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mtk.cpp

/*
 * Adplug - Replayer for many OPL2/OPL3 audio file formats.
 * Copyright (C) 1999 - 2003 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * mtk.cpp - MPU-401 Trakker Loader by Simon Peter (dn.tlp@gmx.net)
 */

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

            // compressed data
            cmd = (cmp[cmpptr] >> 4) & 0x0f;
            cnt = cmp[cmpptr] & 0x0f;
            cmpptr++;
            switch(cmd) {
            case 0: cnt += 3; memset(&org[orgptr],cmp[cmpptr],cnt); cmpptr++; orgptr += cnt; break;
            case 1: cnt += (cmp[cmpptr] << 4) + 19; memset(&org[orgptr],cmp[++cmpptr],cnt); cmpptr++; orgptr += cnt; break;
            case 2: offs = (cnt+3) + (cmp[cmpptr] << 4); cnt = cmp[++cmpptr] + 16; cmpptr++;
                        memcpy(&org[orgptr],&org[orgptr - offs],cnt); orgptr += cnt; break;
            default: 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;
}

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