1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/graphite2/src/inc/bits.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,90 @@
1.4 +/* GRAPHITE2 LICENSING
1.5 +
1.6 + Copyright 2012, SIL International
1.7 + All rights reserved.
1.8 +
1.9 + This library is free software; you can redistribute it and/or modify
1.10 + it under the terms of the GNU Lesser General Public License as published
1.11 + by the Free Software Foundation; either version 2.1 of License, or
1.12 + (at your option) any later version.
1.13 +
1.14 + This program is distributed in the hope that it will be useful,
1.15 + but WITHOUT ANY WARRANTY; without even the implied warranty of
1.16 + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1.17 + Lesser General Public License for more details.
1.18 +
1.19 + You should also have received a copy of the GNU Lesser General Public
1.20 + License along with this library in the file named "LICENSE".
1.21 + If not, write to the Free Software Foundation, 51 Franklin Street,
1.22 + Suite 500, Boston, MA 02110-1335, USA or visit their web page on the
1.23 + internet at http://www.fsf.org/licenses/lgpl.html.
1.24 +
1.25 +Alternatively, the contents of this file may be used under the terms of the
1.26 +Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public
1.27 +License, as published by the Free Software Foundation, either version 2
1.28 +of the License or (at your option) any later version.
1.29 +*/
1.30 +#pragma once
1.31 +
1.32 +namespace graphite2
1.33 +{
1.34 +
1.35 +template<typename T>
1.36 +inline unsigned int bit_set_count(T v)
1.37 +{
1.38 + v = v - ((v >> 1) & T(~T(0)/3)); // temp
1.39 + v = (v & T(~T(0)/15*3)) + ((v >> 2) & T(~T(0)/15*3)); // temp
1.40 + v = (v + (v >> 4)) & T(~T(0)/255*15); // temp
1.41 + return (T)(v * T(~T(0)/255)) >> (sizeof(T)-1)*8; // count
1.42 +}
1.43 +
1.44 +
1.45 +template<int S>
1.46 +inline unsigned long _mask_over_val(unsigned long v)
1.47 +{
1.48 + v = _mask_over_val<S/2>(v);
1.49 + v |= v >> S*4;
1.50 + return v;
1.51 +}
1.52 +
1.53 +template<>
1.54 +inline unsigned long _mask_over_val<1>(unsigned long v)
1.55 +{
1.56 + v |= v >> 1;
1.57 + v |= v >> 2;
1.58 + v |= v >> 4;
1.59 + return v;
1.60 +}
1.61 +
1.62 +template<typename T>
1.63 +inline T mask_over_val(T v)
1.64 +{
1.65 + return _mask_over_val<sizeof(T)>(v);
1.66 +}
1.67 +
1.68 +template<typename T>
1.69 +inline unsigned long next_highest_power2(T v)
1.70 +{
1.71 + return _mask_over_val<sizeof(T)>(v-1)+1;
1.72 +}
1.73 +
1.74 +template<typename T>
1.75 +inline unsigned int log_binary(T v)
1.76 +{
1.77 + return bit_set_count(mask_over_val(v))-1;
1.78 +}
1.79 +
1.80 +template<typename T>
1.81 +inline T has_zero(const T x)
1.82 +{
1.83 + return (x - T(~T(0)/255)) & ~x & T(~T(0)/255*128);
1.84 +}
1.85 +
1.86 +template<typename T>
1.87 +inline T zero_bytes(const T x, unsigned char n)
1.88 +{
1.89 + const T t = T(~T(0)/255*n);
1.90 + return T((has_zero(x^t) >> 7)*n);
1.91 +}
1.92 +
1.93 +}
