360 lines
9.3 KiB
C
360 lines
9.3 KiB
C
/*-
|
|
* 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.
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static char sccsid[] = "@(#)merge.c 8.2 (Berkeley) 2/14/94";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
/*
|
|
* 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 <sys/types.h>
|
|
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#ifdef I_AM_MERGESORT_B
|
|
#include "block_abi.h"
|
|
#define DECLARE_CMP DECLARE_BLOCK(int, cmp, const void *, const void *)
|
|
typedef DECLARE_BLOCK(int, cmp_t, const void *, const void *);
|
|
#define CMP(x, y) CALL_BLOCK(cmp, x, y)
|
|
#else
|
|
typedef int (*cmp_t)(const void *, const void *);
|
|
#define CMP(x, y) cmp(x, y)
|
|
#endif
|
|
|
|
static void setup(u_char *, u_char *, size_t, size_t, cmp_t);
|
|
static void insertionsort(u_char *, size_t, size_t, cmp_t);
|
|
|
|
#define ISIZE sizeof(int)
|
|
#define PSIZE sizeof(u_char *)
|
|
#define ICOPY_LIST(src, dst, last) \
|
|
do \
|
|
*(int*)dst = *(int*)src, src += ISIZE, dst += ISIZE; \
|
|
while(src < last)
|
|
#define ICOPY_ELT(src, dst, i) \
|
|
do \
|
|
*(int*) dst = *(int*) 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 **) \
|
|
((u_char *)0 + \
|
|
(((u_char *)p + PSIZE - 1 - (u_char *) 0) & ~(PSIZE - 1)))
|
|
|
|
#ifdef I_AM_MERGESORT_B
|
|
int mergesort_b(void *, size_t, size_t, cmp_t);
|
|
#else
|
|
int mergesort(void *, size_t, size_t, cmp_t);
|
|
#endif
|
|
|
|
/*
|
|
* Arguments are as for qsort.
|
|
*/
|
|
int
|
|
#ifdef I_AM_MERGESORT_B
|
|
mergesort_b(void *base, size_t nmemb, size_t size, cmp_t cmp)
|
|
#else
|
|
mergesort(void *base, size_t nmemb, size_t size, cmp_t cmp)
|
|
#endif
|
|
{
|
|
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;
|
|
|
|
if (size < PSIZE / 2) { /* Pointers must fit into 2 * size. */
|
|
errno = EINVAL;
|
|
return (-1);
|
|
}
|
|
|
|
if (nmemb == 0)
|
|
return (0);
|
|
|
|
/*
|
|
* 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 */
|
|
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;
|
|
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 >>= 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.)
|
|
*/
|
|
void
|
|
setup(u_char *list1, u_char *list2, size_t n, size_t size, cmp_t cmp)
|
|
{
|
|
int i, length, size2, tmp, sense;
|
|
u_char *f1, *f2, *s, *l2, *last, *p2;
|
|
|
|
size2 = size*2;
|
|
if (n <= 5) {
|
|
insertionsort(list1, n, size, cmp);
|
|
*EVAL(list2) = (u_char*) 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, 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(u_char *a, size_t n, size_t size, cmp_t cmp)
|
|
{
|
|
u_char *ai, *s, *t, *u, tmp;
|
|
int i;
|
|
|
|
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);
|
|
}
|
|
}
|