synchronized void put(long hash, K key, V value, boolean ifPresent, boolean ifAbsent) {
      // search for the previous entry
      int h = smallMap.startSearch(hash);
      boolean foundSmall = false, foundLarge = false;
      while (true) {
        int pos = smallMap.nextPos();
        if (pos < 0) {
          K key2 = key instanceof CharSequence ? (K) key.toString() : key;
          final DirectStore store = map.get(key2);
          if (store == null) {
            if (ifPresent && !ifAbsent) return;
            break;
          }
          if (ifAbsent) return;
          bytes.storePositionAndSize(store, 0, store.size());
          foundLarge = true;
          break;
        } else {
          bytes.storePositionAndSize(store, pos * smallEntrySize, smallEntrySize);
          K key2 = getKey();
          if (equals(key, key2)) {
            if (ifAbsent && !ifPresent) return;
            foundSmall = true;
            break;
          }
        }
      }

      tmpBytes.clear();
      if (csKey)
        //noinspection ConstantConditions
        tmpBytes.writeUTFΔ((CharSequence) key);
      else tmpBytes.writeObject(key);
      long startOfValuePos = tmpBytes.position();
      if (bytesMarshallable) ((BytesMarshallable) value).writeMarshallable(tmpBytes);
      else tmpBytes.writeObject(value);
      long size = tmpBytes.position();
      if (size <= smallEntrySize) {
        if (foundSmall) {
          bytes.position(0);
          bytes.write(tmpBytes, 0, size);
          return;
        } else if (foundLarge) {
          remove(hash, key);
        }
        // look for a free spot.
        int position = h & (entriesPerSegment - 1);
        int free = usedSet.nextClearBit(position);
        if (free >= entriesPerSegment) free = usedSet.nextClearBit(0);
        if (free < entriesPerSegment) {
          bytes.storePositionAndSize(store, free * smallEntrySize, smallEntrySize);
          bytes.write(tmpBytes, 0, size);
          smallMap.put(h, free);
          usedSet.set(free);
          this.size++;
          return;
        }
      }
      if (foundSmall) {
        remove(hash, key);
      } else if (foundLarge) {
        // can it be reused.
        if (bytes.capacity() <= size || bytes.capacity() - size < (size >> 3)) {
          bytes.write(tmpBytes, startOfValuePos, size);
          return;
        }
        remove(hash, key);
      }
      size = size - startOfValuePos;
      DirectStore store = new DirectStore(bmf, size);
      bytes.storePositionAndSize(store, 0, size);
      bytes.write(tmpBytes, startOfValuePos, size);
      K key2 = key instanceof CharSequence ? (K) key.toString() : key;
      map.put(key2, store);
      offHeapUsed += size;
      this.size++;
    }