/* Extended Module Player
 * Copyright (C) 1996-1999 Claudio Matsuoka and Hipolito Carraro Jr
 *
 * This file is part of the Extended Module Player and is distributed
 * under the terms of the GNU General Public License. See doc/COPYING
 * for more information.
 */

/*
 * Sun, 31 May 1998 17:50:02 -0600
 * Reported by ToyKeeper <scriven@CS.ColoState.EDU>:
 * For loop-prevention, I know a way to do it which lets most songs play
 * fine once through even if they have backward-jumps. Just keep a small
 * array (256 bytes, or even bits) of flags, each entry determining if a
 * pattern in the song order has been played. If you get to an entry which
 * is already non-zero, skip to the next song (assuming looping is off).
 */

/*
 * Tue, 6 Oct 1998 21:23:17 +0200 (CEST)
 * Reported by John v/d Kamp <blade_@dds.nl>:
 * scan.c was hanging when it jumps to an invalid restart value.
 * (Fixed by hipolito)
 */


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include "xmpi.h"
#include "effects.h"

#define S3M_END         0xff
#define TIME            6
#define MAX_GVL         0x40

extern int xxo_fstrow[XMP_DEF_MAXORD];
extern struct xmp_ord_info xxo_info[XMP_DEF_MAXORD];
extern int xmp_scan_row, xmp_scan_ord, xmp_scan_num;


int xmpi_scan_module ()
{
    int prm, gvol_slide, f1, f2, ord, ord2;
    int row, last_row, break_row, cnt_row;
    int gvl, bpm, tempo, base_time, chn;
    int alltmp, clock, clock_rst, medbpm;

    int loop_chn, loop_flg;
    int* loop_stk;
    int* loop_row;

    char** tab_cnt;
    struct xxm_event* event;

    medbpm = xmp_ctl->fetch & XMP_CTL_MEDBPM;

    tab_cnt = calloc (sizeof (char *), xxh->len);
    for (ord = xxh->len; ord--;)
	tab_cnt[ord] =
	    calloc (1, xxo[ord] >= xxh->pat ? 1 : xxp[xxo[ord]]->rows ?
		xxp[xxo[ord]]->rows : 1);

    loop_stk = calloc (sizeof (int), xxh->chn);
    loop_row = calloc (sizeof (int), xxh->chn);
    loop_chn = loop_flg = 0;

    memset (xxo_fstrow, 0, XMP_DEF_MAXORD);

    gvl = xxh->gvl;
    bpm = xxh->bpm;
    tempo = (tempo = xmp_ctl->tempo ? xmp_ctl->tempo : xxh->tpo) ? tempo : TIME;
    base_time = xmp_ctl->rrate;

    ord2 = ord = -1;
    gvol_slide = break_row = cnt_row = alltmp = clock_rst = clock = 0;

    while (42) {
	if ((uint32)++ord >= xxh->len) {
	    if ((uint32)++ord >= xxh->len)
		ord = ((uint32)xxh->rst > xxh->len ||
		    (uint32)xxo[xxh->rst] >= xxh->pat) ? 0 : xxh->rst;
		if (xxo[ord] == S3M_END)
		    break;
	    }

	if ((uint32)xxo[ord] >= xxh->pat) {
	    if (xxo[ord] == S3M_END)
		ord = xxh->len;
	    continue;
	}

	if (tab_cnt[ord][break_row])
	    break;

	xxo_info[ord].gvl = gvl;
	xxo_info[ord].bpm = bpm;
	xxo_info[ord].tempo = tempo;
	if (medbpm)
	    xxo_info[ord].time = (clock + 132 * alltmp / 5 / bpm) / 10;
	else
	    xxo_info[ord].time = (clock + 100 * alltmp / bpm) / 10;

	if (!xxo_fstrow[ord] && ord) {
	    if (ord == xmp_ctl->start && !(xmp_ctl->fetch & XMP_CTL_LOOP)) {
		if (medbpm)
	            clock_rst = clock + 132 * alltmp / 5 / bpm;
		else
		    clock_rst = clock + 100 * alltmp / bpm;
	    }

	    xxo_fstrow[ord] = break_row;
	}

	last_row = xxp[xxo[ord]]->rows;
	for (row = break_row, break_row = 0; row < last_row; row++, cnt_row++) {
	    if (!loop_flg && tab_cnt[ord][row]) {
		cnt_row--;
		goto end_module;
	    }
	    tab_cnt[ord][row]++;

	    for (chn = 0; chn < xxh->chn; chn++) {
		event = &EVENT (xxo[ord], chn, row);

		f1 = event->fxt;
		f2 = event->f2t;

		if (f1 == FX_GLOBALVOL || f2 == FX_GLOBALVOL) {
		    gvl = (f1 == FX_GLOBALVOL) ? event->fxp : event->f2p;
		    gvl = gvl > MAX_GVL ? MAX_GVL : gvl < 0 ? 0 : gvl;
		}

		if (f1 == FX_G_VOLSLIDE || f2 == FX_G_VOLSLIDE) {
		    prm = (f1 == FX_G_VOLSLIDE) ? event->fxp : event->f2p;
		    if (prm)
			gvol_slide = MSN (prm) - LSN (prm);
		    gvl += gvol_slide *
			(tempo - !(xmp_ctl->fetch & XMP_CTL_VSALL));
		}

		if (f1 == FX_TEMPO || f2 == FX_TEMPO) {
		    prm = (f1 == FX_TEMPO) ? event->fxp : event->f2p;
		    alltmp += cnt_row * tempo * base_time;
		    cnt_row = 0;
		    if (prm) {
			if (prm <= 0x20)
			    tempo = prm;
			else {
			    if (medbpm)
				clock += 132 * alltmp / 5 / bpm;
			    else
				clock += 100 * alltmp / bpm;

			    alltmp = 0;
			    bpm = prm;
			}
		    }
		}

		if (f1 == FX_S3M_TEMPO || f2 == FX_S3M_TEMPO) {
		    prm = (f1 == FX_S3M_TEMPO) ? event->fxp : event->f2p;
		    alltmp += cnt_row * tempo * base_time;
		    cnt_row  = 0;
		    tempo = prm;
		}

		if (f1 == FX_JUMP || f2 == FX_JUMP) {
		    ord2 = ((f1 == FX_JUMP) ? event->fxp : event->f2p);
		    last_row = 0;
		}

		if (f1 == FX_BREAK || f2 == FX_BREAK) {
		    prm = (f1 == FX_BREAK) ? event->fxp : event->f2p;
		    break_row = 10 * MSN (prm) + LSN (prm);
		    last_row = 0;
		}

		if (f1 == FX_EXTENDED || f2 == FX_EXTENDED) {
		    prm = (f1 == FX_EXTENDED) ? event->fxp : event->f2p;

		    if ((prm >> 4) == EX_PATT_DELAY)
			alltmp += (prm & 0x0f) * tempo * base_time;

		    if ((prm >> 4) == EX_PATTERN_LOOP) {
			if (prm &= 0x0f) {
			    if (loop_stk[chn]) {
				if (--loop_stk[chn])
				    loop_chn = chn + 1;
				else {
				    loop_flg--;
				    if (xmp_ctl->fetch & XMP_CTL_S3MLOOP)
					loop_row[chn] = row + 1;
				}
			    } else {
				if (loop_row[chn] <= row) {
				    loop_stk[chn] = prm;
				    loop_chn = chn + 1;
				    loop_flg++;
				}
			    }
			} else { 
			    loop_row[chn] = row;
			}
		    }
		}

	    }

	    if (loop_chn) {
		row = loop_row[--loop_chn] - 1;
		loop_chn = 0;
	    }
	}

	if (ord2 >= 0) {
	    ord = --ord2;
	    ord2 = -1;
	}

	alltmp += cnt_row * tempo * base_time;
	cnt_row = 0;
    }
    row = break_row;

end_module:
    xmp_scan_num = xmp_ctl->start > ord? 0: tab_cnt[ord][row];
    xmp_scan_row = row;
    xmp_scan_ord = ord;

    free (loop_row);
    free (loop_stk);

    for (ord = xxh->len; ord--; free (tab_cnt[ord]));
    free (tab_cnt);

    clock -= clock_rst;
    alltmp += cnt_row * tempo * base_time;

    if (medbpm)
	return (clock + 132 * alltmp / 5 / bpm) / 10;
    else
	return (clock + 100 * alltmp / bpm) / 10;
}