/*
* 21.04.2004 Original verion. davagin@udm.ru.
*-----------------------------------------------------------------------
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*----------------------------------------------------------------------
*/
package davaguine.jmac.decoder;
/**
* Author: Dmitry Vaguine
* Date: 04.03.2004
* Time: 14:51:31
*/
public class AntiPredictorNormal3800ToCurrent extends AntiPredictor {
private final static int FIRST_ELEMENT = 4;
public void AntiPredict(int[] pInputArray, int[] pOutputArray, int NumberOfElements) {
//short frame handling
if (NumberOfElements < 8) {
System.arraycopy(pInputArray, 0, pOutputArray, 0, NumberOfElements);
return;
}
//make the first five samples identical in both arrays
System.arraycopy(pInputArray, 0, pOutputArray, 0, FIRST_ELEMENT);
//variable declares and initializations
int m2 = 64, m3 = 115, m4 = 64, m5 = 740, m6 = 0;
int p4 = pInputArray[FIRST_ELEMENT - 1];
int p3 = (pInputArray[FIRST_ELEMENT - 1] - pInputArray[FIRST_ELEMENT - 2]) << 1;
int p2 = pInputArray[FIRST_ELEMENT - 1] + ((pInputArray[FIRST_ELEMENT - 3] - pInputArray[FIRST_ELEMENT - 2]) << 3);
int op = FIRST_ELEMENT;
int ip = FIRST_ELEMENT;
int IPP2 = pInputArray[ip - 2];
int p7 = 2 * pInputArray[ip - 1] - pInputArray[ip - 2];
int opp = pOutputArray[op - 1];
//undo the initial prediction stuff
for (int q = 1; q < FIRST_ELEMENT; q++) {
pOutputArray[q] += pOutputArray[q - 1];
}
//pump the primary loop
for (; op < NumberOfElements; op++, ip++) {
int o = pOutputArray[op], i = pInputArray[ip];
/////////////////////////////////////////////
o = i + (((p2 * m2) + (p3 * m3) + (p4 * m4)) >> 11);
if (i > 0) {
m2 -= ((p2 >> 30) & 2) - 1;
m3 -= ((p3 >> 28) & 8) - 4;
m4 -= ((p4 >> 28) & 8) - 4;
} else if (i < 0) {
m2 += ((p2 >> 30) & 2) - 1;
m3 += ((p3 >> 28) & 8) - 4;
m4 += ((p4 >> 28) & 8) - 4;
}
p2 = o + ((IPP2 - p4) << 3);
p3 = (o - p4) << 1;
IPP2 = p4;
p4 = o;
/////////////////////////////////////////////
o += (((p7 * m5) - (opp * m6)) >> 10);
if (p4 > 0) {
m5 -= ((p7 >> 29) & 4) - 2;
m6 += ((opp >> 30) & 2) - 1;
} else if (p4 < 0) {
m5 += ((p7 >> 29) & 4) - 2;
m6 -= ((opp >> 30) & 2) - 1;
}
p7 = 2 * o - opp;
opp = o;
/////////////////////////////////////////////
pOutputArray[op] = o + ((pOutputArray[op - 1] * 31) >> 5);
}
}
}