diff options
author | px4dev <px4@purgatory.org> | 2012-08-04 15:12:36 -0700 |
---|---|---|
committer | px4dev <px4@purgatory.org> | 2012-08-04 15:12:36 -0700 |
commit | 8a365179eafdf3aea98e60ab9f5882b200d4c759 (patch) | |
tree | 4f38d6d4cd80bd0b6e22e2bb534c3f117ce44e56 /nuttx/lib/stdlib/lib_qsort.c | |
download | px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.tar.gz px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.tar.bz2 px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.zip |
Fresh import of the PX4 firmware sources.
Diffstat (limited to 'nuttx/lib/stdlib/lib_qsort.c')
-rw-r--r-- | nuttx/lib/stdlib/lib_qsort.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/nuttx/lib/stdlib/lib_qsort.c b/nuttx/lib/stdlib/lib_qsort.c new file mode 100644 index 000000000..13bca7499 --- /dev/null +++ b/nuttx/lib/stdlib/lib_qsort.c @@ -0,0 +1,238 @@ +/**************************************************************************** + * lib/stdlib/lib_qsort.c + * + * Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Leveraged from: + * + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> +#include <stdlib.h> + +/**************************************************************************** + * Preprocessor Definitions + ****************************************************************************/ + +#define min(a, b) (a) < (b) ? a : b + +#define swapcode(TYPE, parmi, parmj, n) \ + { \ + long i = (n) / sizeof (TYPE); \ + register TYPE *pi = (TYPE *) (parmi); \ + register TYPE *pj = (TYPE *) (parmj); \ + do { \ + register TYPE t = *pi; \ + *pi++ = *pj; \ + *pj++ = t; \ + } while (--i > 0); \ + } + +#define SWAPINIT(a, size) \ + swaptype = ((char *)a - (char *)0) % sizeof(long) || \ + size % sizeof(long) ? 2 : size == sizeof(long)? 0 : 1; + +#define swap(a, b) \ + if (swaptype == 0) \ + { \ + long t = *(long *)(a); \ + *(long *)(a) = *(long *)(b); \ + *(long *)(b) = t; \ + } \ + else \ + { \ + swapfunc(a, b, size, swaptype); \ + } + +#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +static inline void swapfunc(char *a, char *b, int n, int swaptype); +static inline char *med3(char *a, char *b, char *c, + int (*compar)(const void *, const void *)); + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +static inline void swapfunc(char *a, char *b, int n, int swaptype) +{ + if(swaptype <= 1) + { + swapcode(long, a, b, n) + } + else + { + swapcode(char, a, b, n) + } +} + +static inline char *med3(char *a, char *b, char *c, + int (*compar)(const void *, const void *)) +{ + return compar(a, b) < 0 ? + (compar(b, c) < 0 ? b : (compar(a, c) < 0 ? c : a )) + :(compar(b, c) > 0 ? b : (compar(a, c) < 0 ? a : c )); +} + +/**************************************************************************** + * Public Function + ****************************************************************************/ + +/**************************************************************************** + * Name: qsort + * + * Description: + * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". + * + ****************************************************************************/ + +void qsort(void *base, size_t nmemb, size_t size, + int(*compar)(const void *, const void *)) +{ + char *pa, *pb, *pc, *pd, *pl, *pm, *pn; + int d, r, swaptype, swap_cnt; + +loop: + SWAPINIT(base, size); + swap_cnt = 0; + if (nmemb < 7) + { + for (pm = (char *) base + size; pm < (char *) base + nmemb * size; pm += size) + { + for (pl = pm; pl > (char *) base && compar(pl - size, pl) > 0; pl -= size) + { + swap(pl, pl - size); + } + } + return; + } + + pm = (char *) base + (nmemb / 2) * size; + if (nmemb > 7) + { + pl = base; + pn = (char *) base + (nmemb - 1) * size; + if (nmemb > 40) + { + d = (nmemb / 8) * size; + pl = med3(pl, pl + d, pl + 2 * d, compar); + pm = med3(pm - d, pm, pm + d, compar); + pn = med3(pn - 2 * d, pn - d, pn, compar); + } + pm = med3(pl, pm, pn, compar); + } + swap(base, pm); + pa = pb = (char *) base + size; + + pc = pd = (char *) base + (nmemb - 1) * size; + for (;;) + { + while (pb <= pc && (r = compar(pb, base)) <= 0) + { + if (r == 0) + { + swap_cnt = 1; + swap(pa, pb); + pa += size; + } + pb += size; + } + while (pb <= pc && (r = compar(pc, base)) >= 0) + { + if (r == 0) + { + swap_cnt = 1; + swap(pc, pd); + pd -= size; + } + pc -= size; + } + + if (pb > pc) + { + break; + } + + swap(pb, pc); + swap_cnt = 1; + pb += size; + pc -= size; + } + + if (swap_cnt == 0) + { + /* Switch to insertion sort */ + + for (pm = (char *) base + size; pm < (char *) base + nmemb * size; pm += size) + { + for (pl = pm; pl > (char *) base && compar(pl - size, pl) > 0; pl -= size) + { + swap(pl, pl - size); + } + } + return; + } + + pn = (char *) base + nmemb * size; + r = min(pa - (char *)base, pb - pa); + vecswap(base, pb - r, r); + r = min(pd - pc, pn - pd - size); + vecswap(pb, pn - r, r); + + if ((r = pb - pa) > size) + { + qsort(base, r / size, size, compar); + } + + if ((r = pd - pc) > size) + { + /* Iterate rather than recurse to save stack space */ + base = pn - r; + nmemb = r / size; + goto loop; + } +} + |