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2007-10-04 Jakub Jelinek

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* stdlib/msort.c: Include stdint.h.
	(struct msort_param): New type.
	(msort_with_tmp): Use struct msort_param pointer for unchanging
	parameters.  Add optimized handling for several common sizes
	and indirect sorting mode.
	(qsort): Adjust msort_with_tmp callers.  For big S use indirect
	sorting.
	Suggested by Belazougui Djamel .

	* stdlib/Makefile (tests): Add tst-qsort2.
	* stdlib/tst-qsort2.c: New test.
This commit is contained in:
Ulrich Drepper
2007-10-05 06:50:35 +00:00
parent 174420d2bc
commit 375d942968
4 changed files with 309 additions and 72 deletions
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276
stdlib/msort.c
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@@ -1,6 +1,6 @@
/* An alternative to qsort, with an identical interface.
This file is part of the GNU C Library.
Copyright (C) 1992,95-97,99,2000,01,02,04 Free Software Foundation, Inc.
Copyright (C) 1992,95-97,99,2000,01,02,04,07 Free Software Foundation, Inc.
Written by Mike Haertel, September 1988.
The GNU C Library is free software; you can redistribute it and/or
@@ -19,20 +19,25 @@
02111-1307 USA. */
#include <alloca.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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);
struct msort_param
{
size_t s;
size_t var;
__compar_fn_t cmp;
char *t;
};
static void msort_with_tmp (const struct msort_param *p, void *b, size_t n);
static void
msort_with_tmp (void *b, size_t n, size_t s, __compar_fn_t cmp,
char *t)
msort_with_tmp (const struct msort_param *p, void *b, size_t n)
{
char *tmp;
char *b1, *b2;
size_t n1, n2;
@@ -42,65 +47,131 @@ msort_with_tmp (void *b, size_t n, size_t s, __compar_fn_t cmp,
n1 = n / 2;
n2 = n - n1;
b1 = b;
b2 = (char *) b + (n1 * s);
b2 = (char *) b + (n1 * p->s);
msort_with_tmp (b1, n1, s, cmp, t);
msort_with_tmp (b2, n2, s, cmp, t);
msort_with_tmp (p, b1, n1);
msort_with_tmp (p, b2, n2);
tmp = t;
char *tmp = p->t;
const size_t s = p->s;
__compar_fn_t cmp = p->cmp;
switch (p->var)
{
case 0:
while (n1 > 0 && n2 > 0)
{
if ((*cmp) (b1, b2) <= 0)
{
*(uint32_t *) tmp = *(uint32_t *) b1;
b1 += sizeof (uint32_t);
--n1;
}
else
{
*(uint32_t *) tmp = *(uint32_t *) b2;
b2 += sizeof (uint32_t);
--n2;
}
tmp += sizeof (uint32_t);
}
break;
case 1:
while (n1 > 0 && n2 > 0)
{
if ((*cmp) (b1, b2) <= 0)
{
*(uint64_t *) tmp = *(uint64_t *) b1;
b1 += sizeof (uint64_t);
--n1;
}
else
{
*(uint64_t *) tmp = *(uint64_t *) b2;
b2 += sizeof (uint64_t);
--n2;
}
tmp += sizeof (uint64_t);
}
break;
case 2:
while (n1 > 0 && n2 > 0)
{
unsigned long *tmpl = (unsigned long *) tmp;
unsigned long *bl;
tmp += s;
if ((*cmp) (b1, b2) <= 0)
{
bl = (unsigned long *) b1;
b1 += s;
--n1;
}
else
{
bl = (unsigned long *) b2;
b2 += s;
--n2;
}
while (tmpl < (unsigned long *) tmp)
*tmpl++ = *bl++;
}
break;
case 3:
while (n1 > 0 && n2 > 0)
{
if ((*cmp) (*(const void **) b1, *(const void **) b2) <= 0)
{
*(void **) tmp = *(void **) b1;
b1 += sizeof (void *);
--n1;
}
else
{
*(void **) tmp = *(void **) b2;
b2 += sizeof (void *);
--n2;
}
tmp += sizeof (void *);
}
break;
default:
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;
}
}
break;
}
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);
tmp += sizeof (op_t);
b1 += sizeof (op_t);
}
else
{
--n2;
*((op_t *) tmp) = *((op_t *) b2);
tmp += sizeof (op_t);
b2 += sizeof (op_t);
}
}
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);
memcpy (b, p->t, (n - n2) * s);
}
void
qsort (void *b, size_t n, size_t s, __compar_fn_t cmp)
{
const size_t size = n * s;
size_t size = n * s;
char *tmp = NULL;
struct msort_param p;
/* For large object sizes use indirect sorting. */
if (s > 32)
size = 2 * n * sizeof (void *) + s;
if (size < 1024)
{
void *buf = __alloca (size);
/* The temporary array is small, so put it on the stack. */
msort_with_tmp (b, n, s, cmp, buf);
}
/* The temporary array is small, so put it on the stack. */
p.t = __alloca (size);
else
{
/* We should avoid allocating too much memory since this might
@@ -135,26 +206,89 @@ qsort (void *b, size_t n, size_t s, __compar_fn_t cmp)
/* If the memory requirements are too high don't allocate memory. */
if (size / pagesize > (size_t) phys_pages)
_quicksort (b, n, s, cmp);
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. */
__set_errno (save);
_quicksort (b, n, s, cmp);
}
else
{
__set_errno (save);
msort_with_tmp (b, n, s, cmp, tmp);
free (tmp);
}
_quicksort (b, n, s, cmp);
return;
}
/* It's somewhat large, so malloc it. */
int save = errno;
tmp = malloc (size);
__set_errno (save);
if (tmp == NULL)
{
/* Couldn't get space, so use the slower algorithm
that doesn't need a temporary array. */
_quicksort (b, n, s, cmp);
return;
}
p.t = tmp;
}
p.s = s;
p.cmp = cmp;
p.var = 4;
if (s > 32)
{
/* Indirect sorting. */
char *ip = (char *) b;
void **tp = (void **) (p.t + n * sizeof (void *));
void **t = tp;
void *tmp_storage = (void *) (tp + n);
while ((void *) t < tmp_storage)
{
*t++ = ip;
ip += s;
}
p.s = sizeof (void *);
p.var = 3;
msort_with_tmp (&p, p.t + n * sizeof (void *), n);
/* tp[0] .. tp[n - 1] is now sorted, copy around entries of
the original array. Knuth vol. 3 (2nd ed.) exercise 5.2-10. */
char *kp;
size_t i;
for (i = 0, ip = (char *) b; i < n; i++, ip += s)
if ((kp = tp[i]) != ip)
{
size_t j = i;
char *jp = ip;
memcpy (tmp_storage, ip, s);
do
{
size_t k = (kp - (char *) b) / s;
tp[j] = jp;
memcpy (jp, kp, s);
j = k;
jp = kp;
kp = tp[k];
}
while (kp != ip);
tp[j] = jp;
memcpy (jp, tmp_storage, s);
}
}
else
{
if ((s & (sizeof (uint32_t) - 1)) == 0
&& ((char *) b - (char *) 0) % __alignof__ (uint32_t) == 0)
{
if (s == sizeof (uint32_t))
p.var = 0;
else if (s == sizeof (uint64_t)
&& ((char *) b - (char *) 0) % __alignof__ (uint64_t) == 0)
p.var = 1;
else if ((s & (sizeof (unsigned long) - 1)) == 0
&& ((char *) b - (char *) 0)
% __alignof__ (unsigned long) == 0)
p.var = 2;
}
msort_with_tmp (&p, b, n);
}
free (tmp);
}
libc_hidden_def (qsort)