Wireshark  2.9.0-477-g68ec514b
The Wireshark network protocol analyzer
sign_ext.h
1 /*
2  * sign_ext.h
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 #ifndef __WSUTIL_SIGN_EXT_H__
12 #define __WSUTIL_SIGN_EXT_H__
13 
14 #include <glib.h>
15 
16 /* sign extension routines */
17 
18 static inline guint32
19 ws_sign_ext32(guint32 val, int no_of_bits)
20 {
21  g_assert (no_of_bits >= 0 && no_of_bits <= 32);
22 
23  if ((no_of_bits == 0) || (no_of_bits == 32))
24  return val;
25 
26  /*
27  * Don't shift signed values left; that's not valid in C99, at
28  * least, if the value is negative or if the shift count is
29  * the number of bits in the value - 1, and we might get
30  * compile-time or run-time complaints about that.
31  */
32  if (val & (1U << (no_of_bits-1)))
33  val |= (0xFFFFFFFFU << no_of_bits);
34 
35  return val;
36 }
37 
38 static inline guint64
39 ws_sign_ext64(guint64 val, int no_of_bits)
40 {
41  g_assert (no_of_bits >= 0 && no_of_bits <= 64);
42 
43  if ((no_of_bits == 0) || (no_of_bits == 64))
44  return val;
45 
46  /*
47  * Don't shift signed values left; that's not valid in C99, at
48  * least, if the value is negative or if the shift count is
49  * the number of bits in the value - 1, and we might get
50  * compile-time or run-time complaints about that.
51  */
52  if (val & (G_GUINT64_CONSTANT(1) << (no_of_bits-1)))
53  val |= (G_GUINT64_CONSTANT(0xFFFFFFFFFFFFFFFF) << no_of_bits);
54 
55  return val;
56 }
57 
58 /*
59 static inline guint64
60 ws_sign_ext64(guint64 val, int no_of_bits)
61 {
62  gint64 sval = (val << (64 - no_of_bits));
63 
64  return (guint64) (sval >> (64 - no_of_bits));
65 }
66 */
67 
68 #endif /* __WSUTIL_SIGN_EXT_H__ */