/*	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.
*/

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

  $Id$

  Impulse tracker (IT) 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"
#include "mikmod_ctype.h"

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

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

/* header */
typedef struct ITHEADER {
	CHAR	songname[26];
	UBYTE	blank01[2];
	UWORD	ordnum;
	UWORD	insnum;
	UWORD	smpnum;
	UWORD	patnum;
	UWORD	cwt;		/* Created with tracker (y.xx = 0x0yxx) */
	UWORD	cmwt;		/* Compatible with tracker ver > than val. */
	UWORD	flags;
	UWORD	special;	/* bit 0 set = song message attached */
	UBYTE	globvol;
	UBYTE	mixvol;		/* mixing volume [ignored] */
	UBYTE	initspeed;
	UBYTE	inittempo;
	UBYTE	pansep;		/* panning separation between channels */
	UBYTE	zerobyte;
	UWORD	msglength;
	ULONG	msgoffset;
	UBYTE	blank02[4];
	UBYTE	pantable[64];
	UBYTE	voltable[64];
} ITHEADER;

/* sample information */
typedef struct ITSAMPLE {
	UBYTE	id[4];		/* 'IMPS' */
	CHAR	filename[12];
	UBYTE	zerobyte;
	UBYTE	globvol;
	UBYTE	flag;
	UBYTE	volume;
	UBYTE	panning;
	CHAR	sampname[28];
	UWORD	convert;	/* sample conversion flag */
	ULONG	length;
	ULONG	loopbeg;
	ULONG	loopend;
	ULONG	c5spd;
	ULONG	susbegin;
	ULONG	susend;
	ULONG	sampoffset;
	UBYTE	vibspeed;
	UBYTE	vibdepth;
	UBYTE	vibrate;
	UBYTE	vibwave;	/* 0=sine, 1=rampdown, 2=square, 3=random (speed ignored) */
} ITSAMPLE;

/* instrument information */

#define ITENVCNT 25
#define ITNOTECNT 120
typedef struct ITINSTHEADER {
	UBYTE	id[4];			/* 'IMPI' */
	ULONG	size;			/* (dword) Instrument size */
	CHAR	filename[12];	/* (char) Instrument filename */
	UBYTE	zerobyte;		/* (byte) Instrument type (always 0) */
	UBYTE	volflg;
	UBYTE	volpts;
	UBYTE	volbeg;			/* (byte) Volume loop start (node) */
	UBYTE	volend;			/* (byte) Volume loop end (node) */
	UBYTE	volsusbeg;		/* (byte) Volume sustain begin (node) */
	UBYTE	volsusend;		/* (byte) Volume Sustain end (node) */
	UBYTE	panflg;
	UBYTE	panpts;
	UBYTE	panbeg;			/* (byte) channel loop start (node) */
	UBYTE	panend;			/* (byte) channel loop end (node) */
	UBYTE	pansusbeg;		/* (byte) channel sustain begin (node) */
	UBYTE	pansusend;		/* (byte) channel Sustain end (node) */
	UBYTE	pitflg;
	UBYTE	pitpts;
	UBYTE	pitbeg;			/* (byte) pitch loop start (node) */
	UBYTE	pitend;			/* (byte) pitch loop end (node) */
	UBYTE	pitsusbeg;		/* (byte) pitch sustain begin (node) */
	UBYTE	pitsusend;		/* (byte) pitch Sustain end (node) */
	UWORD	blank;
	UBYTE	globvol;
	UBYTE	chanpan;
	UWORD	fadeout;		/* Envelope end / NNA volume fadeout */
	UBYTE	dnc;			/* Duplicate note check */
	UBYTE	dca;			/* Duplicate check action */
	UBYTE	dct;			/* Duplicate check type */
	UBYTE	nna;			/* New Note Action [0,1,2,3] */
	UWORD	trkvers;		/* tracker version used to save [files only] */
	UBYTE	ppsep;			/* Pitch-pan Separation */
	UBYTE	ppcenter;		/* Pitch-pan Center */
	UBYTE	rvolvar;		/* random volume varations */
	UBYTE	rpanvar;		/* random panning varations */
	UWORD	numsmp;			/* Number of samples in instrument [files only] */
	CHAR	name[26];		/* Instrument name */
	UBYTE	blank01[6];
	UWORD	samptable[ITNOTECNT];/* sample for each note [note / samp pairs] */
	UBYTE	volenv[200];	     /* volume envelope (IT 1.x stuff) */
	UBYTE	oldvoltick[ITENVCNT];/* volume tick position (IT 1.x stuff) */
	UBYTE	volnode[ITENVCNT];   /* amplitude of volume nodes */
	UWORD	voltick[ITENVCNT];   /* tick value of volume nodes */
	SBYTE	pannode[ITENVCNT];   /* panenv - node points */
	UWORD	pantick[ITENVCNT];   /* tick value of panning nodes */
	SBYTE	pitnode[ITENVCNT];   /* pitchenv - node points */
	UWORD	pittick[ITENVCNT];   /* tick value of pitch nodes */
} ITINSTHEADER;

/* unpacked note */

typedef struct ITNOTE {
	UBYTE note,ins,volpan,cmd,inf;
} ITNOTE;

/*========== Loader data */

static ULONG *paraptr=NULL;	/* parapointer array (see IT docs) */
static ITHEADER *mh=NULL;
static ITNOTE *itpat=NULL;	/* allocate to space for one full pattern */
static UBYTE *mask=NULL;	/* arrays allocated to 64 elements and used for */
static ITNOTE *last=NULL;	/* uncompressing IT's pattern information */
static int numtrk=0;
static unsigned int old_effect;		/* if set, use S3M old-effects stuffs */

static const CHAR* IT_Version[]={
	"ImpulseTracker  .  ",
	"Compressed ImpulseTracker  .  ",
	"ImpulseTracker 2.14p3",
	"Compressed ImpulseTracker 2.14p3",
	"ImpulseTracker 2.14p4",
	"Compressed ImpulseTracker 2.14p4",
};

/* table for porta-to-note command within volume/panning column */
static const UBYTE portatable[10]= {0,1,4,8,16,32,64,96,128,255};

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

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

	if(!_mm_read_UBYTES(id,4,modreader)) return 0;
	if(!memcmp(id,"IMPM",4)) return 1;
	return 0;
}

static BOOL IT_Init(void)
{
	if(!(mh=(ITHEADER*)MikMod_malloc(sizeof(ITHEADER)))) return 0;
	if(!(poslookup=(UBYTE*)MikMod_malloc(256*sizeof(UBYTE)))) return 0;
	if(!(itpat=(ITNOTE*)MikMod_malloc(200*64*sizeof(ITNOTE)))) return 0;
	if(!(mask=(UBYTE*)MikMod_calloc(64,sizeof(UBYTE)))) return 0;
	if(!(last=(ITNOTE*)MikMod_calloc(64,sizeof(ITNOTE)))) return 0;

	return 1;
}

static void IT_Cleanup(void)
{
	FreeLinear();

	MikMod_free(mh);
	MikMod_free(poslookup);
	MikMod_free(itpat);
	MikMod_free(mask);
	MikMod_free(last);
	MikMod_free(paraptr);
	MikMod_free(origpositions);
	mh=NULL;
	poslookup=NULL;
	itpat=NULL;
	mask=NULL;
	last=NULL;
	paraptr=NULL;
	origpositions=NULL;
}

/* Because so many IT files have 64 channels as the set number used, but really
   only use far less (usually from 8 to 24 still), I had to make this function,
   which determines the number of channels that are actually USED by a pattern.

   NOTE: You must first seek to the file location of the pattern before calling
   this procedure.

   Returns 0 on error
*/
static BOOL IT_GetNumChannels(UWORD patrows)
{
	int row=0,flag,ch;

	do {
		if(_mm_eof(modreader)) {
			_mm_errno=MMERR_LOADING_PATTERN;
			return 0;
		}
		flag=_mm_read_UBYTE(modreader);
		if(!flag)
			row++;
		else {
			ch=(flag-1)&63;
			remap[ch]=0;
			if(flag & 128) mask[ch]=_mm_read_UBYTE(modreader);
			if(mask[ch]&1)   _mm_skip_BYTE(modreader);
			if(mask[ch]&2)   _mm_skip_BYTE(modreader);
			if(mask[ch]&4)   _mm_skip_BYTE(modreader);
			if(mask[ch]&8) { _mm_skip_BYTE(modreader);_mm_skip_BYTE(modreader); }
		}
	} while(row<patrows);

	return 1;
}

static UBYTE* IT_ConvertTrack(ITNOTE* tr,UWORD numrows)
{
	int t;
	UBYTE note,ins,volpan;

	UniReset();

	for(t=0;t<numrows;t++) {
		note=tr[t*of.numchn].note;
		ins=tr[t*of.numchn].ins;
		volpan=tr[t*of.numchn].volpan;

		if(note!=255) {
			if(note==253)
				UniWriteByte(UNI_KEYOFF);
			else if(note==254) {
				UniPTEffect(0xc,-1);	/* note cut command */
				volpan=255;
			} else
				UniNote(note);
		}

		/* Impulse Tracker only allows up to 99 instruments and crashes when it
		   encounters instruments >=100. But the file format supports them just
		   fine and there are many MPT-created ITs with that many instruments. */
		if((ins)&&(ins<253))
			UniInstrument(ins-1);
		else if(ins==253)
			UniWriteByte(UNI_KEYOFF);
		else if(ins!=255) { /* crap */
			_mm_errno=MMERR_LOADING_PATTERN;
			return NULL;
		}

		/* process volume / panning column
		   volume / panning effects do NOT all share the same memory address
		   yet. */
		if(volpan<=64)
			UniVolEffect(VOL_VOLUME,volpan);
		else if(volpan==65) /* fine volume slide up (65-74) - A0 case */
			UniVolEffect(VOL_VOLSLIDE,0);
		else if(volpan<=74)	{ /* fine volume slide up (65-74) - general case */
			UniVolEffect(VOL_VOLSLIDE,0x0f+((volpan-65)<<4));
		} else if(volpan==75)	/* fine volume slide down (75-84) - B0 case */
			UniVolEffect(VOL_VOLSLIDE,0);
		else if(volpan<=84) {	/* fine volume slide down (75-84) - general case*/
			UniVolEffect(VOL_VOLSLIDE,0xf0+(volpan-75));
		} else if(volpan<=94)	/* volume slide up (85-94) */
			UniVolEffect(VOL_VOLSLIDE,((volpan-85)<<4));
		else if(volpan<=104)/* volume slide down (95-104) */
			UniVolEffect(VOL_VOLSLIDE,(volpan-95));
		else if(volpan<=114)/* pitch slide down (105-114) */
			UniVolEffect(VOL_PITCHSLIDEDN,(volpan-105));
		else if(volpan<=124)/* pitch slide up (115-124) */
			UniVolEffect(VOL_PITCHSLIDEUP,(volpan-115));
		else if(volpan<=127) { /* crap */
			_mm_errno=MMERR_LOADING_PATTERN;
			return NULL;
		} else if(volpan<=192)
			UniVolEffect(VOL_PANNING,((volpan-128)==64)?255:((volpan-128)<<2));
		else if(volpan<=202)/* portamento to note */
			UniVolEffect(VOL_PORTAMENTO,portatable[volpan-193]);
		else if(volpan<=212)/* vibrato */
			UniVolEffect(VOL_VIBRATO,(volpan-203));
		else if((volpan!=239)&&(volpan!=255)) { /* crap */
			_mm_errno=MMERR_LOADING_PATTERN;
			return NULL;
		}

		S3MIT_ProcessCmd(tr[t*of.numchn].cmd,tr[t*of.numchn].inf,
		    old_effect|S3MIT_IT);

		UniNewline();
	}
	return UniDup();
}

static BOOL IT_ReadPattern(UWORD patrows)
{
	int row=0,flag,ch;
	unsigned int blah;
	ITNOTE *itt=itpat,dummy,*n,*l;
	ITNOTE *ite=&itpat[200*64 -1];
	UBYTE *m;

	memset(itt,255,200*64*sizeof(ITNOTE));

	do {
		if(_mm_eof(modreader)) {
			_mm_errno = MMERR_LOADING_PATTERN;
			return 0;
		}
		flag=_mm_read_UBYTE(modreader);
		if(!flag) {
			itt=&itt[of.numchn];
			row++;
		} else {
			ch=remap[(flag-1)&63];
			if(ch!=-1) {
				n=&itt[ch];
				l=&last[ch];
				m=&mask[ch];
				if(n > ite) { /* malformed file */
					_mm_errno = MMERR_NOT_A_MODULE;
					return 0;
				}
			} else
			{
				n=l=&dummy;
				blah = 0;
				m=(UBYTE*)&blah;
			}

			if(flag&128) *m=_mm_read_UBYTE(modreader);
			if(*m&1)
				/* convert IT note off to internal note off */
				if((l->note=n->note=_mm_read_UBYTE(modreader))==255)
					l->note=n->note=253;
			if(*m&2)
				l->ins=n->ins=_mm_read_UBYTE(modreader);
			if(*m&4)
				l->volpan=n->volpan=_mm_read_UBYTE(modreader);
			if(*m&8) {
				l->cmd=n->cmd=_mm_read_UBYTE(modreader);
				l->inf=n->inf=_mm_read_UBYTE(modreader);
			}
			if(*m&16)
				n->note=l->note;
			if(*m&32)
				n->ins=l->ins;
			if(*m&64)
				n->volpan=l->volpan;
			if(*m&128) {
				n->cmd=l->cmd;
				n->inf=l->inf;
			}
		}
	} while(row<patrows);

	for(blah=0;blah<of.numchn;blah++) {
		if(!(of.tracks[numtrk++]=IT_ConvertTrack(&itpat[blah],patrows)))
			return 0;
	}

	return 1;
}

static void LoadMidiString(MREADER* r,CHAR* dest)
{
	CHAR *curp,*lastp;

	memset(dest,0,33*sizeof(CHAR));/* caller sends midiline[33] */
	_mm_read_UBYTES(dest,32,r);
	curp=lastp=dest;
	/* remove blanks and uppercase all */
	while(*lastp) {
		if(mik_isalnum((int)*lastp)) *(curp++)=mik_toupper((int)*lastp);
		lastp++;
	}
	*curp=0;
}

/* Load embedded midi information for resonant filters */
static void IT_LoadMidiConfiguration(MREADER* r)
{
	int i;

	memset(filtermacros,0,sizeof(filtermacros));
	memset(filtersettings,0,sizeof(filtersettings));

	if (r) { /* information is embedded in file */
		UWORD dat;
		CHAR midiline[33];

		dat=_mm_read_I_UWORD(r);
		_mm_fseek(r,8*dat+0x120,SEEK_CUR);

		/* read midi macros */
		for(i=0;i<UF_MAXMACRO;i++) {
			LoadMidiString(r,midiline);
			if((!strncmp(midiline,"F0F00",5))&&
			   ((midiline[5]=='0')||(midiline[5]=='1')))
					filtermacros[i]=(midiline[5]-'0')|0x80;
		}

		/* read standalone filters */
		for(i=0x80;i<0x100;i++) {
			LoadMidiString(r,midiline);
			if((!strncmp(midiline,"F0F00",5))&&
			   ((midiline[5]=='0')||(midiline[5]=='1'))) {
				filtersettings[i].filter=(midiline[5]-'0')|0x80;
				dat=(midiline[6])?(midiline[6]-'0'):0;
				if(midiline[7])dat=(dat<<4)|(midiline[7]-'0');
				filtersettings[i].inf=dat;
			}
		}
	} else { /* use default information */
		filtermacros[0]=FILT_CUT;
		for(i=0x80;i<0x90;i++) {
			filtersettings[i].filter=FILT_RESONANT;
			filtersettings[i].inf=(i&0x7f)<<3;
		}
	}
	activemacro=0;
	for(i=0;i<0x80;i++) {
		filtersettings[i].filter=filtermacros[0];
		filtersettings[i].inf=i;
	}
}

static BOOL IT_Load(BOOL curious)
{
	int t,u,lp;
	INSTRUMENT *d;
	SAMPLE *q;
	/*BOOL compressed=0;*/

	numtrk=0;
	filters=0;

	/* try to read module header */
	_mm_read_I_ULONG(modreader);	/* kill the 4 byte header */
	_mm_read_string(mh->songname,26,modreader);
	_mm_read_UBYTES(mh->blank01,2,modreader);
	mh->ordnum      =_mm_read_I_UWORD(modreader);
	mh->insnum      =_mm_read_I_UWORD(modreader);
	mh->smpnum      =_mm_read_I_UWORD(modreader);
	mh->patnum      =_mm_read_I_UWORD(modreader);
	mh->cwt         =_mm_read_I_UWORD(modreader);
	mh->cmwt        =_mm_read_I_UWORD(modreader);
	mh->flags       =_mm_read_I_UWORD(modreader);
	mh->special     =_mm_read_I_UWORD(modreader);
	mh->globvol     =_mm_read_UBYTE(modreader);
	mh->mixvol      =_mm_read_UBYTE(modreader);
	mh->initspeed   =_mm_read_UBYTE(modreader);
	mh->inittempo   =_mm_read_UBYTE(modreader);
	mh->pansep      =_mm_read_UBYTE(modreader);
	mh->zerobyte    =_mm_read_UBYTE(modreader);
	mh->msglength   =_mm_read_I_UWORD(modreader);
	mh->msgoffset   =_mm_read_I_ULONG(modreader);
	_mm_read_UBYTES(mh->blank02,4,modreader);
	_mm_read_UBYTES(mh->pantable,64,modreader);
	_mm_read_UBYTES(mh->voltable,64,modreader);

	if(_mm_eof(modreader)) {
		_mm_errno=MMERR_LOADING_HEADER;
		return 0;
	}
	if(mh->ordnum > 256 || mh->insnum > 255 || mh->smpnum > 255 || mh->patnum > 255) {
		_mm_errno=MMERR_NOT_A_MODULE;
		return 0;
	}

	/* set module variables */
	of.songname    = DupStr(mh->songname,26,0); /* make a cstr of songname  */
	of.reppos      = 0;
	of.numpat      = mh->patnum;
	of.numins      = mh->insnum;
	of.numsmp      = mh->smpnum;
	of.initspeed   = mh->initspeed;
	of.inittempo   = mh->inittempo;
	of.initvolume  = mh->globvol;
	of.flags      |= UF_BGSLIDES | UF_ARPMEM;
	if (!(mh->flags & 1))
			of.flags |= UF_PANNING;
	of.bpmlimit=32;

	if(mh->songname[25]) {
		of.numvoices=1+mh->songname[25];
#ifdef MIKMOD_DEBUG
		fprintf(stderr,"Embedded IT limitation to %d voices\n",of.numvoices);
#endif
	}

	/* set the module type */
	/* 2.17 : IT 2.14p4 */
	/* 2.16 : IT 2.14p3 with resonant filters */
	/* 2.15 : IT 2.14p3 (improved compression) */
	if((mh->cwt<=0x219)&&(mh->cwt>=0x217))
		of.modtype=MikMod_strdup(IT_Version[mh->cmwt<0x214?4:5]);
	else if (mh->cwt>=0x215)
		of.modtype=MikMod_strdup(IT_Version[mh->cmwt<0x214?2:3]);
	else {
		of.modtype = MikMod_strdup(IT_Version[mh->cmwt<0x214?0:1]);
		of.modtype[mh->cmwt<0x214?15:26] = (mh->cwt>>8)+'0';
		of.modtype[mh->cmwt<0x214?17:28] = ((mh->cwt>>4)&0xf)+'0';
		of.modtype[mh->cmwt<0x214?18:29] = ((mh->cwt)&0xf)+'0';
	}

	if(mh->flags&8)
		of.flags |= UF_XMPERIODS | UF_LINEAR;

	if((mh->cwt>=0x106)&&(mh->flags&16))
		old_effect=S3MIT_OLDSTYLE;
	else
		old_effect=0;

	/* set panning positions */
	if (mh->flags & 1)
		for(t=0;t<64;t++) {
			mh->pantable[t]&=0x7f;
			if(mh->pantable[t]<64)
				of.panning[t]=mh->pantable[t]<<2;
			else if(mh->pantable[t]==64)
				of.panning[t]=255;
			else if(mh->pantable[t]==100)
				of.panning[t]=PAN_SURROUND;
			else if(mh->pantable[t]==127)
				of.panning[t]=PAN_CENTER;
			else {
				_mm_errno=MMERR_LOADING_HEADER;
				return 0;
			}
		}
	else
		for(t=0;t<64;t++)
			of.panning[t]=PAN_CENTER;

	/* set channel volumes */
	memcpy(of.chanvol,mh->voltable,64);

	/* read the order data */
	if(!AllocPositions(mh->ordnum)) return 0;
	if(!(origpositions=(UWORD*)MikMod_calloc(mh->ordnum,sizeof(UWORD)))) return 0;

	for(t=0;t<mh->ordnum;t++) {
		origpositions[t]=_mm_read_UBYTE(modreader);
		if((origpositions[t]>mh->patnum)&&(origpositions[t]<254))
			origpositions[t]=255;
	}

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

	poslookupcnt=mh->ordnum;
	S3MIT_CreateOrders(curious);

	if(!(paraptr=(ULONG*)MikMod_malloc((mh->insnum+mh->smpnum+of.numpat)*
	                               sizeof(ULONG)))) return 0;

	/* read the instrument, sample, and pattern parapointers */
	_mm_read_I_ULONGS(paraptr,mh->insnum+mh->smpnum+of.numpat,modreader);

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

	/* Check for and load midi information for resonant filters */
	if(mh->cmwt>=0x216) {
		if(mh->special&8) {
			IT_LoadMidiConfiguration(modreader);
			if(_mm_eof(modreader)) {
				_mm_errno = MMERR_LOADING_HEADER;
				return 0;
			}
		} else
			IT_LoadMidiConfiguration(NULL);
		filters=1;
	}

	/* Check for and load song comment */
	if((mh->special&1)&&(mh->cwt>=0x104)&&(mh->msglength)) {
		_mm_fseek(modreader,(long)(mh->msgoffset),SEEK_SET);
		if(!ReadComment(mh->msglength)) return 0;
	}

	if(!(mh->flags&4)) of.numins=of.numsmp;
	if(!AllocSamples()) return 0;

	if(!AllocLinear()) return 0;

	/* Load all samples */
	q = of.samples;
	for(t=0;t<mh->smpnum;t++) {
		ITSAMPLE s;

		/* seek to sample position */
		_mm_fseek(modreader,(long)(paraptr[mh->insnum+t]),SEEK_SET);
		if(!_mm_read_UBYTES(s.id,4,modreader)||
		   memcmp(s.id,"IMPS",4) != 0) {
			/* no error so that use-brdg.it and use-funk.it
			 * to load correctly (both IT 2.04) (from libxmp) */
#ifdef MIKMOD_DEBUG
			fprintf(stderr,"Bad magic in sample %d\n",t);
#endif
			continue;
		}

		/* load sample info */
		_mm_read_string(s.filename,12,modreader);
		s.zerobyte    = _mm_read_UBYTE(modreader);
		s.globvol     = _mm_read_UBYTE(modreader);
		s.flag        = _mm_read_UBYTE(modreader);
		s.volume      = _mm_read_UBYTE(modreader);
		_mm_read_string(s.sampname,26,modreader);
		s.convert     = _mm_read_UBYTE(modreader);
		s.panning     = _mm_read_UBYTE(modreader);
		s.length      = _mm_read_I_ULONG(modreader);
		s.loopbeg     = _mm_read_I_ULONG(modreader);
		s.loopend     = _mm_read_I_ULONG(modreader);
		s.c5spd       = _mm_read_I_ULONG(modreader);
		s.susbegin    = _mm_read_I_ULONG(modreader);
		s.susend      = _mm_read_I_ULONG(modreader);
		s.sampoffset  = _mm_read_I_ULONG(modreader);
		s.vibspeed    = _mm_read_UBYTE(modreader);
		s.vibdepth    = _mm_read_UBYTE(modreader);
		s.vibrate     = _mm_read_UBYTE(modreader);
		s.vibwave     = _mm_read_UBYTE(modreader);

		/* Generate an error if c5spd is > 512k, or samplelength > 256 megs
		   (nothing would EVER be that high) */

		if(_mm_eof(modreader)||(s.c5spd>0x7ffffL)||(s.length>0xfffffffUL)) {
			_mm_errno = MMERR_LOADING_SAMPLEINFO;
			return 0;
		}

		/* Reality check for sample loop information */
		if((s.flag&16)&&
		   ((s.loopbeg>0xfffffffUL)||(s.loopend>0xfffffffUL))) {
			_mm_errno = MMERR_LOADING_SAMPLEINFO;
			return 0;
		}

		q->samplename = DupStr(s.sampname,26,0);
		q->speed      = s.c5spd / 2;
		q->panning    = ((s.panning&127)==64)?255:(s.panning&127)<<2;
		q->length     = s.length;
		q->loopstart  = s.loopbeg;
		q->loopend    = s.loopend;
		q->volume     = s.volume;
		q->globvol    = s.globvol;
		q->seekpos    = s.sampoffset;

		/* Convert speed to XM linear finetune */
		if(of.flags&UF_LINEAR)
			q->speed=speed_to_finetune(s.c5spd,t);

		if(s.panning&128) q->flags|=SF_OWNPAN;

		if(s.vibrate) {
			q->vibflags |= AV_IT;
			q->vibtype   = s.vibwave;
			q->vibsweep  = s.vibrate * 2;
			q->vibdepth  = s.vibdepth;
			q->vibrate   = s.vibspeed;
		}

		if(s.flag&2) q->flags|=SF_16BITS;
		if((s.flag&8)&&(mh->cwt>=0x214)) {
			q->flags|=SF_ITPACKED;
			/*compressed=1;*/
		}
		if(s.flag&16) q->flags|=SF_LOOP;
		if(s.flag&64) q->flags|=SF_BIDI;

		if(s.convert==0xff) q->flags|=SF_ADPCM4|SF_SIGNED; /* MODPlugin ADPCM */
		else if(mh->cwt>=0x200) {
			if(s.convert&1) q->flags|=SF_SIGNED;
			if(s.convert&4) q->flags|=SF_DELTA;
		}
		q++;
	}

	/* Load instruments if instrument mode flag enabled */
	if(mh->flags&4) {
		if(!AllocInstruments()) return 0;
		d=of.instruments;
		of.flags|=UF_NNA|UF_INST;

		for(t=0;t<mh->insnum;t++) {
			ITINSTHEADER ih;

			/* seek to instrument position */
			_mm_fseek(modreader,paraptr[t],SEEK_SET);
			if(!_mm_read_UBYTES(ih.id,4,modreader)||
			   memcmp(ih.id,"IMPI",4) != 0) {
				_mm_errno = MMERR_LOADING_SAMPLEINFO;
				return 0;
			}

			/* load instrument info */
			_mm_read_string(ih.filename,12,modreader);
			ih.zerobyte  = _mm_read_UBYTE(modreader);
			if(mh->cwt<0x200) {
				/* load IT 1.xx inst header */
				ih.volflg    = _mm_read_UBYTE(modreader);
				ih.volbeg    = _mm_read_UBYTE(modreader);
				ih.volend    = _mm_read_UBYTE(modreader);
				ih.volsusbeg = _mm_read_UBYTE(modreader);
				ih.volsusend = _mm_read_UBYTE(modreader);
				_mm_read_I_UWORD(modreader);
				ih.fadeout   = _mm_read_I_UWORD(modreader);
				ih.nna       = _mm_read_UBYTE(modreader);
				ih.dnc       = _mm_read_UBYTE(modreader);
			} else {
				/* Read IT200+ header */
				ih.nna       = _mm_read_UBYTE(modreader);
				ih.dct       = _mm_read_UBYTE(modreader);
				ih.dca       = _mm_read_UBYTE(modreader);
				ih.fadeout   = _mm_read_I_UWORD(modreader);
				ih.ppsep     = _mm_read_UBYTE(modreader);
				ih.ppcenter  = _mm_read_UBYTE(modreader);
				ih.globvol   = _mm_read_UBYTE(modreader);
				ih.chanpan   = _mm_read_UBYTE(modreader);
				ih.rvolvar   = _mm_read_UBYTE(modreader);
				ih.rpanvar   = _mm_read_UBYTE(modreader);
			}

			ih.trkvers   = _mm_read_I_UWORD(modreader);
			ih.numsmp    = _mm_read_UBYTE(modreader);
			_mm_skip_BYTE(modreader);
			_mm_read_string(ih.name,26,modreader);
			_mm_read_UBYTES(ih.blank01,6,modreader);
			_mm_read_I_UWORDS(ih.samptable,ITNOTECNT,modreader);
			if(mh->cwt<0x200) {
				/* load IT 1xx volume envelope */
				_mm_read_UBYTES(ih.volenv,200,modreader);
				for(lp=0;lp<ITENVCNT;lp++) {
					ih.oldvoltick[lp] = _mm_read_UBYTE(modreader);
					ih.volnode[lp]    = _mm_read_UBYTE(modreader);
				}
			} else {
				/* load IT 2xx volume, pan and pitch envelopes */
#if defined __STDC__ || defined _MSC_VER || defined __WATCOMC__ || defined MPW_C
#define IT_LoadEnvelope(name,type) 										\
				ih. name##flg   =_mm_read_UBYTE(modreader);				\
				ih. name##pts   =_mm_read_UBYTE(modreader);				\
				if (ih. name##pts > ITENVCNT)							\
					ih. name##pts = ITENVCNT;							\
				ih. name##beg   =_mm_read_UBYTE(modreader);				\
				ih. name##end   =_mm_read_UBYTE(modreader);				\
				ih. name##susbeg=_mm_read_UBYTE(modreader);				\
				ih. name##susend=_mm_read_UBYTE(modreader);				\
				for(lp=0;lp<ITENVCNT;lp++) {							\
					ih. name##node[lp]=_mm_read_##type (modreader);		\
					ih. name##tick[lp]=_mm_read_I_UWORD(modreader);		\
				}														\
				_mm_skip_BYTE(modreader)
#else
#define IT_LoadEnvelope(name,type) 										\
				ih. name/**/flg   =_mm_read_UBYTE(modreader);			\
				ih. name/**/pts   =_mm_read_UBYTE(modreader);			\
				if (ih. name/**/pts > ITENVCNT)							\
					ih. name/**/pts = ITENVCNT;							\
				ih. name/**/beg   =_mm_read_UBYTE(modreader);			\
				ih. name/**/end   =_mm_read_UBYTE(modreader);			\
				ih. name/**/susbeg=_mm_read_UBYTE(modreader);			\
				ih. name/**/susend=_mm_read_UBYTE(modreader);			\
				for(lp=0;lp<ITENVCNT;lp++) {							\
					ih. name/**/node[lp]=_mm_read_/**/type (modreader);	\
					ih. name/**/tick[lp]=_mm_read_I_UWORD(modreader);	\
				}														\
				_mm_skip_BYTE(modreader)
#endif

				IT_LoadEnvelope(vol,UBYTE);
				IT_LoadEnvelope(pan,SBYTE);
				IT_LoadEnvelope(pit,SBYTE);
#undef IT_LoadEnvelope
			}

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

			d->volflg|=EF_VOLENV;
			d->insname = DupStr(ih.name,26,0);
			d->nnatype = ih.nna & NNA_MASK;

			if(mh->cwt<0x200) {
				d->volfade=ih.fadeout<< 6;
				if(ih.dnc) {
					d->dct=DCT_NOTE;
					d->dca=DCA_CUT;
				}

				if(ih.volflg&1) d->volflg|=EF_ON;
				if(ih.volflg&2) d->volflg|=EF_LOOP;
				if(ih.volflg&4) d->volflg|=EF_SUSTAIN;

				/* XM conversion of IT envelope Array */
				d->volbeg    = ih.volbeg;
				d->volend    = ih.volend;
				d->volsusbeg = ih.volsusbeg;
				d->volsusend = ih.volsusend;

				if(ih.volflg&1) {
					for(u=0;u<ITENVCNT;u++)
						if(ih.oldvoltick[d->volpts]!=0xff) {
							d->volenv[d->volpts].val=(ih.volnode[d->volpts]<<2);
							d->volenv[d->volpts].pos=ih.oldvoltick[d->volpts];
							d->volpts++;
						} else
							break;
				}
			} else {
				d->panning=((ih.chanpan&127)==64)?255:(ih.chanpan&127)<<2;
				if(!(ih.chanpan&128)) d->flags|=IF_OWNPAN;

				if(!(ih.ppsep & 128)) {
					d->pitpansep=ih.ppsep<<2;
					d->pitpancenter=ih.ppcenter;
					d->flags|=IF_PITCHPAN;
				}
				d->globvol=ih.globvol>>1;
				d->volfade=ih.fadeout<<5;
				d->dct    =ih.dct;
				d->dca    =ih.dca;

				if(mh->cwt>=0x204) {
					d->rvolvar = ih.rvolvar;
					d->rpanvar = ih.rpanvar;
				}

#if defined __STDC__ || defined _MSC_VER || defined __WATCOMC__ || defined MPW_C
#define IT_ProcessEnvelope(name) 										\
				if(ih. name##flg&1) d-> name##flg|=EF_ON;				\
				if(ih. name##flg&2) d-> name##flg|=EF_LOOP;				\
				if(ih. name##flg&4) d-> name##flg|=EF_SUSTAIN;			\
				d-> name##pts=ih. name##pts;							\
				d-> name##beg=ih. name##beg;							\
				d-> name##end=ih. name##end;							\
				d-> name##susbeg=ih. name##susbeg;						\
				d-> name##susend=ih. name##susend;						\
																		\
				for(u=0;u<ih. name##pts;u++)							\
					d-> name##env[u].pos=ih. name##tick[u];				\
																		\
				if((d-> name##flg&EF_ON)&&(d-> name##pts<2))			\
					d-> name##flg&=~EF_ON
#else
#define IT_ProcessEnvelope(name) 									\
				if(ih. name/**/flg&1) d-> name/**/flg|=EF_ON;		\
				if(ih. name/**/flg&2) d-> name/**/flg|=EF_LOOP;		\
				if(ih. name/**/flg&4) d-> name/**/flg|=EF_SUSTAIN;	\
				d-> name/**/pts=ih. name/**/pts;					\
				d-> name/**/beg=ih. name/**/beg;					\
				d-> name/**/end=ih. name/**/end;					\
				d-> name/**/susbeg=ih. name/**/susbeg;				\
				d-> name/**/susend=ih. name/**/susend;				\
																	\
				for(u=0;u<ih. name/**/pts;u++)						\
					d-> name/**/env[u].pos=ih. name/**/tick[u];		\
																	\
				if((d-> name/**/flg&EF_ON)&&(d-> name/**/pts<2))	\
					d-> name/**/flg&=~EF_ON
#endif

				IT_ProcessEnvelope(vol);

				for(u=0;u<ih.volpts;u++)
					d->volenv[u].val=(ih.volnode[u]<<2);

				IT_ProcessEnvelope(pan);
				for(u=0;u<ih.panpts;u++)
					d->panenv[u].val=
					  ih.pannode[u]==32?255:(ih.pannode[u]+32)<<2;

				IT_ProcessEnvelope(pit);
				for(u=0;u<ih.pitpts;u++)
					d->pitenv[u].val=ih.pitnode[u]+32;
#undef IT_ProcessEnvelope

				if(ih.pitflg&0x80) {
					/* filter envelopes not supported yet */
					d->pitflg&=~EF_ON;
					ih.pitpts=ih.pitbeg=ih.pitend=0;
#ifdef MIKMOD_DEBUG
					{
						static int warn=0;

						if(!warn)
							fprintf(stderr, "\rFilter envelopes not supported yet\n");
						warn=1;
					}
#endif
				}
			}

			for(u=0;u<ITNOTECNT;u++) {
				d->samplenote[u]=(ih.samptable[u]&255);
				d->samplenumber[u]=
				  (ih.samptable[u]>>8)?((ih.samptable[u]>>8)-1):0xffff;
				if(d->samplenumber[u]>=of.numsmp)
					d->samplenote[u]=255;
				else if (of.flags&UF_LINEAR) {
					int note=(int)d->samplenote[u]+noteindex[d->samplenumber[u]];
					d->samplenote[u]=(note<0)?0:(note>255?255:note);
				}
			}

			d++;
		}
	} else if(of.flags & UF_LINEAR) {
		if(!AllocInstruments()) return 0;
		d=of.instruments;
		of.flags|=UF_INST;

		for(t=0;t<mh->smpnum;t++,d++)
			for(u=0;u<ITNOTECNT;u++) {
				if(d->samplenumber[u]>=of.numsmp)
					d->samplenote[u]=255;
				else {
					int note=(int)d->samplenote[u]+noteindex[d->samplenumber[u]];
					d->samplenote[u]=(note<0)?0:(note>255?255:note);
				}
			}
	}

	/* Figure out how many channels this song actually uses */
	of.numchn=0;
	memset(remap,-1,UF_MAXCHAN*sizeof(UBYTE));
	for(t=0;t<of.numpat;t++) {
		UWORD packlen;

		/* seek to pattern position */
		if(paraptr[mh->insnum+mh->smpnum+t]) { /* 0 -> empty 64 row pattern */
			_mm_fseek(modreader,((long)paraptr[mh->insnum+mh->smpnum+t]),SEEK_SET);
			_mm_read_I_UWORD(modreader);
			/* read pattern length (# of rows)
			   Impulse Tracker never creates patterns with less than 32 rows,
			   but some other trackers do, so we only check for more than 256
			   rows */
			packlen=_mm_read_I_UWORD(modreader);
			if(packlen>256) {
				_mm_errno=MMERR_LOADING_PATTERN;
				return 0;
			}
			_mm_read_I_ULONG(modreader);
			if(!IT_GetNumChannels(packlen)) return 0;
		}
	}

	/* give each of them a different number */
	for(t=0;t<UF_MAXCHAN;t++)
		if(!remap[t])
			remap[t]=of.numchn++;

	of.numtrk = of.numpat*of.numchn;
	if(of.numvoices)
		if (of.numvoices<of.numchn) of.numvoices=of.numchn;

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

	for(t=0;t<of.numpat;t++) {
		/* seek to pattern position */
		if(!paraptr[mh->insnum+mh->smpnum+t]) { /* 0 -> empty 64 row pattern */
			of.pattrows[t]=64;
			for(u=0;u<of.numchn;u++) {
				int k;

				UniReset();
				for(k=0;k<64;k++) UniNewline();
				of.tracks[numtrk++]=UniDup();
			}
		} else {
			_mm_fseek(modreader,((long)paraptr[mh->insnum+mh->smpnum+t]),SEEK_SET);
			(void) _mm_read_I_UWORD(modreader);			/* packlen */
			of.pattrows[t]=_mm_read_I_UWORD(modreader);
			_mm_read_I_ULONG(modreader);
			if(!IT_ReadPattern(of.pattrows[t])) return 0;
		}
	}

	return 1;
}

static CHAR *IT_LoadTitle(void)
{
	CHAR s[26];

	_mm_fseek(modreader,4,SEEK_SET);
	if(!_mm_read_UBYTES(s,26,modreader)) return NULL;

	return(DupStr(s,26,0));
}

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

MIKMODAPI MLOADER load_it={
	NULL,
	"IT",
	"IT (Impulse Tracker)",
	IT_Init,
	IT_Test,
	IT_Load,
	IT_Cleanup,
	IT_LoadTitle
};

/* ex:set ts=4: */
