philippe lhardy
36e58808d5
use directly sharedrawweb java code here Signed-off-by: philippe lhardy <philippe.lhardy@astrolabe.coop>
126 lines
3.6 KiB
Java
126 lines
3.6 KiB
Java
/*
|
|
This file is part of ShareDrawWeb.
|
|
|
|
ShareDrawWeb is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
ShareDrawWeb is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with ShareDrawWeb; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
*/
|
|
|
|
package org.artisanlogiciel.compression.graphics;
|
|
|
|
/*
|
|
simple class to write bitfields
|
|
@see BitFieldReader
|
|
@author Philippe Lhardy
|
|
*/
|
|
|
|
import java.io.*;
|
|
|
|
class BitFieldWriter {
|
|
|
|
// size of nextWord
|
|
final int dataSize = 32;
|
|
|
|
/* bitOffset is number of bits already used in word
|
|
should ensure bitOffset < dataSize
|
|
*/
|
|
private int bitOffset;
|
|
|
|
/* word used waiting to be filled to be written
|
|
dataSize is bit size of nextWord
|
|
*/
|
|
private int nextWord;
|
|
|
|
private DataOutputStream outputStream;
|
|
|
|
public void write( int field, int bits) throws java.io.IOException {
|
|
// if more bits needed that word currently used.
|
|
if ( bits + bitOffset > dataSize) {
|
|
// warning recursive call ( not terminal )
|
|
// fill and write current word
|
|
int bitsize = dataSize - bitOffset;
|
|
int head;
|
|
// most significant bits first
|
|
// suppress at left least significant bits
|
|
head = field >> (bits - bitsize);
|
|
write( head, dataSize - bitOffset);
|
|
// no need of newWord() previous write already done it
|
|
// least significant bits last
|
|
field = field & ( 0x7FFFFFFF >> ( bitsize - 1));
|
|
write( field, bits - bitsize);
|
|
}
|
|
else {
|
|
if ( bits == dataSize ) {
|
|
// special case to keep sign
|
|
nextWord = field;
|
|
bitOffset = 0;
|
|
}
|
|
else {
|
|
// keep only meaning part of field
|
|
field = field & ( 0x7FFFFFFF >> ( dataSize - 1 - bits));
|
|
nextWord = nextWord | ( field << ( dataSize - bits - bitOffset));
|
|
bitOffset = ( bitOffset + bits ) % dataSize;
|
|
}
|
|
// a new word is needed
|
|
if ( bitOffset == 0 ) {
|
|
newWord();
|
|
}
|
|
}
|
|
/*
|
|
System.out.println( "nextWord " + Integer.toString( nextWord) + " size "
|
|
+ Integer.toString( bits) + " field " + Integer.toString( field));
|
|
*/
|
|
}
|
|
|
|
/**
|
|
* seems to works correctly as DataOutputStream.writeInt()
|
|
*/
|
|
private void writeInt( int i)
|
|
throws IOException
|
|
{
|
|
long j = i;
|
|
byte bytes[]=new byte[4];
|
|
bytes[0] = (byte) ((j & 0xFF000000) >> 24);
|
|
bytes[1] = (byte) ((j & 0x00FF0000) >> 16);
|
|
bytes[2] = (byte) ((j & 0x0000FF00) >> 8);
|
|
bytes[3] = (byte) (j & 0x000000FF);
|
|
outputStream.write( bytes, 0, 4);
|
|
}
|
|
|
|
private void newWord() throws java.io.IOException {
|
|
// do really write current word;
|
|
//writeInt( nextWord);
|
|
outputStream.writeInt(nextWord);
|
|
// reset nextWord
|
|
bitOffset = 0;
|
|
nextWord = 0;
|
|
}
|
|
|
|
/*
|
|
write all current datas if any
|
|
to have a clean word ready.
|
|
*/
|
|
public void padToWord() throws java.io.IOException {
|
|
if ( bitOffset != 0) {
|
|
newWord();
|
|
}
|
|
}
|
|
|
|
/* set OutputStream */
|
|
public void setOutputStream( OutputStream output) {
|
|
outputStream = new DataOutputStream(output);
|
|
}
|
|
|
|
}
|