furnace/src/engine/fileOps/xm.cpp

/**
 * Furnace Tracker - multi-system chiptune tracker
 * Copyright (C) 2021-2024 tildearrow and contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "fileOpsCommon.h"

bool DivEngine::loadXM(unsigned char* file, size_t len) {
  struct InvalidHeaderException {};
  bool success=false;
  char magic[32];
  unsigned char sampleVol[256][256];

  unsigned short patLen[256];

  bool doesPitchSlide[128];
  bool doesVibrato[128];
  bool doesPanning[128];
  bool doesVolSlide[128];
  bool doesArp[128];

  SafeReader reader=SafeReader(file,len);
  warnings="";

  memset(sampleVol,0,256*256);

  memset(patLen,0,256*sizeof(unsigned short));

  memset(doesPitchSlide,0,128*sizeof(bool));
  memset(doesVibrato,0,128*sizeof(bool));
  memset(doesPanning,0,128*sizeof(bool));
  memset(doesVolSlide,0,128*sizeof(bool));
  memset(doesArp,0,128*sizeof(bool));

  try {
    DivSong ds;
    ds.version=DIV_VERSION_XM;
    //ds.linearPitch=0;
    //ds.pitchMacroIsLinear=false;
    ds.noSlidesOnFirstTick=true;
    ds.rowResetsArpPos=true;
    ds.ignoreJumpAtEnd=false;
    ds.pitchSlideSpeed=12;

    logV("Extended Module");

    // load here
    if (!reader.seek(0,SEEK_SET)) {
      logE("premature end of file!");
      lastError="incomplete file";
      delete[] file;
      return false;
    }
    reader.read(magic,17);

    if (memcmp(magic,DIV_XM_MAGIC,17)!=0) {
      logW("invalid magic");
      throw EndOfFileException(&reader,reader.tell());
    }

    ds.name=reader.readStringLatin1(20);

    // 0x1a
    reader.readC();

    String trackerName=reader.readStringLatin1(20);
    unsigned short trackerVer=reader.readS();

    if (trackerName!="") logV("made with %s",trackerName);
    logV("version %x",trackerVer);

    unsigned int headerSeek=reader.tell();
    headerSeek+=reader.readI();

    ds.subsong[0]->ordersLen=(unsigned short)reader.readS();
    ds.subsong[0]->patLen=1;
    unsigned short loopPos=reader.readS();
    unsigned short totalChans=reader.readS();
    unsigned short patCount=reader.readS();
    ds.insLen=(unsigned short)reader.readS();
    ds.linearPitch=(reader.readS()&1)?2:0;
    ds.subsong[0]->speeds.val[0]=reader.readS();
    ds.subsong[0]->speeds.len=1;
    double bpm=(unsigned short)reader.readS();
    ds.subsong[0]->hz=(double)bpm/2.5;

    if (ds.insLen<0 || ds.insLen>256) {
      logE("invalid instrument count!");
      lastError="invalid instrument count";
      delete[] file;
      return false;
    }

    logV("channels: %d",totalChans);

    if (totalChans>127) {
      logE("invalid channel count!");
      lastError="invalid channel count";
      delete[] file;
      return false;
    }

    logV("repeat pos: %d",loopPos);

    logV("reading orders...");
    for (int i=0; i<256; i++) {
      unsigned char val=reader.readC();
      for (int j=0; j<DIV_MAX_CHANS; j++) {
        ds.subsong[0]->orders.ord[j][i]=val;
      }
    }

    for (int i=0; i<(totalChans+31)>>5; i++) {
      ds.system[i]=DIV_SYSTEM_ES5506;
      ds.systemFlags[i].set("amigaVol",true);
      ds.systemFlags[i].set("amigaPitch",(ds.linearPitch==0));
    }
    ds.systemLen=(totalChans+31)>>5;

    size_t patBegin=headerSeek;
    logV("seeking to %x...",patBegin);

    if (!reader.seek(patBegin,SEEK_SET)) {
      logE("premature end of file!");
      lastError="incomplete file";
      delete[] file;
      return false;
    }

    // scan pattern data for effect use
    logD("scanning patterns...");
    for (unsigned short i=0; i<patCount; i++) {
      logV("pattern %d",i);
      headerSeek=reader.tell();
      headerSeek+=reader.readI();

      unsigned char packType=reader.readC();
      if (packType!=0) {
        logE("unknown packing type %d!",packType);
        lastError="unknown packing type";
        ds.unload();
        delete[] file;
        return false;
      }

      unsigned short totalRows=reader.readS();
      logV("total rows: %d",totalRows);
      if (totalRows>ds.subsong[0]->patLen) ds.subsong[0]->patLen=totalRows;
      patLen[i]=totalRows;

      if (totalRows>256) {
        logE("too many rows! %d",totalRows);
        lastError="too many rows";
        delete[] file;
        return false;
      }

      unsigned int packedSeek=headerSeek+(unsigned short)reader.readS();

      logV("seeking to %x...",headerSeek);
      if (!reader.seek(headerSeek,SEEK_SET)) {
        logE("premature end of file!");
        lastError="incomplete file";
        delete[] file;
        return false;
      }

      // read data
      for (int j=0; j<totalRows; j++) {
        for (int k=0; k<totalChans; k++) {
          unsigned char note=reader.readC();
          unsigned char vol=0;
          unsigned char effect=0;
          unsigned char effectVal=0;
          bool hasNote=false;
          bool hasIns=false;
          bool hasVol=false;
          bool hasEffect=false;
          bool hasEffectVal=false;

          if (note&0x80) { // packed
            hasNote=note&1;
            hasIns=note&2;
            hasVol=note&4;
            hasEffect=note&8;
            hasEffectVal=note&16;
            if (hasNote) {
              note=reader.readC();
            }
          } else { // unpacked
            hasNote=true;
            hasIns=true;
            hasVol=true;
            hasEffect=true;
            hasEffectVal=true;
          }

          if (hasIns) {
            reader.readC();
          }
          if (hasVol) {
            vol=reader.readC();
            switch (vol>>4) {
              case 0x6: // vol slide down
                doesVolSlide[k]=true;
                break;
              case 0x7: // vol slide up
                doesVolSlide[k]=true;
                break;
              case 0x8: // vol slide down (fine)
                doesVolSlide[k]=true;
                break;
              case 0x9: // vol slide up (fine)
                doesVolSlide[k]=true;
                break;
              case 0xa: // vibrato speed
                doesVibrato[k]=true;
                break;
              case 0xb: // vibrato depth
                doesVibrato[k]=true;
                break;
              case 0xc: // panning
                doesPanning[k]=true;
                break;
              case 0xd: // pan slide left
                doesPanning[k]=true;
                break;
              case 0xe: // pan slide right
                doesPanning[k]=true;
                break;
              case 0xf: // porta
                doesPitchSlide[k]=true;
                break;
            }
          }
          if (hasEffect) {
            effect=reader.readC();
            switch (effect) {
              case 0:
                doesArp[k]=true;
                break;
              case 1:
                doesPitchSlide[k]=true;
                break;
              case 2:
                doesPitchSlide[k]=true;
                break;
              case 3:
                doesPitchSlide[k]=true;
                break;
              case 4:
                doesVibrato[k]=true;
                break;
              case 5:
                doesPitchSlide[k]=true;
                doesVolSlide[k]=true;
                break;
              case 6:
                doesVibrato[k]=true;
                doesVolSlide[k]=true;
                break;
              case 8:
                doesPanning[k]=true;
                break;
              case 0xe:
                doesPanning[k]=true;
                break;
              case 0x19: // P
                doesPanning[k]=true;
                break;
              case 0x21: // X
                doesPitchSlide[k]=true;
                break;
            }
          }
          if (hasEffectVal) {
            effectVal=reader.readC();
            if (effect==0xe) {
              switch (effectVal>>4) {
                case 1:
                  doesPitchSlide[k]=true;
                  break;
                case 2:
                  doesPitchSlide[k]=true;
                  break;
                case 0xa:
                  doesVolSlide[k]=true;
                  break;
                case 0xb:
                  doesVolSlide[k]=true;
                  break;
              }
            }
          }
        }
      }

      logV("seeking to %x...",packedSeek);
      if (!reader.seek(packedSeek,SEEK_SET)) {
        logE("premature end of file!");
        lastError="incomplete file";
        delete[] file;
        return false;
      }
    }

    if (!reader.seek(patBegin,SEEK_SET)) {
      logE("premature end of file!");
      lastError="incomplete file";
      delete[] file;
      return false;
    }

    // read patterns
    logD("reading patterns...");
    for (unsigned short i=0; i<patCount; i++) {
      unsigned char effectCol[128];
      unsigned char vibStatus[128];
      bool vibStatusChanged[128];
      bool vibing[128];
      bool vibingOld[128];
      unsigned char volSlideStatus[128];
      bool volSlideStatusChanged[128];
      bool volSliding[128];
      bool volSlidingOld[128];
      unsigned char portaStatus[128];
      bool portaStatusChanged[128];
      bool porting[128];
      bool portingOld[128];
      unsigned char portaType[128];
      unsigned char arpStatus[128];
      bool arpStatusChanged[128];
      bool arping[128];
      bool arpingOld[128];

      bool mustCommitInitial=true;

      memset(effectCol,4,128);
      memset(vibStatus,0,128);
      memset(vibStatusChanged,0,128*sizeof(bool));
      memset(vibing,0,128*sizeof(bool));
      memset(vibingOld,0,128*sizeof(bool));
      memset(volSlideStatus,0,128);
      memset(volSlideStatusChanged,0,128*sizeof(bool));
      memset(volSliding,0,128*sizeof(bool));
      memset(volSlidingOld,0,128*sizeof(bool));
      memset(portaStatus,0,128);
      memset(portaStatusChanged,0,128*sizeof(bool));
      memset(porting,0,128*sizeof(bool));
      memset(portingOld,0,128*sizeof(bool));
      memset(portaType,0,128);
      memset(arpStatus,0,128);
      memset(arpStatusChanged,0,128*sizeof(bool));
      memset(arping,0,128*sizeof(bool));
      memset(arpingOld,0,128*sizeof(bool));

      logV("pattern %d",i);
      headerSeek=reader.tell();
      headerSeek+=reader.readI();

      unsigned char packType=reader.readC();
      if (packType!=0) {
        logE("unknown packing type %d!",packType);
        lastError="unknown packing type";
        ds.unload();
        delete[] file;
        return false;
      }

      unsigned short totalRows=reader.readS();
      logV("total rows: %d",totalRows);
      if (totalRows>ds.subsong[0]->patLen) ds.subsong[0]->patLen=totalRows;
      patLen[i]=totalRows;

      if (totalRows>256) {
        logE("too many rows! %d",totalRows);
        lastError="too many rows";
        delete[] file;
        return false;
      }

      unsigned int packedSeek=headerSeek+(unsigned short)reader.readS();

      logV("seeking to %x...",headerSeek);
      if (!reader.seek(headerSeek,SEEK_SET)) {
        logE("premature end of file!");
        lastError="incomplete file";
        delete[] file;
        return false;
      }

      // read data
      for (int j=0; j<totalRows; j++) {
        for (int k=0; k<totalChans; k++) {
          DivPattern* p=ds.subsong[0]->pat[k].getPattern(i,true);

          unsigned char note=reader.readC();
          unsigned char ins=0;
          unsigned char vol=0;
          unsigned char effect=0;
          unsigned char effectVal=0;
          bool hasNote=false;
          bool hasIns=false;
          bool hasVol=false;
          bool hasEffect=false;
          bool hasEffectVal=false;

          if (note&0x80) { // packed
            hasNote=note&1;
            hasIns=note&2;
            hasVol=note&4;
            hasEffect=note&8;
            hasEffectVal=note&16;
            if (hasNote) {
              note=reader.readC();
            }
          } else { // unpacked
            hasNote=true;
            hasIns=true;
            hasVol=true;
            hasEffect=true;
            hasEffectVal=true;
          }

          if (hasNote) {
            if (note>=96) {
              p->data[j][0]=100;
              p->data[j][1]=0;
            } else {
              p->data[j][0]=note%12;
              p->data[j][1]=note/12;
              if (p->data[j][0]==0) {
                p->data[j][0]=12;
                p->data[j][1]=(unsigned char)(p->data[j][1]-1);
              }
            }
          }
          if (hasIns) {
            ins=reader.readC();
            p->data[j][2]=((int)ins)-1;
          }
          if (hasVol) {
            vol=reader.readC();
            if (vol>=0x10 && vol<=0x50) {
              p->data[j][3]=vol-0x10;
            } else { // effects in volume column
              // TODO
            }
          }
          if (vol==0) {
            if (hasNote && hasIns && note<96 && ins>0) {
              // TODO: default volume
              p->data[j][3]=0x40;
            }
          }
          if (hasEffect) {
            effect=reader.readC();
          }
          if (hasEffectVal) {
            effectVal=reader.readC();
          }

          if (hasEffect) {
            switch (effect) {
              case 0: // arp
                if (effectVal!=0) {
                  arpStatus[k]=effectVal;
                  arpStatusChanged[k]=true;
                }
                arping[k]=true;
                break;
              case 1: // pitch up
                if (effectVal!=0) {
                  portaStatus[k]=effectVal;
                  portaStatusChanged[k]=true;
                }
                portaType[k]=1;
                porting[k]=true;
                break;
              case 2: // pitch down
                if (effectVal!=0) {
                  portaStatus[k]=effectVal;
                  portaStatusChanged[k]=true;
                }
                portaType[k]=2;
                porting[k]=true;
                break;
              case 3: // porta
                if (effectVal!=0) {
                  portaStatus[k]=effectVal;
                  portaStatusChanged[k]=true;
                }
                portaType[k]=3;
                porting[k]=true;
                break;
              case 4: // vibrato
                if (effectVal!=0) {
                  vibStatus[k]=effectVal;
                  vibStatusChanged[k]=true;
                }
                vibing[k]=true;
                break;
              case 5: // vol slide + porta
                if (effectVal!=0) {
                  volSlideStatus[k]=effectVal;
                  volSlideStatusChanged[k]=true;
                }
                volSliding[k]=true;
                porting[k]=true;
                portaType[k]=3;
                break;
              case 6: // vol slide + vibrato
                if (effectVal!=0) {
                  volSlideStatus[k]=effectVal;
                  volSlideStatusChanged[k]=true;
                }
                volSliding[k]=true;
                vibing[k]=true;
                break;
              case 7: // tremolo
                break;
              case 8: // panning
                p->data[j][effectCol[k]++]=0x80;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 9: // offset
                p->data[j][effectCol[k]++]=0x91;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0xa: // vol slide
                if (effectVal!=0) {
                  volSlideStatus[k]=effectVal;
                  volSlideStatusChanged[k]=true;
                }
                if (hasIns) {
                  volSlideStatusChanged[k]=true;
                }
                volSliding[k]=true;
                break;
              case 0xb: // go to order
                p->data[j][effectCol[k]++]=0x0b;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0xc: // set volume
                p->data[j][3]=effectVal;
                break;
              case 0xd: // next order
                p->data[j][effectCol[k]++]=0x0d;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0xe: // special...
                // TODO: implement the rest
                switch (effectVal>>4) {
                  case 0xc:
                    p->data[j][effectCol[k]++]=0xec;
                    p->data[j][effectCol[k]++]=effectVal&15;
                    break;
                  case 0xd:
                    p->data[j][effectCol[k]++]=0xed;
                    p->data[j][effectCol[k]++]=effectVal&15;
                    break;
                }
                break;
              case 0x10: // G: global volume (!)
                break;
              case 0xf: // speed/tempp
                if (effectVal>=0x20) {
                  p->data[j][effectCol[k]++]=0xf0;
                } else {
                  p->data[j][effectCol[k]++]=0x0f;
                }
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0x11: // H: global volume slide (!)
                break;
              case 0x14: // K: key off
                p->data[j][effectCol[k]++]=0xe7;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0x15: // L: set envelope position (!)
                break;
              case 0x19: // P: pan slide
                break;
              case 0x1b: // R: retrigger
                p->data[j][effectCol[k]++]=0x0c;
                p->data[j][effectCol[k]++]=effectVal;
                break;
              case 0x1d: // T: tremor (!)
                break;
              case 0x21: // X: extra fine volume
                break;
            }
          }
        }

        // commit effects
        for (int k=0; k<totalChans; k++) {
          DivPattern* p=ds.subsong[0]->pat[k].getPattern(i,true);
          if (vibing[k]!=vibingOld[k] || vibStatusChanged[k]) {
            p->data[j][effectCol[k]++]=0x04;
            p->data[j][effectCol[k]++]=vibing[k]?vibStatus[k]:0;
            doesVibrato[k]=true;
          } else if (doesVibrato[k] && mustCommitInitial) {
            p->data[j][effectCol[k]++]=0x04;
            p->data[j][effectCol[k]++]=0;
          }

          if (volSliding[k]!=volSlidingOld[k] || volSlideStatusChanged[k]) {
            if (volSlideStatus[k]>=0xf1 && volSliding[k]) {
              p->data[j][effectCol[k]++]=0xf9;
              p->data[j][effectCol[k]++]=volSlideStatus[k]&15;
              volSliding[k]=false;
            } else if ((volSlideStatus[k]&15)==15 && volSlideStatus[k]>=0x10 && volSliding[k]) {
              p->data[j][effectCol[k]++]=0xf8;
              p->data[j][effectCol[k]++]=volSlideStatus[k]>>4;
              volSliding[k]=false;
            } else {
              p->data[j][effectCol[k]++]=0xfa;
              p->data[j][effectCol[k]++]=volSliding[k]?volSlideStatus[k]:0;
            }
            doesVolSlide[k]=true;
          } else if (doesVolSlide[k] && mustCommitInitial) {
            p->data[j][effectCol[k]++]=0xfa;
            p->data[j][effectCol[k]++]=0;
          }

          if (porting[k]!=portingOld[k] || portaStatusChanged[k]) {
            if (portaStatus[k]>=0xe0 && portaType[k]!=3 && porting[k]) {
              p->data[j][effectCol[k]++]=portaType[k]|0xf0;
              p->data[j][effectCol[k]++]=(portaStatus[k]&15)*((portaStatus[k]>=0xf0)?1:1);
              porting[k]=false;
            } else {
              p->data[j][effectCol[k]++]=portaType[k];
              p->data[j][effectCol[k]++]=porting[k]?portaStatus[k]:0;
            }
            doesPitchSlide[k]=true;
          } else if (doesPitchSlide[k] && mustCommitInitial) {
            p->data[j][effectCol[k]++]=0x01;
            p->data[j][effectCol[k]++]=0;
          }

          if (arping[k]!=arpingOld[k] || arpStatusChanged[k]) {
            p->data[j][effectCol[k]++]=0x00;
            p->data[j][effectCol[k]++]=arping[k]?arpStatus[k]:0;
            doesArp[k]=true;
          } else if (doesArp[k] && mustCommitInitial) {
            p->data[j][effectCol[k]++]=0x00;
            p->data[j][effectCol[k]++]=0;
          }

          if ((effectCol[k]>>1)-2>ds.subsong[0]->pat[k].effectCols) {
            ds.subsong[0]->pat[k].effectCols=(effectCol[k]>>1)-1;
          }
        }

        memset(effectCol,4,64);
        memcpy(vibingOld,vibing,64*sizeof(bool));
        memcpy(volSlidingOld,volSliding,64*sizeof(bool));
        memcpy(portingOld,porting,64*sizeof(bool));
        memcpy(arpingOld,arping,64*sizeof(bool));
        memset(vibStatusChanged,0,64*sizeof(bool));
        memset(volSlideStatusChanged,0,64*sizeof(bool));
        memset(portaStatusChanged,0,64*sizeof(bool));
        memset(arpStatusChanged,0,64*sizeof(bool));
        memset(vibing,0,64*sizeof(bool));
        memset(volSliding,0,64*sizeof(bool));
        memset(porting,0,64*sizeof(bool));
        memset(arping,0,64*sizeof(bool));
        mustCommitInitial=false;
        if (j==totalRows-1) {
          // place end of pattern marker
          DivPattern* p=ds.subsong[0]->pat[0].getPattern(i,true);
          p->data[j][effectCol[0]++]=0x0d;
          p->data[j][effectCol[0]++]=0;

          if ((effectCol[0]>>1)-2>ds.subsong[0]->pat[0].effectCols) {
            ds.subsong[0]->pat[0].effectCols=(effectCol[0]>>1)-1;
          }
        }
      }

      logV("seeking to %x...",packedSeek);
      if (!reader.seek(packedSeek,SEEK_SET)) {
        logE("premature end of file!");
        lastError="incomplete file";
        delete[] file;
        return false;
      }
    }

    // read instruments
    for (int i=0; i<ds.insLen; i++) {
      unsigned char volEnv[48];
      unsigned char panEnv[48];

      DivInstrument* ins=new DivInstrument;
      logD("instrument %d",i);
      headerSeek=reader.tell();
      headerSeek+=reader.readI();

      logV("the freaking thing ends at %x",headerSeek);

      ins->name=reader.readStringLatin1(22);
      ins->type=DIV_INS_ES5506;
      ins->amiga.useNoteMap=true;

      unsigned char insType=reader.readC();

      /*
      if (insType!=0) {
        logE("unknown instrument type!");
        lastError="unknown instrument type";
        delete ins;
        song.unload();
        delete[] file;
        return false;
      }*/

      logV("type: %d",insType);

      unsigned short sampleCount=reader.readS();
      logV("%d samples",sampleCount);

      if (sampleCount>0) {
        unsigned int sampleHeaderSize=reader.readI();
        logV("sample header size: %d",sampleHeaderSize);
        for (int j=0; j<96; j++) {
          unsigned char nextMap=reader.readC();
          if (nextMap==0) {
            ins->amiga.noteMap[j].map=-1;
          } else {
            ins->amiga.noteMap[j].map=ds.sample.size()+nextMap-1;
          }
        }

        reader.read(volEnv,48);
        reader.read(panEnv,48);

        unsigned char volEnvLen=reader.readC();
        unsigned char panEnvLen=reader.readC();
        unsigned char volSusPoint=reader.readC();
        unsigned char volLoopStart=reader.readC();
        unsigned char volLoopEnd=reader.readC();
        unsigned char panSusPoint=reader.readC();
        unsigned char panLoopStart=reader.readC();
        unsigned char panLoopEnd=reader.readC();
        unsigned char volType=reader.readC();
        unsigned char panType=reader.readC();

        unsigned char vibType=reader.readC();
        unsigned char vibSweep=reader.readC();
        unsigned char vibDepth=reader.readC();
        unsigned char vibRate=reader.readC();

        unsigned short volFade=reader.readS();
        reader.readS(); // reserved

        logV("%d",volEnvLen);
        logV("%d",panEnvLen);
        logV("%d",volSusPoint);
        logV("%d",volLoopStart);
        logV("%d",volLoopEnd);
        logV("%d",panSusPoint);
        logV("%d",panLoopStart);
        logV("%d",panLoopEnd);
        logV("%d",volType);
        logV("%d",panType);
        logV("%d",vibType);
        logV("%d",vibSweep);
        logV("%d",vibDepth);
        logV("%d",vibRate);
        logV("%d",volFade);

        if (!reader.seek(headerSeek,SEEK_SET)) {
          logE("premature end of file!");
          lastError="incomplete file";
          delete[] file;
          return false;
        }

        // read samples for this instrument
        std::vector<DivSample*> toAdd;
        for (int j=0; j<sampleCount; j++) {
          DivSample* s=new DivSample;

          unsigned int numSamples=reader.readI();
          if (numSamples>16777216) {
            logE("abnormal sample size! %x",reader.tell());
            lastError="bad sample size";
            delete s;
            delete[] file;
            return false;
          }

          s->loopStart=reader.readI();
          s->loopEnd=reader.readI()+s->loopStart;

          sampleVol[i][j]=reader.readC();

          signed char fine=reader.readC();
          unsigned char flags=reader.readC();
          unsigned char pan=reader.readC();
          unsigned char note=reader.readC();

          logV("%d %d %d",fine,pan,note);

          switch (flags&3) {
            case 0:
              s->loop=false;
              break;
            case 1:
              s->loop=true;
              s->loopMode=DIV_SAMPLE_LOOP_FORWARD;
              break;
            case 2:
              s->loop=true;
              s->loopMode=DIV_SAMPLE_LOOP_PINGPONG;
              break;
          }

          reader.readC(); // reserved

          s->name=reader.readStringLatin1(22);
          s->depth=(flags&4)?DIV_SAMPLE_DEPTH_16BIT:DIV_SAMPLE_DEPTH_8BIT;
          s->init(numSamples);


          // seek here???
          toAdd.push_back(s);
        }

        for (int j=0; j<sampleCount; j++) {
          DivSample* s=toAdd[j];

          // load sample data
          if (s->depth==DIV_SAMPLE_DEPTH_16BIT) {
            short next=0;
            for (unsigned int i=0; i<s->samples; i++) {
              next+=reader.readS();
              s->data16[i]=next;
            }
          } else {
            signed char next=0;
            for (unsigned int i=0; i<s->samples; i++) {
              next+=reader.readC();
              s->data8[i]=next;
            }
          }
        }

        for (DivSample* i: toAdd) {
          ds.sample.push_back(i);
        }
        toAdd.clear();
      } else {
        if (!reader.seek(headerSeek,SEEK_SET)) {
          logE("premature end of file!");
          lastError="incomplete file";
          delete[] file;
          return false;
        }
      }
      
      ds.ins.push_back(ins);
    }

    ds.sampleLen=ds.sample.size();
    if (ds.sampleLen>256) {
      logE("too many samples!");
      lastError="too many samples";
      ds.unload();
      delete[] file;
      return false;
    }

    // find subsongs
    ds.findSubSongs(totalChans);

    if (active) quitDispatch();
    BUSY_BEGIN_SOFT;
    saveLock.lock();
    song.unload();
    song=ds;
    changeSong(0);
    recalcChans();
    saveLock.unlock();
    BUSY_END;
    if (active) {
      initDispatch();
      BUSY_BEGIN;
      renderSamples();
      reset();
      BUSY_END;
    }
    success=true;
  } catch (EndOfFileException& e) {
    //logE("premature end of file!");
    lastError="incomplete file";
  } catch (InvalidHeaderException& e) {
    //logE("invalid header!");
    lastError="invalid header!";
  }
  return success;
}