forked from osmocom/wireshark
9eda2fa063
Output from BASE_HEX et al has always been zero-padded to according to the field type - 8 digits for FT_UINT32, etc. When the field has a bitmask, this is definitely not appropriate - the field type is used to indicate the size of the bitfield container, and tells us nothing about the size of this field. Instead, determine the actual size of the field by inspecting the bitmask, and output the corresponding number of hex digits. Change-Id: I10ec4e93e1e40e8b1354d5368cc8945cf671a617 Reviewed-on: https://code.wireshark.org/review/13225 Reviewed-by: João Valverde <j@v6e.pt> Petri-Dish: João Valverde <j@v6e.pt> Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org> Reviewed-by: Michael Mann <mmann78@netscape.net>
106 lines
2.5 KiB
C
106 lines
2.5 KiB
C
/*
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* bitz_ctz.h
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef __WSUTIL_BITS_CTZ_H__
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#define __WSUTIL_BITS_CTZ_H__
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#include <glib.h>
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/* ws_ctz == trailing zeros == position of lowest set bit [0..63] */
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/* ws_ilog2 == position of highest set bit == 63 - leading zeros [0..63] */
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/* The return value of both ws_ctz and ws_ilog2 is undefined for x == 0 */
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#if defined(__GNUC__) && ((__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
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static inline int
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ws_ctz(guint64 x)
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{
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return __builtin_ctzll(x);
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}
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static inline int
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ws_ilog2(guint64 x)
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{
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return 63 - __builtin_clzll(x);
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}
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#else
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static inline int
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__ws_ctz32(guint32 x)
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{
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/* From http://graphics.stanford.edu/~seander/bithacks.html#ZerosOnRightMultLookup */
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static const guint8 table[32] = {
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0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
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31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
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};
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return table[((guint32)((x & -(gint32)x) * 0x077CB531U)) >> 27];
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}
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static inline int
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ws_ctz(guint64 x)
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{
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guint32 hi = x >> 32;
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guint32 lo = (guint32) x;
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if (lo == 0)
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return 32 + __ws_ctz32(hi);
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else
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return __ws_ctz32(lo);
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}
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static inline int
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__ws_ilog2_32(guint32 x)
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{
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/* From http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn */
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static const guint8 table[32] = {
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0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
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8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
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};
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x |= x >> 1;
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x |= x >> 2;
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x |= x >> 4;
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x |= x >> 8;
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x |= x >> 16;
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return table[((guint32)(x * 0x07C4ACDDU)) >> 27];
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}
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static inline int
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ws_ilog2(guint64 x)
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{
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guint32 hi = x >> 32;
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guint32 lo = (guint32) x;
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if (hi == 0)
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return __ws_ilog2_32(lo);
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else
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return 32 + __ws_ilog2_32(hi);
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}
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#endif
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#endif /* __WSUTIL_BITS_CTZ_H__ */
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