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333 bondari 1 
/*
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 * Copyright (C) 2005 Sergey Bondari
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1264 jermar 29 
/**
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 * @file    sort.c
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 * @brief   Sorting functions.
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 *
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 * This files contains functions implementing several sorting
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 * algorithms (e.g. quick sort and bubble sort).
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 */
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814 palkovsky 37 
#include <mm/slab.h>
331 bondari 38 
#include <memstr.h>
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#include <sort.h>
335 bondari 40 
#include <panic.h>
331 bondari 41 
 
349 jermar 42 
#define EBUFSIZE    32
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351 jermar 44 
void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot);
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void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot);
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/** Quicksort wrapper
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 *
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 * This is only a wrapper that takes care of memory allocations for storing
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 * the pivot and temporary elements for generic quicksort algorithm.
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 *
822 palkovsky 52 
 * This function _can_ sleep
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 *
351 jermar 54 
 * @param data Pointer to data to be sorted.
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 * @param n Number of elements to be sorted.
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 * @param e_size Size of one element.
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 * @param cmp Comparator function.
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 *
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 */
350 jermar 60 
void qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
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{
349 jermar 62 
    __u8 buf_tmp[EBUFSIZE];
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    __u8 buf_pivot[EBUFSIZE];
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    void * tmp = buf_tmp;
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    void * pivot = buf_pivot;
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    if (e_size > EBUFSIZE) {
822 palkovsky 68 
        pivot = (void *) malloc(e_size, 0);
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        tmp = (void *) malloc(e_size, 0);
335 bondari 70 
    }
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351 jermar 72 
    _qsort(data, n, e_size, cmp, tmp, pivot);
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    if (e_size > EBUFSIZE) {
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        free(tmp);
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        free(pivot);
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    }
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}
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/** Quicksort
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 *
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 * Apply generic quicksort algorithm on supplied data, using pre-allocated buffers.
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 *
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 * @param data Pointer to data to be sorted.
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 * @param n Number of elements to be sorted.
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 * @param e_size Size of one element.
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 * @param cmp Comparator function.
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 * @param tmp Pointer to scratch memory buffer e_size bytes long.
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 * @param pivot Pointer to scratch memory buffer e_size bytes long.
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 *
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 */
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void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot)
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{
350 jermar 94 
    if (n > 4) {
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        int i = 0, j = n - 1;
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        memcpy(pivot, data, e_size);
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        while (1) {
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            while ((cmp(data + i * e_size, pivot) < 0) && i < n) i++;
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            while ((cmp(data + j * e_size, pivot) >=0) && j > 0) j--;
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            if (i<j) {
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                memcpy(tmp, data + i * e_size, e_size);
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                memcpy(data + i * e_size, data + j * e_size, e_size);
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                memcpy(data + j * e_size, tmp, e_size);
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            } else {
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                break;
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            }
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        }
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351 jermar 111 
        _qsort(data, j + 1, e_size, cmp, tmp, pivot);
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        _qsort(data + (j + 1) * e_size, n - j - 1, e_size, cmp, tmp, pivot);
350 jermar 113 
    } else {
351 jermar 114 
        _bubblesort(data, n, e_size, cmp, tmp);
350 jermar 115 
    }
335 bondari 116 
}
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351 jermar 118 
/** Bubblesort wrapper
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 *
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 * This is only a wrapper that takes care of memory allocation for storing
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 * the slot element for generic bubblesort algorithm.
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 *
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 * @param data Pointer to data to be sorted.
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 * @param n Number of elements to be sorted.
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 * @param e_size Size of one element.
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 * @param cmp Comparator function.
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 *
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 */
350 jermar 129 
void bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))
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{
349 jermar 131 
    __u8 buf_slot[EBUFSIZE];
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    void * slot = buf_slot;
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    if (e_size > EBUFSIZE) {
822 palkovsky 135 
        slot = (void *) malloc(e_size, 0);
349 jermar 136 
    }
335 bondari 137 
 
351 jermar 138 
    _bubblesort(data, n, e_size, cmp, slot);
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    if (e_size > EBUFSIZE) {
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        free(slot);
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    }
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}
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/** Bubblesort
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 *
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 * Apply generic bubblesort algorithm on supplied data, using pre-allocated buffer.
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 *
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 * @param data Pointer to data to be sorted.
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 * @param n Number of elements to be sorted.
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 * @param e_size Size of one element.
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 * @param cmp Comparator function.
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 * @param slot Pointer to scratch memory buffer e_size bytes long.
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 *
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 */
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void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot)
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{
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    bool done = false;
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    void * p;
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335 bondari 161 
    while (!done) {
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        done = true;
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        for (p = data; p < data + e_size * (n - 1); p = p + e_size) {
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            if (cmp(p, p + e_size) == 1) {
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                memcpy(slot, p, e_size);
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                memcpy(p, p + e_size, e_size);
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                memcpy(p + e_size, slot, e_size);
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                done = false;
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            }
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        }
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    }
351 jermar 172 
 
335 bondari 173 
}
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331 bondari 175 
/*
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 * Comparator returns 1 if a > b, 0 if a == b, -1 if a < b
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 */
350 jermar 178 
int int_cmp(void * a, void * b)
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{
333 bondari 180 
    return (* (int *) a > * (int*)b) ? 1 : (*(int *)a < * (int *)b) ? -1 : 0;
331 bondari 181 
}
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350 jermar 183 
int __u8_cmp(void * a, void * b)
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{
333 bondari 185 
    return (* (__u8 *) a > * (__u8 *)b) ? 1 : (*(__u8 *)a < * (__u8 *)b) ? -1 : 0;
331 bondari 186 
}
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350 jermar 188 
int __u16_cmp(void * a, void * b)
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{
333 bondari 190 
    return (* (__u16 *) a > * (__u16 *)b) ? 1 : (*(__u16 *)a < * (__u16 *)b) ? -1 : 0;
331 bondari 191 
}
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350 jermar 193 
int __u32_cmp(void * a, void * b)
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{
333 bondari 195 
    return (* (__u32 *) a > * (__u32 *)b) ? 1 : (*(__u32 *)a < * (__u32 *)b) ? -1 : 0;
331 bondari 196 
}