add subtitle language detection

Emby.Common.Implementations/TextEncoding/NLangDetect/DetectorFactory.cs

@@ -0,0 +1,127 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using NLangDetect.Core.Utils;
+using MediaBrowser.Model.Serialization;
+using System.Linq;
+
+namespace NLangDetect.Core
+{
+    public class DetectorFactory
+    {
+        public Dictionary<string, ProbVector> WordLangProbMap;
+        public List<string> Langlist;
+
+        private static readonly DetectorFactory _instance = new DetectorFactory();
+
+        #region Constructor(s)
+
+        private DetectorFactory()
+        {
+            WordLangProbMap = new Dictionary<string, ProbVector>();
+            Langlist = new List<string>();
+        }
+
+        #endregion
+
+        #region Public methods
+
+        public static void LoadProfiles(IJsonSerializer json)
+        {
+            var assembly = typeof(DetectorFactory).Assembly;
+            var names = assembly.GetManifestResourceNames()
+                      .Where(i => i.IndexOf("NLangDetect.Profiles", StringComparison.Ordinal) != -1)
+                      .ToList();
+
+            var index = 0;
+
+            foreach (var name in names)
+            {
+                using (var stream = assembly.GetManifestResourceStream(name))
+                {
+                    var langProfile = (LangProfile)json.DeserializeFromStream(stream, typeof(LangProfile));
+
+                    AddProfile(langProfile, index);
+                }
+
+                index++;
+            }
+        }
+
+        public static Detector Create()
+        {
+            return CreateDetector();
+        }
+
+        public static Detector Create(double alpha)
+        {
+            Detector detector = CreateDetector();
+
+            detector.SetAlpha(alpha);
+
+            return detector;
+        }
+
+        public static void SetSeed(int? seed)
+        {
+            _instance.Seed = seed;
+        }
+
+        #endregion
+
+        #region Internal methods
+
+        internal static void AddProfile(LangProfile profile, int index)
+        {
+            var lang = profile.name;
+
+            if (_instance.Langlist.Contains(lang))
+            {
+                throw new NLangDetectException("duplicate the same language profile", ErrorCode.DuplicateLangError);
+            }
+
+            _instance.Langlist.Add(lang);
+
+            foreach (string word in profile.freq.Keys)
+            {
+                if (!_instance.WordLangProbMap.ContainsKey(word))
+                {
+                    _instance.WordLangProbMap.Add(word, new ProbVector());
+                }
+
+                double prob = (double)profile.freq[word] / profile.n_words[word.Length - 1];
+
+                _instance.WordLangProbMap[word][index] = prob;
+            }
+        }
+
+        internal static void Clear()
+        {
+            _instance.Langlist.Clear();
+            _instance.WordLangProbMap.Clear();
+        }
+
+        #endregion
+
+        #region Private helper methods
+
+        private static Detector CreateDetector()
+        {
+            if (_instance.Langlist.Count == 0)
+            {
+                throw new NLangDetectException("need to load profiles", ErrorCode.NeedLoadProfileError);
+            }
+
+            return new Detector(_instance);
+        }
+
+        #endregion
+
+        #region Properties
+
+        public int? Seed { get; private set; }
+
+        #endregion
+    }
+}