2 Jun
2018
2 Jun
'18
11:57 a.m.
https://git.reactos.org/?p=reactos.git;a=commitdiff;h=2dfe5e3f463ca4d7eb920…
commit 2dfe5e3f463ca4d7eb920d25c2a33b29a70f3e27
Author: Pierre Schweitzer <pierre(a)reactos.org>
AuthorDate: Sat Jun 2 13:52:09 2018 +0200
Commit: Pierre Schweitzer <pierre(a)reactos.org>
CommitDate: Sat Jun 2 13:56:42 2018 +0200
[CRT] Reimplement qsort() using FreeBSD implementation.
Our implementation had a bug that could be triggered while
building our USBD library on ReactOS: the compare function
could be called with a NULL pointer instead of a valid value.
With this bug fixed (and the cmd hack in CORE-14648), ReactOS
can totally selfhost :-)! I was able to build LiveCD and BootCD
without any trouble, crash, deadlock or whatever.
(Next step: having a buildbot slave hosted on ReactOS ;-)).
Enjoy: https://twitter.com/HeisSpiter/status/1002880397103988737
CORE-14680
---
sdk/lib/crt/stdlib/qsort.c | 353 ++++++++++++++++++---------------------------
1 file changed, 138 insertions(+), 215 deletions(-)
diff --git a/sdk/lib/crt/stdlib/qsort.c b/sdk/lib/crt/stdlib/qsort.c
index 62f365177d..d6bca5f06c 100644
--- a/sdk/lib/crt/stdlib/qsort.c
+++ b/sdk/lib/crt/stdlib/qsort.c
@@ -1,170 +1,81 @@
-/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
-
-#include <stdlib.h>
-#include <search.h>
-
/*-
- * Copyright (c) 1980, 1983 The Regents of the University of California.
- * All rights reserved.
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
*
- * Redistribution and use in source and binary forms are permitted
- * provided that: (1) source distributions retain this entire copyright
- * notice and comment, and (2) distributions including binaries display
- * the following acknowledgement: ``This product includes software
- * developed by the University of California, Berkeley and its contributors''
- * in the documentation or other materials provided with the distribution
- * and in all advertising materials mentioning features or use of this
- * software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ * 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.
+ * 4. 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.
*/
-/*
- * qsort.c:
- * Our own version of the system qsort routine which is faster by an average
- * of 25%, with lows and highs of 10% and 50%.
- * The THRESHold below is the insertion sort threshold, and has been adjusted
- * for records of size 48 bytes.
- * The MTHREShold is where we stop finding a better median.
- */
+#include <stdlib.h>
+#include <search.h>
-#define THRESH 4 /* threshold for insertion */
-#define MTHRESH 6 /* threshold for median */
+#define min(a, b) (a) < (b) ? (a) : (b)
/*
- * qst:
- * Do a quicksort
- * First, find the median element, and put that one in the first place as the
- * discriminator. (This "median" is just the median of the first, last and
- * middle elements). (Using this median instead of the first element is a big
- * win). Then, the usual partitioning/swapping, followed by moving the
- * discriminator into the right place. Then, figure out the sizes of the two
- * partions, do the smaller one recursively and the larger one via a repeat of
- * this code. Stopping when there are less than THRESH elements in a partition
- * and cleaning up with an insertion sort (in our caller) is a huge win.
- * All data swaps are done in-line, which is space-losing but time-saving.
- * (And there are only three places where this is done).
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort
Function".
*/
+#define swapcode(TYPE, parmi, parmj, n) { \
+ long i = (n) / sizeof (TYPE); \
+ register TYPE *pi = (TYPE *) (parmi); \
+ register TYPE *pj = (TYPE *) (parmj); \
+ do { \
+ register TYPE t = *pi; \
+ *pi++ = *pj; \
+ *pj++ = t; \
+ } while (--i > 0); \
+}
-static void __cdecl
-qst(size_t size, int (__cdecl *compar)(const void*, const void*), char *base, char *max)
+#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)
{
- char c, *i, *j, *jj;
- size_t ii;
- char *mid, *tmp;
- size_t lo, hi;
- size_t thresh;
- size_t mthresh;
+ if(swaptype <= 1)
+ swapcode(long, a, b, n)
+ else
+ swapcode(char, a, b, n)
+}
- thresh = size * THRESH;
- mthresh = size * MTHRESH;
+#define swap(a, b) \
+ if (swaptype == 0) { \
+ long t = *(long *)(a); \
+ *(long *)(a) = *(long *)(b); \
+ *(long *)(b) = t; \
+ } else \
+ swapfunc(a, b, es, swaptype)
- /*
- * At the top here, lo is the number of characters of elements in the
- * current partition. (Which should be max - base).
- * Find the median of the first, last, and middle element and make
- * that the middle element. Set j to largest of first and middle.
- * If max is larger than that guy, then it's that guy, else compare
- * max with loser of first and take larger. Things are set up to
- * prefer the middle, then the first in case of ties.
- */
- lo = max - base; /* number of elements as chars */
- do {
- mid = i = base + size * ((lo / size) >> 1);
- if (lo >= mthresh)
- {
- j = (compar((jj = base), i) > 0 ? jj : i);
- if (compar(j, (tmp = max - size)) > 0)
- {
- /* switch to first loser */
- j = (j == jj ? i : jj);
- if (compar(j, tmp) < 0)
- j = tmp;
- }
- if (j != i)
- {
- ii = size;
- do {
- c = *i;
- *i++ = *j;
- *j++ = c;
- } while (--ii);
- }
- }
- /*
- * Semi-standard quicksort partitioning/swapping
- */
- for (i = base, j = max - size; ; )
- {
- while (i < mid && compar(i, mid) <= 0)
- i += size;
- while (j > mid)
- {
- if (compar(mid, j) <= 0)
- {
- j -= size;
- continue;
- }
- tmp = i + size; /* value of i after swap */
- if (i == mid)
- {
- /* j <-> mid, new mid is j */
- mid = jj = j;
- }
- else
- {
- /* i <-> j */
- jj = j;
- j -= size;
- }
- goto swap;
- }
- if (i == mid)
- {
- break;
- }
- else
- {
- /* i <-> mid, new mid is i */
- jj = mid;
- tmp = mid = i; /* value of i after swap */
- j -= size;
- }
- swap:
- ii = size;
- do {
- c = *i;
- *i++ = *jj;
- *jj++ = c;
- } while (--ii);
- i = tmp;
- }
- /*
- * Look at sizes of the two partitions, do the smaller
- * one first by recursion, then do the larger one by
- * making sure lo is its size, base and max are update
- * correctly, and branching back. But only repeat
- * (recursively or by branching) if the partition is
- * of at least size THRESH.
- */
- i = (j = mid) + size;
- if ((lo = j - base) <= (hi = max - i))
- {
- if (lo >= thresh)
- qst(size, compar, base, j);
- base = i;
- lo = hi;
- }
- else
- {
- if (hi >= thresh)
- qst(size, compar, i, max);
- max = j;
- }
- } while (lo >= thresh);
+#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
+
+#define CMP(x, y) (cmp((x), (y)))
+
+static __inline char *
+med3(char *a, char *b, char *c, int (__cdecl *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 ));
}
/*
@@ -177,67 +88,79 @@ qst(size_t size, int (__cdecl *compar)(const void*, const void*),
char *base, ch
*/
void
__cdecl
-qsort(void *base0, size_t n, size_t size, int (__cdecl *compar)(const void*, const
void*))
+qsort(void *a, size_t n, size_t es, int (__cdecl *cmp)(const void*, const void*))
{
- char *base = (char *)base0;
- char c, *i, *j, *lo, *hi;
- char *min, *max;
- size_t thresh;
+ char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+ int d, r, swaptype, swap_cnt;
- if (n <= 1)
- return;
+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 = 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;
+ }
- if (size == 0)
- return;
- thresh = size * THRESH;
- max = base + n * size;
- if (n >= THRESH)
- {
- qst(size, compar, base, max);
- hi = base + thresh;
- }
- else
- {
- hi = max;
- }
- /*
- * First put smallest element, which must be in the first THRESH, in
- * the first position as a sentinel. This is done just by searching
- * the first THRESH elements (or the first n if n < THRESH), finding
- * the min, and swapping it into the first position.
- */
- for (j = lo = base; (lo += size) < hi; )
- if (compar(j, lo) > 0)
- j = lo;
- if (j != base)
- {
- /* swap j into place */
- for (i = base, hi = base + size; i < hi; )
- {
- c = *j;
- *j++ = *i;
- *i++ = c;
- }
- }
- /*
- * With our sentinel in place, we now run the following hyper-fast
- * insertion sort. For each remaining element, min, from [1] to [n-1],
- * set hi to the index of the element AFTER which this one goes.
- * Then, do the standard insertion sort shift on a character at a time
- * basis for each element in the frob.
- */
- for (min = base; (hi = min += size) < max; )
- {
- while (compar(hi -= size, min) > 0)
- /* void */;
- if ((hi += size) != min) {
- for (lo = min + size; --lo >= min; )
- {
- c = *lo;
- for (i = j = lo; (j -= size) >= hi; i = j)
- *i = *j;
- *i = c;
- }
- }
- }
+ pn = (char *)a + n * es;
+ r = min(pa - (char *)a, pb - pa);
+ vecswap(a, pb - r, r);
+ r = min(pd - pc, pn - pd - es);
+ vecswap(pb, pn - r, r);
+ if ((r = pb - pa) > es)
+ qsort(a, r / es, es, cmp);
+ if ((r = pd - pc) > es) {
+ /* Iterate rather than recurse to save stack space */
+ a = pn - r;
+ n = r / es;
+ goto loop;
+ }
}
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Pierre Schweitzer