rockbox/apps/plugins/zxbox/compr.c

67 lines
1.5 KiB
C

/*
* Copyright (C) 1996-1998 Szeredi Miklos
* Email: mszeredi@inf.bme.hu
*
* 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. See the file COPYING.
*
* 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.
*
*/
#include "compr.h"
void compr(void)
{
int j, c, lc, lled, rep, num;
rep = 0;
c = compr_read_byte();
lc = 0;
num = 0;
while(c >= 0) {
if(lc == 0xED) lled = 1;
else lled = 0;
lc = c;
c = compr_read_byte();
if(c == lc && num != 255 && (!lled || rep)) {
if(!rep) {
num = 1;
rep = 1;
}
num++;
}
else {
if(rep) {
if(num < 5 && lc != 0xED) for(j = 0; j < num; j++) compr_put_byte(lc);
else{
compr_put_byte(0xED);
compr_put_byte(0xED);
compr_put_byte(num);
compr_put_byte(lc);
num = 0;
}
rep = 0;
}
else compr_put_byte(lc);
}
}
compr_put_byte(0x00);
compr_put_byte(0xED);
compr_put_byte(0xED);
compr_put_byte(0x00);
}