Java UTF-16 Encoding

[skiforfun]

I'm doing some research work on java and unicode, and I need the algorithm that codes a unicode point into bytes (How it is EXACTLY implemented by Java). I found that this function is described in the Character.java library, but unfortunately it only shows the following casting to get the char byte(s) from a unicode point value:

public static char[] toChars(int codePoint) {
....
[INDENT]return new char[] { (char) codePoint };[/INDENT]
}

I tried to find elsewhere how this conversion is done, but no luck so far.

Does anyone know where can I find how the conversion from a code point value to a byte is actually done ?

Thanks in advance for any help provided :)

[JosAH]

I'm doing some research work on java and unicode, and I need the algorithm that codes a unicode point into bytes (How it is EXACTLY implemented by Java). I found that this function is described in the Character.java library, but unfortunately it only shows the following casting to get the char byte(s) from a unicode point value:

public static char[] toChars(int codePoint) {
....
[INDENT]return new char[] { (char) codePoint };[/INDENT]
}

I tried to find elsewhere how this conversion is done, but no luck so far.

Does anyone know where can I find how the conversion from a code point value to a byte is actually done ?

Thanks in advance for any help provided :)

Strange, because this is what my copy of the source code says:

    public static char[] toChars(int codePoint) {
        if (codePoint < 0 || codePoint > MAX_CODE_POINT) {
            throw new IllegalArgumentException();
        }
        if (codePoint < MIN_SUPPLEMENTARY_CODE_POINT) {
                return new char[] { (char) codePoint };
        }
        char[] result = new char[2];
        toSurrogates(codePoint, result, 0);
        return result;
    }

Pay special attention to the toSurrogates( ... ) method.

kind regards,

Jos

[skiforfun]

The problem remains there, in your code you are in fact returning:

return new char[] { [B](char) codePoint[/B] };

Which doesn't explain how that particular conversion is done. The surrogate pair distinction is just done to return 2 chars instead of 1, but the conversion is done in the same way. What i need to know is how does it cast an integer value (codePoint) to a char (bytes).

[JosAH]

The problem remains there, in your code you are in fact returning:

return new char[] { [B](char) codePoint[/B] };

Which doesn't explain how that particular conversion is done. The surrogate pair distinction is just done to return 2 chars instead of 1, but the conversion is done in the same way. What i need to know is how does it cast an integer value (codePoint) to a char (bytes).

Conversion from an int B0B1B2B3, where B3 is the least significant byte, to a char is just B2B3. (the most significant bytes B0 and B1 are chopped off).

kind regards,

Jos

[skiforfun]

You are right, i was forgetting that the BMP plane of characters are just encoded as their numerical value in UTF-16 so there is no need to encode anything unless they are surrogates. The surrogates encoding I get it.

Thanks for your time.