Annotation of src/lib/libc/stdlib/qsort.c, Revision 1.13
1.13 ! agc 1: /* $NetBSD: qsort.c,v 1.12 1999/09/20 04:39:40 lukem Exp $ */
1.5 thorpej 2:
1.1 cgd 3: /*-
1.4 mycroft 4: * Copyright (c) 1992, 1993
5: * The Regents of the University of California. All rights reserved.
1.1 cgd 6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
1.13 ! agc 15: * 3. Neither the name of the University nor the names of its contributors
1.1 cgd 16: * may be used to endorse or promote products derived from this software
17: * without specific prior written permission.
18: *
19: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29: * SUCH DAMAGE.
30: */
31:
1.8 christos 32: #include <sys/cdefs.h>
1.1 cgd 33: #if defined(LIBC_SCCS) && !defined(lint)
1.5 thorpej 34: #if 0
1.7 mikel 35: static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
1.5 thorpej 36: #else
1.13 ! agc 37: __RCSID("$NetBSD: qsort.c,v 1.12 1999/09/20 04:39:40 lukem Exp $");
1.5 thorpej 38: #endif
1.1 cgd 39: #endif /* LIBC_SCCS and not lint */
40:
41: #include <sys/types.h>
1.11 lukem 42:
43: #include <assert.h>
44: #include <errno.h>
1.1 cgd 45: #include <stdlib.h>
46:
1.8 christos 47: static __inline char *med3 __P((char *, char *, char *,
48: int (*)(const void *, const void *)));
1.10 christos 49: static __inline void swapfunc __P((char *, char *, size_t, int));
1.4 mycroft 50:
51: #define min(a, b) (a) < (b) ? a : b
52:
1.1 cgd 53: /*
1.4 mycroft 54: * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
1.1 cgd 55: */
1.4 mycroft 56: #define swapcode(TYPE, parmi, parmj, n) { \
1.10 christos 57: size_t i = (n) / sizeof (TYPE); \
58: TYPE *pi = (TYPE *)(void *)(parmi); \
59: TYPE *pj = (TYPE *)(void *)(parmj); \
1.4 mycroft 60: do { \
1.10 christos 61: TYPE t = *pi; \
1.4 mycroft 62: *pi++ = *pj; \
63: *pj++ = t; \
64: } while (--i > 0); \
65: }
1.1 cgd 66:
1.4 mycroft 67: #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
68: es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
1.1 cgd 69:
1.6 cgd 70: static __inline void
1.4 mycroft 71: swapfunc(a, b, n, swaptype)
72: char *a, *b;
1.10 christos 73: size_t n;
74: int swaptype;
1.1 cgd 75: {
1.7 mikel 76: if (swaptype <= 1)
1.4 mycroft 77: swapcode(long, a, b, n)
1.1 cgd 78: else
1.4 mycroft 79: swapcode(char, a, b, n)
1.1 cgd 80: }
81:
1.10 christos 82: #define swap(a, b) \
83: if (swaptype == 0) { \
84: long t = *(long *)(void *)(a); \
85: *(long *)(void *)(a) = *(long *)(void *)(b); \
86: *(long *)(void *)(b) = t; \
87: } else \
1.4 mycroft 88: swapfunc(a, b, es, swaptype)
89:
1.10 christos 90: #define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
1.4 mycroft 91:
1.6 cgd 92: static __inline char *
1.4 mycroft 93: med3(a, b, c, cmp)
94: char *a, *b, *c;
1.8 christos 95: int (*cmp) __P((const void *, const void *));
1.4 mycroft 96: {
97: return cmp(a, b) < 0 ?
98: (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
99: :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
1.1 cgd 100: }
101:
1.4 mycroft 102: void
103: qsort(a, n, es, cmp)
104: void *a;
105: size_t n, es;
1.8 christos 106: int (*cmp) __P((const void *, const void *));
1.4 mycroft 107: {
108: char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
109: int d, r, swaptype, swap_cnt;
1.11 lukem 110:
111: _DIAGASSERT(a != NULL);
112: _DIAGASSERT(cmp != NULL);
1.1 cgd 113:
1.4 mycroft 114: loop: SWAPINIT(a, es);
115: swap_cnt = 0;
116: if (n < 7) {
1.7 mikel 117: for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
1.4 mycroft 118: for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
119: pl -= es)
120: swap(pl, pl - es);
121: return;
122: }
1.7 mikel 123: pm = (char *) a + (n / 2) * es;
1.4 mycroft 124: if (n > 7) {
1.7 mikel 125: pl = (char *) a;
126: pn = (char *) a + (n - 1) * es;
1.4 mycroft 127: if (n > 40) {
128: d = (n / 8) * es;
129: pl = med3(pl, pl + d, pl + 2 * d, cmp);
130: pm = med3(pm - d, pm, pm + d, cmp);
131: pn = med3(pn - 2 * d, pn - d, pn, cmp);
1.1 cgd 132: }
1.4 mycroft 133: pm = med3(pl, pm, pn, cmp);
1.1 cgd 134: }
1.4 mycroft 135: swap(a, pm);
1.7 mikel 136: pa = pb = (char *) a + es;
1.1 cgd 137:
1.7 mikel 138: pc = pd = (char *) a + (n - 1) * es;
1.4 mycroft 139: for (;;) {
140: while (pb <= pc && (r = cmp(pb, a)) <= 0) {
141: if (r == 0) {
142: swap_cnt = 1;
143: swap(pa, pb);
144: pa += es;
1.1 cgd 145: }
1.4 mycroft 146: pb += es;
147: }
148: while (pb <= pc && (r = cmp(pc, a)) >= 0) {
149: if (r == 0) {
150: swap_cnt = 1;
151: swap(pc, pd);
152: pd -= es;
1.1 cgd 153: }
1.4 mycroft 154: pc -= es;
1.1 cgd 155: }
1.4 mycroft 156: if (pb > pc)
1.1 cgd 157: break;
1.4 mycroft 158: swap(pb, pc);
159: swap_cnt = 1;
160: pb += es;
161: pc -= es;
1.1 cgd 162: }
1.4 mycroft 163: if (swap_cnt == 0) { /* Switch to insertion sort */
1.7 mikel 164: for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
1.4 mycroft 165: for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
166: pl -= es)
167: swap(pl, pl - es);
1.1 cgd 168: return;
169: }
170:
1.7 mikel 171: pn = (char *) a + n * es;
172: r = min(pa - (char *) a, pb - pa);
1.4 mycroft 173: vecswap(a, pb - r, r);
174: r = min(pd - pc, pn - pd - es);
175: vecswap(pb, pn - r, r);
176: if ((r = pb - pa) > es)
177: qsort(a, r / es, es, cmp);
178: if ((r = pd - pc) > es) {
179: /* Iterate rather than recurse to save stack space */
180: a = pn - r;
181: n = r / es;
182: goto loop;
1.1 cgd 183: }
1.4 mycroft 184: /* qsort(pn - r, r / es, es, cmp);*/
1.1 cgd 185: }
CVSweb <webmaster@jp.NetBSD.org>
![[BACK]](/icons/back.gif){kind=icon}
Return to qsort.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [cvs.NetBSD.org] / src / lib / libc / stdlib