org.mozilla.universalchardet.prober.distributionanalysis.CharDistributionAnalysis Maven / Gradle / Ivy
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* for the specific language governing rights and limitations under the
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* The Original Code is Mozilla Communicator client code.
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* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
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* Contributor(s):
* Kohei TAKETA (Java port)
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package org.mozilla.universalchardet.prober.distributionanalysis;
public abstract class CharDistributionAnalysis {
////////////////////////////////////////////////////////////////
// constants
////////////////////////////////////////////////////////////////
public static final float SURE_NO = 0.01f;
public static final float SURE_YES = 0.99f;
public static final int ENOUGH_DATA_THRESHOLD = 1024;
public static final int MINIMUM_DATA_THRESHOLD = 4;
////////////////////////////////////////////////////////////////
// fields
////////////////////////////////////////////////////////////////
private int freqChars;
private int totalChars;
protected int[] charToFreqOrder; // set by subclasses
protected float typicalDistributionRatio; // set by subclasses
////////////////////////////////////////////////////////////////
// methods
////////////////////////////////////////////////////////////////
public CharDistributionAnalysis() {
reset();
}
public void handleData(final byte[] buf, int offset, int length) {
}
public void handleOneChar(final byte[] buf, int offset, int charLength) {
int order = -1;
if (charLength == 2) {
order = getOrder(buf, offset);
}
if (order >= 0) {
++this.totalChars;
if (order < this.charToFreqOrder.length) {
if (512 > this.charToFreqOrder[order]) {
++this.freqChars;
}
}
}
}
public float getConfidence() {
if (this.totalChars <= 0 || this.freqChars <= MINIMUM_DATA_THRESHOLD) {
return SURE_NO;
}
if (this.totalChars != this.freqChars) {
float r = this.freqChars / ((this.totalChars - this.freqChars) * this.typicalDistributionRatio);
if (r < SURE_YES) {
return r;
}
}
return SURE_YES;
}
public final void reset() {
this.totalChars = 0;
this.freqChars = 0;
}
public void setOption() {
}
public boolean gotEnoughData() {
return (this.totalChars > ENOUGH_DATA_THRESHOLD);
}
protected abstract int getOrder(final byte[] buf, int offset);
}