wsutil/type_util.c

   1 /* type_util.c
   2  * Types utility routines
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #include "config.h"
  12
  13 #include <glib.h>
  14
  15 #include "type_util.h"
  16
  17 /*
  18  * uint64_t to double conversions taken from gstutils.c of GStreamer project
  19  *
  20  * GStreamer
  21  * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
  22  *                    2000 Wim Taymans <wtay@chello.be>
  23  *                    2002 Thomas Vander Stichele <thomas@apestaart.org>
  24  *
  25  * gstutils.h: Header for various utility functions
  26  *
  27  * GNU GPL v2
  28  *
  29  */
  30
  31 /* work around error C2520: conversion from unsigned __int64 to double
  32  * not implemented, use signed __int64
  33  *
  34  * These are implemented as functions because on some platforms a 64bit int to
  35  * double conversion is not defined/implemented.
  36  */
  37
  38 double
  39 type_util_uint64_to_double(uint64_t value)
  40 {
  41   if (value & UINT64_C (0x8000000000000000))
  42     return (double) ((int64_t) value) + (double) 18446744073709551616.;
  43   else
  44     return (double) ((int64_t) value);
  45 }
  46
  47 uint64_t
  48 type_util_double_to_uint64(double value)
  49 {
  50   if (value < (double) 9223372036854775808.)   /* 1 << 63 */
  51     return ((uint64_t) ((int64_t) value));
  52
  53   value -= (double) 18446744073709551616.;
  54   return ((uint64_t) ((int64_t) value));
  55 }
  56
  57 /*
  58  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  59  *
  60  * Local Variables:
  61  * c-basic-offset: 2
  62  * tab-width: 8
  63  * indent-tabs-mode: nil
  64  * End:
  65  *
  66  * ex: set shiftwidth=2 tabstop=8 expandtab:
  67  * :indentSize=2:tabSize=8:noTabs=true:
  68  */