minix/lib/libc/stdlib/merge.c
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

380 lines
9.6 KiB
C

/* $NetBSD: merge.c,v 1.12 2009/02/12 03:12:36 lukem Exp $ */
/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Peter McIlroy.
*
* 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "from: @(#)merge.c 8.2 (Berkeley) 2/14/94";
#else
__RCSID("$NetBSD: merge.c,v 1.12 2009/02/12 03:12:36 lukem Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
/*
* Hybrid exponential search/linear search merge sort with hybrid
* natural/pairwise first pass. Requires about .3% more comparisons
* for random data than LSMS with pairwise first pass alone.
* It works for objects as small as two bytes.
*/
#define NATURAL
#define THRESHOLD 16 /* Best choice for natural merge cut-off. */
/* #define NATURAL to get hybrid natural merge.
* (The default is pairwise merging.)
*/
#include "namespace.h"
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#ifdef __weak_alias
__weak_alias(mergesort,_mergesort)
#endif
static void setup __P((u_char *, u_char *, size_t, size_t,
int (*)(const void *, const void *)));
static void insertionsort __P((u_char *, size_t, size_t,
int (*)(const void *, const void *)));
#define ISIZE sizeof(int)
#define PSIZE sizeof(u_char *)
#define ICOPY_LIST(src, dst, last) \
do \
*(int*)(void *)dst = *(int*)(void *)src, \
src += ISIZE, dst += ISIZE; \
while(src < last)
#define ICOPY_ELT(src, dst, i) \
do \
*(int*)(void *)dst = *(int*)(void *)src, \
src += ISIZE, dst += ISIZE; \
while (i -= ISIZE)
#define CCOPY_LIST(src, dst, last) \
do \
*dst++ = *src++; \
while (src < last)
#define CCOPY_ELT(src, dst, i) \
do \
*dst++ = *src++; \
while (i -= 1)
/*
* Find the next possible pointer head. (Trickery for forcing an array
* to do double duty as a linked list when objects do not align with word
* boundaries.
*/
/* Assumption: PSIZE is a power of 2. */
#define EVAL(p) ((u_char **)(void *) \
((u_char *)0 + \
(((u_char *)(void *)(p) + PSIZE - 1 - (u_char *) 0) & ~(PSIZE - 1))))
/*
* Arguments are as for qsort.
*/
int
mergesort(base, nmemb, size, cmp)
void *base;
size_t nmemb;
size_t size;
int (*cmp) __P((const void *, const void *));
{
size_t i;
int sense;
int big, iflag;
u_char *f1, *f2, *t, *b, *tp2, *q, *l1, *l2;
u_char *list2, *list1, *p2, *p, *last, **p1;
_DIAGASSERT(base != NULL);
_DIAGASSERT(cmp != NULL);
if (size < PSIZE / 2) { /* Pointers must fit into 2 * size. */
errno = EINVAL;
return (-1);
}
/*
* XXX
* Stupid subtraction for the Cray.
*/
iflag = 0;
if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE))
iflag = 1;
if ((list2 = malloc(nmemb * size + PSIZE)) == NULL)
return (-1);
list1 = base;
setup(list1, list2, nmemb, size, cmp);
last = list2 + nmemb * size;
i = big = 0;
while (*EVAL(list2) != last) {
l2 = list1;
p1 = EVAL(list1);
for (tp2 = p2 = list2; p2 != last; p1 = EVAL(l2)) {
p2 = *EVAL(p2);
f1 = l2;
f2 = l1 = list1 + (p2 - list2);
if (p2 != last)
p2 = *EVAL(p2);
l2 = list1 + (p2 - list2);
while (f1 < l1 && f2 < l2) {
if ((*cmp)(f1, f2) <= 0) {
q = f2;
b = f1, t = l1;
sense = -1;
} else {
q = f1;
b = f2, t = l2;
sense = 0;
}
if (!big) { /* here i = 0 */
#if 0
LINEAR:
#endif
while ((b += size) < t && cmp(q, b) >sense)
if (++i == 6) {
big = 1;
goto EXPONENTIAL;
}
} else {
EXPONENTIAL: for (i = size; ; i <<= 1)
if ((p = (b + i)) >= t) {
if ((p = t - size) > b &&
(*cmp)(q, p) <= sense)
t = p;
else
b = p;
break;
} else if ((*cmp)(q, p) <= sense) {
t = p;
if (i == size)
big = 0;
goto FASTCASE;
} else
b = p;
#if 0
SLOWCASE:
#endif
while (t > b+size) {
i = (((t - b) / size) >> 1) * size;
if ((*cmp)(q, p = b + i) <= sense)
t = p;
else
b = p;
}
goto COPY;
FASTCASE: while (i > size)
if ((*cmp)(q,
p = b +
(i = (unsigned int) i >> 1)) <= sense)
t = p;
else
b = p;
COPY: b = t;
}
i = size;
if (q == f1) {
if (iflag) {
ICOPY_LIST(f2, tp2, b);
ICOPY_ELT(f1, tp2, i);
} else {
CCOPY_LIST(f2, tp2, b);
CCOPY_ELT(f1, tp2, i);
}
} else {
if (iflag) {
ICOPY_LIST(f1, tp2, b);
ICOPY_ELT(f2, tp2, i);
} else {
CCOPY_LIST(f1, tp2, b);
CCOPY_ELT(f2, tp2, i);
}
}
}
if (f2 < l2) {
if (iflag)
ICOPY_LIST(f2, tp2, l2);
else
CCOPY_LIST(f2, tp2, l2);
} else if (f1 < l1) {
if (iflag)
ICOPY_LIST(f1, tp2, l1);
else
CCOPY_LIST(f1, tp2, l1);
}
*p1 = l2;
}
tp2 = list1; /* swap list1, list2 */
list1 = list2;
list2 = tp2;
last = list2 + nmemb*size;
}
if (base == list2) {
memmove(list2, list1, nmemb*size);
list2 = list1;
}
free(list2);
return (0);
}
#define swap(a, b) { \
s = b; \
i = size; \
do { \
tmp = *a; *a++ = *s; *s++ = tmp; \
} while (--i); \
a -= size; \
}
#define reverse(bot, top) { \
s = top; \
do { \
i = size; \
do { \
tmp = *bot; *bot++ = *s; *s++ = tmp; \
} while (--i); \
s -= size2; \
} while(bot < s); \
}
/*
* Optional hybrid natural/pairwise first pass. Eats up list1 in runs of
* increasing order, list2 in a corresponding linked list. Checks for runs
* when THRESHOLD/2 pairs compare with same sense. (Only used when NATURAL
* is defined. Otherwise simple pairwise merging is used.)
*/
/* XXX: shouldn't this function be static? - lukem 990810 */
void
setup(list1, list2, n, size, cmp)
size_t n, size;
int (*cmp) __P((const void *, const void *));
u_char *list1, *list2;
{
int i, length, size2, tmp, sense;
u_char *f1, *f2, *s, *l2, *last, *p2;
_DIAGASSERT(cmp != NULL);
_DIAGASSERT(list1 != NULL);
_DIAGASSERT(list2 != NULL);
size2 = size*2;
if (n <= 5) {
insertionsort(list1, n, size, cmp);
*EVAL(list2) = list2 + n*size;
return;
}
/*
* Avoid running pointers out of bounds; limit n to evens
* for simplicity.
*/
i = 4 + (n & 1);
insertionsort(list1 + (n - i) * size, (size_t)i, size, cmp);
last = list1 + size * (n - i);
*EVAL(list2 + (last - list1)) = list2 + n * size;
#ifdef NATURAL
p2 = list2;
f1 = list1;
sense = (cmp(f1, f1 + size) > 0);
for (; f1 < last; sense = !sense) {
length = 2;
/* Find pairs with same sense. */
for (f2 = f1 + size2; f2 < last; f2 += size2) {
if ((cmp(f2, f2+ size) > 0) != sense)
break;
length += 2;
}
if (length < THRESHOLD) { /* Pairwise merge */
do {
p2 = *EVAL(p2) = f1 + size2 - list1 + list2;
if (sense > 0)
swap (f1, f1 + size);
} while ((f1 += size2) < f2);
} else { /* Natural merge */
l2 = f2;
for (f2 = f1 + size2; f2 < l2; f2 += size2) {
if ((cmp(f2-size, f2) > 0) != sense) {
p2 = *EVAL(p2) = f2 - list1 + list2;
if (sense > 0)
reverse(f1, f2-size);
f1 = f2;
}
}
if (sense > 0)
reverse (f1, f2-size);
f1 = f2;
if (f2 < last || cmp(f2 - size, f2) > 0)
p2 = *EVAL(p2) = f2 - list1 + list2;
else
p2 = *EVAL(p2) = list2 + n*size;
}
}
#else /* pairwise merge only. */
for (f1 = list1, p2 = list2; f1 < last; f1 += size2) {
p2 = *EVAL(p2) = p2 + size2;
if (cmp (f1, f1 + size) > 0)
swap(f1, f1 + size);
}
#endif /* NATURAL */
}
/*
* This is to avoid out-of-bounds addresses in sorting the
* last 4 elements.
*/
static void
insertionsort(a, n, size, cmp)
u_char *a;
size_t n, size;
int (*cmp) __P((const void *, const void *));
{
u_char *ai, *s, *t, *u, tmp;
int i;
_DIAGASSERT(a != NULL);
_DIAGASSERT(cmp != NULL);
for (ai = a+size; --n >= 1; ai += size)
for (t = ai; t > a; t -= size) {
u = t - size;
if (cmp(u, t) <= 0)
break;
swap(u, t);
}
}