Re: determining character encoding format of a file

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 06 Oct 2007 20:32:10 -0400
Message-ID:
<470828be$0$90268$14726298@news.sunsite.dk>
Alan wrote:

    Is there any easy way to determine what character encoding format
(e.g., UTF-8) a text file uses?


Not in general.

For ISO-8859-1 versus UTF-8 for a western language you may make
a qualified guess.

See attached code as a stating point (note that the
code is designed to identify text in danish).

Arne

=============================

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class CharSetGuesser {
     public static String guess(String filename) throws IOException {
         int[] freq = new int[256];
         InputStream is = new FileInputStream(filename);
         int c;
         while((c = is.read()) >= 0) {
             freq[c]++;
         }
         is.close();
         if((freq[197] + freq[198] + freq[200] +
             freq[201] + freq[203] + freq[216] +
             freq[229] + freq[230] + freq[232] +
             freq[233] + freq[235] + freq[248]) >
            (freq[133] + freq[134] + freq[136] +
             freq[137] + freq[139] + freq[152] +
             freq[165] + freq[166] + freq[168] +
             freq[169] + freq[171] + freq[184] +
             freq[195])) {
             return "ISO-8859-1";
         } else {
             return "UTF-8";
         }
     }
     public static void main(String[] args) throws Exception {
         System.out.println(guess("C:\\iso-8859-1.txt"));
         System.out.println(guess("C:\\utf-8.txt"));
     }
}

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