autotag/AutoTag.cli/AlphaNumComparer.cs
2022-03-22 16:03:31 +01:00

122 lines
3.7 KiB
C#

/*
* The Alphanum Algorithm is an improved sorting algorithm for strings
* containing numbers. Instead of sorting numbers in ASCII order like
* a standard sort, this algorithm sorts numbers in numeric order.
*
* The Alphanum Algorithm is discussed at http://www.DaveKoelle.com
*
* Based on the Java implementation of Dave Koelle's Alphanum algorithm.
* Contributed by Jonathan Ruckwood <jonathan.ruckwood@gmail.com>
*
* Adapted by Dominik Hurnaus <dominik.hurnaus@gmail.com> to
* - correctly sort words where one word starts with another word
* - have slightly better performance
*
* Released under the MIT License - https://opensource.org/licenses/MIT
*
* 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.
*
*/
using System;
using System.Collections.Generic;
using System.Text;
/*
* Please compare against the latest Java version at http://www.DaveKoelle.com
* to see the most recent modifications
*/
namespace AutoTag.cli;
public class AlphanumComparator : IComparer<string> {
public int Compare(string x, string y) {
var s1 = x;
var s2 = y;
if (s1 == null || s2 == null)
return 0;
var thisMarker = 0;
var thatMarker = 0;
while (thisMarker < s1.Length || thatMarker < s2.Length) {
if (thisMarker >= s1.Length)
return -1;
if (thatMarker >= s2.Length)
return 1;
var thisCh = s1[thisMarker];
var thatCh = s2[thatMarker];
var thisChunk = new StringBuilder();
var thatChunk = new StringBuilder();
while (thisMarker < s1.Length && (thisChunk.Length == 0 || InChunk(thisCh, thisChunk[0]))) {
thisChunk.Append(thisCh);
thisMarker++;
if (thisMarker < s1.Length)
thisCh = s1[thisMarker];
}
while (thatMarker < s2.Length && (thatChunk.Length == 0 || InChunk(thatCh, thatChunk[0]))) {
thatChunk.Append(thatCh);
thatMarker++;
if (thatMarker < s2.Length)
thatCh = s2[thatMarker];
}
var result = 0;
// If both chunks contain numeric characters, sort them numerically
if (char.IsDigit(thisChunk[0]) && char.IsDigit(thatChunk[0])) {
var thisNumericChunk = Convert.ToInt32(thisChunk.ToString());
var thatNumericChunk = Convert.ToInt32(thatChunk.ToString());
if (thisNumericChunk < thatNumericChunk)
result = -1;
if (thisNumericChunk > thatNumericChunk)
result = 1;
}
else {
result = string.Compare(thisChunk.ToString(), thatChunk.ToString(), StringComparison.Ordinal);
}
if (result != 0)
return result;
}
return 0;
}
private static bool InChunk(char ch, char otherCh) {
var type = ChunkType.Alphanumeric;
if (char.IsDigit(otherCh))
type = ChunkType.Numeric;
return (type != ChunkType.Alphanumeric || !char.IsDigit(ch)) && (type != ChunkType.Numeric || char.IsDigit(ch));
}
private enum ChunkType {
Alphanumeric,
Numeric
}
}