/*

 Name: LOAD_DSM.C

 Description:
 DSIK Internal Format (DSM) module loader

 Portability:
 All systems - all compilers (hopefully)

 If this module is found to not be portable to any particular platform,
 please contact Jake Stine at dracoirs@epix.net (see MIKMOD.TXT for
 more information on contacting the author).
*/

#include <string.h>
#include "mikmod.h"


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


typedef struct DSMINST
{   CHAR  filename[13];
    UWORD flags;
    UBYTE volume;
    ULONG length;
    ULONG loopstart;
    ULONG loopend;
    ULONG reserved1;
    UWORD c2spd;
    UWORD reserved2;
    CHAR  samplename[28];
} DSMINST;


typedef struct DSMSONG
{  CHAR  songname[28];
   UWORD reserved1;
   UWORD flags;
   ULONG reserved2;
   UWORD numord;
   UWORD numsmp;
   UWORD numpat;
   UWORD numtrk;
   UBYTE globalvol;
   UBYTE mastervol;
   UBYTE speed;
   UBYTE bpm;
   UBYTE panpos[16];
   UBYTE orders[128];
} DSMSONG;



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";


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

    if(_mm_read_UBYTES((UBYTE *)id,12,modfp)) return 0;
    if(!memcmp(id,"RIFF",4) && !memcmp(&id[8],"DSMF",4)) return 1;
    
    return 0;
}


BOOL DSM_Init(void)
{
    if(!(dsmbuf=(DSMNOTE *)_mm_malloc(16*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;
}


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(modfp, blocklp+blockln, SEEK_SET);
   
   while(1)
   {   _mm_read_UBYTES(blockid,4,modfp);
       blockln = _mm_read_I_ULONG(modfp);
       if(feof(modfp))
       {   _mm_errno = MMERR_LOADING_HEADER;
           return 0;
       }
       
       if(memcmp(blockid,SONGID,4) && memcmp(blockid,INSTID,4) && memcmp(blockid,PATTID,4))
       {   //printf("Skipping unknown block type %4.4s\n",&blockid);
           _mm_fseek(modfp, blockln, SEEK_CUR);
       } else break;
   }

   blocklp = _mm_ftell(modfp);
   return 1;
}


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

    // clear pattern data
    memset(dsmbuf,255,16*64*sizeof(DSMNOTE));
    _mm_read_UBYTE(modfp);
    _mm_read_UBYTE(modfp);

    while(row<64)
    {   flag = _mm_read_UBYTE(modfp);
        if(feof(modfp))
        {   _mm_errno = MMERR_LOADING_PATTERN;
            return 0;
        }

        if(flag)
        {   n = &dsmbuf[((flag&0xf)*64)+row];
            if(flag&0x80) n->note = _mm_read_UBYTE(modfp);
            if(flag&0x40) n->ins  = _mm_read_UBYTE(modfp);
            if(flag&0x20) n->vol  = _mm_read_UBYTE(modfp);
            if(flag&0x10)
            {   n->cmd = _mm_read_UBYTE(modfp);
                n->inf = _mm_read_UBYTE(modfp);
            }
        } else row++;
    }
    return 1;
}


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<=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(void)
{
       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,modfp);
       mh->reserved1   = _mm_read_I_UWORD(modfp);
       mh->flags       = _mm_read_I_UWORD(modfp);
       mh->reserved2   = _mm_read_I_ULONG(modfp);
       mh->numord      = _mm_read_I_UWORD(modfp);
       mh->numsmp      = _mm_read_I_UWORD(modfp);
       mh->numpat      = _mm_read_I_UWORD(modfp);
       mh->numtrk      = _mm_read_I_UWORD(modfp);
       mh->globalvol   = _mm_read_UBYTE(modfp);
       mh->mastervol   = _mm_read_UBYTE(modfp);
       mh->speed       = _mm_read_UBYTE(modfp);
       mh->bpm         = _mm_read_UBYTE(modfp);
       _mm_read_UBYTES(mh->panpos,16,modfp);
       _mm_read_UBYTES(mh->orders,128,modfp);

       // 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);    // make a cstr of songname

       for(t=0; t<16; t++)
          of.panning[t] = 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,modfp);
               s.flags     = _mm_read_I_UWORD(modfp);
               s.volume    = _mm_read_UBYTE(modfp);
               s.length    = _mm_read_I_ULONG(modfp);
               s.loopstart = _mm_read_I_ULONG(modfp);
               s.loopend   = _mm_read_I_ULONG(modfp);
               s.reserved1 = _mm_read_I_ULONG(modfp);
               s.c2spd     = _mm_read_I_UWORD(modfp);
               s.reserved2 = _mm_read_I_UWORD(modfp);
               _mm_read_UBYTES(s.samplename,28,modfp);

               q->samplename= DupStr(s.samplename,28);
               q->seekpos   = _mm_ftell(modfp);
               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;
               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(modfp,12,SEEK_SET);
   if(!fread(s,28,1,modfp)) return NULL;
   
   return(DupStr(s,28));
}


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