/*
 *  PSX-Tools Bundle Pack
 *  Copyright (C) 2002-2003 Nicolas "Pixel" Noble
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* $Id: dvdabstract.cpp,v 1.1 2005-11-02 21:34:02 pixel Exp $ */

#include "dvdabstract.h"

dvdabstract::dvdabstract(Handle * h, int _m) : Handle(-1), r(h), v(h->tell()), m(_m) {
}

off_t dvdabstract::seek(off_t offset, int wheel) throw (GeneralException) {
    switch (wheel) {
    case SEEK_SET:
	v = offset;
	break;
    case SEEK_CUR:
	v += offset;
	break;
    case SEEK_END:
	throw IOGeneral("Can't seek from the end of the dvdabstract...");
    }
}

off_t dvdabstract::tell() const {
    return v;
}

ssize_t dvdabstract::read(void * _buf, size_t count) throw (GeneralException) {
    char i_buf[2352], * buf = (char *) _buf;
    int sector, start, reminder, i_count;
    
    if (!count) return 0;
    
    sector = v / 2352;
    start = v % 2352;
    
    read_sector(i_buf, sector);
    
    if ((start + count) < 2352) {
	memcpy(buf, i_buf + start, count);
	return count;
    }
    
    reminder = 2352 - start;
    memcpy(buf, i_buf + start, reminder);
    sector++;
    i_count = count - reminder;
    buf += reminder;
    
    while (i_count >= 2352) {
	read_sector(buf, sector);
	i_count -= 2352;
	sector++;
	buf += 2352;
    }
    
    reminder = i_count;
    
    if (reminder >= 0) {
	read_sector(i_buf, sector);
	memcpy(buf, i_buf, reminder);
    }
    
    return count;
}

ssize_t dvdabstract::write(const void * _buf, size_t count) throw (GeneralException) {
    char i_buf[2352], * buf = (char *) _buf;
    int sector, start, reminder, i_count;
    
    if (!count) return 0;
    
    sector = v / 2352;
    start = v % 2352;
    
    memcpy(i_buf + start, buf, 2352 - start);
    if (start >= 16) {
	i_buf[15] = m;
	if (m == MODE2_FORM1) {
	    i_buf[18] = i_buf[22] = 1;
	}
    }
    write_sector(i_buf, sector);
    
    if ((start + count) < 2352) {
	return count;
    }
    
    reminder = 2352 - start;
    sector++;
    i_count = count - reminder;
    buf += reminder;
    
    while (i_count >= 2352) {
	write_sector(buf, sector);
	i_count -= 2352;
	sector++;
	buf += 2352;
    }
    
    reminder = i_count;
    memcpy(i_buf, buf, reminder);
    if (reminder >= 0) {
	memcpy(buf, i_buf, reminder);
	if (reminder <= 22) {
	    if (reminder <= 15) {
		i_buf[15] = m;
		if (m == MODE2_FORM1) {
		    i_buf[18] = i_buf[22] = 1;
		}
	    } else if (i_buf[15] == MODE2_FORM1) {
		i_buf[18] = i_buf[22] = 1;
	    }
	}
	write_sector(i_buf, sector);
    }
    
    return count;
}

void dvdabstract::read_sector(char * buf, int sector) {
    r->seek(sector * 2048);
    r->read(buf + 16, 2048);
    buf[0] = buf[11] = 0;
    buf[1] = buf[2] = buf[3] = buf[4] = buf[5] = buf[6] = buf[7] = buf[8] = buf[9] = buf[10] = -1;
    buf[12] = buf[13] = buf[14] = 0;
    buf[15] = 1;
}

void dvdabstract::write_sector(const char * buf, int sector) throw (GeneralException) {
    r->seek(sector * 2048);
    switch(buf[15]) {
    case 0:
    case 1:
	r->write(buf + 16, 2048);
	break;
    case 2:
	if ((buf[18] == 1) && (buf[22] == 1)) {
	    r->write(buf + 24, 2048);
	    break;
	}
    default:
	throw GeneralException("dvdabstract::write_sector: unknown sector mode.");
    }
}