[BACK]Return to qsort.c CVS log [TXT][DIR] Up to [cvs.NetBSD.org] / src / lib / libc / stdlib

Annotation of src/lib/libc/stdlib/qsort.c, Revision 1.4

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

CVSweb <webmaster@jp.NetBSD.org>