initial import of NetBSD tree

1 files changed, 348 insertions, 0 deletions

diff --git a/src/lib/libc/stdlib/merge.c b/src/lib/libc/stdlib/merge.c
new file mode 100644
index 0000000000..381fdc0830
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+++ b/src/lib/libc/stdlib/merge.c
@@ -0,0 +1,348 @@
+/*-
+ * 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. 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
+ *    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[] = "from: @(#)merge.c     8.2 (Berkeley) 2/14/94";*/
+static char *rcsid = "$Id: merge.c,v 1.1.1.1 1995/10/18 08:42:18 deraadt Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * 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>
+
+static void setup __P((u_char *, u_char *, size_t, size_t, int (*)()));
+static void insertionsort __P((u_char *, size_t, size_t, int (*)()));
+
+#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)))
+
+/*
+ * Arguments are as for qsort.
+ */
+int
+mergesort(base, nmemb, size, cmp)
+        void *base;
+        size_t nmemb;
+        register size_t size;
+        int (*cmp) __P((const void *, const void *));
+{
+        register int i, sense;
+        int big, iflag;
+        register 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);
+        }
+
+        /*
+         * 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 */
+LINEAR:                         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;
+SLOWCASE:                       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(list1, list2, n, size, cmp)
+        size_t n, size;
+        int (*cmp) __P((const void *, const void *));
+        u_char *list1, *list2;
+{
+        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(a, n, size, cmp)
+        u_char *a;
+        size_t n, size;
+        int (*cmp) __P((const void *, const void *));
+{
+        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);
+                }
+}