/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you 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 org.jboss.netty.handler.codec.compression;
  
  import org.jboss.netty.util.internal.jzlib.JZlib;
  import org.jboss.netty.util.internal.jzlib.ZStream;
  
  /**
   * Utility methods used by {@link ZlibEncoder} and {@link ZlibDecoder}.
   */
  final class ZlibUtil {
  
      static void fail(ZStream z, String message, int resultCode) {
          throw exception(z, message, resultCode);
      }
  
      static CompressionException exception(ZStream z, String message, int resultCode) {
          return new CompressionException(message + " (" + resultCode + ')' +
                  (z.msg != null? ": " + z.msg : ""));
      }
  
      static Enum<?> convertWrapperType(ZlibWrapper wrapper) {
          Enum<?> convertedWrapperType;
          switch (wrapper) {
          case NONE:
              convertedWrapperType = JZlib.W_NONE;
              break;
          case ZLIB:
              convertedWrapperType = JZlib.W_ZLIB;
              break;
          case GZIP:
              convertedWrapperType = JZlib.W_GZIP;
              break;
          case ZLIB_OR_NONE:
              convertedWrapperType = JZlib.W_ZLIB_OR_NONE;
              break;
          default:
              throw new Error();
          }
          return convertedWrapperType;
      }
  
      static int wrapperOverhead(ZlibWrapper wrapper) {
          int overhead;
          switch (wrapper) {
          case NONE:
              overhead = 0;
              break;
          case ZLIB:
          case ZLIB_OR_NONE:
              overhead = 2;
              break;
          case GZIP:
              overhead = 10;
              break;
          default:
              throw new Error();
          }
          return overhead;
      }
  
      private ZlibUtil() {
      }
  }