reactos/lib/crt/stdlib/rot.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS system libraries
   4  * FILE:        lib/msvcrt/stdlib/rot.c
   5  * PURPOSE:     Performs a bitwise rotation
   6  * PROGRAMER:   Ariadne
   7  * UPDATE HISTORY:
   8  *              03/04/99: Created
   9  */
  10
  11 #include <stdlib.h>
  12
  13 /*
  14  * @implemented
  15  */
  16 unsigned int _rotl( unsigned int value, int shift )
  17 {
  18         int max_bits = sizeof(unsigned int)<<3;
  19         if ( shift < 0 )
  20                 return _rotr(value,-shift);
  21
  22         if ( shift > max_bits )
  23                 shift = shift % max_bits;
  24         return (value << shift) | (value >> (max_bits-shift));
  25 }
  26
  27 /*
  28  * @implemented
  29  */
  30 unsigned int _rotr( unsigned int value, int shift )
  31 {
  32         int max_bits = sizeof(unsigned int)<<3;
  33         if ( shift < 0 )
  34                 return _rotl(value,-shift);
  35
  36         if ( shift > max_bits<<3 )
  37                 shift = shift % max_bits;
  38         return (value >> shift) | (value <<  (max_bits-shift));
  39 }
  40
  41
  42 /*
  43  * @implemented
  44  */
  45 unsigned long _lrotl( unsigned long value, int shift )
  46 {
  47         int max_bits = sizeof(unsigned long)<<3;
  48         if ( shift < 0 )
  49                 return _lrotr(value,-shift);
  50
  51         if ( shift > max_bits )
  52                 shift = shift % max_bits;
  53         return (value << shift) | (value >> (max_bits-shift));
  54 }
  55
  56 /*
  57  * @implemented
  58  */
  59 unsigned long _lrotr( unsigned long value, int shift )
  60 {
  61         int max_bits = sizeof(unsigned long)<<3;
  62         if ( shift < 0 )
  63                 return _lrotl(value,-shift);
  64
  65         if ( shift > max_bits )
  66                 shift = shift % max_bits;
  67         return (value >> shift) | (value << (max_bits-shift));
  68 }