I hereby relicense all my work on Sortix under the ISC license as below. All Sortix contributions by other people are already under this license, are not substantial enough to be copyrightable, or have been removed. All imported code from other projects is compatible with this license. All GPL licensed code from other projects had previously been removed. Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors. Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
100 lines
3 KiB
C
100 lines
3 KiB
C
/*
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* Copyright (c) 2012, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdlib/qsort_r.c
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* Sort an array.
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*/
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#include <stdlib.h>
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#include <string.h>
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static void memswap(unsigned char* a, unsigned char* b, size_t size)
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{
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unsigned char tmp;
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for ( size_t i = 0; i < size; i++ )
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{
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tmp = a[i];
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a[i] = b[i];
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b[i] = tmp;
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}
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}
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static
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unsigned char* array_index(unsigned char* base,
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size_t element_size,
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size_t index)
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{
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return base + element_size * index;
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}
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static
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size_t partition(unsigned char* base,
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size_t element_size,
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size_t num_elements,
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size_t pivot_index,
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int (*compare)(const void*, const void*, void*),
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void* arg)
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{
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if ( pivot_index != num_elements - 1 )
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{
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unsigned char* pivot = array_index(base, element_size, pivot_index);
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unsigned char* other = array_index(base, element_size, num_elements - 1);
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memswap(pivot, other, element_size);
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pivot_index = num_elements - 1;
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}
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size_t store_index = 0;
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for ( size_t i = 0; i < num_elements - 1; i++ )
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{
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unsigned char* pivot = array_index(base, element_size, pivot_index);
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unsigned char* value = array_index(base, element_size, i);
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if ( compare(value, pivot, arg) <= 0 )
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{
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unsigned char* other = array_index(base, element_size, store_index);
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if ( value != other )
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memswap(value, other, element_size);
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store_index++;
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}
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}
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unsigned char* pivot = array_index(base, element_size, pivot_index);
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unsigned char* value = array_index(base, element_size, store_index);
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memswap(pivot, value, element_size);
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return store_index;
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}
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void qsort_r(void* base_ptr,
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size_t num_elements,
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size_t element_size,
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int (*compare)(const void*, const void*, void*),
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void* arg)
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{
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unsigned char* base = (unsigned char*) base_ptr;
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if ( !element_size || num_elements < 2 )
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return;
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size_t pivot_index = num_elements / 2;
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pivot_index = partition(base, element_size, num_elements, pivot_index, compare, arg);
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if ( 2 <= pivot_index )
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qsort_r(base, pivot_index, element_size, compare, arg);
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if ( 2 <= num_elements - (pivot_index + 1) )
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qsort_r(array_index(base, element_size, pivot_index + 1),
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num_elements - (pivot_index + 1), element_size, compare, arg);
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}
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