ACE/ace/Hashable.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file   Hashable.h
   6  *
   7  *  @author Doug Schmidt
   8  */
   9 //=============================================================================
  10
  11 #ifndef ACE_HASHABLE_H
  12 #define ACE_HASHABLE_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include /**/ "ace/ACE_export.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  23
  24 /**
  25  * @class ACE_Hashable
  26  *
  27  * @brief ACE_Hashable
  28  */
  29 class ACE_Export ACE_Hashable
  30 {
  31 public:
  32   /// Destructor.
  33   virtual ~ACE_Hashable () = default;
  34
  35   /// Computes and returns hash value.  This "caches" the hash value to
  36   /// improve performance.
  37   virtual unsigned long hash () const;
  38
  39 protected:
  40   /// Protected constructor.
  41   ACE_Hashable () = default;
  42
  43   /// This is the method that actually performs the non-cached hash
  44   /// computation.
  45   virtual unsigned long hash_i () const = 0;
  46
  47 protected:
  48   /// Pre-computed hash-value.
  49   mutable unsigned long hash_value_ {};
  50 };
  51
  52 ACE_END_VERSIONED_NAMESPACE_DECL
  53
  54 #include /**/ "ace/post.h"
  55
  56 #endif /*ACE_HASHABLE_H*/