content: /* ***** 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>
   *          Kohei Taketa <k-tak@void.in> (Java 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 ***** */
  
  package org.mozilla.universalchardet.prober;
  
  import java.nio.ByteBuffer;
  import org.mozilla.universalchardet.Constants;
  
  
  public class Latin1Prober extends CharsetProber {
      public static final byte UDF = 0;
      public static final byte OTH = 1;
      public static final byte ASC = 2;
      public static final byte ASS = 3;
      public static final byte ACV = 4;
      public static final byte ACO = 5;
      public static final byte ASV = 6;
      public static final byte ASO = 7;
      public static final int CLASS_NUM = 8;
      public static final int FREQ_CAT_NUM = 4;
      
  
      ////////////////////////////////////////////////////////////////
      // constants continued
      ////////////////////////////////////////////////////////////////
      private static final byte[] latin1CharToClass = new byte[] {
            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
      };
      
      private static final byte[] latin1ClassModel = new byte[] {
          /*      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 ProbingState state;
  	private byte lastCharClass;
  	private int[] freqCounter;
  
  
  	public Latin1Prober() {
  		super();
  		this.freqCounter = new int[FREQ_CAT_NUM];
  		reset();
  	}
  
  	@Override
  	public String getCharSetName() {
  		return Constants.CHARSET_WINDOWS_1252;
  	}
  
  	@Override
  	public float getConfidence() {
  		if (this.state == ProbingState.NOT_ME) {
  			return 0.01f;
  		}
  
  		float confidence;
  		int total = 0;
  		for (int i = 0; i < this.freqCounter.length; ++i) {
  			total += this.freqCounter[i];
  		}
  
  		if (total <= 0) {
  			confidence = 0.0f;
  		} else {
  			confidence = this.freqCounter[3] * 1.0f / total;
  			confidence -= this.freqCounter[1] * 20.0f / total;
  		}
  
  		if (confidence < 0.0f) {
  			confidence = 0.0f;
  		}
  
  		// lower the confidence of latin1 so that other more accurate detector
  		// can take priority.
  		confidence *= 0.50f;
  
  		return confidence;
  	}
  
  	@Override
  	public ProbingState getState() {
  		return this.state;
  	}
  
  	@Override
  	public ProbingState handleData(byte[] buf, int offset, int length) {
  		ByteBuffer newBufTmp = filterWithEnglishLetters(buf, offset, length);
  
  		byte charClass;
  		byte freq;
  
  		byte[] newBuf = newBufTmp.array();
  		int newBufLen = newBufTmp.position();
  
  		for (int i = 0; i < newBufLen; ++i) {
  			int c = newBuf[i] & 0xFF;
  			charClass = latin1CharToClass[c];
  			freq = latin1ClassModel[this.lastCharClass * CLASS_NUM + charClass];
  			if (freq == 0) {
  				this.state = ProbingState.NOT_ME;
  				break;
  			}
  			++this.freqCounter[freq];
  			this.lastCharClass = charClass;
  		}
  
  		return this.state;
  	}
  
  	@Override
  	public final void reset() {
  		this.state = ProbingState.DETECTING;
  		this.lastCharClass = OTH;
  		for (int i = 0; i < this.freqCounter.length; ++i) {
  			this.freqCounter[i] = 0;
  		}
  	}
  
  	@Override
  	public void setOption() {
  	}
  
      
  
  }
  