FolkerKinzel.Strings 1.2.0

FolkerKinzel.Strings

.NET library, containing extension methods for String, StringBuilder and ReadOnlySpan<Char>.

• Project Reference and Release Notes

Content:

• Extension methods which return an equal (and therefore persistable) Int32 hashcode for an identical Char sequence everytime they are called - even on String, StringBuilder or ReadOnlySpan<Char>. The hashcodes can be specified to hash the sequence ordinal, ordinal case insensitive or alphanumeric case insensitive. The hashcodes produced by this library are not equivalent to the hashcodes produced by the .NET-Framework 4.0 System.String class, because they use roundshifting to keep more information. Don't use these hashcodes for security critical purposes (such as hashing passwords)!

Example:

using System;
using System.Text;
using FolkerKinzel.Strings;

namespace Examples
{
  public static class ShortExample
  {
    public static void CreateConstantStringHashes()
    {
       Console.WriteLine("Ordinal:");
       const string s1 = "Hello Folker!";
       Console.WriteLine(
         $"{s1.GetStableHashCode(HashType.Ordinal),10:X08}");
       Console.WriteLine(
         $"{new StringBuilder().Append(s1).GetStableHashCode(HashType.Ordinal),10:X08}");
       Console.WriteLine("OrdinalIgnoreCase:");
       Console.WriteLine(
         $"{"HELLO FOLKER!".GetStableHashCode(HashType.Ordinal),10:X08}");
       Console.WriteLine(
         $"{"Hello Folker!".AsSpan().GetStableHashCode(HashType.OrdinalIgnoreCase),10:X08}");
       Console.WriteLine("AlphaNumericIgnoreCase:");
       Console.WriteLine(
         $"{"HELLO FOLKER!".AsSpan().GetStableHashCode(HashType.AlphaNumericIgnoreCase),10:X08}");
       Console.WriteLine(
         $"{new StringBuilder().Append("&: !heL##Lof OLker *").GetStableHashCode(HashType.AlphaNumericIgnoreCase),10:X08}");

       // Different HashTypes may produce different hashcodes on the same Char sequence
       // and must therefore not be mixed:
       Console.WriteLine("Same String - different HashTypes:");
       Console.WriteLine(
          $"{s1.GetStableHashCode(HashType.Ordinal),10:X08}");
       Console.WriteLine(
         $"{s1.GetStableHashCode(HashType.OrdinalIgnoreCase),10:X08}");
       Console.WriteLine(
         $"{s1.GetStableHashCode(HashType.AlphaNumericIgnoreCase),10:X08}");
   }
 }
}
/*
Output:

Ordinal:
  A31FA6EC
  A31FA6EC
OrdinalIgnoreCase:
  1BBFB34C
  1BBFB34C
AlphaNumericIgnoreCase:
  C672C38C
  C672C38C
Same String - different HashTypes:
  A31FA6EC
  1BBFB34C
  C672C38C
*/