![Guy Harris](/assets/img/avatar_default.png)
That's not valid in C99, at least, if the value is negative or if the shift count is the number of bits in the value - 1, and we might get compile-time or run-time complaints about that. Also, make bit masks unsigned; to quote a run-time error reported in https://www.wireshark.org/lists/wireshark-dev/201504/msg00084.html "left shift of 1 by 31 places cannot be represented in type 'int'", so use type "unsigned int" instead, by shifting 1U rather than 1 left. Change-Id: I62220808058cb93f83329c1916b888a2067d524c Reviewed-on: https://code.wireshark.org/review/8254 Reviewed-by: Guy Harris <guy@alum.mit.edu>
81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
/*
|
|
* sign_ext.h
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 1998 Gerald Combs
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#ifndef __WSUTIL_SIGN_EXT_H__
|
|
#define __WSUTIL_SIGN_EXT_H__
|
|
|
|
#include <glib.h>
|
|
|
|
/* sign extension routines */
|
|
|
|
static inline guint32
|
|
ws_sign_ext32(guint32 val, int no_of_bits)
|
|
{
|
|
g_assert (no_of_bits >= 0 && no_of_bits <= 32);
|
|
|
|
if (no_of_bits == 0)
|
|
return val;
|
|
|
|
/*
|
|
* Don't shift signed values left; that's not valid in C99, at
|
|
* least, if the value is negative or if the shift count is
|
|
* the number of bits in the value - 1, and we might get
|
|
* compile-time or run-time complaints about that.
|
|
*/
|
|
if (val & (1U << (no_of_bits-1)))
|
|
val |= (0xFFFFFFFFU << no_of_bits);
|
|
|
|
return val;
|
|
}
|
|
|
|
static inline guint64
|
|
ws_sign_ext64(guint64 val, int no_of_bits)
|
|
{
|
|
g_assert (no_of_bits >= 0 && no_of_bits <= 64);
|
|
|
|
if (no_of_bits == 0)
|
|
return val;
|
|
|
|
/*
|
|
* Don't shift signed values left; that's not valid in C99, at
|
|
* least, if the value is negative or if the shift count is
|
|
* the number of bits in the value - 1, and we might get
|
|
* compile-time or run-time complaints about that.
|
|
*/
|
|
if (val & (G_GUINT64_CONSTANT(1) << (no_of_bits-1)))
|
|
val |= (G_GUINT64_CONSTANT(0xFFFFFFFFFFFFFFFF) << no_of_bits);
|
|
|
|
return val;
|
|
}
|
|
|
|
/*
|
|
static inline guint64
|
|
ws_sign_ext64(guint64 val, int no_of_bits)
|
|
{
|
|
gint64 sval = (val << (64 - no_of_bits));
|
|
|
|
return (guint64) (sval >> (64 - no_of_bits));
|
|
}
|
|
*/
|
|
|
|
#endif /* __WSUTIL_SIGN_EXT_H__ */
|