/*	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_dsm.c,v 1.20 1999/02/08 07:24:03 miod Exp $

  DSIK internal format (DSM) module loader

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

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

#include <string.h>

#include <mikmod_internals.h>

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

#define DSM_MAXCHAN (16)
#define DSM_MAXORDERS (128)

typedef struct DSMSONG {
	CHAR	songname[28];
	UWORD	version;
	UWORD	flags;
	ULONG	reserved2;
	UWORD	numord;
	UWORD	numsmp;
	UWORD	numpat;
	UWORD	numtrk;
	UBYTE	globalvol;
	UBYTE	mastervol;
	UBYTE	speed;
	UBYTE	bpm;
	UBYTE	panpos[DSM_MAXCHAN];
	UBYTE	orders[DSM_MAXORDERS];
} DSMSONG;

typedef struct DSMINST {
	CHAR	filename[13];
	UWORD	flags;
	UBYTE	volume;
	ULONG	length;
	ULONG	loopstart;
	ULONG	loopend;
	ULONG	reserved1;
	UWORD	c2spd;
	UWORD	period;
	CHAR	samplename[28];
} DSMINST;

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

#define DSM_SURROUND (0xa4)

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

static	CHAR* SONGID="SONG";
static	CHAR* INSTID="INST";
static	CHAR* PATTID="PATT";

static	UBYTE blockid[4];
static	ULONG blockln;
static	ULONG blocklp;
static	DSMSONG* mh=NULL;
static	DSMNOTE* dsmbuf=NULL;

static	CHAR DSM_Version[]="DSIK DSM-format";

static	unsigned char DSMSIG[4+4]={'R','I','F','F','D','S','M','F'};

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

BOOL DSM_Test(void)
{
	UBYTE id[12];

	if(!_mm_read_UBYTES(id,12,modreader)) return 0;
	if(!memcmp(id,DSMSIG,4) && !memcmp(id+8,DSMSIG+4,4)) return 1;

	return 0;
}

BOOL DSM_Init(void)
{
	if(!(dsmbuf=(DSMNOTE *)_mm_malloc(DSM_MAXCHAN*64*sizeof(DSMNOTE)))) return 0;
	if(!(mh=(DSMSONG *)_mm_calloc(1,sizeof(DSMSONG)))) return 0;
	return 1;
}

void DSM_Cleanup(void)
{
	if(dsmbuf!=NULL) free(dsmbuf);
	if(mh!=NULL) free(mh);

	dsmbuf=NULL;
	mh=NULL;
}

static BOOL GetBlockHeader(void)
{
	/* make sure we're at the right position for reading the
	   next riff block, no matter how many bytes read */
	_mm_fseek(modreader, blocklp+blockln, SEEK_SET);
   
	while(1) {
		_mm_read_UBYTES(blockid,4,modreader);
		blockln=_mm_read_I_ULONG(modreader);
		if(_mm_eof(modreader)) {
			_mm_errno = MMERR_LOADING_HEADER;
			return 0;
		}

		if(memcmp(blockid,SONGID,4) && memcmp(blockid,INSTID,4) &&
		   memcmp(blockid,PATTID,4)) {
#ifdef MIKMOD_DEBUG
				fprintf(stderr,"\rDSM: Skipping unknown block type %4.4s\n",blockid);
#endif
				_mm_fseek(modreader, blockln, SEEK_CUR);
		} else
			break;
	}

	blocklp = _mm_ftell(modreader);

	return 1;
}

static BOOL DSM_ReadPattern(void)
{
	int flag,row=0;
	SWORD length;
	DSMNOTE *n;

	/* clear pattern data */
	memset(dsmbuf,255,DSM_MAXCHAN*64*sizeof(DSMNOTE));
	length=_mm_read_I_SWORD(modreader);

	while(row<64) {
		flag=_mm_read_UBYTE(modreader);
		if((_mm_eof(modreader))||(--length<0)) {
			_mm_errno = MMERR_LOADING_PATTERN;
			return 0;
		}

		if(flag) {
			n=&dsmbuf[((flag&0xf)*64)+row];
			if(flag&0x80) n->note=_mm_read_UBYTE(modreader);
			if(flag&0x40) n->ins=_mm_read_UBYTE(modreader);
			if(flag&0x20) n->vol=_mm_read_UBYTE(modreader);
			if(flag&0x10) {
				n->cmd=_mm_read_UBYTE(modreader);
				n->inf=_mm_read_UBYTE(modreader);
			}
		} else
			row++;
	}

	return 1;
}

static UBYTE *DSM_ConvertTrack(DSMNOTE *tr)
{
	int t;
	UBYTE note,ins,vol,cmd,inf;

	UniReset();
	for(t=0;t<64;t++) {
		note=tr[t].note;
		ins=tr[t].ins;
		vol=tr[t].vol;
		cmd=tr[t].cmd;
		inf=tr[t].inf;

		if(ins!=0 && ins!=255) UniInstrument(ins-1);
		if(note!=255) UniNote(note-1); /* normal note */
		if(vol<65) UniPTEffect(0xc,vol);

		if(cmd!=255) {
			if(cmd==0x8) {
				if(inf==DSM_SURROUND)
					UniEffect(UNI_ITEFFECTS0,0x91);
				else
				  if(inf<=0x80) {
					inf=(inf<0x80)?inf<<1:255;
					UniPTEffect(cmd,inf);
				}
			} else
			  if(cmd==0xb) {
				if(inf<=0x7f) UniPTEffect(cmd,inf);
			} else {
				/* Convert pattern jump from Dec to Hex */
				if(cmd == 0xd)
					inf = (((inf&0xf0)>>4)*10)+(inf&0xf);
				UniPTEffect(cmd,inf);
			}
		}
		UniNewline();
	}
	return UniDup();
}

BOOL DSM_Load(BOOL curious)
{
	int t;
	DSMINST s;
	SAMPLE *q;
	int cursmp=0,curpat=0,track=0;

	blocklp=0;
	blockln=12;

	if(!GetBlockHeader()) return 0;
	if(memcmp(blockid,SONGID,4)) {
		_mm_errno = MMERR_LOADING_HEADER;
		return 0;
	}

	_mm_read_UBYTES(mh->songname,28,modreader);
	mh->version=_mm_read_I_UWORD(modreader);
	mh->flags=_mm_read_I_UWORD(modreader);
	mh->reserved2=_mm_read_I_ULONG(modreader);
	mh->numord=_mm_read_I_UWORD(modreader);
	mh->numsmp=_mm_read_I_UWORD(modreader);
	mh->numpat=_mm_read_I_UWORD(modreader);
	mh->numtrk=_mm_read_I_UWORD(modreader);
	mh->globalvol=_mm_read_UBYTE(modreader);
	mh->mastervol=_mm_read_UBYTE(modreader);
	mh->speed=_mm_read_UBYTE(modreader);
	mh->bpm=_mm_read_UBYTE(modreader);
	_mm_read_UBYTES(mh->panpos,DSM_MAXCHAN,modreader);
	_mm_read_UBYTES(mh->orders,DSM_MAXORDERS,modreader);

	/* set module variables */
	of.initspeed=mh->speed;
	of.inittempo=mh->bpm;
	of.modtype=strdup(DSM_Version);
	of.numchn=mh->numtrk;
	of.numpat=mh->numpat;
	of.numtrk=of.numchn*of.numpat;
	of.songname=DupStr(mh->songname,28,1); /* make a cstr of songname */
	of.reppos=0;

	for(t=0;t<DSM_MAXCHAN;t++)
		of.panning[t]=mh->panpos[t]==DSM_SURROUND?PAN_SURROUND:
		              mh->panpos[t]<0x80?(mh->panpos[t]<<1):255;

	if(!AllocPositions(mh->numord)) return 0;
	of.numpos=0;
	for(t=0;t<mh->numord;t++) {
		of.positions[of.numpos]=mh->orders[t];
		if(mh->orders[t]<254) of.numpos++;
	}

	of.numins=of.numsmp=mh->numsmp;

	if(!AllocSamples()) return 0;
	if(!AllocTracks()) return 0;
	if(!AllocPatterns()) return 0;

	while(cursmp<of.numins||curpat<of.numpat) {
		if(!GetBlockHeader()) return 0;
		if(!memcmp(blockid,INSTID,4) && cursmp<of.numins) {
			q=&of.samples[cursmp];

			/* try to read sample info */
			_mm_read_UBYTES(s.filename,13,modreader);
			s.flags=_mm_read_I_UWORD(modreader);
			s.volume=_mm_read_UBYTE(modreader);
			s.length=_mm_read_I_ULONG(modreader);
			s.loopstart=_mm_read_I_ULONG(modreader);
			s.loopend=_mm_read_I_ULONG(modreader);
			s.reserved1=_mm_read_I_ULONG(modreader);
			s.c2spd=_mm_read_I_UWORD(modreader);
			s.period=_mm_read_I_UWORD(modreader);
			_mm_read_UBYTES(s.samplename,28,modreader);

			q->samplename=DupStr(s.samplename,28,1);
			q->seekpos=_mm_ftell(modreader);
			q->speed=s.c2spd;
			q->length=s.length;
			q->loopstart=s.loopstart;
			q->loopend=s.loopend;
			q->volume=s.volume;

			if(s.flags&1) q->flags|=SF_LOOP;
			if(s.flags&2) q->flags|=SF_SIGNED;
			/* (s.flags&4) means packed sample,
			   but did they really exist in dsm ?*/
			cursmp++;
		} else
		  if(!memcmp(blockid,PATTID,4) && curpat<of.numpat) {
			DSM_ReadPattern();
			for(t=0;t<of.numchn;t++)
				if(!(of.tracks[track++]=DSM_ConvertTrack(&dsmbuf[t*64]))) return 0;
			curpat++;
		}
	}

	return 1;
}

CHAR *DSM_LoadTitle(void)
{
	CHAR s[28];

	_mm_fseek(modreader,12,SEEK_SET);
	if(!_mm_read_UBYTES(s,28,modreader)) return NULL;
   
	return(DupStr(s,28,1));
}

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

MLOADER load_dsm={
	NULL,
	"DSM",
	"DSM loader v0.1",
	DSM_Init,
	DSM_Test,
	DSM_Load,
	DSM_Cleanup,
	DSM_LoadTitle
};

