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61 lines
2 KiB
C++
61 lines
2 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdlib/qsort.cpp
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Utility functions related to sorting and sorted data.
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*******************************************************************************/
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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// TODO: This is an ugly hack!
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static void memswap(uint8_t* a, uint8_t* b, size_t size)
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{
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uint8_t* tmp = (uint8_t*) malloc(size);
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if ( !tmp ) { abort(); }
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memcpy(tmp, a, size);
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memcpy(a, b, size);
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memcpy(b, tmp, size);
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free(tmp);
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}
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// TODO: This is just a quick and dirty insertion sort. It'd be nice to have a
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// good old quick sort here soon. Combined with the slow memswap above, this
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// results in a very slow sorting algorithm.
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extern "C" void qsort(void* base, size_t nmemb, size_t size,
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int (* compare)(const void*, const void*))
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{
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uint8_t* buf = (uint8_t*) base;
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for ( size_t i = 0; i < nmemb; i++ )
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{
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for ( size_t c = i; c; c-- )
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{
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size_t currentoff = c * size;
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uint8_t* current = buf + currentoff;
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size_t p = c-1;
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size_t prevoff = p * size;
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uint8_t* prev = buf + prevoff;
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int cmp = compare(prev, current);
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if ( cmp <= 0 ) { break; }
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memswap(prev, current, size);
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}
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}
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}
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