Tutorial Addendum on Unicode - JDK - Encoding Map Counts

accessible changeless byte encodeByEncoder(char c, Cord cs) {

    

Charset cso = null;

    

byte b = null;

    

try {

    

cso = Charset.forName(cs);

    

CharsetEncoder e = cso.newEncoder();

    

e.reset();

    

ByteBuffer bb = e.encode(CharBuffer.wrap(new char {c}));

    

if (bb.limit()>0) b = copyBytes(bb.array(),bb.limit());

    

} bolt (IllegalCharsetNameException e) {

    

System.out.println(e.toString());

    

} bolt (CharacterCodingException e) {

    

// invalid character, acknowledgment null

    

}

    

acknowledgment b;

    

}

    

accessible changeless abandoned printBytes(byte b) {

    

if (b!=null) {

    

for (int j=0; j<b.length; j++)

    

System.out.print(" "+byteToHex(b));

    

} abroad {

    

System.out.print(" XX");

    

}

    

}

    

accessible changeless byte copyBytes(byte a, int l) {

    

byte b = new byte;

    

for (int i=0; i<Math.min(l,a.length); i++) b = a;

    

acknowledgment b;

    

}

    

accessible changeless Cord byteToHex(byte b) {

    

char a = { hexDigit, hexDigit };

    

acknowledgment new String(a);

    

}

    

accessible changeless Cord charToHex(char c) {

    

byte hi = (byte) (c >>> 8);

    

byte lo = (byte) (c & 0xff);

    

acknowledgment byteToHex(hi) + byteToHex(lo);

    

}

    

}

    

Note that:

    

    
• CharsetEncoder.encode() is acclimated to encode the cipher credibility stored as "char" type.


    
• Since Java can alone encode cipher credibility in the 0x0000 - 0xFFFF range, only
  
      

  a subset of the appearance set will be encoded for some encodings, like UTF-8,
  
      

  which can encode cipher credibility up to 0x10FFFF.



    
• The encoding name should be defined as command argument.


    

Run this program with US-ASCII as argument, you will get:

    

US-ASCII encoding:

    

0000 > 00 - 007F > 7F = 128

    

0080 > XX - FFFF > XX = 65408

    

Total characters = 65536

    

Valid characters = 128

    

Invalid characters = 65408

    

This tells us that the US-ASCII appearance set has alone 128 characters.

    

Run this program with ISO-8859-1 (Latin 1) as argument, you will get:

    

ISO-8859-1 encoding:

    

0000 > 00 - 00FF > FF = 256

    

0100 > XX - FFFF > XX = 65280

    

Total characters = 65536

    

Valid characters = 256

    

Invalid characters = 65280

    

This tells us that the US-ASCII appearance set has alone 256 characters.

    

Comparison of encoding Maps

    

The afterward table is based on the achievement of the EncodingCouter program with

    

different accurate encoding names. It provides a abrupt allegory between

    

the some altered encodings.

    

Encoding Map US-ASCII

    

Name Admeasurement Accordant Notes

    

US-ASCII 128 Y 7-bit characters only

    

ISO-8859-1 256 Y 8-bit (single byte) characters

    

CP1252 251 Y One byte output, with cipher credibility up to 0x2122

    

UTF-8 63488 Y 1-3 bytes,

    

UTF-16BE 63488 N 2 bytes, carbon artful the cipher points

    

UTF-16LE 63488 N 2 bytes, abandoning the cipher credibility

    

UTF-16 63488 N 4 bytes, endure 2 bytes = UTF-16BE

    

GBK 24068 Y 1-2 bytes, Chinese 1993 standard

    

GB18030 63488 Y 1-4 bytes, superset of GBK, 2000 standard

    

Source: s Addendum on JDK.