/*
 * raster-cache-nibbles.h - Raster line cache.
 *
 * Written by
 *  Andreas Boose <viceteam@t-online.de>
 *  Ettore Perazzoli <ettore@comm2000.it>
 *
 * This file is part of VICE, the Versatile Commodore Emulator.
 * See README for copyright notice.
 *
 *  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.
 *
 */

#ifndef VICE_RASTER_CACHE_NIBBLES_H
#define VICE_RASTER_CACHE_NIBBLES_H

#include <string.h>

#include "types.h"

inline static int raster_cache_data_fill_nibbles(uint8_t *dest_hi,
                                                 uint8_t *dest_lo,
                                                 const uint8_t *src,
                                                 const unsigned int length,
                                                 const int src_step,
                                                 unsigned int *xs,
                                                 unsigned int *xe,
                                                 int no_check)
{
    if (no_check) {
        unsigned int i;

        *xs = 0;
        *xe = length - 1;

        for (i = 0; i < length; i++, src += src_step) {
            dest_hi[i] = src[0] >> 4;
            dest_lo[i] = src[0] & 0xf;
        }

        return 1;
    } else {
        unsigned int i, x = 0;
        uint8_t b;

        for (i = 0;
             dest_hi[i] == (src[0] >> 4)
             && dest_lo[i] == (src[0] & 0xf) && i < length;
             i++, src += src_step) {
            /* do nothing */
        }

        if (i < length) {
            if (*xs > i) {
                *xs = i;
            }

            for (; i < length; i++, src += src_step) {
                if (dest_hi[i] != (b = (src[0] >> 4))) {
                    dest_hi[i] = b;
                    x = i;
                }
                if (dest_lo[i] != (b = (src[0] & 0xf))) {
                    dest_lo[i] = b;
                    x = i;
                }
            }

            if (*xe < x) {
                *xe = x;
            }

            return 1;
        } else {
            return 0;
        }
    }
}

#endif