Line data    Source code

       1             : /* src/toolbox/util.hpp - contains some utility functions
       2             : 
       3             :    Copyright (C) 1996-2013
       4             :    CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO
       5             : 
       6             :    This file is part of CACAO.
       7             : 
       8             :    This program is free software; you can redistribute it and/or
       9             :    modify it under the terms of the GNU General Public License as
      10             :    published by the Free Software Foundation; either version 2, or (at
      11             :    your option) any later version.
      12             : 
      13             :    This program is distributed in the hope that it will be useful, but
      14             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      16             :    General Public License for more details.
      17             : 
      18             :    You should have received a copy of the GNU General Public License
      19             :    along with this program; if not, write to the Free Software
      20             :    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
      21             :    02110-1301, USA.
      22             : 
      23             : */
      24             : 
      25             : 
      26             : #ifndef UTIL_HPP_
      27             : #define UTIL_HPP_ 1
      28             : 
      29             : #include <config.h>
      30             : #include <cstdarg>
      31             : 
      32             : #include "toolbox/assert.hpp"
      33             : 
      34             : /* function prototypes ********************************************************/
      35             : 
      36             : int get_variable_message_length(const char *fmt, va_list ap);
      37             : 
      38             : /**
      39             :  * find the smallest power of two >= n
      40             :  */
      41        1984 : static inline size_t next_power_of_two(size_t n) {
      42             :    // the 'n--' and 'n++' make sure that a power of two is mapped to itself
      43             : 
      44        1984 :         n--;
      45             : 
      46             :         // this must be repeated log2(bits in size_t) times
      47             :         // i.e. for 5 times for 32 bit, 6 times for 64 bit
      48             : 
      49        1984 :         n = (n >>  1) | n;
      50        1984 :         n = (n >>  2) | n;
      51        1984 :         n = (n >>  4) | n;
      52        1984 :         n = (n >>  8) | n;
      53        1984 :         n = (n >> 16) | n;
      54             : #if SIZEOF_VOID_P == 8
      55        1984 :         n = (n >> 32) | n;
      56             : #endif
      57             : 
      58        1984 :         n++;
      59             : 
      60        1984 :         return n;
      61             : }
      62             : 
      63       74054 : static inline bool is_power_of_two(size_t n) {
      64       74054 :         return (n & (n - 1)) == 0;
      65             : }
      66             : 
      67             : /**
      68             :  * fast computation of n % m.
      69             :  *
      70             :  * m MUST be a power of two and greater than zero
      71             :  */
      72    25097239 : static inline size_t fast_modulo(size_t n, size_t modul) {
      73             :    EXPENSIVE_ASSERT(modul > 0);
      74             :    EXPENSIVE_ASSERT(is_power_of_two(modul));
      75             : 
      76    25097239 :         return n & (modul - 1);
      77             : }
      78             : 
      79             : /**
      80             :  * Perform unsigned integer division.
      81             :  * But instead of rounding the result down, round it up.
      82             :  */
      83         326 : static inline size_t divide_rounding_up(size_t a, size_t b) {
      84         326 :    return (a + b - 1) / b;
      85             : }
      86             : 
      87             : 
      88             : #endif // UTIL_HPP_
      89             : 
      90             : 
      91             : /*
      92             :  * These are local overrides for various environment variables in Emacs.
      93             :  * Please do not remove this and leave it at the end of the file, where
      94             :  * Emacs will automagically detect them.
      95             :  * ---------------------------------------------------------------------
      96             :  * Local variables:
      97             :  * mode: c++
      98             :  * indent-tabs-mode: t
      99             :  * c-basic-offset: 4
     100             :  * tab-width: 4
     101             :  * End:
     102             :  * vim:noexpandtab:sw=4:ts=4:
     103             :  */