diff --git a/MediaBrowser.Controller/Sorting/AlphanumComparator.cs b/MediaBrowser.Controller/Sorting/AlphanumComparator.cs index 65dc120ca8..de7f72d1c2 100644 --- a/MediaBrowser.Controller/Sorting/AlphanumComparator.cs +++ b/MediaBrowser.Controller/Sorting/AlphanumComparator.cs @@ -1,94 +1,132 @@ +#nullable enable + +using System; using System.Collections.Generic; -using System.Text; -using MediaBrowser.Controller.Sorting; namespace MediaBrowser.Controller.Sorting { - public class AlphanumComparator : IComparer + public class AlphanumComparator : IComparer { - public static int CompareValues(string s1, string s2) + public static int CompareValues(string? s1, string? s2) { - if (s1 == null || s2 == null) + if (s1 == null && s2 == null) { return 0; } - - int thisMarker = 0, thisNumericChunk = 0; - int thatMarker = 0, thatNumericChunk = 0; - - while ((thisMarker < s1.Length) || (thatMarker < s2.Length)) + else if (s1 == null) { - if (thisMarker >= s1.Length) - { - return -1; - } - else if (thatMarker >= s2.Length) - { - return 1; - } - char thisCh = s1[thisMarker]; - char thatCh = s2[thatMarker]; + return -1; + } + else if (s2 == null) + { + return 1; + } - var thisChunk = new StringBuilder(); - var thatChunk = new StringBuilder(); - bool thisNumeric = char.IsDigit(thisCh), thatNumeric = char.IsDigit(thatCh); + int len1 = s1.Length; + int len2 = s2.Length; - while (thisMarker < s1.Length && char.IsDigit(thisCh) == thisNumeric) + // Early return for empty strings + if (len1 == 0 && len2 == 0) + { + return 0; + } + else if (len1 == 0) + { + return -1; + } + else if (len2 == 0) + { + return 1; + } + + int pos1 = 0; + int pos2 = 0; + + do + { + int start1 = pos1; + int start2 = pos2; + + bool isNum1 = char.IsDigit(s1[pos1++]); + bool isNum2 = char.IsDigit(s2[pos2++]); + + while (pos1 < len1 && char.IsDigit(s1[pos1]) == isNum1) { - thisChunk.Append(thisCh); - thisMarker++; - - if (thisMarker < s1.Length) - { - thisCh = s1[thisMarker]; - } + pos1++; } - while (thatMarker < s2.Length && char.IsDigit(thatCh) == thatNumeric) + while (pos2 < len2 && char.IsDigit(s2[pos2]) == isNum2) { - thatChunk.Append(thatCh); - thatMarker++; - - if (thatMarker < s2.Length) - { - thatCh = s2[thatMarker]; - } + pos2++; } + var span1 = s1.AsSpan(start1, pos1 - start1); + var span2 = s2.AsSpan(start2, pos2 - start2); - // If both chunks contain numeric characters, sort them numerically - if (thisNumeric && thatNumeric) + if (isNum1 && isNum2) { - if (!int.TryParse(thisChunk.ToString(), out thisNumericChunk) - || !int.TryParse(thatChunk.ToString(), out thatNumericChunk)) - { - return 0; - } - - if (thisNumericChunk < thatNumericChunk) + // Trim leading zeros so we can compare the length + // of the strings to find the largest number + span1 = span1.TrimStart('0'); + span2 = span2.TrimStart('0'); + var span1Len = span1.Length; + var span2Len = span2.Length; + if (span1Len < span2Len) { return -1; } + else if (span1Len > span2Len) + { + return 1; + } + else if (span1Len >= 20) // Number is probably too big for a ulong + { + // Trim all the first digits that are the same + int i = 0; + while (i < span1Len && span1[i] == span2[i]) + { + i++; + } - if (thisNumericChunk > thatNumericChunk) + // If there are no more digits it's the same number + if (i == span1Len) + { + continue; + } + + // Only need to compare the most significant digit + span1 = span1.Slice(i, 1); + span2 = span2.Slice(i, 1); + } + + if (!ulong.TryParse(span1, out var num1) + || !ulong.TryParse(span2, out var num2)) + { + return 0; + } + else if (num1 < num2) + { + return -1; + } + else if (num1 > num2) { return 1; } } else { - int result = thisChunk.ToString().CompareTo(thatChunk.ToString()); + int result = span1.CompareTo(span2, StringComparison.InvariantCulture); if (result != 0) { return result; } } + } while (pos1 < len1 && pos2 < len2); - } - - return 0; + return len1 - len2; } + /// public int Compare(string x, string y) { return CompareValues(x, y);