reactos/lib/sdk/crt/stdlib/rot.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS system libraries
   4  * FILE:        lib/sdk/crt/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 #ifdef _MSC_VER
  14 #pragma function(_rotr, _rotl, _rotr, _lrotl, _lrotr)
  15 #endif
  16
  17 unsigned int _rotr( unsigned int value, int shift );
  18 /*
  19  * @implemented
  20  */
  21 unsigned int _rotl( unsigned int value, int shift )
  22 {
  23         int max_bits = sizeof(unsigned int)<<3;
  24         if ( shift < 0 )
  25                 return _rotr(value,-shift);
  26
  27         if ( shift > max_bits )
  28                 shift = shift % max_bits;
  29         return (value << shift) | (value >> (max_bits-shift));
  30 }
  31
  32 /*
  33  * @implemented
  34  */
  35 unsigned int _rotr( unsigned int value, int shift )
  36 {
  37         int max_bits = sizeof(unsigned int)<<3;
  38         if ( shift < 0 )
  39                 return _rotl(value,-shift);
  40
  41         if ( shift > max_bits<<3 )
  42                 shift = shift % max_bits;
  43         return (value >> shift) | (value <<  (max_bits-shift));
  44 }
  45
  46
  47 /*
  48  * @implemented
  49  */
  50 unsigned long _lrotl( unsigned long value, int shift )
  51 {
  52         int max_bits = sizeof(unsigned long)<<3;
  53         if ( shift < 0 )
  54                 return _lrotr(value,-shift);
  55
  56         if ( shift > max_bits )
  57                 shift = shift % max_bits;
  58         return (value << shift) | (value >> (max_bits-shift));
  59 }
  60
  61 /*
  62  * @implemented
  63  */
  64 unsigned long _lrotr( unsigned long value, int shift )
  65 {
  66         int max_bits = sizeof(unsigned long)<<3;
  67         if ( shift < 0 )
  68                 return _lrotl(value,-shift);
  69
  70         if ( shift > max_bits )
  71                 shift = shift % max_bits;
  72         return (value >> shift) | (value << (max_bits-shift));
  73 }