code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package net.openhft.chronicle.hash.impl.stage.entry;
  
  public interface Alloc {
  
      /**
       * Allocates a block of specified number of chunks in a segment tier, optionally clears the
       * previous allocation.
       *
       * @param chunks     chunks to allocate
       * @param prevPos    the previous position to clear, -1 if not needed
       * @param prevChunks the size of the previous allocation to clear, 0 if not needed
       * @return the new allocation position
       * @throws RuntimeException if fails to allocate a block
       */
      long alloc(int chunks, long prevPos, int prevChunks);
  }
  