/*	MikMod sound library
	(c) 1998, 1999 Miodrag Vallat and others - see file AUTHORS for
	complete list.

	This library is free software; you can redistribute it and/or modify
	it under the terms of the GNU Library 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 Library General Public License for more details.
 
	You should have received a copy of the GNU Library General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
	02111-1307, USA.
*/

/*==============================================================================

  $Id: load_stx.c,v 1.2 1999/02/08 07:24:18 miod Exp $

  STMIK 0.2 (STX) module loader

==============================================================================*/

/*

	Written by Claudio Matsuoka <claudio@helllabs.org>

*/

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

#include <string.h>

#include <mikmod_internals.h>

/*========== Module structure */

/* header */
typedef struct STXHEADER {
	CHAR  songname[20];
	CHAR  scream[8];
	UWORD patsize;
	UWORD unknown1;
	UWORD patptr;
	UWORD insptr;
	UWORD chnptr;	/* not sure */
	UWORD unknown2;
	UWORD unknown3;
	UBYTE mastermult;
	UBYTE initspeed;
	UWORD unknown4;
	UWORD unknown5;
	UWORD patnum;
	UWORD insnum;
	UWORD ordnum;
	UWORD unknown6;
	UWORD unknown7;
	UWORD unknown8;
	CHAR  scrm[4];
} STXHEADER;

/* sample information */
typedef struct STXSAMPLE {
	UBYTE type;
	CHAR  filename[12];
	UBYTE memsegh;
	UWORD memsegl;
	ULONG length;
	ULONG loopbeg;
	ULONG loopend;
	UBYTE volume;
	UBYTE dsk;
	UBYTE pack;
	UBYTE flags;
	ULONG c2spd;
	UBYTE unused[12];
	CHAR  sampname[28];
	CHAR  scrs[4];
} STXSAMPLE;

typedef struct STXNOTE {
	UBYTE note,ins,vol,cmd,inf;
} STXNOTE;

/*========== Loader variables */

static STXNOTE   *stxbuf  = NULL; /* pointer to a complete STX pattern */
static STXHEADER *mh      = NULL;
static UWORD     *paraptr = NULL; /* parapointer array (see STX docs) */

/*========== Loader code */

static BOOL STX_Test(void)
{
	UBYTE id[4];

	_mm_fseek(modreader,0x3c,SEEK_SET);
	if(!_mm_read_UBYTES(id,4,modreader)) return 0;
	if(!memcmp(id,"SCRM",4)) return 1;
	return 0;
}

static BOOL STX_Init(void)
{
	if(!(stxbuf=(STXNOTE*)_mm_malloc(4*64*sizeof(STXNOTE)))) return 0;
	if(!(mh=(STXHEADER*)_mm_malloc(sizeof(STXHEADER)))) return 0;
	if(!(poslookup=(UBYTE*)_mm_malloc(sizeof(UBYTE)*256))) return 0;

	return 1;
}

static void STX_Cleanup(void)
{
	if(stxbuf) free(stxbuf);
	if(paraptr) free(paraptr);
	if(poslookup) free(poslookup);
	if(mh) free(mh);

	paraptr   = NULL;
	stxbuf    = NULL;
	poslookup = NULL;
	mh        = NULL;
}

static BOOL STX_ReadPattern(void)
{
	int row=0,flag,ch;
	STXNOTE *n,dummy;

	/* clear pattern data */
	memset(stxbuf,255,4*64*sizeof(STXNOTE));

	while(row<64) {
		flag=_mm_read_UBYTE(modreader);

		if(_mm_eof(modreader)) {
			_mm_errno = MMERR_LOADING_PATTERN;
			return 0;
		}

		if(flag) {
			ch=flag&31;

			if((ch>=0)&&(ch<4))
				n=&stxbuf[(64U*ch)+row];
			else
				n=&dummy;

			if(flag&32) {
				n->note=_mm_read_UBYTE(modreader);
				n->ins=_mm_read_UBYTE(modreader);
			}
			if(flag&64)
				n->vol=_mm_read_UBYTE(modreader);
			if(flag&128) {
				n->cmd=_mm_read_UBYTE(modreader);
				n->inf=_mm_read_UBYTE(modreader);
			}
		} else row++;
	}
	return 1;
}

static UBYTE* STX_ConvertTrack(STXNOTE* tr)
{
	int t;

	UniReset();
	for(t=0;t<64;t++) {
		UBYTE note,ins,vol,cmd,inf;

		note=tr[t].note;
		ins=tr[t].ins;
		vol=tr[t].vol;
		cmd=tr[t].cmd;
		inf=tr[t].inf;

		if((ins)&&(ins!=255)) UniInstrument(ins-1);
		if((note)&&(note!=255)) {
			if(note==254) UniPTEffect(0xc,0);	/* note cut command */
			else UniNote(24+((note>>4)*OCTAVE)+(note&0xf));	/* normal note */
		}

		if(vol<255) UniPTEffect(0xc,vol);

		if(cmd<255) switch(cmd) {
			case 1:	/* Axx set speed to xx */
				UniPTEffect(0xf,inf>>4);
				break;
			case 2:	/* Bxx position jump */
				UniPTEffect(0xb,inf);
				break;
			case 3:	/* Cxx patternbreak to row xx */
				UniPTEffect(0xd,(((inf&0xf0)>>4)*10)+(inf&0xf));
				break;
			case 4:	/* Dxy volumeslide */
				UniEffect(UNI_S3MEFFECTD,inf);
				break;
			case 5:	/* Exy toneslide down */
				UniEffect(UNI_S3MEFFECTE,inf);
				break;
			case 6:	/* Fxy toneslide up */
				UniEffect(UNI_S3MEFFECTF,inf);
				break;
			case 7:	/* Gxx Tone portamento,speed xx */
				UniPTEffect(0x3,inf);
				break;
			case 8:	/* Hxy vibrato */
				UniPTEffect(0x4,inf);
				break;
			case 9:	/* Ixy tremor, ontime x, offtime y */
				UniEffect(UNI_S3MEFFECTI,inf);
			break;
			case 0:		/* protracker arpeggio */
				if(!inf) break;
				/* fall through */
			case 0xa:	/* Jxy arpeggio */
				UniPTEffect(0x0,inf);
				break;
			case 0xb:	/* Kxy Dual command H00 & Dxy */
				UniPTEffect(0x4,0);
				UniEffect(UNI_S3MEFFECTD,inf);
				break;
			case 0xc:	/* Lxy Dual command G00 & Dxy */
				UniPTEffect(0x3,0);
				UniEffect(UNI_S3MEFFECTD,inf);
				break;
			/* Support all these above, since ST2 can LOAD these values but can
			   actually only play up to J - and J is only half-way implemented
			   in ST2 */
			case 0x18:	/* Xxx amiga panning command 8xx */
				UniPTEffect(0x8,inf);
				break;
		}
		UniNewline();
	}
	return UniDup();
}

static BOOL STX_Load(BOOL curious)
{
	int t,u,track = 0;
	int version = 0;
	SAMPLE *q;

	/* try to read module header */
	_mm_read_string(mh->songname,20,modreader);
	_mm_read_string(mh->scream,8,modreader);
	mh->patsize     =_mm_read_I_UWORD(modreader);
	mh->unknown1    =_mm_read_I_UWORD(modreader);
	mh->patptr      =_mm_read_I_UWORD(modreader);
	mh->insptr      =_mm_read_I_UWORD(modreader);
	mh->chnptr      =_mm_read_I_UWORD(modreader);
	mh->unknown2    =_mm_read_I_UWORD(modreader);
	mh->unknown3    =_mm_read_I_UWORD(modreader);
	mh->mastermult  =_mm_read_UBYTE(modreader);
	mh->initspeed   =_mm_read_UBYTE(modreader)>>4;
	mh->unknown4    =_mm_read_I_UWORD(modreader);
	mh->unknown5    =_mm_read_I_UWORD(modreader);
	mh->patnum      =_mm_read_I_UWORD(modreader);
	mh->insnum      =_mm_read_I_UWORD(modreader);
	mh->ordnum      =_mm_read_I_UWORD(modreader);
	mh->unknown6    =_mm_read_I_UWORD(modreader);
	mh->unknown7    =_mm_read_I_UWORD(modreader);
	mh->unknown8    =_mm_read_I_UWORD(modreader);
	_mm_read_string(mh->scrm,4,modreader);

	if(_mm_eof(modreader)) {
		_mm_errno = MMERR_LOADING_HEADER;
		return 0;
	}

	/* set module variables */
	of.songname    = DupStr(mh->songname,20,1);
	of.numpat      = mh->patnum;
	of.reppos      = 0;
	of.numins      = of.numsmp = mh->insnum;
	of.initspeed   = mh->initspeed;
	of.inittempo   = 125;
	of.numchn      = 4;

	if(!(paraptr=(UWORD*)_mm_malloc((of.numins+of.numpat)*sizeof(UWORD))))
		return 0;

	/* read the instrument+pattern parapointers */
	_mm_fseek(modreader,mh->insptr<<4,SEEK_SET);
	_mm_read_I_UWORDS(paraptr,of.numins,modreader);
	_mm_fseek(modreader,mh->patptr<<4,SEEK_SET);
	_mm_read_I_UWORDS(paraptr+of.numins,of.numpat,modreader);

	/* check module version */
	_mm_fseek(modreader,paraptr[of.numins]<<4,SEEK_SET);
	version=_mm_read_I_UWORD(modreader);
	if(version==mh->patsize) {
		version    = 0x10;
		of.modtype = strdup("STMIK 0.2 (STM2STX 1.0)");
	} else {
		version    = 0x11;
		of.modtype = strdup("STMIK 0.2 (STM2STX 1.1)");
	}

	/* read the order data */
	_mm_fseek(modreader,(mh->chnptr<<4)+32,SEEK_SET);
	if(!AllocPositions(mh->ordnum)) return 0;
	for(t=0;t<mh->ordnum;t++) {
		of.positions[t]=_mm_read_UBYTE(modreader);
		_mm_fseek(modreader,4,SEEK_CUR);
	}

	of.numpos=0;poslookupcnt=mh->ordnum;
	for(t=0;t<mh->ordnum;t++) {
		of.positions[of.numpos]=of.positions[t];
		poslookup[t]=of.numpos;	/* bug fix for freaky S3Ms */
		if(of.positions[t]<254) of.numpos++;        
		else
		  /* special end of song pattern */
		  if((of.positions[t]==255)&&(!curious)) break;
	}

	if(_mm_eof(modreader)) {
		_mm_errno = MMERR_LOADING_HEADER;
		return 0;
	}

	/* load samples */
	if(!AllocSamples()) return 0;
	for(q=of.samples,t=0;t<of.numins;t++,q++) {
		STXSAMPLE s;

		/* seek to instrument position */
		_mm_fseek(modreader,((long)paraptr[t])<<4,SEEK_SET);
		/* and load sample info */
		s.type      =_mm_read_UBYTE(modreader);
		_mm_read_string(s.filename,12,modreader);
		s.memsegh   =_mm_read_UBYTE(modreader);
		s.memsegl   =_mm_read_I_UWORD(modreader);
		s.length    =_mm_read_I_ULONG(modreader);
		s.loopbeg   =_mm_read_I_ULONG(modreader);
		s.loopend   =_mm_read_I_ULONG(modreader);
		s.volume    =_mm_read_UBYTE(modreader);
		s.dsk       =_mm_read_UBYTE(modreader);
		s.pack      =_mm_read_UBYTE(modreader);
		s.flags     =_mm_read_UBYTE(modreader);
		s.c2spd     =_mm_read_I_ULONG(modreader);
		_mm_read_UBYTES(s.unused,12,modreader);
		_mm_read_string(s.sampname,28,modreader);
		_mm_read_string(s.scrs,4,modreader);

		if(_mm_eof(modreader)) {
			_mm_errno = MMERR_LOADING_SAMPLEINFO;
			return 0;
		}

		q->samplename = DupStr(s.sampname,28,1);
		q->speed      = s.c2spd;
		q->length     = s.length;
		q->loopstart  = s.loopbeg;
		q->loopend    = s.loopend;
		q->volume     = s.volume;
		q->seekpos    = (((long)s.memsegh)<<16|s.memsegl)<<4;
		q->flags     |= SF_SIGNED;

		/* fix for bad converted STMs */
		if (q->loopstart>=q->length) {
			q->loopstart=q->loopend=0;
			s.flags&=~1;
		}

		if(s.flags&1) {
			q->flags |= SF_LOOP;
			if(q->loopend>q->length) q->loopend=q->length;
		}
		if(s.flags&4) q->flags |= SF_16BITS;
	}

	/* load pattern info */
	of.numtrk=of.numpat*of.numchn;
	if(!AllocTracks()) return 0;
	if(!AllocPatterns()) return 0;

	for(t=0;t<of.numpat;t++) {
		/* seek to pattern position (+2 skip pattern length) */
		_mm_fseek(modreader,(((long)paraptr[of.numins+t])<<4)+
			(version==0x10?2:0),SEEK_SET);
		if(!STX_ReadPattern()) return 0;
		for(u=0;u<of.numchn;u++)
			if(!(of.tracks[track++]=STX_ConvertTrack(&stxbuf[u*64]))) return 0;
	}

	return 1;
}

static CHAR *STX_LoadTitle(void)
{
	CHAR s[28];

	_mm_fseek(modreader,0,SEEK_SET);
	if(!_mm_read_UBYTES(s,20,modreader)) return NULL;

	return(DupStr(s,28,1));
}

/*========== Loader information */

MLOADER load_stx={
	NULL,
	"STX",
	"STX loader v0.1",
	STX_Init,
	STX_Test,
	STX_Load,
	STX_Cleanup,
	STX_LoadTitle
};
