kernel/generic/src/lib/sort.c

   1 /*
   2  * Copyright (c) 2005 Sergey Bondari
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup generic
  30  * @{
  31  */
  32
  33 /**
  34  * @file
  35  * @brief       Sorting functions.
  36  *
  37  * This files contains functions implementing several sorting
  38  * algorithms (e.g. quick sort and bubble sort).
  39  */
  40
  41 #include <mm/slab.h>
  42 #include <memstr.h>
  43 #include <sort.h>
  44 #include <panic.h>
  45
  46 #define EBUFSIZE        32
  47
  48 void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot);
  49 void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot);
  50
  51 /** Quicksort wrapper
  52  *
  53  * This is only a wrapper that takes care of memory allocations for storing
  54  * the pivot and temporary elements for generic quicksort algorithm.
  55  *
  56  * This function _can_ sleep
  57  *
  58  * @param data Pointer to data to be sorted.
  59  * @param n Number of elements to be sorted.
  60  * @param e_size Size of one element.
  61  * @param cmp Comparator function.
  62  *
  63  */
  64 void qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
  65 {
  66         uint8_t buf_tmp[EBUFSIZE];
  67         uint8_t buf_pivot[EBUFSIZE];
  68         void * tmp = buf_tmp;
  69         void * pivot = buf_pivot;
  70
  71         if (e_size > EBUFSIZE) {
  72                 pivot = (void *) malloc(e_size, 0);
  73                 tmp = (void *) malloc(e_size, 0);
  74         }
  75
  76         _qsort(data, n, e_size, cmp, tmp, pivot);
  77
  78         if (e_size > EBUFSIZE) {
  79                 free(tmp);
  80                 free(pivot);
  81         }
  82 }
  83
  84 /** Quicksort
  85  *
  86  * Apply generic quicksort algorithm on supplied data, using pre-allocated buffers.
  87  *
  88  * @param data Pointer to data to be sorted.
  89  * @param n Number of elements to be sorted.
  90  * @param e_size Size of one element.
  91  * @param cmp Comparator function.
  92  * @param tmp Pointer to scratch memory buffer e_size bytes long.
  93  * @param pivot Pointer to scratch memory buffer e_size bytes long.
  94  *
  95  */
  96 void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot)
  97 {
  98         if (n > 4) {
  99                 int i = 0, j = n - 1;
 100
 101                 memcpy(pivot, data, e_size);
 102
 103                 while (1) {
 104                         while ((cmp(data + i * e_size, pivot) < 0) && i < n) i++;
 105                         while ((cmp(data + j * e_size, pivot) >=0) && j > 0) j--;
 106                         if (i<j) {
 107                                 memcpy(tmp, data + i * e_size, e_size);
 108                                 memcpy(data + i * e_size, data + j * e_size, e_size);
 109                                 memcpy(data + j * e_size, tmp, e_size);
 110                         } else {
 111                                 break;
 112                         }
 113                 }
 114
 115                 _qsort(data, j + 1, e_size, cmp, tmp, pivot);
 116                 _qsort(data + (j + 1) * e_size, n - j - 1, e_size, cmp, tmp, pivot);
 117         } else {
 118                 _bubblesort(data, n, e_size, cmp, tmp);
 119         }
 120 }
 121
 122 /** Bubblesort wrapper
 123  *
 124  * This is only a wrapper that takes care of memory allocation for storing
 125  * the slot element for generic bubblesort algorithm.
 126  *
 127  * @param data Pointer to data to be sorted.
 128  * @param n Number of elements to be sorted.
 129  * @param e_size Size of one element.
 130  * @param cmp Comparator function.
 131  *
 132  */
 133 void bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
 134 {
 135         uint8_t buf_slot[EBUFSIZE];
 136         void * slot = buf_slot;
 137
 138         if (e_size > EBUFSIZE) {
 139                 slot = (void *) malloc(e_size, 0);
 140         }
 141
 142         _bubblesort(data, n, e_size, cmp, slot);
 143
 144         if (e_size > EBUFSIZE) {
 145                 free(slot);
 146         }
 147 }
 148
 149 /** Bubblesort
 150  *
 151  * Apply generic bubblesort algorithm on supplied data, using pre-allocated buffer.
 152  *
 153  * @param data Pointer to data to be sorted.
 154  * @param n Number of elements to be sorted.
 155  * @param e_size Size of one element.
 156  * @param cmp Comparator function.
 157  * @param slot Pointer to scratch memory buffer e_size bytes long.
 158  *
 159  */
 160 void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot)
 161 {
 162         bool done = false;
 163         void * p;
 164
 165         while (!done) {
 166                 done = true;
 167                 for (p = data; p < data + e_size * (n - 1); p = p + e_size) {
 168                         if (cmp(p, p + e_size) == 1) {
 169                                 memcpy(slot, p, e_size);
 170                                 memcpy(p, p + e_size, e_size);
 171                                 memcpy(p + e_size, slot, e_size);
 172                                 done = false;
 173                         }
 174                 }
 175         }
 176
 177 }
 178
 179 /*
 180  * Comparator returns 1 if a > b, 0 if a == b, -1 if a < b
 181  */
 182 int int_cmp(void * a, void * b)
 183 {
 184         return (* (int *) a > * (int*)b) ? 1 : (*(int *)a < * (int *)b) ? -1 : 0;
 185 }
 186
 187 int uint8_t_cmp(void * a, void * b)
 188 {
 189         return (* (uint8_t *) a > * (uint8_t *)b) ? 1 : (*(uint8_t *)a < * (uint8_t *)b) ? -1 : 0;
 190 }
 191
 192 int uint16_t_cmp(void * a, void * b)
 193 {
 194         return (* (uint16_t *) a > * (uint16_t *)b) ? 1 : (*(uint16_t *)a < * (uint16_t *)b) ? -1 : 0;
 195 }
 196
 197 int uint32_t_cmp(void * a, void * b)
 198 {
 199         return (* (uint32_t *) a > * (uint32_t *)b) ? 1 : (*(uint32_t *)a < * (uint32_t *)b) ? -1 : 0;
 200 }
 201
 202 /** @}
 203  */