lib/sdk/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 unsigned int _rotr( unsigned int value, int shift );
  14 /*
  15  * @implemented
  16  */
  17 unsigned int _rotl( unsigned int value, int shift )
  18 {
  19         int max_bits = sizeof(unsigned int)<<3;
  20         if ( shift < 0 )
  21                 return _rotr(value,-shift);
  22
  23         if ( shift > max_bits )
  24                 shift = shift % max_bits;
  25         return (value << shift) | (value >> (max_bits-shift));
  26 }
  27
  28 /*
  29  * @implemented
  30  */
  31 unsigned int _rotr( unsigned int value, int shift )
  32 {
  33         int max_bits = sizeof(unsigned int)<<3;
  34         if ( shift < 0 )
  35                 return _rotl(value,-shift);
  36
  37         if ( shift > max_bits<<3 )
  38                 shift = shift % max_bits;
  39         return (value >> shift) | (value <<  (max_bits-shift));
  40 }
  41
  42
  43 /*
  44  * @implemented
  45  */
  46 unsigned long _lrotl( unsigned long value, int shift )
  47 {
  48         int max_bits = sizeof(unsigned long)<<3;
  49         if ( shift < 0 )
  50                 return _lrotr(value,-shift);
  51
  52         if ( shift > max_bits )
  53                 shift = shift % max_bits;
  54         return (value << shift) | (value >> (max_bits-shift));
  55 }
  56
  57 /*
  58  * @implemented
  59  */
  60 unsigned long _lrotr( unsigned long value, int shift )
  61 {
  62         int max_bits = sizeof(unsigned long)<<3;
  63         if ( shift < 0 )
  64                 return _lrotl(value,-shift);
  65
  66         if ( shift > max_bits )
  67                 shift = shift % max_bits;
  68         return (value >> shift) | (value << (max_bits-shift));
  69 }