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Re: [Minios-devel] [UNIKRAFT PATCH v2 1/2] lib/nolib: Add qsort



Hi Vlad, this patch looks good, thanks.

Reviewed-by: Felipe Huici <felipe.huici@xxxxxxxxx>

On Sun, Apr 5, 2020 at 1:57 PM Vlad-Andrei Badoiu
<vlad_andrei.badoiu@xxxxxx> wrote:
>
> From: Vlad-Andrei BĂDOIU <vlad_andrei.badoiu@xxxxxxxxxxxxxxx>
>
> This qsort implementation is an adapted version of android bionic's
> qsort. It is the Qsort routine from Bentley & McIlroy's "Engineering
> a Sort Function".
>
> Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxx>
> ---
>  lib/nolibc/Makefile.uk      |   3 +
>  lib/nolibc/exportsyms.uk    |   1 +
>  lib/nolibc/include/stdlib.h |   3 +
>  lib/nolibc/qsort.c          | 157 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 164 insertions(+)
>  create mode 100644 lib/nolibc/qsort.c
>
> diff --git a/lib/nolibc/Makefile.uk b/lib/nolibc/Makefile.uk
> index 7cb2e7d1..9d4a9ec3 100644
> --- a/lib/nolibc/Makefile.uk
> +++ b/lib/nolibc/Makefile.uk
> @@ -35,5 +35,8 @@ LIBNOLIBC_SRCS-y += $(LIBNOLIBC_BASE)/sscanf.c
>  LIBNOLIBC_SRCS-y += $(LIBNOLIBC_BASE)/asprintf.c
>  LIBNOLIBC_SRCS-$(CONFIG_LIBUKALLOC) += $(LIBNOLIBC_BASE)/malloc.c
>
> +
> +LIBNOLIBC_SRCS-y += $(LIBNOLIBC_BASE)/qsort.c
> +
>  # Localize internal symbols (starting with __*)
>  LIBNOLIBC_OBJCFLAGS-y += -w -L __*
> diff --git a/lib/nolibc/exportsyms.uk b/lib/nolibc/exportsyms.uk
> index f2d50f1f..f283d458 100644
> --- a/lib/nolibc/exportsyms.uk
> +++ b/lib/nolibc/exportsyms.uk
> @@ -45,6 +45,7 @@ strtoul
>  strtoll
>  strtoull
>  atoi
> +qsort
>
>  # string
>  memcpy
> diff --git a/lib/nolibc/include/stdlib.h b/lib/nolibc/include/stdlib.h
> index cd6651c4..522da824 100644
> --- a/lib/nolibc/include/stdlib.h
> +++ b/lib/nolibc/include/stdlib.h
> @@ -89,6 +89,9 @@ void *memalign(size_t align, size_t size);
>
>  void abort(void) __noreturn;
>
> +void qsort(void *base, size_t nmemb, size_t size,
> +           int (*compar)(const void *, const void *));
> +
>  #if CONFIG_LIBPOSIX_PROCESS
>  int system(const char *command);
>  #endif
> diff --git a/lib/nolibc/qsort.c b/lib/nolibc/qsort.c
> new file mode 100644
> index 00000000..d8b3ddc5
> --- /dev/null
> +++ b/lib/nolibc/qsort.c
> @@ -0,0 +1,157 @@
> +/*     $OpenBSD: qsort.c,v 1.10 2005/08/08 08:05:37 espie Exp $ */
> +/*-
> + * 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. 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.
> + */
> +#include <sys/types.h>
> +#include <stdlib.h>
> +static inline char     *med3(char *, char *, char *, int (*)
> +                               (const void *, const void *));
> +static inline void      swapfunc(char *, char *, int, int);
> +#define min(a, b)      ((a) < (b) ? a : b)
> +/*
> + * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
> + */
> +#define swapcode(TYPE, parmi, parmj, n) {              \
> +       long i = (n) / sizeof(TYPE);                    \
> +       TYPE *pi = (TYPE *) (parmi);                    \
> +       TYPE *pj = (TYPE *) (parmj);                    \
> +       do {                                            \
> +               TYPE    t = *pi;                        \
> +               *pi++ = *pj;                            \
> +               *pj++ = t;                              \
> +       } while (--i > 0);                              \
> +}
> +#define SWAPINIT(a, es) (swaptype = ((char *)a - (char *)0) % sizeof(long) 
> || \
> +       es % sizeof(long) ? 2 : es == sizeof(long) ? 0 : 1)
> +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)
> +}
> +#define swap(a, b)                                     \
> +       do {                                            \
> +               if (swaptype == 0) {                            \
> +                       long t = *(long *)(a);                  \
> +                       *(long *)(a) = *(long *)(b);            \
> +                       *(long *)(b) = t;                       \
> +               } else                                          \
> +                       swapfunc(a, b, es, swaptype);           \
> +       } while (0)
> +
> +#define vecswap(a, b, n)                                       \
> +       do {                                                    \
> +               if ((n) > 0)                                    \
> +                       swapfunc(a, b, n, swaptype);            \
> +       } while (0)
> +static inline char *
> +med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
> +{
> +       return cmp(a, b) < 0 ?
> +               (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a))
> +               : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
> +}
> +void
> +qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
> +{
> +       char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
> +       int d, r, swaptype, swap_cnt;
> +       char *a = aa;
> +loop:
> +       SWAPINIT(a, es);
> +       swap_cnt = 0;
> +       if (n < 7) {
> +               for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
> +                       for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
> +                            pl -= es)
> +                               swap(pl, pl - es);
> +               return;
> +       }
> +       pm = (char *)a + (n / 2) * es;
> +       if (n > 7) {
> +               pl = (char *)a;
> +               pn = (char *)a + (n - 1) * es;
> +               if (n > 40) {
> +                       d = (n / 8) * es;
> +                       pl = med3(pl, pl + d, pl + 2 * d, cmp);
> +                       pm = med3(pm - d, pm, pm + d, cmp);
> +                       pn = med3(pn - 2 * d, pn - d, pn, cmp);
> +               }
> +               pm = med3(pl, pm, pn, cmp);
> +       }
> +       swap(a, pm);
> +       pa = pb = (char *)a + es;
> +
> +       pc = pd = (char *)a + (n - 1) * es;
> +       for (;;) {
> +               while (pb <= pc && (r = cmp(pb, a)) <= 0) {
> +                       if (r == 0) {
> +                               swap_cnt = 1;
> +                               swap(pa, pb);
> +                               pa += es;
> +                       }
> +                       pb += es;
> +               }
> +               while (pb <= pc && (r = cmp(pc, a)) >= 0) {
> +                       if (r == 0) {
> +                               swap_cnt = 1;
> +                               swap(pc, pd);
> +                               pd -= es;
> +                       }
> +                       pc -= es;
> +               }
> +               if (pb > pc)
> +                       break;
> +               swap(pb, pc);
> +               swap_cnt = 1;
> +               pb += es;
> +               pc -= es;
> +       }
> +       if (swap_cnt == 0) {  /* Switch to insertion sort */
> +               for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
> +                       for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
> +                            pl -= es)
> +                               swap(pl, pl - es);
> +               return;
> +       }
> +       pn = (char *)a + n * es;
> +       r = min(pa - (char *)a, pb - pa);
> +       vecswap(a, pb - r, r);
> +       r = min(pd - pc, pn - pd - (int)es);
> +       vecswap(pb, pn - r, r);
> +       if ((r = pb - pa) > (int)es)
> +               qsort(a, r / es, es, cmp);
> +       if ((r = pd - pc) > (int)es) {
> +               /* Iterate rather than recurse to save stack space */
> +               a = pn - r;
> +               n = r / es;
> +               goto loop;
> +       }
> +}
> --
> 2.20.1
>
>
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