diff options
Diffstat (limited to 'Emby.Server.Implementations/TextEncoding/UniversalDetector/Core/Latin1Prober.cs')
| -rw-r--r-- | Emby.Server.Implementations/TextEncoding/UniversalDetector/Core/Latin1Prober.cs | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/Emby.Server.Implementations/TextEncoding/UniversalDetector/Core/Latin1Prober.cs b/Emby.Server.Implementations/TextEncoding/UniversalDetector/Core/Latin1Prober.cs new file mode 100644 index 000000000..c79a10aa7 --- /dev/null +++ b/Emby.Server.Implementations/TextEncoding/UniversalDetector/Core/Latin1Prober.cs @@ -0,0 +1,180 @@ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Mozilla Universal charset detector code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 2001 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Shy Shalom <shooshX@gmail.com> + * Rudi Pettazzi <rudi.pettazzi@gmail.com> (C# port) + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +using System; + +namespace UniversalDetector.Core +{ + // TODO: Using trigrams the detector should be able to discriminate between + // latin-1 and iso8859-2 + public class Latin1Prober : CharsetProber + { + private const int FREQ_CAT_NUM = 4; + + private const int UDF = 0; // undefined + private const int OTH = 1; // other + private const int ASC = 2; // ascii capital letter + private const int ASS = 3; // ascii small letter + private const int ACV = 4; // accent capital vowel + private const int ACO = 5; // accent capital other + private const int ASV = 6; // accent small vowel + private const int ASO = 7; // accent small other + + private const int CLASS_NUM = 8; // total classes + + private readonly static byte[] Latin1_CharToClass = { + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 00 - 07 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 08 - 0F + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 10 - 17 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 18 - 1F + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 20 - 27 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 28 - 2F + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 30 - 37 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 38 - 3F + OTH, ASC, ASC, ASC, ASC, ASC, ASC, ASC, // 40 - 47 + ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC, // 48 - 4F + ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC, // 50 - 57 + ASC, ASC, ASC, OTH, OTH, OTH, OTH, OTH, // 58 - 5F + OTH, ASS, ASS, ASS, ASS, ASS, ASS, ASS, // 60 - 67 + ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS, // 68 - 6F + ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS, // 70 - 77 + ASS, ASS, ASS, OTH, OTH, OTH, OTH, OTH, // 78 - 7F + OTH, UDF, OTH, ASO, OTH, OTH, OTH, OTH, // 80 - 87 + OTH, OTH, ACO, OTH, ACO, UDF, ACO, UDF, // 88 - 8F + UDF, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // 90 - 97 + OTH, OTH, ASO, OTH, ASO, UDF, ASO, ACO, // 98 - 9F + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // A0 - A7 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // A8 - AF + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // B0 - B7 + OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, // B8 - BF + ACV, ACV, ACV, ACV, ACV, ACV, ACO, ACO, // C0 - C7 + ACV, ACV, ACV, ACV, ACV, ACV, ACV, ACV, // C8 - CF + ACO, ACO, ACV, ACV, ACV, ACV, ACV, OTH, // D0 - D7 + ACV, ACV, ACV, ACV, ACV, ACO, ACO, ACO, // D8 - DF + ASV, ASV, ASV, ASV, ASV, ASV, ASO, ASO, // E0 - E7 + ASV, ASV, ASV, ASV, ASV, ASV, ASV, ASV, // E8 - EF + ASO, ASO, ASV, ASV, ASV, ASV, ASV, OTH, // F0 - F7 + ASV, ASV, ASV, ASV, ASV, ASO, ASO, ASO, // F8 - FF + }; + + /* 0 : illegal + 1 : very unlikely + 2 : normal + 3 : very likely + */ + private readonly static byte[] Latin1ClassModel = { + /* UDF OTH ASC ASS ACV ACO ASV ASO */ + /*UDF*/ 0, 0, 0, 0, 0, 0, 0, 0, + /*OTH*/ 0, 3, 3, 3, 3, 3, 3, 3, + /*ASC*/ 0, 3, 3, 3, 3, 3, 3, 3, + /*ASS*/ 0, 3, 3, 3, 1, 1, 3, 3, + /*ACV*/ 0, 3, 3, 3, 1, 2, 1, 2, + /*ACO*/ 0, 3, 3, 3, 3, 3, 3, 3, + /*ASV*/ 0, 3, 1, 3, 1, 1, 1, 3, + /*ASO*/ 0, 3, 1, 3, 1, 1, 3, 3, + }; + + private byte lastCharClass; + private int[] freqCounter = new int[FREQ_CAT_NUM]; + + public Latin1Prober() + { + Reset(); + } + + public override string GetCharsetName() + { + return "windows-1252"; + } + + public override void Reset() + { + state = ProbingState.Detecting; + lastCharClass = OTH; + for (int i = 0; i < FREQ_CAT_NUM; i++) + freqCounter[i] = 0; + } + + public override ProbingState HandleData(byte[] buf, int offset, int len) + { + byte[] newbuf = FilterWithEnglishLetters(buf, offset, len); + byte charClass, freq; + + for (int i = 0; i < newbuf.Length; i++) { + charClass = Latin1_CharToClass[newbuf[i]]; + freq = Latin1ClassModel[lastCharClass * CLASS_NUM + charClass]; + if (freq == 0) { + state = ProbingState.NotMe; + break; + } + freqCounter[freq]++; + lastCharClass = charClass; + } + return state; + } + + public override float GetConfidence() + { + if (state == ProbingState.NotMe) + return 0.01f; + + float confidence = 0.0f; + int total = 0; + for (int i = 0; i < FREQ_CAT_NUM; i++) { + total += freqCounter[i]; + } + + if (total <= 0) { + confidence = 0.0f; + } else { + confidence = freqCounter[3] * 1.0f / total; + confidence -= freqCounter[1] * 20.0f / total; + } + + // lower the confidence of latin1 so that other more accurate detector + // can take priority. + return confidence < 0.0f ? 0.0f : confidence * 0.5f; + } + + public override void DumpStatus() + { + //Console.WriteLine(" Latin1Prober: {0} [{1}]", GetConfidence(), GetCharsetName()); + } + } +} + |