/*
 * Adplug - Replayer for many OPL2/OPL3 audio file formats.
 * Copyright (C) 1999 - 2006 Simon Peter, <dn.tlp@gmx.net>, et al.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * mtk.cpp - MPU-401 Trakker Loader by Simon Peter (dn.tlp@gmx.net)
 */

#include <cstring>
#include "mtk.h"

/*** public methods **************************************/

CPlayer *CmtkLoader::factory(Copl *newopl)
{
  return new CmtkLoader(newopl);
}

bool CmtkLoader::load(const std::string &filename, const CFileProvider &fp)
{
  binistream *f = fp.open(filename); if(!f) return false;
  struct {
    char id[18];
    unsigned short crc,size;
  } header;
  struct mtkdata {
    char songname[34],composername[34],instname[0x80][34];
    unsigned char insts[0x80][12],order[0x80],dummy,patterns[0x32][0x40][9];
  } *data;
  unsigned char *cmp,*org;
  unsigned int i;
  unsigned long cmpsize,cmpptr=0,orgptr=0;
  unsigned short ctrlbits=0,ctrlmask=0,cmd,cnt,offs;

  // read header
  f->readString(header.id, 18);
  header.crc = f->readInt(2);
  header.size = f->readInt(2);

  // file validation section
  if(strncmp(header.id,"mpu401tr\x92kk\xeer@data",18))
    { fp.close(f); return false; }

  // load section
  cmpsize = fp.filesize(f) - 22;
  cmp = new unsigned char[cmpsize];
  org = new unsigned char[header.size];
  for(i = 0; i < cmpsize; i++) cmp[i] = f->readInt(1);
  fp.close(f);

  while(cmpptr < cmpsize) {     // decompress
    ctrlmask >>= 1;
    if(!ctrlmask) {
      ctrlbits = cmp[cmpptr] + (cmp[cmpptr + 1] << 8);
      cmpptr += 2;
      ctrlmask = 0x8000;
    }
    if(!(ctrlbits & ctrlmask)) {        // uncompressed data
      if(orgptr >= header.size)
        goto err;

      org[orgptr] = cmp[cmpptr];
      orgptr++; cmpptr++;
      continue;
    }

    // compressed data
    cmd = (cmp[cmpptr] >> 4) & 0x0f;
    cnt = cmp[cmpptr] & 0x0f;
    cmpptr++;
    switch(cmd) {
    case 0:
      if(orgptr + cnt > header.size) goto err;
      cnt += 3;
      memset(&org[orgptr],cmp[cmpptr],cnt);
      cmpptr++; orgptr += cnt;
      break;

    case 1:
      if(orgptr + cnt > header.size) goto err;
      cnt += (cmp[cmpptr] << 4) + 19;
      memset(&org[orgptr],cmp[++cmpptr],cnt);
      cmpptr++; orgptr += cnt;
      break;

    case 2:
      if(orgptr + cnt > header.size) goto err;
      offs = (cnt+3) + (cmp[cmpptr] << 4);
      cnt = cmp[++cmpptr] + 16; cmpptr++;
      memcpy(&org[orgptr],&org[orgptr - offs],cnt);
      orgptr += cnt;
      break;

    default:
      if(orgptr + cmd > header.size) goto err;
      offs = (cnt+3) + (cmp[cmpptr++] << 4);
      memcpy(&org[orgptr],&org[orgptr-offs],cmd);
      orgptr += cmd;
      break;
    }
  }
  delete [] cmp;
  data = (struct mtkdata *) org;

  // convert to HSC replay data
  memset(title,0,34); strncpy(title,data->songname+1,33);
  memset(composer,0,34); strncpy(composer,data->composername+1,33);
  memset(instname,0,0x80*34);
  for(i=0;i<0x80;i++)
    strncpy(instname[i],data->instname[i]+1,33);
  memcpy(instr,data->insts,0x80 * 12);
  memcpy(song,data->order,0x80);
  memcpy(patterns,data->patterns,header.size-6084);
  for (i=0;i<128;i++) {                         // correct instruments
    instr[i][2] ^= (instr[i][2] & 0x40) << 1;
    instr[i][3] ^= (instr[i][3] & 0x40) << 1;
    instr[i][11] >>= 4;         // make unsigned
  }

  delete [] org;
  rewind(0);
  return true;

 err:
  delete [] cmp;
  delete [] org;
  return false;
}
