wsutil/type_util.c

   1 /* type_util.c
   2  * Types utility routines
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #include "config.h"
  26
  27 #include <glib.h>
  28 #include "type_util.h"
  29
  30 /*
  31  * guint64 to gdouble conversions taken from gstutils.c of GStreamer project
  32  *
  33  * GStreamer
  34  * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
  35  *                    2000 Wim Taymans <wtay@chello.be>
  36  *                    2002 Thomas Vander Stichele <thomas@apestaart.org>
  37  *
  38  * gstutils.h: Header for various utility functions
  39  *
  40  * GNU GPL v2
  41  *
  42  */
  43
  44 /* work around error C2520: conversion from unsigned __int64 to double
  45  * not implemented, use signed __int64
  46  *
  47  * These are implemented as functions because on some platforms a 64bit int to
  48  * double conversion is not defined/implemented.
  49  */
  50
  51 gdouble
  52 type_util_guint64_to_gdouble(guint64 value)
  53 {
  54   if (value & G_GINT64_CONSTANT (0x8000000000000000))
  55     return (gdouble) ((gint64) value) + (gdouble) 18446744073709551616.;
  56   else
  57     return (gdouble) ((gint64) value);
  58 }
  59
  60 guint64
  61 type_util_gdouble_to_guint64(gdouble value)
  62 {
  63   if (value < (gdouble) 9223372036854775808.)   /* 1 << 63 */
  64     return ((guint64) ((gint64) value));
  65
  66   value -= (gdouble) 18446744073709551616.;
  67   return ((guint64) ((gint64) value));
  68 }