MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4using System.Collections.Generic;5using System.Globalization;6 7namespace System.Management.Automation8{9    internal class FuzzyMatcher10    {11        internal readonly uint MinimumDistance;12 13        internal FuzzyMatcher(uint minimumDistance)14        {15            MinimumDistance = minimumDistance;16        }17 18        /// <summary>19        /// Determine if the two strings are considered similar.20        /// </summary>21        internal bool IsFuzzyMatch(string candidate, string pattern)22        {23            return IsFuzzyMatch(candidate, pattern, out _);24        }25 26        /// <summary>27        /// Determine if the two strings are considered similar, and return the similarity score.28        /// </summary>29        /// <param name="candidate">The candidate string to be compared.</param>30        /// <param name="pattern">The pattern string to be compared with.</param>31        /// <returns>True if the two strings have a distance <= MinimumDistance.</returns>32        internal bool IsFuzzyMatch(string candidate, string pattern, out int score)33        {34            score = GetDamerauLevenshteinDistance(candidate, pattern);35            return score <= MinimumDistance;36        }37 38        /// <summary>39        /// Compute the case-insensitive distance between two strings.40        /// Based off https://www.csharpstar.com/csharp-string-distance-algorithm/.41        /// </summary>42        /// <param name="string1">The first string to compare.</param>43        /// <param name="string2">The second string to compare.</param>44        /// <returns>The distance value where the lower the value the shorter the distance between the two strings representing a closer match.</returns>45        internal static int GetDamerauLevenshteinDistance(string string1, string string2)46        {47            string1 = string1.ToUpper(CultureInfo.CurrentCulture);48            string2 = string2.ToUpper(CultureInfo.CurrentCulture);49 50            var bounds = new { Height = string1.Length + 1, Width = string2.Length + 1 };51 52            int[,] matrix = new int[bounds.Height, bounds.Width];53 54            for (int height = 0; height < bounds.Height; height++)55            {56                matrix[height, 0] = height;57            }58 59            for (int width = 0; width < bounds.Width; width++)60            {61                matrix[0, width] = width;62            }63 64            for (int height = 1; height < bounds.Height; height++)65            {66                for (int width = 1; width < bounds.Width; width++)67                {68                    int cost = (string1[height - 1] == string2[width - 1]) ? 0 : 1;69                    int insertion = matrix[height, width - 1] + 1;70                    int deletion = matrix[height - 1, width] + 1;71                    int substitution = matrix[height - 1, width - 1] + cost;72 73                    int distance = Math.Min(insertion, Math.Min(deletion, substitution));74 75                    if (height > 1 && width > 1 && string1[height - 1] == string2[width - 2] && string1[height - 2] == string2[width - 1])76                    {77                        distance = Math.Min(distance, matrix[height - 2, width - 2] + cost);78                    }79 80                    matrix[height, width] = distance;81                }82            }83 84            return matrix[bounds.Height - 1, bounds.Width - 1];85        }86    }87}88