/*	MikMod sound library
	(c) 1998, 1999, 2000, 2001, 2002 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.
*/

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

  Ultratracker (ULT) module loader

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

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

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <stdio.h>
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <string.h>

#include "mikmod_internals.h"

#ifdef SUNOS
extern int fprintf(FILE *, const char *, ...);
#endif

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

/* header */
typedef struct ULTHEADER {
	CHAR  id[16];
	CHAR  songtitle[32];
	UBYTE reserved;
} ULTHEADER;

/* sample information */
typedef struct ULTSAMPLE {
	CHAR  samplename[32];
	CHAR  dosname[12];
	SLONG loopstart;
	SLONG loopend;
	SLONG sizestart;
	SLONG sizeend;
	UBYTE volume;
	UBYTE flags;
	UWORD speed;
	SWORD finetune;
} ULTSAMPLE;

typedef struct ULTEVENT {
	UBYTE note,sample,eff,dat1,dat2;
} ULTEVENT;

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

#define ULTS_16BITS     4
#define ULTS_LOOP       8
#define ULTS_REVERSE    16

#define ULT_VERSION_LEN 18
static	CHAR ULT_Version[ULT_VERSION_LEN+1]="Ultra Tracker v1.x";

static	ULTEVENT ev;

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

static int ULT_Test(void)
{
	CHAR id[16];

	if(!_mm_read_string(id,15,modreader)) return 0;
	if(strncmp(id,"MAS_UTrack_V00",14)) return 0;
	if((id[14]<'1')||(id[14]>'4')) return 0;
	return 1;
}

static int ULT_Init(void)
{
	return 1;
}

static void ULT_Cleanup(void)
{
}

static UBYTE ReadUltEvent(ULTEVENT* event)
{
	UBYTE flag,rep=1;

	flag = _mm_read_UBYTE(modreader);
	if(flag==0xfc) {
		rep = _mm_read_UBYTE(modreader);
		event->note =_mm_read_UBYTE(modreader);
	} else
		event->note = flag;

	event->sample   =_mm_read_UBYTE(modreader);
	event->eff      =_mm_read_UBYTE(modreader);
	event->dat1     =_mm_read_UBYTE(modreader);
	event->dat2     =_mm_read_UBYTE(modreader);

	return rep;
}

static int ULT_Load(int curious)
{
	int t,u,tracks=0;
	SAMPLE *q;
	ULTSAMPLE s;
	ULTHEADER mh;
	UBYTE nos,noc,RBnop;
	(void)curious;

	/* try to read module header */
	_mm_read_string(mh.id,15,modreader);
	_mm_read_string(mh.songtitle,32,modreader);
	mh.reserved=_mm_read_UBYTE(modreader);

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

	ULT_Version[ULT_VERSION_LEN-1]='3'+(mh.id[14]-'1');
	of.modtype   = DupStr(ULT_Version,ULT_VERSION_LEN,1);
	of.initspeed = 6;
	of.inittempo = 125;
	of.reppos    = 0;

	/* read songtext */
	if ((mh.id[14]>'1')&&(mh.reserved))
		if(!ReadLinedComment(mh.reserved * 32, 32)) return 0;

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

	of.songname=DupStr(mh.songtitle,32,1);
	of.numins=of.numsmp=nos;

	if(!AllocSamples()) return 0;
	q = of.samples;
	for(t=0;t<nos;t++) {
		/* try to read sample info */
		_mm_read_string(s.samplename,32,modreader);
		_mm_read_string(s.dosname,12,modreader);
		s.loopstart     =_mm_read_I_ULONG(modreader);
		s.loopend       =_mm_read_I_ULONG(modreader);
		s.sizestart     =_mm_read_I_ULONG(modreader);
		s.sizeend       =_mm_read_I_ULONG(modreader);
		s.volume        =_mm_read_UBYTE(modreader);
		s.flags         =_mm_read_UBYTE(modreader);
		s.speed         =(mh.id[14]>='4')?_mm_read_I_UWORD(modreader):8363;
		s.finetune      =_mm_read_I_SWORD(modreader);

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

		q->samplename=DupStr(s.samplename,32,1);
		/* The correct formula would be
		   s.speed * pow(2, (double)s.finetune / (OCTAVE * 32768))
		   but to avoid libm, we'll use a first order approximation.
		   1/567290 == Ln(2)/OCTAVE/32768 */
		if(!s.finetune) q->speed = s.speed;
		else q->speed= s.speed*((double)s.finetune/567290.0 + 1.0);
		q->length    = s.sizeend-s.sizestart;
		q->volume    = s.volume>>2;
		q->loopstart = s.loopstart;
		q->loopend   = s.loopend;
		q->flags = SF_SIGNED;
		if(s.flags&ULTS_LOOP) q->flags|=SF_LOOP;
		else q->loopstart = q->loopend = 0;
		if(s.flags&ULTS_16BITS) {
			s.sizeend+=(s.sizeend-s.sizestart);
			s.sizestart<<=1;
			q->flags|=SF_16BITS;
			q->loopstart>>=1;
			q->loopend>>=1;
		}
		q++;
	}

	if(!AllocPositions(256)) return 0;
	for(t=0;t<256;t++)
		of.positions[t]=_mm_read_UBYTE(modreader);

	noc=_mm_read_UBYTE(modreader);
	RBnop=_mm_read_UBYTE(modreader);

	of.numchn=++noc;
	of.numpat=++RBnop;
	of.numtrk=of.numchn*of.numpat;

	for(t=0;t<256;t++) {
		if(of.positions[t]==255) {
			of.positions[t]=LAST_PATTERN;
			break;
		}
		if (of.positions[t]>of.numpat) { /* SANITIY CHECK */
		/*	fprintf(stderr,"positions[%d]=%d > numpat=%d\n",t,of.positions[t],of.numpat);*/
			_mm_errno = MMERR_LOADING_HEADER;
			return 0;
		}
	}
	of.numpos=t;

	if(!AllocTracks()) return 0;
	if(!AllocPatterns()) return 0;
	for(u=0;u<of.numchn;u++)
		for(t=0;t<of.numpat;t++)
			of.patterns[(t*of.numchn)+u]=tracks++;

	/* Secunia SA37775 / CVE-2009-3996 */
	if (of.numchn>=UF_MAXCHAN)
		of.numchn=UF_MAXCHAN - 1;

	/* read pan position table for v1.5 and higher */
	if(mh.id[14]>='3') {
		for(t=0;t<of.numchn;t++) of.panning[t]=_mm_read_UBYTE(modreader)<<4;
		of.flags |= UF_PANNING;
	}

	for(t=0;t<of.numtrk;t++) {
		int rep,row=0;
		/* FIXME: unrolling continuous portamento is a HACK and needs to
		 * be replaced with a real continuous effect. This implementation
		 * breaks when tone portamento continues between patterns. See
		 * discussion in https://github.com/sezero/mikmod/pull/40 . */
		int continuePortaToNote = 0;

		UniReset();
		while(row<64) {
			rep=ReadUltEvent(&ev);

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

			while(rep--) {
				UBYTE eff;
				int offset;

				if(ev.sample) UniInstrument(ev.sample-1);
				if(ev.note) {
					UniNote(ev.note+2*OCTAVE-1);
					continuePortaToNote = 0;
				}

				/* first effect - various fixes by Alexander Kerkhove and
				                  Thomas Neumann */
				eff = ev.eff>>4;

				if (continuePortaToNote && (eff != 0x3) && ((ev.eff & 0xf) != 0x3))
					UniEffect(UNI_ITEFFECTG, 0);

				switch(eff) {
					case 0x3: /* tone portamento */
						UniEffect(UNI_ITEFFECTG,ev.dat2);
						continuePortaToNote = 1;
						break;
					case 0x5:
						break;
					case 0x9: /* sample offset */
						offset=(ev.dat2<<8)|((ev.eff&0xf)==9?ev.dat1:0);
						UniEffect(UNI_ULTEFFECT9,offset);
						break;
					case 0xb: /* panning */
						UniPTEffect(8,ev.dat2*0xf);
						of.flags |= UF_PANNING;
						break;
					case 0xc: /* volume */
						UniPTEffect(eff,ev.dat2>>2);
						break;
					default:
						UniPTEffect(eff,ev.dat2);
						break;
				}

				/* second effect */
				eff=ev.eff&0xf;
				switch(eff) {
					case 0x3: /* tone portamento */
						UniEffect(UNI_ITEFFECTG,ev.dat1);
						continuePortaToNote = 1;
						break;
					case 0x5:
						break;
					case 0x9: /* sample offset */
						if((ev.eff>>4)!=9)
							UniEffect(UNI_ULTEFFECT9,((UWORD)ev.dat1)<<8);
						break;
					case 0xb: /* panning */
						UniPTEffect(8,ev.dat1*0xf);
						of.flags |= UF_PANNING;
						break;
					case 0xc: /* volume */
						UniPTEffect(eff,ev.dat1>>2);
						break;
					default:
						UniPTEffect(eff,ev.dat1);
						break;
				}

				UniNewline();
				row++;
			}
		}
		if(!(of.tracks[t]=UniDup())) return 0;
	}
	return 1;
}

static CHAR * ULT_LoadTitle(void)
{
	CHAR s[32];

	_mm_fseek(modreader,15,SEEK_SET);
	if(!_mm_read_UBYTES(s,32,modreader)) return NULL;

	return(DupStr(s,32,1));
}

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

MIKMODAPI MLOADER load_ult={
	NULL,
	"ULT",
	"ULT (UltraTracker)",
	ULT_Init,
	ULT_Test,
	ULT_Load,
	ULT_Cleanup,
	ULT_LoadTitle
};

/* ex:set ts=4: */