mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-27 03:41:23 +08:00
061d137bd7
1999-10-26 Andreas Jaeger <aj@suse.de> * stdlib/msort.c: Include <alloca.h> for prototype. Remove K&R compatibility and _quicksort prototype. * stdlib/qsort.c: Make code and comments 64 bit clean; clarify some comments. Reported by Bernd Löchner <loechner@informatik.uni-kl.de>. Remove K&R compatibility. Move prototype declaration to include/stdlib.h. Include <alloca.h> for prototype; include <limits.h> for CHAR_BIT. * include/stdlib.h: Prototype declaration for _quicksort.
114 lines
2.7 KiB
C
114 lines
2.7 KiB
C
/* An alternative to qsort, with an identical interface.
|
|
This file is part of the GNU C Library.
|
|
Copyright (C) 1992, 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
|
|
Written by Mike Haertel, September 1988.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#include <alloca.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <memcopy.h>
|
|
#include <errno.h>
|
|
|
|
static void msort_with_tmp (void *b, size_t n, size_t s,
|
|
__compar_fn_t cmp, char *t);
|
|
|
|
static void
|
|
msort_with_tmp (void *b, size_t n, size_t s, __compar_fn_t cmp,
|
|
char *t)
|
|
{
|
|
char *tmp;
|
|
char *b1, *b2;
|
|
size_t n1, n2;
|
|
|
|
if (n <= 1)
|
|
return;
|
|
|
|
n1 = n / 2;
|
|
n2 = n - n1;
|
|
b1 = b;
|
|
b2 = (char *) b + (n1 * s);
|
|
|
|
msort_with_tmp (b1, n1, s, cmp, t);
|
|
msort_with_tmp (b2, n2, s, cmp, t);
|
|
|
|
tmp = t;
|
|
|
|
if (s == OPSIZ && (b1 - (char *) 0) % OPSIZ == 0)
|
|
/* We are operating on aligned words. Use direct word stores. */
|
|
while (n1 > 0 && n2 > 0)
|
|
{
|
|
if ((*cmp) (b1, b2) <= 0)
|
|
{
|
|
--n1;
|
|
*((op_t *) tmp)++ = *((op_t *) b1)++;
|
|
}
|
|
else
|
|
{
|
|
--n2;
|
|
*((op_t *) tmp)++ = *((op_t *) b2)++;
|
|
}
|
|
}
|
|
else
|
|
while (n1 > 0 && n2 > 0)
|
|
{
|
|
if ((*cmp) (b1, b2) <= 0)
|
|
{
|
|
tmp = (char *) __mempcpy (tmp, b1, s);
|
|
b1 += s;
|
|
--n1;
|
|
}
|
|
else
|
|
{
|
|
tmp = (char *) __mempcpy (tmp, b2, s);
|
|
b2 += s;
|
|
--n2;
|
|
}
|
|
}
|
|
if (n1 > 0)
|
|
memcpy (tmp, b1, n1 * s);
|
|
memcpy (b, t, (n - n2) * s);
|
|
}
|
|
|
|
void
|
|
qsort (void *b, size_t n, size_t s, __compar_fn_t cmp)
|
|
{
|
|
const size_t size = n * s;
|
|
|
|
if (size < 1024)
|
|
/* The temporary array is small, so put it on the stack. */
|
|
msort_with_tmp (b, n, s, cmp, __alloca (size));
|
|
else
|
|
{
|
|
/* It's somewhat large, so malloc it. */
|
|
int save = errno;
|
|
char *tmp = malloc (size);
|
|
if (tmp == NULL)
|
|
{
|
|
/* Couldn't get space, so use the slower algorithm
|
|
that doesn't need a temporary array. */
|
|
_quicksort (b, n, s, cmp);
|
|
}
|
|
else
|
|
{
|
|
msort_with_tmp (b, n, s, cmp, tmp);
|
|
free (tmp);
|
|
}
|
|
__set_errno (save);
|
|
}
|
|
}
|