)
		{
			if (count < 0)
				throw new ArgumentOutOfRangeException ("count", "Count cannot be less than zero.");
			if ((options != StringSplitOptions.None) && (options != StringSplitOptions.RemoveEmptyEntries))
				throw new ArgumentException ("Illegal enum value: " + options + ".");

			if (count <= 1) {
				return count == 0 ?
					EmptyArray<string>.Value :
					new String[1] { this };
			}

			bool removeEmpty = (options & StringSplitOptions.RemoveEmptyEntries) != 0;

			if (separator == null || separator.Length == 0)
				return SplitByCharacters (null, count, removeEmpty);

			if (Length == 0 && removeEmpty)
				return EmptyArray<string>.Value;

			List<String> arr = new List<String> ();

			int pos = 0;
			int matchCount = 0;
			while (pos < this.Length) {
				int matchIndex = -1;
				int matchPos = Int32.MaxValue;

				// Find the first position where any of the separators matches
				for (int i = 0; i < separator.Length; ++i) {
					string sep = separator [i];
					if (sep == null || sep.Length == 0)
						continue;

					int match = IndexOfOrdinalUnchecked (sep, pos, length - pos);
					if (match >= 0 && match < matchPos) {
						matchIndex = i;
						matchPos = match;
					}
				}

				if (matchIndex == -1)
					break;

				if (!(matchPos == pos && removeEmpty)) {
					if (arr.Count == count - 1)
						break;
					arr.Add (this.Substring (pos, matchPos - pos));
				}

				pos = matchPos + separator [matchIndex].Length;

				matchCount ++;
			}

			if (matchCount == 0)
				return new String [] { this };

			// string contained only separators
			if (removeEmpty && matchCount != 0 && pos == this.Length && arr.Count == 0)
				return EmptyArray<string>.Value;

			if (!(removeEmpty && pos == this.Length))
				arr.Add (this.Substring (pos));

			return arr.ToArray ();
		}

		// .NET 2.0 compatibility only
#if !NET_4_0 && !MOBILE
		static readonly char[] WhiteChars = {
			(char) 0x9, (char) 0xA, (char) 0xB, (char) 0xC, (char) 0xD,
			(char) 0x85, (char) 0x1680, (char) 0x2028, (char) 0x2029,
			(char) 0x20, (char) 0xA0, (char) 0x2000, (char) 0x2001, (char) 0x2002, (char) 0x2003, (char) 0x2004,
			(char) 0x2005, (char) 0x2006, (char) 0x2007, (char) 0x2008, (char) 0x2009, (char) 0x200A, (char) 0x200B,
			(char) 0x3000, (char) 0xFEFF
		};
#endif

		unsafe string[] SplitByCharacters (char[] sep, int count, bool removeEmpty)
		{
#if !NET_4_0 && !MOBILE
			if (sep == null || sep.Length == 0)
				sep = WhiteChars;
#endif

			int[] split_points = null;
			int total_points = 0;
			--count;

			if (sep == null || sep.Length == 0) {
				fixed (char* src = this) {
					char* src_ptr = src;
					int len = Length;

					while (len > 0) {
						if (char.IsWhiteSpace (*src_ptr++)) {
							if (split_points == null) {
								split_points = new int[8];
							} else if (split_points.Length == total_points) {
								Array.Resize (ref split_points, split_points.Length * 2);
							}

							split_points[total_points++] = Length - len;
							if (total_points == count && !removeEmpty)
								break;
						}
						--len;
					}
				}
			} else {
				fixed (char* src = this) {
					fixed (char* sep_src = sep) {
						char* src_ptr = src;
						char* sep_ptr_end = sep_src + sep.Length;
						int len = Length;
						while (len > 0) {
							char* sep_ptr = sep_src;
							do {
								if (*sep_ptr++ == *src_ptr) {
									if (split_points == null) {
										split_points = new int[8];
									} else if (split_points.Length == total_points) {
										Array.Resize (ref split_points, split_points.Length * 2);
									}

									split_points[total_points++] = Length - len;
									if (total_points == count && !removeEmpty)
										len = 0;

									break;
								}
							} while (sep_ptr != sep_ptr_end);

							++src_ptr;
							--len;
						}
					}
				}
			}

			if (total_points == 0)
				return new string[] { this };

			var res = new string[Math.Min (total_points, count) + 1];
			int prev_index = 0;
			int i = 0;
			if (!removeEmpty) {
				for (; i < total_points; ++i) {
					var start = split_points[i];
					res[i] = SubstringUnchecked (prev_index, start - prev_index);
					prev_index = start + 1;
				}

				res[i] = SubstringUnchecked (prev_index, Length - prev_index);
			} else {
				int used = 0;
				int length;
				for (; i < total_points; ++i) {
					var start = split_points[i];
					length = start - prev_index;
					if (length != 0) {
						if (used == count)
							break;

						res[used++] = SubstringUnchecked (prev_index, length);
					}

					prev_index = start + 1;
				}

				length = Length - prev_index;
				if (length != 0)
					res[used++] = SubstringUnchecked (prev_index, length);

				if (used != res.Length)
					Array.Resize (ref res, used);
			}

			return res;
		}

		public String Substring (int startIndex)
		{
			if (startIndex == 0)
				return this;
			if (startIndex < 0 || startIndex > this.length)
				throw new ArgumentOutOfRangeException ("startIndex");

			return SubstringUnchecked (startIndex, this.length - startIndex);
		}

		public String Substring (int startIndex, int length)
		{
			if (length < 0)
				throw new ArgumentOutOfRangeException ("length", "Cannot be negative.");
			if (startIndex < 0)
				throw new ArgumentOutOfRangeException ("startIndex", "Cannot be negative.");
			if (startIndex > this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "Cannot exceed length of string.");
			if (startIndex > this.length - length)
				throw new ArgumentOutOfRangeException ("length", "startIndex + length cannot exceed length of string.");
			if (startIndex == 0 && length == this.length)
				return this;

			return SubstringUnchecked (startIndex, length);
		}

		// This method is used by StringBuilder.ToString() and is expected to
		// always create a new string object (or return String.Empty). 
		internal unsafe String SubstringUnchecked (int startIndex, int length)
		{
			if (length == 0)
				return Empty;

			string tmp = InternalAllocateStr (length);
			fixed (char* dest = tmp, src = this) {
				CharCopy (dest, src + startIndex, length);
			}
			return tmp;
		}

		public String Trim ()
		{
			if (length == 0) 
				return Empty;
			int start = FindNotWhiteSpace (0, length, 1);

			if (start == length)
				return Empty;

			int end = FindNotWhiteSpace (length - 1, start, -1);

			int newLength = end - start + 1;
			if (newLength == length)
				return this;

			return SubstringUnchecked (start, newLength);
		}

		public String Trim (params char[] trimChars)
		{
			if (trimChars == null || trimChars.Length == 0)
				return Trim ();

			if (length == 0) 
				return Empty;
			int start = FindNotInTable (0, length, 1, trimChars);

			if (start == length)
				return Empty;

			int end = FindNotInTable (length - 1, start, -1, trimChars);

			int newLength = end - start + 1;
			if (newLength == length)
				return this;

			return SubstringUnchecked (start, newLength);
		}

		public String TrimStart (params char[] trimChars)
		{
			if (length == 0) 
				return Empty;
			int start;
			if (trimChars == null || trimChars.Length == 0)
				start = FindNotWhiteSpace (0, length, 1);
			else
				start = FindNotInTable (0, length, 1, trimChars);

			if (start == 0)
				return this;

			return SubstringUnchecked (start, length - start);
		}

		public String TrimEnd (params char[] trimChars)
		{
			if (length == 0) 
				return Empty;
			int end;
			if (trimChars == null || trimChars.Length == 0)
				end = FindNotWhiteSpace (length - 1, -1, -1);
			else
				end = FindNotInTable (length - 1, -1, -1, trimChars);

			end++;
			if (end == length)
				return this;

			return SubstringUnchecked (0, end);
		}

		unsafe int FindNotWhiteSpace (int pos, int target, int change)
		{
#if NET_4_0
			fixed (char* src = this) {
				while (pos != target) {
					if (!char.IsWhiteSpace (src[pos]))
						return pos;

					pos += change;
				}
			}
#else
			while (pos != target) {
				char c = this[pos];
				if (c < 0x85) {
					if (c != 0x20) {
						if (c < 0x9 || c > 0xD)
							return pos;
					}
				}
				else {
					if (c != 0xA0 && c != 0xFEFF && c != 0x3000) {
						if (c != 0x85 && c != 0x1680 && c != 0x2028 && c != 0x2029)
							if (c < 0x2000 || c > 0x200B)
								return pos;
					}
				}
				pos += change;
			}
#endif
			return pos;
		}

		private unsafe int FindNotInTable (int pos, int target, int change, char[] table)
		{
			fixed (char* tablePtr = table, thisPtr = this) {
				while (pos != target) {
					char c = thisPtr[pos];
					int x = 0;
					while (x < table.Length) {
						if (c == tablePtr[x])
							break;
						x++;
					}
					if (x == table.Length)
						return pos;
					pos += change;
				}
			}
			return pos;
		}

		public static int Compare (String strA, String strB)
		{
			return CultureInfo.CurrentCulture.CompareInfo.Compare (strA, strB, CompareOptions.None);
		}

		public static int Compare (String strA, String strB, bool ignoreCase)
		{
			return CultureInfo.CurrentCulture.CompareInfo.Compare (strA, strB, ignoreCase ? CompareOptions.IgnoreCase : CompareOptions.None);
		}

		public static int Compare (String strA, String strB, bool ignoreCase, CultureInfo culture)
		{
			if (culture == null)
				throw new ArgumentNullException ("culture");

			return culture.CompareInfo.Compare (strA, strB, ignoreCase ? CompareOptions.IgnoreCase : CompareOptions.None);
		}

		public static int Compare (String strA, int indexA, String strB, int indexB, int length)
		{
			return Compare (strA, indexA, strB, indexB, length, false, CultureInfo.CurrentCulture);
		}

		public static int Compare (String strA, int indexA, String strB, int indexB, int length, bool ignoreCase)
		{
			return Compare (strA, indexA, strB, indexB, length, ignoreCase, CultureInfo.CurrentCulture);
		}
		
		public static int Compare (String strA, int indexA, String strB, int indexB, int length, bool ignoreCase, CultureInfo culture)
		{
			if (culture == null)
				throw new ArgumentNullException ("culture");

			if ((indexA > strA.Length) || (indexB > strB.Length) || (indexA < 0) || (indexB < 0) || (length < 0))
				throw new ArgumentOutOfRangeException ();

			if (length == 0)
				return 0;
			
			if (strA == null) {
				if (strB == null) {
					return 0;
				} else {
					return -1;
				}
			}
			else if (strB == null) {
				return 1;
			}

			CompareOptions compopts;

			if (ignoreCase)
				compopts = CompareOptions.IgnoreCase;
			else
				compopts = CompareOptions.None;

			// Need to cap the requested length to the
			// length of the string, because
			// CompareInfo.Compare will insist that length
			// <= (string.Length - offset)

			int len1 = length;
			int len2 = length;
			
			if (length > (strA.Length - indexA)) {
				len1 = strA.Length - indexA;
			}

			if (length > (strB.Length - indexB)) {
				len2 = strB.Length - indexB;
			}

			// ENHANCE: Might call internal_compare_switch directly instead of doing all checks twice
			return culture.CompareInfo.Compare (strA, indexA, len1, strB, indexB, len2, compopts);
		}

		public static int Compare (string strA, string strB, StringComparison comparisonType)
		{
			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return Compare (strA, strB, false, CultureInfo.CurrentCulture);
			case StringComparison.CurrentCultureIgnoreCase:
				return Compare (strA, strB, true, CultureInfo.CurrentCulture);
			case StringComparison.InvariantCulture:
				return Compare (strA, strB, false, CultureInfo.InvariantCulture);
			case StringComparison.InvariantCultureIgnoreCase:
				return Compare (strA, strB, true, CultureInfo.InvariantCulture);
			case StringComparison.Ordinal:
				return CompareOrdinalUnchecked (strA, 0, Int32.MaxValue, strB, 0, Int32.MaxValue);
			case StringComparison.OrdinalIgnoreCase:
				return CompareOrdinalCaseInsensitiveUnchecked (strA, 0, Int32.MaxValue, strB, 0, Int32.MaxValue);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				throw new ArgumentException (msg, "comparisonType");
			}
		}

		public static int Compare (string strA, int indexA, string strB, int indexB, int length, StringComparison comparisonType)
		{
			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return Compare (strA, indexA, strB, indexB, length, false, CultureInfo.CurrentCulture);
			case StringComparison.CurrentCultureIgnoreCase:
				return Compare (strA, indexA, strB, indexB, length, true, CultureInfo.CurrentCulture);
			case StringComparison.InvariantCulture:
				return Compare (strA, indexA, strB, indexB, length, false, CultureInfo.InvariantCulture);
			case StringComparison.InvariantCultureIgnoreCase:
				return Compare (strA, indexA, strB, indexB, length, true, CultureInfo.InvariantCulture);
			case StringComparison.Ordinal:
				return CompareOrdinal (strA, indexA, strB, indexB, length);
			case StringComparison.OrdinalIgnoreCase:
				return CompareOrdinalCaseInsensitive (strA, indexA, strB, indexB, length);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				throw new ArgumentException (msg, "comparisonType");
			}
		}

		public static bool Equals (string a, string b, StringComparison comparisonType)
		{
			return Compare (a, b, comparisonType) == 0;
		}

		public bool Equals (string value, StringComparison comparisonType)
		{
			return Compare (value, this, comparisonType) == 0;
		}

		public static int Compare (string strA, string strB, CultureInfo culture, CompareOptions options)
		{
			if (culture == null)
				throw new ArgumentNullException ("culture");

			return culture.CompareInfo.Compare (strA, strB, options);
		}

		public static int Compare (string strA, int indexA, string strB, int indexB, int length, CultureInfo culture, CompareOptions options)
		{
			if (culture == null)
				throw new ArgumentNullException ("culture");

			int len1 = length;
			int len2 = length;
			
			if (length > (strA.Length - indexA))
				len1 = strA.Length - indexA;

			if (length > (strB.Length - indexB))
				len2 = strB.Length - indexB;

			return culture.CompareInfo.Compare (strA, indexA, len1, strB, indexB, len2, options);
		}

		public int CompareTo (Object value)
		{
			if (value == null)
				return 1;

			if (!(value is String))
				throw new ArgumentException ();

			return String.Compare (this, (String) value);
		}

		public int CompareTo (String strB)
		{
			if (strB == null)
				return 1;

			return Compare (this, strB);
		}

		public static int CompareOrdinal (String strA, String strB)
		{
			return CompareOrdinalUnchecked (strA, 0, Int32.MaxValue, strB, 0, Int32.MaxValue);
		}

		public static int CompareOrdinal (String strA, int indexA, String strB, int indexB, int length)
		{
			if (strA != null && strB != null)
			{
				if (indexA > strA.Length || indexA < 0)
					throw new ArgumentOutOfRangeException ("indexA");
				if (indexB > strB.Length || indexB < 0)
					throw new ArgumentOutOfRangeException ("indexB");
				if (length < 0)
					throw new ArgumentOutOfRangeException ("length");
			}

			return CompareOrdinalUnchecked (strA, indexA, length, strB, indexB, length);
		}

		internal static int CompareOrdinalCaseInsensitive (String strA, int indexA, String strB, int indexB, int length)
		{
			if (strA != null && strB != null)
			{
				if (indexA > strA.Length || indexA < 0)
					throw new ArgumentOutOfRangeException ("indexA");
				if (indexB > strB.Length || indexB < 0)
					throw new ArgumentOutOfRangeException ("indexB");
				if (length < 0)
					throw new ArgumentOutOfRangeException ("length");
			}

			return CompareOrdinalCaseInsensitiveUnchecked (strA, indexA, length, strB, indexB, length);
		}

		internal static unsafe int CompareOrdinalUnchecked (String strA, int indexA, int lenA, String strB, int indexB, int lenB)
		{
			if (strA == null) {
				return strB == null ? 0 : -1;
			}
			if (strB == null) {
				return 1;
			}
			int lengthA = Math.Min (lenA, strA.Length - indexA);
			int lengthB = Math.Min (lenB, strB.Length - indexB);

			if (lengthA == lengthB && indexA == indexB && Object.ReferenceEquals (strA, strB))
				return 0;

			fixed (char* aptr = strA, bptr = strB) {
				char* ap = aptr + indexA;
				char* end = ap + Math.Min (lengthA, lengthB);
				char* bp = bptr + indexB;
				while (ap < end) {
					if (*ap != *bp)
						return *ap - *bp;
					ap++;
					bp++;
				}
				return lengthA - lengthB;
			}
		}

		//
		// Fastest method for internal case insensitive comparison
		//
		internal static int CompareOrdinalCaseInsensitiveUnchecked (string strA, string strB)
		{
			return CompareOrdinalCaseInsensitiveUnchecked (strA, 0, int.MaxValue, strB, 0, int.MaxValue);
		}

		internal static unsafe int CompareOrdinalCaseInsensitiveUnchecked (String strA, int indexA, int lenA, String strB, int indexB, int lenB)
		{
			// Same as above, but checks versus uppercase characters
			if (strA == null) {
				return strB == null ? 0 : -1;
			}
			if (strB == null) {
				return 1;
			}
			int lengthA = Math.Min (lenA, strA.Length - indexA);
			int lengthB = Math.Min (lenB, strB.Length - indexB);

			if (lengthA == lengthB && Object.ReferenceEquals (strA, strB))
				return 0;

			fixed (char* aptr = strA, bptr = strB) {
				char* ap = aptr + indexA;
				char* end = ap + Math.Min (lengthA, lengthB);
				char* bp = bptr + indexB;
				while (ap < end) {
					if (*ap != *bp) {
						char c1 = Char.ToUpperInvariant (*ap);
						char c2 = Char.ToUpperInvariant (*bp);
						if (c1 != c2)
							return c1 - c2;
					}
					ap++;
					bp++;
				}
				return lengthA - lengthB;
			}
		}

		public bool EndsWith (String value)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			return CultureInfo.CurrentCulture.CompareInfo.IsSuffix (this, value, CompareOptions.None);
		}

		public bool EndsWith (String value, bool ignoreCase, CultureInfo culture)
		{
			if (value == null)
				throw new ArgumentNullException ("value");
			if (culture == null)
				culture = CultureInfo.CurrentCulture;

			return culture.CompareInfo.IsSuffix (this, value,
				ignoreCase ? CompareOptions.IgnoreCase : CompareOptions.None);
		}

		// Following methods are culture-insensitive
		public int IndexOfAny (char [] anyOf)
		{
			if (anyOf == null)
				throw new ArgumentNullException ();
			if (this.length == 0)
				return -1;

			return IndexOfAnyUnchecked (anyOf, 0, this.length);
		}

		public int IndexOfAny (char [] anyOf, int startIndex)
		{
			if (anyOf == null)
				throw new ArgumentNullException ();
			if (startIndex < 0 || startIndex > this.length)
				throw new ArgumentOutOfRangeException ();

			return IndexOfAnyUnchecked (anyOf, startIndex, this.length - startIndex);
		}

		public int IndexOfAny (char [] anyOf, int startIndex, int count)
		{
			if (anyOf == null)
				throw new ArgumentNullException ();
			if (startIndex < 0 || startIndex > this.length)
				throw new ArgumentOutOfRangeException ();
			if (count < 0 || startIndex > this.length - count)
				throw new ArgumentOutOfRangeException ("count", "Count cannot be negative, and startIndex + count must be less than length of the string.");

			return IndexOfAnyUnchecked (anyOf, startIndex, count);
		}

		private unsafe int IndexOfAnyUnchecked (char[] anyOf, int startIndex, int count)
		{
			if (anyOf.Length == 0)
				return -1;

			if (anyOf.Length == 1)
				return IndexOfUnchecked (anyOf[0], startIndex, count);

			fixed (char* any = anyOf) {
				int highest = *any;
				int lowest = *any;

				char* end_any_ptr = any + anyOf.Length;
				char* any_ptr = any;
				while (++any_ptr != end_any_ptr) {
					if (*any_ptr > highest) {
						highest = *any_ptr;
						continue;
					}

					if (*any_ptr < lowest)
						lowest = *any_ptr;
				}

				fixed (char* start = &start_char) {
					char* ptr = start + startIndex;
					char* end_ptr = ptr + count;

					while (ptr != end_ptr) {
						if (*ptr > highest || *ptr < lowest) {
							ptr++;
							continue;
						}

						if (*ptr == *any)
							return (int)(ptr - start);

						any_ptr = any;
						while (++any_ptr != end_any_ptr) {
							if (*ptr == *any_ptr)
								return (int)(ptr - start);
						}

						ptr++;
					}
				}
			}
			return -1;
		}


		public int IndexOf (string value, StringComparison comparisonType)
		{
			return IndexOf (value, 0, this.Length, comparisonType);
		}

		public int IndexOf (string value, int startIndex, StringComparison comparisonType)
		{
			return IndexOf (value, startIndex, this.Length - startIndex, comparisonType);
		}

		public int IndexOf (string value, int startIndex, int count, StringComparison comparisonType)
		{
			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return CultureInfo.CurrentCulture.CompareInfo.IndexOf (this, value, startIndex, count, CompareOptions.None);
			case StringComparison.CurrentCultureIgnoreCase:
				return CultureInfo.CurrentCulture.CompareInfo.IndexOf (this, value, startIndex, count, CompareOptions.IgnoreCase);
			case StringComparison.InvariantCulture:
				return CultureInfo.InvariantCulture.CompareInfo.IndexOf (this, value, startIndex, count, CompareOptions.None);
			case StringComparison.InvariantCultureIgnoreCase:
				return CultureInfo.InvariantCulture.CompareInfo.IndexOf (this, value, startIndex, count, CompareOptions.IgnoreCase);
			case StringComparison.Ordinal:
				return IndexOfOrdinal (value, startIndex, count, CompareOptions.Ordinal);
			case StringComparison.OrdinalIgnoreCase:
				return IndexOfOrdinal (value, startIndex, count, CompareOptions.OrdinalIgnoreCase);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				throw new ArgumentException (msg, "comparisonType");
			}
		}

		internal int IndexOfOrdinal (string value, int startIndex, int count, CompareOptions options)
		{
			if (value == null)
				throw new ArgumentNullException ("value");
			if (startIndex < 0)
				throw new ArgumentOutOfRangeException ("startIndex");
			if (count < 0 || (this.length - startIndex) < count)
				throw new ArgumentOutOfRangeException ("count");

			if (options == CompareOptions.Ordinal)
				return IndexOfOrdinalUnchecked (value, startIndex, count);
			return IndexOfOrdinalIgnoreCaseUnchecked (value, startIndex, count);
		}

		internal unsafe int IndexOfOrdinalUnchecked (string value)
		{
			return IndexOfOrdinalUnchecked (value, 0, length);
		}

		internal unsafe int IndexOfOrdinalUnchecked (string value, int startIndex, int count)
		{
			int valueLen = value.Length;
			if (count < valueLen)
				return -1;

			if (valueLen <= 1) {
				if (valueLen == 1)
					return IndexOfUnchecked (value[0], startIndex, count);
				return startIndex;
			}

			fixed (char* thisptr = this, valueptr = value) {
				char* ap = thisptr + startIndex;
				char* thisEnd = ap + count - valueLen + 1;
				while (ap != thisEnd) {
					if (*ap == *valueptr) {
						for (int i = 1; i < valueLen; i++) {
							if (ap[i] != valueptr[i])
								goto NextVal;
						}
						return (int)(ap - thisptr);
					}
					NextVal:
					ap++;
				}
			}
			return -1;
		}

		internal unsafe int IndexOfOrdinalIgnoreCaseUnchecked (string value, int startIndex, int count)
		{
			int valueLen = value.Length;
			if (count < valueLen)
				return -1;

			if (valueLen == 0)
				return startIndex;

			fixed (char* thisptr = this, valueptr = value) {
				char* ap = thisptr + startIndex;
				char* thisEnd = ap + count - valueLen + 1;
				while (ap != thisEnd) {
					for (int i = 0; i < valueLen; i++) {
						if (Char.ToUpperInvariant (ap[i]) != Char.ToUpperInvariant (valueptr[i]))
							goto NextVal;
					}
					return (int)(ap - thisptr);
					NextVal:
					ap++;
				}
			}
			return -1;
		}

		public int LastIndexOf (string value, StringComparison comparisonType)
		{
			if (this.Length == 0)
				return value.Length == 0 ? 0 : -1;
			else
				return LastIndexOf (value, this.Length - 1, this.Length, comparisonType);
		}

		public int LastIndexOf (string value, int startIndex, StringComparison comparisonType)
		{
			return LastIndexOf (value, startIndex, startIndex + 1, comparisonType);
		}

		public int LastIndexOf (string value, int startIndex, int count, StringComparison comparisonType)
		{
			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return CultureInfo.CurrentCulture.CompareInfo.LastIndexOf (this, value, startIndex, count, CompareOptions.None);
			case StringComparison.CurrentCultureIgnoreCase:
				return CultureInfo.CurrentCulture.CompareInfo.LastIndexOf (this, value, startIndex, count, CompareOptions.IgnoreCase);
			case StringComparison.InvariantCulture:
				return CultureInfo.InvariantCulture.CompareInfo.LastIndexOf (this, value, startIndex, count, CompareOptions.None);
			case StringComparison.InvariantCultureIgnoreCase:
				return CultureInfo.InvariantCulture.CompareInfo.LastIndexOf (this, value, startIndex, count, CompareOptions.IgnoreCase);
			case StringComparison.Ordinal:
				return LastIndexOfOrdinal (value, startIndex, count, CompareOptions.Ordinal);
			case StringComparison.OrdinalIgnoreCase:
				return LastIndexOfOrdinal (value, startIndex, count, CompareOptions.OrdinalIgnoreCase);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				throw new ArgumentException (msg, "comparisonType");
			}
		}

		internal int LastIndexOfOrdinal (string value, int startIndex, int count, CompareOptions options)
		{
			if (value == null)
				throw new ArgumentNullException ("value");
			if (this.Length == 0)
				return value.Length == 0 ? 0 : -1;
			if (value.Length == 0)
				return Math.Min (this.Length - 1, startIndex);
			if (startIndex < 0 || startIndex > length)
				throw new ArgumentOutOfRangeException ("startIndex");
			if (count < 0 || (startIndex < count - 1))
				throw new ArgumentOutOfRangeException ("count");

			if (options == CompareOptions.Ordinal)
				return LastIndexOfOrdinalUnchecked (value, startIndex, count);
			return LastIndexOfOrdinalIgnoreCaseUnchecked (value, startIndex, count);
		}

		internal unsafe int LastIndexOfOrdinalUnchecked (string value, int startIndex, int count)
		{
			int valueLen = value.Length;
			if (count < valueLen)
				return -1;

			if (valueLen <= 1) {
				if (valueLen == 1)
					return LastIndexOfUnchecked (value[0], startIndex, count);
				return startIndex;
			}

			fixed (char* thisptr = this, valueptr = value) {
				char* ap = thisptr + startIndex - valueLen + 1;
				char* thisEnd = ap - count + valueLen - 1;
				while (ap != thisEnd) {
					if (*ap == *valueptr) {
						for (int i = 1; i < valueLen; i++) {
							if (ap[i] != valueptr[i])
								goto NextVal;
						}
						return (int)(ap - thisptr);
					}
					NextVal:
					ap--;
				}
			}
			return -1;
		}

		internal unsafe int LastIndexOfOrdinalIgnoreCaseUnchecked (string value, int startIndex, int count)
		{
			int valueLen = value.Length;
			if (count < valueLen)
				return -1;

			if (valueLen == 0)
				return startIndex;

			fixed (char* thisptr = this, valueptr = value) {
				char* ap = thisptr + startIndex - valueLen + 1;
				char* thisEnd = ap - count + valueLen - 1;
				while (ap != thisEnd) {
					for (int i = 0; i < valueLen; i++) {
						if (Char.ToUpperInvariant (ap[i]) != Char.ToUpperInvariant (valueptr[i]))
							goto NextVal;
					}
					return (int)(ap - thisptr);
					NextVal:
					ap--;
				}
			}
			return -1;
		}

		// Following methods are culture-insensitive
		public int IndexOf (char value)
		{
			if (this.length == 0)
				return -1;

			return IndexOfUnchecked (value, 0, this.length);
		}

		public int IndexOf (char value, int startIndex)
		{
			if (startIndex < 0)
				throw new ArgumentOutOfRangeException ("startIndex", "< 0");
			if (startIndex > this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "startIndex > this.length");

			if ((startIndex == 0 && this.length == 0) || (startIndex == this.length))
				return -1;

			return IndexOfUnchecked (value, startIndex, this.length - startIndex);
		}

		public int IndexOf (char value, int startIndex, int count)
		{
			if (startIndex < 0 || startIndex > this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "Cannot be negative and must be< 0");
			if (count < 0)
				throw new ArgumentOutOfRangeException ("count", "< 0");
			if (startIndex > this.length - count)
				throw new ArgumentOutOfRangeException ("count", "startIndex + count > this.length");

			if ((startIndex == 0 && this.length == 0) || (startIndex == this.length) || (count == 0))
				return -1;

			return IndexOfUnchecked (value, startIndex, count);
		}

		internal unsafe int IndexOfUnchecked (char value, int startIndex, int count)
		{
			// It helps JIT compiler to optimize comparison
			int value_32 = (int)value;

			fixed (char* start = &start_char) {
				char* ptr = start + startIndex;
				char* end_ptr = ptr + (count >> 3 << 3);

				while (ptr != end_ptr) {
					if (*ptr == value_32)
						return (int)(ptr - start);
					if (ptr[1] == value_32)
						return (int)(ptr - start + 1);
					if (ptr[2] == value_32)
						return (int)(ptr - start + 2);
					if (ptr[3] == value_32)
						return (int)(ptr - start + 3);
					if (ptr[4] == value_32)
						return (int)(ptr - start + 4);
					if (ptr[5] == value_32)
						return (int)(ptr - start + 5);
					if (ptr[6] == value_32)
						return (int)(ptr - start + 6);
					if (ptr[7] == value_32)
						return (int)(ptr - start + 7);

					ptr += 8;
				}

				end_ptr += count & 0x07;
				while (ptr != end_ptr) {
					if (*ptr == value_32)
						return (int)(ptr - start);

					ptr++;
				}
				return -1;
			}
		}

		internal unsafe int IndexOfOrdinalIgnoreCase (char value, int startIndex, int count)
		{
			if (length == 0)
				return -1;
			int end = startIndex + count;
			char c = Char.ToUpperInvariant (value);
			fixed (char* s = &start_char) {
				for (int i = startIndex; i < end; i++)
					if (Char.ToUpperInvariant (s [i]) == c)
						return i;
			}
			return -1;
		}

		// Following methods are culture-sensitive
		public int IndexOf (String value)
		{
			if (value == null)
				throw new ArgumentNullException ("value");
			if (value.length == 0)
				return 0;
			if (this.length == 0)
				return -1;
			return CultureInfo.CurrentCulture.CompareInfo.IndexOf (this, value, 0, length, CompareOptions.Ordinal);
		}

		public int IndexOf (String value, int startIndex)
		{
			return IndexOf (value, startIndex, this.length - startIndex);
		}

		public int IndexOf (String value, int startIndex, int count)
		{
			if (value == null)
				throw new ArgumentNullException ("value");
			if (startIndex < 0 || startIndex > this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "Cannot be negative, and should not exceed length of string.");
			if (count < 0 || startIndex > this.length - count)
				throw new ArgumentOutOfRangeException ("count", "Cannot be negative, and should point to location in string.");

			if (value.length == 0)
				return startIndex;

			if (startIndex == 0 && this.length == 0)
				return -1;

			if (count == 0)
				return -1;

			return CultureInfo.CurrentCulture.CompareInfo.IndexOf (this, value, startIndex, count);
		}

		// Following methods are culture-insensitive
		public int LastIndexOfAny (char [] anyOf)
		{
			if (anyOf == null)
				throw new ArgumentNullException ();
			if (this.length == 0)
				return -1;

			return LastIndexOfAnyUnchecked (anyOf, this.length - 1, this.length);
		}

		public int LastIndexOfAny (char [] anyOf, int startIndex)
		{
			if (anyOf == null)
				throw new ArgumentNullException ();
			if (this.length == 0)
				return -1;

			if (startIndex < 0 || startIndex >= this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "Cannot be negative, and should be less than length of string.");

			if (this.length == 0)
				return -1;

			return LastIndexOfAnyUnchecked (anyOf, startIndex, startIndex + 1);
		}

		public int LastIndexOfAny (char [] anyOf, int startIndex, int count)
		{
			if (anyOf == null) 
				throw new ArgumentNullException ();
			if (this.length == 0)
				return -1;

			if ((startIndex < 0) || (startIndex >= this.Length))
				throw new ArgumentOutOfRangeException ("startIndex", "< 0 || > this.Length");
			if ((count < 0) || (count > this.Length))
				throw new ArgumentOutOfRangeException ("count", "< 0 || > this.Length");
			if (startIndex - count + 1 < 0)
				throw new ArgumentOutOfRangeException ("startIndex - count + 1 < 0");

			if (this.length == 0)
				return -1;

			return LastIndexOfAnyUnchecked (anyOf, startIndex, count);
		}

		private unsafe int LastIndexOfAnyUnchecked (char [] anyOf, int startIndex, int count)
		{
			if (anyOf.Length == 1)
				return LastIndexOfUnchecked (anyOf[0], startIndex, count);

			fixed (char* start = this, testStart = anyOf) {
				char* ptr = start + startIndex;
				char* ptrEnd = ptr - count;
				char* test;
				char* testEnd = testStart + anyOf.Length;

				while (ptr != ptrEnd) {
					test = testStart;
					while (test != testEnd) {
						if (*test == *ptr)
							return (int)(ptr - start);
						test++;
					}
					ptr--;
				}
				return -1;
			}
		}

		// Following methods are culture-insensitive
		public int LastIndexOf (char value)
		{
			if (this.length == 0)
				return -1;
			
			return LastIndexOfUnchecked (value, this.length - 1, this.length);
		}

		public int LastIndexOf (char value, int startIndex)
		{
			return LastIndexOf (value, startIndex, startIndex + 1);
		}

		public int LastIndexOf (char value, int startIndex, int count)
		{
			if (this.length == 0)
				return -1;
 
			// >= for char (> for string)
			if ((startIndex < 0) || (startIndex >= this.Length))
				throw new ArgumentOutOfRangeException ("startIndex", "< 0 || >= this.Length");
			if ((count < 0) || (count > this.Length))
				throw new ArgumentOutOfRangeException ("count", "< 0 || > this.Length");
			if (startIndex - count + 1 < 0)
				throw new ArgumentOutOfRangeException ("startIndex - count + 1 < 0");

			return LastIndexOfUnchecked (value, startIndex, count);
		}

		internal unsafe int LastIndexOfUnchecked (char value, int startIndex, int count)
		{
			// It helps JIT compiler to optimize comparison
			int value_32 = (int)value;

			fixed (char* start = &start_char) {
				char* ptr = start + startIndex;
				char* end_ptr = ptr - (count >> 3 << 3);

				while (ptr != end_ptr) {
					if (*ptr == value_32)
						return (int)(ptr - start);
					if (ptr[-1] == value_32)
						return (int)(ptr - start) - 1;
					if (ptr[-2] == value_32)
						return (int)(ptr - start) - 2;
					if (ptr[-3] == value_32)
						return (int)(ptr - start) - 3;
					if (ptr[-4] == value_32)
						return (int)(ptr - start) - 4;
					if (ptr[-5] == value_32)
						return (int)(ptr - start) - 5;
					if (ptr[-6] == value_32)
						return (int)(ptr - start) - 6;
					if (ptr[-7] == value_32)
						return (int)(ptr - start) - 7;

					ptr -= 8;
				}

				end_ptr -= count & 0x07;
				while (ptr != end_ptr) {
					if (*ptr == value_32)
						return (int)(ptr - start);

					ptr--;
				}
				return -1;
			}
		}

		internal unsafe int LastIndexOfOrdinalIgnoreCase (char value, int startIndex, int count)
		{
			if (length == 0)
				return -1;
			int end = startIndex - count;
			char c = Char.ToUpperInvariant (value);
			fixed (char* s = &start_char) {
				for (int i = startIndex; i > end; i--)
					if (Char.ToUpperInvariant (s [i]) == c)
						return i;
			}
			return -1;
		}

		// Following methods are culture-sensitive
		public int LastIndexOf (String value)
		{
			return LastIndexOf (value, this.length - 1, this.length);
		}

		public int LastIndexOf (String value, int startIndex)
		{
			int max = startIndex;
			if (max < this.Length)
				max++;
			return LastIndexOf (value, startIndex, max);
		}

		public int LastIndexOf (String value, int startIndex, int count)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			if (this.length == 0)
				return value.Length == 0 ? 0 : -1;
			// -1 > startIndex > for string (0 > startIndex >= for char)
			if ((startIndex < -1) || (startIndex > this.Length))
				throw new ArgumentOutOfRangeException ("startIndex", "< 0 || > this.Length");
			if ((count < 0) || (count > this.Length))
				throw new ArgumentOutOfRangeException ("count", "< 0 || > this.Length");
			if (startIndex - count + 1 < 0)
				throw new ArgumentOutOfRangeException ("startIndex - count + 1 < 0");

			if (value.Length == 0)
				return Math.Min (this.Length - 1, startIndex);

			if (startIndex == 0 && this.length == 0)
				return -1;

			// This check is needed to match undocumented MS behaviour
			if (this.length == 0 && value.length > 0)
				return -1;

			if (count == 0)
				return -1;

			if (startIndex == this.Length)
				startIndex--;
			return CultureInfo.CurrentCulture.CompareInfo.LastIndexOf (this, value, startIndex, count);
		}

		public bool Contains (String value)
		{
			return IndexOf (value) != -1;
		}

		public static bool IsNullOrEmpty (String value)
		{
			return (value == null) || (value.Length == 0);
		}

		public string Normalize ()
		{
			return Normalization.Normalize (this, 0);
		}

		public string Normalize (NormalizationForm normalizationForm)
		{
			switch (normalizationForm) {
			default:
				return Normalization.Normalize (this, 0);
			case NormalizationForm.FormD:
				return Normalization.Normalize (this, 1);
			case NormalizationForm.FormKC:
				return Normalization.Normalize (this, 2);
			case NormalizationForm.FormKD:
				return Normalization.Normalize (this, 3);
			}
		}

		public bool IsNormalized ()
		{
			return Normalization.IsNormalized (this, 0);
		}

		public bool IsNormalized (NormalizationForm normalizationForm)
		{
			switch (normalizationForm) {
			default:
				return Normalization.IsNormalized (this, 0);
			case NormalizationForm.FormD:
				return Normalization.IsNormalized (this, 1);
			case NormalizationForm.FormKC:
				return Normalization.IsNormalized (this, 2);
			case NormalizationForm.FormKD:
				return Normalization.IsNormalized (this, 3);
			}
		}

		public string Remove (int startIndex)
		{
			if (startIndex < 0)
				throw new ArgumentOutOfRangeException ("startIndex", "StartIndex can not be less than zero");
			if (startIndex >= this.length)
				throw new ArgumentOutOfRangeException ("startIndex", "StartIndex must be less than the length of the string");

			return Remove (startIndex, this.length - startIndex);
		}

		public String PadLeft (int totalWidth)
		{
			return PadLeft (totalWidth, ' ');
		}

		public unsafe String PadLeft (int totalWidth, char paddingChar)
		{
			//LAMESPEC: MSDN Doc says this is reversed for RtL languages, but this seems to be untrue

			if (totalWidth < 0)
				throw new ArgumentOutOfRangeException ("totalWidth", "< 0");

			if (totalWidth < this.length)
				return this;
			if (totalWidth == 0)
				return Empty;

			String tmp = InternalAllocateStr (totalWidth);

			fixed (char* dest = tmp, src = this) {
				char* padPos = dest;
				char* padTo = dest + (totalWidth - length);
				while (padPos != padTo)
					*padPos++ = paddingChar;

				CharCopy (padTo, src, length);
			}
			return tmp;
		}

		public String PadRight (int totalWidth)
		{
			return PadRight (totalWidth, ' ');
		}

		public unsafe String PadRight (int totalWidth, char paddingChar)
		{
			//LAMESPEC: MSDN Doc says this is reversed for RtL languages, but this seems to be untrue

			if (totalWidth < 0)
				throw new ArgumentOutOfRangeException ("totalWidth", "< 0");

			if (totalWidth < this.length)
				return this;
			if (totalWidth == 0)
				return Empty;

			String tmp = InternalAllocateStr (totalWidth);

			fixed (char* dest = tmp, src = this) {
				CharCopy (dest, src, length);

				char* padPos = dest + length;
				char* padTo = dest + totalWidth;
				while (padPos != padTo)
					*padPos++ = paddingChar;
			}
			return tmp;
		}

		public bool StartsWith (String value)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			return CultureInfo.CurrentCulture.CompareInfo.IsPrefix (this, value, CompareOptions.None);
		}

		[ComVisible (false)]
		public bool StartsWith (string value, StringComparison comparisonType)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return CultureInfo.CurrentCulture.CompareInfo.IsPrefix (this, value, CompareOptions.None);
			case StringComparison.CurrentCultureIgnoreCase:
				return CultureInfo.CurrentCulture.CompareInfo.IsPrefix (this, value, CompareOptions.IgnoreCase);
			case StringComparison.InvariantCulture:
				return CultureInfo.InvariantCulture.CompareInfo.IsPrefix (this, value, CompareOptions.None);
			case StringComparison.InvariantCultureIgnoreCase:
				return CultureInfo.InvariantCulture.CompareInfo.IsPrefix (this, value, CompareOptions.IgnoreCase);
			case StringComparison.Ordinal:
				return StartsWithOrdinalUnchecked (value);
			case StringComparison.OrdinalIgnoreCase:
				return StartsWithOrdinalCaseInsensitiveUnchecked (value);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				throw new ArgumentException (msg, "comparisonType");
			}
		}

		internal bool StartsWithOrdinalUnchecked (string value)
		{
			return length >= value.length && CompareOrdinalUnchecked (this, 0, value.length, value, 0, value.length) == 0;
		}

		internal bool StartsWithOrdinalCaseInsensitiveUnchecked (string value)
		{
			return length >= value.Length && CompareOrdinalCaseInsensitiveUnchecked (this, 0, value.length, value, 0, value.length) == 0;
		}

		[ComVisible (false)]
		public bool EndsWith (string value, StringComparison comparisonType)
		{
			if (value == null)
				throw new ArgumentNullException ("value");

			switch (comparisonType) {
			case StringComparison.CurrentCulture:
				return CultureInfo.CurrentCulture.CompareInfo.IsSuffix (this, value, CompareOptions.None);
			case StringComparison.CurrentCultureIgnoreCase:
				return CultureInfo.CurrentCulture.CompareInfo.IsSuffix (this, value, CompareOptions.IgnoreCase);
			case StringComparison.InvariantCulture:
				return CultureInfo.InvariantCulture.CompareInfo.IsSuffix (this, value, CompareOptions.None);
			case StringComparison.InvariantCultureIgnoreCase:
				return CultureInfo.InvariantCulture.CompareInfo.IsSuffix (this, value, CompareOptions.IgnoreCase);
			case StringComparison.Ordinal:
				return CultureInfo.CurrentCulture.CompareInfo.IsSuffix (this, value, CompareOptions.Ordinal);
			case StringComparison.OrdinalIgnoreCase:
				return CultureInfo.CurrentCulture.CompareInfo.IsSuffix (this, value, CompareOptions.OrdinalIgnoreCase);
			default:
				string msg = Locale.GetText ("Invalid value '{0}' for StringComparison", comparisonType);
				thr…