Free Hero Mesh

    fseek(fp,t,SEEK_CUR);
  }
  done:
  sqlite3_finalize(st);
  return id;
}

unsigned char*read_lump_or_userstate(int sol,int lvl,long*sz,char us) {
  // Returns a pointer to the data; must be freed using free().
  // If there is no data, returns null and sets *sz and *us to zero.
  // Third argument is a pointer to a variable to store the data size (must be not null).
  // Fourth argument is 1 for user state or 0 for lump data.
  unsigned char*buf=0;
  sqlite3_reset(readusercachest);
  sqlite3_bind_int64(readusercachest,1,sol?solutionuc:leveluc);
  sqlite3_bind_int(readusercachest,2,lvl);
  sqlite3_bind_int(readusercachest,3,us);
  if(sqlite3_step(readusercachest)==SQLITE_ROW) {

    if(sqlite3_column_type(readusercachest,1)==SQLITE_BLOB) {
      const unsigned char*con=sqlite3_column_blob(readusercachest,1);
      *sz=sqlite3_column_bytes(readusercachest,1);
      buf=malloc(*sz);
      if(*sz && !buf) fatal("Allocation failed\n");
      memcpy(buf,con,*sz);
    } else if(us) {
      *sz=0;
    } else {
      FILE*fp=sol?solutionfp:levelfp;
      rewind(fp);
      fseek(fp,sqlite3_column_int64(readusercachest,0)-4,SEEK_SET);
      *sz=fgetc(fp)<<16; *sz|=fgetc(fp)<<24; *sz|=fgetc(fp); *sz|=fgetc(fp)<<8;
      if(feof(fp) || *sz<0) fatal("Invalid Hamster archive\n");
      buf=malloc(*sz);
      if(!buf) fatal("Allocation failed\n");
      if(!fread(buf,1,*sz,fp)) fatal("Unable to read data\n");
      rewind(fp);
    }
  } else {
    *sz=0;

  }
  sqlite3_reset(readusercachest);
  return buf;
}

void write_lump(int sol,int lvl,long sz,const unsigned char*data) {
  // Writes a lump to the user cache.
  // The actual Hamster archive files will be updated when the program terminates.
  sqlite3_stmt*st;
  int e;
  if(e=sqlite3_prepare_v2(userdb,"INSERT INTO `USERCACHEDATA`(`FILE`,`LEVEL`,`NAME`,`DATA`) VALUES(?1,?2,CASE WHEN ?2 < 0 THEN ?3 ELSE ?2 || ?3 END,?4)"
   " ON CONFLICT(`FILE`,`LEVEL`) DO UPDATE SET `DATA` = ?4;",-1,&st,0)) fatal("SQL error (%d): %s\n",e,sqlite3_errmsg(userdb));
  sqlite3_bind_int64(st,1,sol?solutionuc:leveluc);
  sqlite3_bind_int(st,2,lvl);
  sqlite3_bind_text(st,3,lvl==LUMP_CLASS_DEF?"CLASS.DEF":lvl==LUMP_LEVEL_IDX?"LEVEL.IDX":sol?".SOL":".LVL",-1,SQLITE_STATIC);
  sqlite3_bind_blob64(st,4,data,sz,0);
  while((e=sqlite3_step(st))==SQLITE_ROW);
  if(e!=SQLITE_DONE) fatal("SQL error (%d): %s\n",e,sqlite3_errmsg(userdb));
  sqlite3_finalize(st);
}

void write_userstate(int sol,int lvl,long sz,const unsigned char*data) {
  sqlite3_stmt*st;
  int e;
  if(e=sqlite3_prepare_v2(userdb,"UPDATE `USERCACHEDATA` SET `USERSTATE` = ?3"
   " WHERE `FILE` = ?1 AND `LEVEL` = ?2;",-1,&st,0)) fatal("SQL error (%d): %s\n",e,sqlite3_errmsg(userdb));
  sqlite3_bind_int64(st,1,sol?solutionuc:leveluc);
  sqlite3_bind_int(st,2,lvl);
  sqlite3_bind_blob64(st,3,data,sz,0);
  while((e=sqlite3_step(st))==SQLITE_ROW);
  if(e!=SQLITE_DONE) fatal("SQL error (%d): %s\n",e,sqlite3_errmsg(userdb));
  sqlite3_finalize(st);
}

static void load_level_index(void) {
  long sz;
  int i;
  unsigned char*data=read_lump(FIL_LEVEL,LUMP_LEVEL_IDX,&sz);
  if(!data) return;
  if(sz>65536) fatal("Too many levels\n");
  level_index=malloc((level_nindex=sz>>1)*sizeof(Uint16));
  if(!level_index) fatal("Allocation failed\n");
  for(i=0;i<level_nindex;i++) level_index[i]=data[i+i]|(data[i+i+1]<<8);
  free(data);
}

const char*load_level(int lvl) {
  // Load level by ID. Returns null pointer if successful, or an error message if it failed.
  long sz=0;
  unsigned char*buf=lvl>=0?read_lump(FIL_LEVEL,lvl,&sz):0;
  unsigned char*p=buf;
  unsigned char*end=buf+sz;
  unsigned char*q;
  int i,n,x,y,z;
  Uint16 lo=0;
  Uint32 o;
  Uint32 mru[2];
  if(lvl<0 && level_index && -lvl<=level_nindex) {
    lo=-lvl;
    lvl=level_index[~lvl];
    p=buf=read_lump(FIL_LEVEL,lvl,&sz);
    end=buf+sz;
  }
  if(lvl<0) return "Invalid level ID";
  if(!buf) return "Cannot find level";
  free(level_title);
  level_title=0;
  annihilate();

  if(stat(nam2,&fst)) fatal("Unable to stat '%s': %m\n",nam2);
  if(!fst.st_size) fatal("File '%s' has zero size\n",nam2);
  if(fst.st_mtime>t1 || fst.st_ctime>t1) leveluc=reset_usercache(levelfp,nam2,&fst,".LVL");
  if(stat(nam3,&fst)) fatal("Unable to stat '%s': %m\n",nam3);
  if(fst.st_mtime>t2 || fst.st_ctime>t2) solutionuc=reset_usercache(solutionfp,nam3,&fst,".SOL");
  free(nam2);
  free(nam3);
  if(z=sqlite3_prepare_v3(userdb,"SELECT `OFFSET`, CASE WHEN ?3 THEN `DATA` ELSE `USERSTATE` END "
   "FROM `USERCACHEDATA` WHERE `FILE` = ?1 AND `LEVEL` = ?2;",-1,SQLITE_PREPARE_PERSISTENT,&readusercachest,0)) {
    fatal("SQL error (%d): %s\n",z,sqlite3_errmsg(userdb));
  }
  if(z=sqlite3_exec(userdb,"COMMIT;",0,0,0)) fatal("SQL error (%d): %s\n",z,sqlite3_errmsg(userdb));
  fprintf(stderr,"Done\n");
}

static void init_sql(void) {