//
   //  ========================================================================
   //  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.http;
  
  import java.nio.ByteBuffer;
  
  import org.eclipse.jetty.util.ArrayTrie;
  import org.eclipse.jetty.util.StringUtil;
  import org.eclipse.jetty.util.Trie;
  
  
  /* ------------------------------------------------------------------------------- */
  /**
   */
  public enum HttpMethod
  {
      GET,
      POST,
      HEAD,
      PUT,
      OPTIONS,
      DELETE,
      TRACE,
      CONNECT,
      MOVE,
      PROXY;
  
      /* ------------------------------------------------------------ */
      /**
       * Optimised lookup to find a method name and trailing space in a byte array.
       * @param bytes Array containing ISO-8859-1 characters
       * @param position The first valid index
       * @param limit The first non valid index
       * @return A HttpMethod if a match or null if no easy match.
       */
      public static HttpMethod lookAheadGet(byte[] bytes, final int position, int limit)
      {
          int length=limit-position;
          if (length<4)
              return null;
          switch(bytes[position])
          {
              case 'G':
                  if (bytes[position+1]=='E' && bytes[position+2]=='T' && bytes[position+3]==' ')
                      return GET;
                  break;
              case 'P':
                  if (bytes[position+1]=='O' && bytes[position+2]=='S' && bytes[position+3]=='T' && length>=5 && bytes[position+4]==' ')
                      return POST;
                  if (bytes[position+1]=='R' && bytes[position+2]=='O' && bytes[position+3]=='X' && length>=6 && bytes[position+4]=='Y' && bytes[position+5]==' ')
                      return PROXY;
                  if (bytes[position+1]=='U' && bytes[position+2]=='T' && bytes[position+3]==' ')
                      return PUT;
                  break;
              case 'H':
                  if (bytes[position+1]=='E' && bytes[position+2]=='A' && bytes[position+3]=='D' && length>=5 && bytes[position+4]==' ')
                      return HEAD;
                  break;
              case 'O':
                  if (bytes[position+1]=='O' && bytes[position+2]=='T' && bytes[position+3]=='I' && length>=8 &&
                  bytes[position+4]=='O' && bytes[position+5]=='N' && bytes[position+6]=='S' && bytes[position+7]==' ' )
                      return OPTIONS;
                  break;
              case 'D':
                  if (bytes[position+1]=='E' && bytes[position+2]=='L' && bytes[position+3]=='E' && length>=7 &&
                  bytes[position+4]=='T' && bytes[position+5]=='E' && bytes[position+6]==' ' )
                      return DELETE;
                  break;
              case 'T':
                  if (bytes[position+1]=='R' && bytes[position+2]=='A' && bytes[position+3]=='C' && length>=6 &&
                  bytes[position+4]=='E' && bytes[position+5]==' ' )
                      return TRACE;
                  break;
              case 'C':
                  if (bytes[position+1]=='O' && bytes[position+2]=='N' && bytes[position+3]=='N' && length>=8 &&
                  bytes[position+4]=='E' && bytes[position+5]=='C' && bytes[position+6]=='T' && bytes[position+7]==' ' )
                      return CONNECT;
                  break;
              case 'M':
                  if (bytes[position+1]=='O' && bytes[position+2]=='V' && bytes[position+3]=='E' &&  bytes[position+4]==' ')
                      return MOVE;
                  break;
  
             default:
                 break;
         }
         return null;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Optimised lookup to find a method name and trailing space in a byte array.
      * @param buffer buffer containing ISO-8859-1 characters
      * @return A HttpMethod if a match or null if no easy match.
      */
     public static HttpMethod lookAheadGet(ByteBuffer buffer)
     {
         if (buffer.hasArray())
             return lookAheadGet(buffer.array(),buffer.arrayOffset()+buffer.position(),buffer.arrayOffset()+buffer.limit());
 
         // TODO use cache and check for space
         // return CACHE.getBest(buffer,0,buffer.remaining());
         return null;
     }
 
     /* ------------------------------------------------------------ */
     public final static Trie<HttpMethod> CACHE= new ArrayTrie<>();
     static
     {
         for (HttpMethod method : HttpMethod.values())
             CACHE.put(method.toString(),method);
     }
 
     /* ------------------------------------------------------------ */
     private final ByteBuffer _buffer;
     private final byte[] _bytes;
 
     /* ------------------------------------------------------------ */
     HttpMethod()
     {
         _bytes=StringUtil.getBytes(toString());
         _buffer=ByteBuffer.wrap(_bytes);
     }
 
     /* ------------------------------------------------------------ */
     public byte[] getBytes()
     {
         return _bytes;
     }
 
     /* ------------------------------------------------------------ */
     public boolean is(String s)
     {
         return toString().equalsIgnoreCase(s);
     }
 
     /* ------------------------------------------------------------ */
     public ByteBuffer asBuffer()
     {
         return _buffer.asReadOnlyBuffer();
     }
 
     /* ------------------------------------------------------------ */
     public String asString()
     {
         return toString();
     }
 
     /**
      * Converts the given String parameter to an HttpMethod
      * @param method the String to get the equivalent HttpMethod from
      * @return the HttpMethod or null if the parameter method is unknown
      */
     public static HttpMethod fromString(String method)
     {
         return CACHE.get(method);
     }
 }