1 files changed, 185 insertions, 0 deletions

diff --git a/examples/redis-unstable/src/pqsort.c b/examples/redis-unstable/src/pqsort.c
new file mode 100644
index 0000000..6252717
--- /dev/null
+++ b/examples/redis-unstable/src/pqsort.c
@@ -0,0 +1,185 @@
+/* The following is the NetBSD libc qsort implementation modified in order to
+ * support partial sorting of ranges for Redis.
+ *
+ * Copyright(C) 2009-current Redis Ltd.. All rights reserved.
+ *
+ * The original copyright notice follows. */
+
+
+/*      $NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $ */
+
+/*-
+ * Copyright (c) 1992, 1993
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * 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. 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.
+ */
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <errno.h>
+#include <stdlib.h>
+
+static inline char      *med3 (char *, char *, char *,
+    int (*)(const void *, const void *));
+static inline void       swapfunc (char *, char *, size_t, int);
+
+#define min(a, b)       (a) < (b) ? a : b
+
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+#define swapcode(TYPE, parmi, parmj, n) {               \
+        size_t i = (n) / sizeof (TYPE);                 \
+        TYPE *pi = (TYPE *)(void *)(parmi);             \
+        TYPE *pj = (TYPE *)(void *)(parmj);             \
+        do {                                            \
+                TYPE    t = *pi;                        \
+                *pi++ = *pj;                            \
+                *pj++ = t;                              \
+        } while (--i > 0);                              \
+}
+
+#define SWAPINIT(a, es) swaptype = (uintptr_t)a % sizeof(long) || \
+        es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+
+static inline void
+swapfunc(char *a, char *b, size_t n, int swaptype)
+{
+
+        if (swaptype <= 1)
+                swapcode(long, a, b, n)
+        else
+                swapcode(char, a, b, n)
+}
+
+#define swap(a, b)                                              \
+        if (swaptype == 0) {                                    \
+                long t = *(long *)(void *)(a);                  \
+                *(long *)(void *)(a) = *(long *)(void *)(b);    \
+                *(long *)(void *)(b) = t;                       \
+        } else                                                  \
+                swapfunc(a, b, es, swaptype)
+
+#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
+
+static inline char *
+med3(char *a, char *b, char *c,
+    int (*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 ));
+}
+
+static void
+_pqsort(void *a, size_t n, size_t es,
+    int (*cmp) (const void *, const void *), void *lrange, void *rrange)
+{
+        char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+        size_t d, r;
+        int swaptype, cmp_result;
+
+loop:   SWAPINIT(a, es);
+        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 = (char *) 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 && (cmp_result = cmp(pb, a)) <= 0) {
+                        if (cmp_result == 0) {
+                                swap(pa, pb);
+                                pa += es;
+                        }
+                        pb += es;
+                }
+                while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
+                        if (cmp_result == 0) {
+                                swap(pc, pd);
+                                pd -= es;
+                        }
+                        pc -= es;
+                }
+                if (pb > pc)
+                        break;
+                swap(pb, pc);
+                pb += es;
+                pc -= es;
+        }
+
+        pn = (char *) a + n * es;
+        r = min(pa - (char *) a, pb - pa);
+        vecswap(a, pb - r, r);
+        r = min((size_t)(pd - pc), pn - pd - es);
+        vecswap(pb, pn - r, r);
+        if ((r = pb - pa) > es) {
+                void *_l = a, *_r = ((unsigned char*)a)+r-1;
+                if (!((lrange < _l && rrange < _l) ||
+                    (lrange > _r && rrange > _r)))
+                    _pqsort(a, r / es, es, cmp, lrange, rrange);
+        }
+        if ((r = pd - pc) > es) {
+                void *_l, *_r;
+
+                /* Iterate rather than recurse to save stack space */
+                a = pn - r;
+                n = r / es;
+
+                _l = a;
+                _r = ((unsigned char*)a)+r-1;
+                if (!((lrange < _l && rrange < _l) ||
+                    (lrange > _r && rrange > _r)))
+                    goto loop;
+        }
+/*              qsort(pn - r, r / es, es, cmp);*/
+}
+
+void
+pqsort(void *a, size_t n, size_t es,
+    int (*cmp) (const void *, const void *), size_t lrange, size_t rrange)
+{
+    _pqsort(a,n,es,cmp,((unsigned char*)a)+(lrange*es),
+                       ((unsigned char*)a)+((rrange+1)*es)-1);
+}