* 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. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 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.
*
static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.12 2002/09/10 02:04:49 wollman Exp $");
+__FBSDID("$FreeBSD$");
+#include <stdbool.h>
#include <stdlib.h>
+#include <string.h>
#ifdef I_AM_QSORT_R
typedef int cmp_t(void *, const void *, const void *);
typedef int cmp_t(const void *, const void *);
#endif
static inline char *med3(char *, char *, char *, cmp_t *, void *);
-static inline void swapfunc(char *, char *, int, int);
+static inline void swapfunc(char *, char *, size_t, int, int);
-#define min(a, b) (a) < (b) ? a : b
+#define MIN(a, b) ((a) < (b) ? a : b)
/*
* Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
*/
-#define swapcode(TYPE, parmi, parmj, n) { \
- long i = (n) / sizeof (TYPE); \
- TYPE *pi = (TYPE *) (parmi); \
- TYPE *pj = (TYPE *) (parmj); \
+#define swapcode(TYPE, parmi, parmj, n) { \
+ size_t i = (n) / sizeof (TYPE); \
+ TYPE *pi = (TYPE *) (parmi); \
+ TYPE *pj = (TYPE *) (parmj); \
do { \
TYPE t = *pi; \
*pi++ = *pj; \
*pj++ = t; \
- } while (--i > 0); \
+ } while (--i > 0); \
}
-#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
- es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+#define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \
+ ((char *)a - (char *)0) % sizeof(TYPE) || \
+ es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
static inline void
-swapfunc(a, b, n, swaptype)
- char *a, *b;
- int n, swaptype;
+swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
{
- if(swaptype <= 1)
+ if (swaptype_long <= 1)
swapcode(long, a, b, n)
+ else if (swaptype_int <= 1)
+ swapcode(int, a, b, n)
else
swapcode(char, a, b, n)
}
-#define swap(a, b) \
- if (swaptype == 0) { \
+#define swap(a, b) \
+ if (swaptype_long == 0) { \
long t = *(long *)(a); \
*(long *)(a) = *(long *)(b); \
*(long *)(b) = t; \
+ } else if (swaptype_int == 0) { \
+ int t = *(int *)(a); \
+ *(int *)(a) = *(int *)(b); \
+ *(int *)(b) = t; \
} else \
- swapfunc(a, b, es, swaptype)
+ swapfunc(a, b, es, swaptype_long, swaptype_int)
-#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
+#define vecswap(a, b, n) \
+ if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int)
#ifdef I_AM_QSORT_R
#define CMP(t, x, y) (cmp((t), (x), (y)))
#define CMP(t, x, y) (cmp((x), (y)))
#endif
+/*
+ * Find the median of 3 elements
+ */
static inline char *
med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
#ifndef I_AM_QSORT_R
{
return CMP(thunk, a, b) < 0 ?
(CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
- :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
+ :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
}
+#ifdef __LP64__
+#define DEPTH(x) (2 * (flsl((long)(x)) - 1))
+#else /* !__LP64__ */
+#define DEPTH(x) (2 * (fls((int)(x)) - 1))
+#endif /* __LP64__ */
+
#ifdef I_AM_QSORT_R
-void
-qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
+int __heapsort_r(void *, size_t, size_t, void *, int (*)(void *, const void *, const void *));
+#endif
+
+/*
+ * Simple insertion sort routine.
+ */
+static bool
+_isort(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp, int swap_limit, int swaptype_long, int swaptype_int)
+{
+ int swap_cnt = 0;
+ for (char *pm = (char *)a + es; pm < (char *)a + n * es; pm += es) {
+ for (char *pl = pm; pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
+ pl -= es) {
+ swap(pl, pl - es);
+ if (swap_limit && ++swap_cnt > swap_limit) return false;
+ }
+ }
+ return true;
+}
+
+#ifdef I_AM_QSORT_R
+static void
+_qsort(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp, int depth_limit)
#else
-#define thunk NULL
-void
-qsort(void *a, size_t n, size_t es, cmp_t *cmp)
+#define thunk NULL
+static void
+_qsort(void *a, size_t n, size_t es, cmp_t *cmp, int depth_limit)
#endif
{
char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
- int d, r, swaptype, swap_cnt;
+ size_t d1, d2;
+ int cmp_result;
+ int swaptype_long, swaptype_int, swap_cnt;
-loop: SWAPINIT(a, es);
+loop:
+ SWAPINIT(long, a, es);
+ SWAPINIT(int, 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(thunk, pl - es, pl) > 0;
- pl -= es)
- swap(pl, pl - es);
+
+ if (depth_limit-- <= 0) {
+ /*
+ * We've hit our recursion limit, switch to heapsort
+ */
+#ifdef I_AM_QSORT_R
+ __heapsort_r(a, n, es, thunk, cmp);
+#else
+ heapsort(a, n, es, cmp);
+#endif
return;
}
+
+ if (n <= 7) {
+ /*
+ * For sufficiently small inputs, we'll just insertion sort.
+ *
+ * Pass 0 as swap limit, since this must complete.
+ */
+ _isort(a, n, es, thunk, cmp, 0, swaptype_long, swaptype_int);
+ return;
+ }
+
+ /*
+ * Compute the pseudomedian. Small arrays use 3 samples, large ones use 9.
+ */
+ pl = a;
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, thunk);
- pm = med3(pm - d, pm, pm + d, cmp, thunk);
- pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
- }
- pm = med3(pl, pm, pn, cmp, thunk);
+ pn = (char *)a + (n - 1) * es;
+ if (n > 40) {
+ size_t d = (n / 8) * es;
+
+ pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
+ pm = med3(pm - d, pm, pm + d, cmp, thunk);
+ pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
}
+ pm = med3(pl, pm, pn, cmp, thunk);
+
+ /*
+ * Pull the median to the front, starting us with:
+ *
+ * +-+-------------+
+ * |=| ? |
+ * +-+-------------+
+ * a pa,pb pc,pd
+ */
swap(a, pm);
pa = pb = (char *)a + es;
-
pc = pd = (char *)a + (n - 1) * es;
+
for (;;) {
- while (pb <= pc && (r = CMP(thunk, pb, a)) <= 0) {
- if (r == 0) {
+ /*
+ * - Move b forward while it's less than the median
+ * - Move c backwards while it's greater than the median
+ * - When equal to the median, swap to the outside
+ */
+ while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
+ if (cmp_result == 0) {
swap_cnt = 1;
swap(pa, pb);
pa += es;
}
pb += es;
}
- while (pb <= pc && (r = CMP(thunk, pc, a)) >= 0) {
- if (r == 0) {
+ while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
+ if (cmp_result == 0) {
swap_cnt = 1;
swap(pc, pd);
pd -= es;
pb += es;
pc -= es;
}
+
+ /*
+ * Now we've got:
+ *
+ * +---+-----+-----+---+
+ * | = | < | > | = |
+ * +---+-----+-----+---+
+ * a pa pc,pb pd pn
+ *
+ * So swap the '=' into the middle
+ */
+
+ pn = (char *)a + n * es;
+ d1 = MIN(pa - (char *)a, pb - pa);
+ vecswap(a, pb - d1, d1);
+ d1 = MIN(pd - pc, pn - pd - es);
+ vecswap(pb, pn - d1, d1);
+
+ /*
+ * +-----+---+---+-----+
+ * | < | = | > |
+ * +-----+---+---+-----+
+ * a pn
+ */
+
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(thunk, pl - es, pl) > 0;
- pl -= es)
- swap(pl, pl - es);
+ int r = 1 + n / 4; /* n > 7, so r >= 2 */
+ if (!_isort(a, n, es, thunk, cmp, r, swaptype_long, swaptype_int)) {
+ goto nevermind;
+ }
return;
}
+nevermind:
- 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)
+ d1 = pb - pa;
+ d2 = pd - pc;
+ if (d1 <= d2) {
+ /* Recurse on left partition, then iterate on right partition */
+ if (d1 > es) {
+#ifdef I_AM_QSORT_R
+ _qsort(a, d1 / es, es, thunk, cmp, depth_limit);
+#else
+ _qsort(a, d1 / es, es, cmp, depth_limit);
+#endif
+ }
+ if (d2 > es) {
+ /* Iterate rather than recurse to save stack space */
+ /* qsort(pn - d2, d2 / es, es, cmp); */
+ a = pn - d2;
+ n = d2 / es;
+ goto loop;
+ }
+ } else {
+ /* Recurse on right partition, then iterate on left partition */
+ if (d2 > es) {
#ifdef I_AM_QSORT_R
- qsort_r(a, r / es, es, thunk, cmp);
+ _qsort(pn - d2, d2 / es, es, thunk, cmp, depth_limit);
#else
- qsort(a, r / es, es, cmp);
+ _qsort(pn - d2, d2 / es, es, cmp, depth_limit);
#endif
- if ((r = pd - pc) > es) {
- /* Iterate rather than recurse to save stack space */
- a = pn - r;
- n = r / es;
- goto loop;
+ }
+ if (d1 > es) {
+ /* Iterate rather than recurse to save stack space */
+ /* qsort(a, d1 / es, es, cmp); */
+ n = d1 / es;
+ goto loop;
+ }
}
-/* qsort(pn - r, r / es, es, cmp);*/
+}
+
+void
+#ifdef I_AM_QSORT_R
+qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
+#else
+qsort(void *a, size_t n, size_t es, cmp_t *cmp)
+#endif
+{
+ _qsort(a, n, es,
+#ifdef I_AM_QSORT_R
+ thunk,
+#endif
+ cmp, DEPTH(n));
}
projects / apple / libc.git / blobdiff