From 64bc6412188b141c010ac3b8e813b837dd991e80 Mon Sep 17 00:00:00 2001
From: Erik Andersen <andersen@codepoet.org>
Date: Sun, 14 May 2000 04:16:35 +0000
Subject: Initial revision

---
 libc/stdlib/qsort.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 libc/stdlib/qsort.c

(limited to 'libc/stdlib/qsort.c')

diff --git a/libc/stdlib/qsort.c b/libc/stdlib/qsort.c
new file mode 100644
index 000000000..cee53c398
--- /dev/null
+++ b/libc/stdlib/qsort.c
@@ -0,0 +1,166 @@
+/*
+ * This file lifted in toto from 'Dlibs' on the atari ST  (RdeBath)
+ *
+ * 
+ *    Dale Schumacher                         399 Beacon Ave.
+ *    (alias: Dalnefre')                      St. Paul, MN  55104
+ *    dal@syntel.UUCP                         United States of America
+ *  "It's not reality that's important, but how you perceive things."
+ */
+#include <string.h>
+
+char *_qbuf = 0;		/* pointer to storage for qsort() */
+
+#define	PIVOT			((i+j)>>1)
+#define moveitem(dst,src,size)	if(dst != src) memcpy(dst, src, size)
+
+static 
+_wqsort(base, lo, hi, cmp)
+register int *base;
+register int lo;
+register int hi;
+register int (*cmp) ();
+{
+   int   k;
+   register int i, j, t;
+   register int *p = &k;
+
+   while (hi > lo)
+   {
+      i = lo;
+      j = hi;
+      t = PIVOT;
+      *p = base[t];
+      base[t] = base[i];
+      base[i] = *p;
+      while (i < j)
+      {
+	 while (((*cmp) ((base + j), p)) > 0)
+	    --j;
+	 base[i] = base[j];
+	 while ((i < j) && (((*cmp) ((base + i), p)) <= 0))
+	    ++i;
+	 base[j] = base[i];
+      }
+      base[i] = *p;
+      if ((i - lo) < (hi - i))
+      {
+	 _wqsort(base, lo, (i - 1), cmp);
+	 lo = i + 1;
+      }
+      else
+      {
+	 _wqsort(base, (i + 1), hi, cmp);
+	 hi = i - 1;
+      }
+   }
+}
+
+static 
+_lqsort(base, lo, hi, cmp)
+register long *base;
+register int lo;
+register int hi;
+register int (*cmp) ();
+{
+   long  k;
+   register int i, j, t;
+   register long *p = &k;
+
+   while (hi > lo)
+   {
+      i = lo;
+      j = hi;
+      t = PIVOT;
+      *p = base[t];
+      base[t] = base[i];
+      base[i] = *p;
+      while (i < j)
+      {
+	 while (((*cmp) ((base + j), p)) > 0)
+	    --j;
+	 base[i] = base[j];
+	 while ((i < j) && (((*cmp) ((base + i), p)) <= 0))
+	    ++i;
+	 base[j] = base[i];
+      }
+      base[i] = *p;
+      if ((i - lo) < (hi - i))
+      {
+	 _lqsort(base, lo, (i - 1), cmp);
+	 lo = i + 1;
+      }
+      else
+      {
+	 _lqsort(base, (i + 1), hi, cmp);
+	 hi = i - 1;
+      }
+   }
+}
+
+static 
+_nqsort(base, lo, hi, size, cmp)
+register char *base;
+register int lo;
+register int hi;
+register int size;
+register int (*cmp) ();
+{
+   register int i, j;
+   register char *p = _qbuf;
+
+   while (hi > lo)
+   {
+      i = lo;
+      j = hi;
+      p = (base + size * PIVOT);
+      moveitem(_qbuf, p, size);
+      moveitem(p, (base + size * i), size);
+      moveitem((base + size * i), _qbuf, size);
+      p = _qbuf;
+      while (i < j)
+      {
+	 while (((*cmp) ((base + size * j), p)) > 0)
+	    --j;
+	 moveitem((base + size * i), (base + size * j), size);
+	 while ((i < j) && (((*cmp) ((base + size * i), p)) <= 0))
+	    ++i;
+	 moveitem((base + size * j), (base + size * i), size);
+      }
+      moveitem((base + size * i), p, size);
+      if ((i - lo) < (hi - i))
+      {
+	 _nqsort(base, lo, (i - 1), size, cmp);
+	 lo = i + 1;
+      }
+      else
+      {
+	 _nqsort(base, (i + 1), hi, size, cmp);
+	 hi = i - 1;
+      }
+   }
+}
+
+qsort(base, num, size, cmp)
+char *base;
+int   num;
+int   size;
+int   (*cmp) ();
+{
+   char  _qtemp[128];
+
+   if (_qbuf == 0)
+   {
+      if (size > sizeof(_qtemp))/* records too large! */
+	 return;
+      _qbuf = _qtemp;
+   }
+   if (size == 2)
+      _wqsort(base, 0, num - 1, cmp);
+   else if (size == 4)
+      _lqsort(base, 0, num - 1, cmp);
+   else
+      _nqsort(base, 0, num - 1, size, cmp);
+   if (_qbuf == _qtemp)
+      _qbuf = 0;
+}
-- 
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