//
// W_sortLevels
//
// Static qsort callback for W_FindAllMapsInLevelWad
//
static int W_sortLevels(const void *first, const void *second)
{
   wadlevel_t *firstLevel  = (wadlevel_t *)first;
   wadlevel_t *secondLevel = (wadlevel_t *)second;

   return strncasecmp(firstLevel->header, secondLevel->header, 9);
}

//
// W_FindAllMapsInLevelWad
//
// haleyjd 10/23/10: Finds all valid maps in a wad directory and returns them
// as a sorted set of wadlevel_t's.
//
wadlevel_t *W_FindAllMapsInLevelWad(waddir_t *dir)
{
   int i, format;
   wadlevel_t *levels;
   int numlevels;
   int numlevelsalloc;

   // start out with a small set of levels
   numlevels = 0;
   numlevelsalloc = 8;
   levels = calloc(numlevelsalloc, sizeof(wadlevel_t));

   // find all the lumps
   for(i = 0; i < dir->numlumps; i++)
   {
      if((format = P_CheckLevel(dir, i)) != LEVEL_FORMAT_INVALID)
      {
         // grow the array if needed, leaving one at the end
         if(numlevels + 1 >= numlevelsalloc)
         {
            numlevelsalloc *= 2;
            levels = realloc(levels, numlevelsalloc * sizeof(wadlevel_t));
         }
         memset(&levels[numlevels], 0, sizeof(wadlevel_t));
         levels[numlevels].dir = dir;
         levels[numlevels].lumpnum = i;
         strncpy(levels[numlevels].header, dir->lumpinfo[i]->name, 9);
         ++numlevels;

         // skip past the level's directory entries
         i += (format == LEVEL_FORMAT_HEXEN ? 11 : 10);
      }
   }

   // sort the levels
   qsort(levels, numlevels, sizeof(wadlevel_t), W_sortLevels);

   // set the entry at numlevels to all zeroes
   memset(&levels[numlevels], 0, sizeof(wadlevel_t));

   return levels;
}