source: trunk/third/firefox/xpcom/base/nsID.h @ 21695

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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#ifndef nsID_h__
#define nsID_h__

#include <string.h>

#ifndef nscore_h___
#include "nscore.h"
#endif

/**
 * A "unique identifier". This is modeled after OSF DCE UUIDs.
 * @status FROZEN
 */

struct nsID {
  /**
   * @name Indentifier values
   */

  //@{
  PRUint32 m0;
  PRUint16 m1;
  PRUint16 m2;
  PRUint8 m3[8];
  //@}

  /**
   * @name Methods
   */

  //@{
  /**
   * Equivalency method. Compares this nsID with another.
   * @return <b>PR_TRUE</b> if they are the same, <b>PR_FALSE</b> if not.
   */

  inline PRBool Equals(const nsID& other) const {
    // One would think that this could be done faster with a really
    // efficient implementation of memcmp(), but evidently no
    // memcmp()'s out there are better than this code.
    //
    // See bug http://bugzilla.mozilla.org/show_bug.cgi?id=164580 for
    // details.

    return (PRBool)
      ((((PRUint32*) &m0)[0] == ((PRUint32*) &other.m0)[0]) &&
       (((PRUint32*) &m0)[1] == ((PRUint32*) &other.m0)[1]) &&
       (((PRUint32*) &m0)[2] == ((PRUint32*) &other.m0)[2]) &&
       (((PRUint32*) &m0)[3] == ((PRUint32*) &other.m0)[3]));
  }

  /**
   * nsID Parsing method. Turns a {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
   * string into an nsID
   */
  NS_COM PRBool Parse(const char *aIDStr);

  /**
   * nsID string encoder. Returns an allocated string in 
   * {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} format. Caller should free string.
   */
  NS_COM char* ToString() const;
  //@}
};

/*
 * Class IDs
 */

typedef nsID nsCID;

// Define an CID
#define NS_DEFINE_CID(_name, _cidspec) \
  const nsCID _name = _cidspec

#define REFNSCID const nsCID&

/**
 * An "interface id" which can be used to uniquely identify a given
 * interface.
 */

typedef nsID nsIID;

/**
 * A macro shorthand for <tt>const nsIID&<tt>
 */

#define REFNSIID const nsIID&

/**
 * Define an IID
 * obsolete - do not use this macro
 */
 
#define NS_DEFINE_IID(_name, _iidspec) \
  const nsIID _name = _iidspec

/**
 * A macro to build the static const IID accessor method
 */

#define NS_DEFINE_STATIC_IID_ACCESSOR(the_iid) \
  static const nsIID& GetIID() {static const nsIID iid = the_iid; return iid;}

/**
 * A macro to build the static const CID accessor method
 */

#define NS_DEFINE_STATIC_CID_ACCESSOR(the_cid) \
  static const nsID& GetCID() {static const nsID cid = the_cid; return cid;}

#endif