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  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. /**
  30.  * @file    sort.c
  31.  * @brief   Sorting functions.
  32.  *
  33.  * This files contains functions implementing several sorting
  34.  * algorithms (e.g. quick sort and bubble sort).
  35.  */
  36.  
  37. #include <mm/slab.h>
  38. #include <memstr.h>
  39. #include <sort.h>
  40. #include <panic.h>
  41.  
  42. #define EBUFSIZE    32
  43.  
  44. void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot);
  45. void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot);
  46.  
  47. /** Quicksort wrapper
  48.  *
  49.  * This is only a wrapper that takes care of memory allocations for storing
  50.  * the pivot and temporary elements for generic quicksort algorithm.
  51.  *
  52.  * This function _can_ sleep
  53.  *
  54.  * @param data Pointer to data to be sorted.
  55.  * @param n Number of elements to be sorted.
  56.  * @param e_size Size of one element.
  57.  * @param cmp Comparator function.
  58.  *
  59.  */
  60. void qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
  61. {
  62.     __u8 buf_tmp[EBUFSIZE];
  63.     __u8 buf_pivot[EBUFSIZE];
  64.     void * tmp = buf_tmp;
  65.     void * pivot = buf_pivot;
  66.  
  67.     if (e_size > EBUFSIZE) {
  68.         pivot = (void *) malloc(e_size, 0);
  69.         tmp = (void *) malloc(e_size, 0);
  70.     }
  71.  
  72.     _qsort(data, n, e_size, cmp, tmp, pivot);
  73.    
  74.     if (e_size > EBUFSIZE) {
  75.         free(tmp);
  76.         free(pivot);
  77.     }
  78. }
  79.  
  80. /** Quicksort
  81.  *
  82.  * Apply generic quicksort algorithm on supplied data, using pre-allocated buffers.
  83.  *
  84.  * @param data Pointer to data to be sorted.
  85.  * @param n Number of elements to be sorted.
  86.  * @param e_size Size of one element.
  87.  * @param cmp Comparator function.
  88.  * @param tmp Pointer to scratch memory buffer e_size bytes long.
  89.  * @param pivot Pointer to scratch memory buffer e_size bytes long.
  90.  *
  91.  */
  92. void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot)
  93. {
  94.     if (n > 4) {
  95.         int i = 0, j = n - 1;
  96.  
  97.         memcpy(pivot, data, e_size);
  98.  
  99.         while (1) {
  100.             while ((cmp(data + i * e_size, pivot) < 0) && i < n) i++;
  101.             while ((cmp(data + j * e_size, pivot) >=0) && j > 0) j--;
  102.             if (i<j) {
  103.                 memcpy(tmp, data + i * e_size, e_size);
  104.                 memcpy(data + i * e_size, data + j * e_size, e_size);
  105.                 memcpy(data + j * e_size, tmp, e_size);
  106.             } else {
  107.                 break;
  108.             }
  109.         }
  110.  
  111.         _qsort(data, j + 1, e_size, cmp, tmp, pivot);
  112.         _qsort(data + (j + 1) * e_size, n - j - 1, e_size, cmp, tmp, pivot);
  113.     } else {
  114.         _bubblesort(data, n, e_size, cmp, tmp);
  115.     }
  116. }
  117.  
  118. /** Bubblesort wrapper
  119.  *
  120.  * This is only a wrapper that takes care of memory allocation for storing
  121.  * the slot element for generic bubblesort algorithm.
  122.  *
  123.  * @param data Pointer to data to be sorted.
  124.  * @param n Number of elements to be sorted.
  125.  * @param e_size Size of one element.
  126.  * @param cmp Comparator function.
  127.  *
  128.  */
  129. void bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
  130. {
  131.     __u8 buf_slot[EBUFSIZE];
  132.     void * slot = buf_slot;
  133.    
  134.     if (e_size > EBUFSIZE) {
  135.         slot = (void *) malloc(e_size, 0);
  136.     }
  137.  
  138.     _bubblesort(data, n, e_size, cmp, slot);
  139.    
  140.     if (e_size > EBUFSIZE) {
  141.         free(slot);
  142.     }
  143. }
  144.  
  145. /** Bubblesort
  146.  *
  147.  * Apply generic bubblesort algorithm on supplied data, using pre-allocated buffer.
  148.  *
  149.  * @param data Pointer to data to be sorted.
  150.  * @param n Number of elements to be sorted.
  151.  * @param e_size Size of one element.
  152.  * @param cmp Comparator function.
  153.  * @param slot Pointer to scratch memory buffer e_size bytes long.
  154.  *
  155.  */
  156. void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot)
  157. {
  158.     bool done = false;
  159.     void * p;
  160.  
  161.     while (!done) {
  162.         done = true;
  163.         for (p = data; p < data + e_size * (n - 1); p = p + e_size) {
  164.             if (cmp(p, p + e_size) == 1) {
  165.                 memcpy(slot, p, e_size);
  166.                 memcpy(p, p + e_size, e_size);
  167.                 memcpy(p + e_size, slot, e_size);
  168.                 done = false;
  169.             }
  170.         }
  171.     }
  172.  
  173. }
  174.  
  175. /*
  176.  * Comparator returns 1 if a > b, 0 if a == b, -1 if a < b
  177.  */
  178. int int_cmp(void * a, void * b)
  179. {
  180.     return (* (int *) a > * (int*)b) ? 1 : (*(int *)a < * (int *)b) ? -1 : 0;
  181. }
  182.  
  183. int __u8_cmp(void * a, void * b)
  184. {
  185.     return (* (__u8 *) a > * (__u8 *)b) ? 1 : (*(__u8 *)a < * (__u8 *)b) ? -1 : 0;
  186. }
  187.  
  188. int __u16_cmp(void * a, void * b)
  189. {
  190.     return (* (__u16 *) a > * (__u16 *)b) ? 1 : (*(__u16 *)a < * (__u16 *)b) ? -1 : 0;
  191. }
  192.  
  193. int __u32_cmp(void * a, void * b)
  194. {
  195.     return (* (__u32 *) a > * (__u32 *)b) ? 1 : (*(__u32 *)a < * (__u32 *)b) ? -1 : 0;
  196. }
  197.