shuffle-def.h

Go to the documentation of this file.

/*
Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
All rights reserved.

This file is part of the VLFeat library and is made available under
the terms of the BSD license (see the COPYING file).
*/

#include "host.h"
#include "random.h"
#include <assert.h>

#ifndef VL_SHUFFLE_prefix
#error "VL_SHUFFLE_prefix must be defined"
#endif

#ifndef VL_SHUFFLE_array
#ifndef VL_SHUFFLE_type
#error "VL_SHUFFLE_type must be defined if VL_SHUFFLE_array is not"
#endif
#define VL_SHUFFLE_array VL_SHUFFLE_type*
#endif

#ifdef __DOXYGEN__
#define VL_SHUFFLE_prefix  ShufflePrefix       
#define VL_SHUFFLE_type    ShuffleType         
#define VL_SHUFFLE_array   ShuffleType*        
#endif

/* ---------------------------------------------------------------- */

#if ! defined(VL_SHUFFLE_swap) || defined(__DOXYGEN__)
#define VL_SHUFFLE_swap VL_XCAT(VL_SHUFFLE_prefix, _swap)

VL_INLINE void
VL_SHUFFLE_swap
(VL_SHUFFLE_array array,
 vl_uindex indexA,
 vl_uindex indexB)
{
  VL_SHUFFLE_type t = array [indexA] ;
  array [indexA] = array [indexB] ;
  array [indexB] = t ;
}

/* VL_SHUFFLE_swap */
#endif

/* ---------------------------------------------------------------- */

#if ! defined(VL_SHUFFLE_shuffle) || defined(__DOXYGEN__)
#define VL_SHUFFLE_shuffle VL_XCAT(VL_SHUFFLE_prefix, _shuffle)

VL_INLINE void
VL_SHUFFLE_shuffle
(VL_SHUFFLE_array array, vl_size size, VlRand * rand)
{
  vl_uindex n = size ;
  while (n > 1) {
    vl_uindex k = vl_rand_uindex (rand, n) ;
    n -- ;
    VL_SHUFFLE_swap (array, n, k) ;
  }
}

/* VL_SHUFFLE_shuffle */
#endif

#undef VL_SHUFFLE_prefix
#undef VL_SHUFFLE_swap
#undef VL_SHUFFLE_shuffle
#undef VL_SHUFFLE_type
#undef VL_SHUFFLE_array