libc: Sync qsort(3) with FreeBSD revision r318515.

r279663: enhance to handle 32-bit aligned data on 64-bit systems

r279666: qsort(3): small style(9) cleanups.

r288030: Use ANSI C prototypes.  Eliminates -Wold-style-definition
warnings.

r318514: Use size_t.

r318515: Reduce the possible recursion level to log2(N) by always
recursing on the smaller partition instead.

Bug: 38450217
Test: builds, ./tests/run-on-host.sh 64
Change-Id: Ieb622e6f54f8f6d6f62e1bdb491d3b5c8e2f9965

libc/upstream-freebsd/lib/libc/stdlib/qsort.c

@@ -41,47 +41,53 @@ typedef int		 cmp_t(void *, const void *, const void *);
 typedef int		 cmp_t(const void *, const void *);
 #endif
 static inline char	*med3(char *, char *, char *, cmp_t *, void *);
-static inline void	 swapfunc(char *, char *, int, int);
+static inline void	 swapfunc(char *, char *, size_t, int, int);
 
-#define min(a, b)	(a) < (b) ? a : b
+#define	MIN(a, b)	((a) < (b) ? a : b)
 
 /*
  * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  */
-#define swapcode(TYPE, parmi, parmj, n) { 		\
+#define	swapcode(TYPE, parmi, parmj, n) {		\
-	long i = (n) / sizeof (TYPE); 			\
+	size_t i = (n) / sizeof (TYPE);			\
-	TYPE *pi = (TYPE *) (parmi); 		\
+	TYPE *pi = (TYPE *) (parmi);		\
-	TYPE *pj = (TYPE *) (parmj); 		\
+	TYPE *pj = (TYPE *) (parmj);		\
 	do { 						\
 		TYPE	t = *pi;		\
 		*pi++ = *pj;				\
 		*pj++ = t;				\
-        } while (--i > 0);				\
+	} while (--i > 0);				\
 }
 
-#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
+#define	SWAPINIT(TYPE, a, es) swaptype_ ## TYPE =	\
-	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+	((char *)a - (char *)0) % sizeof(TYPE) ||	\
+	es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
 
 static inline void
-swapfunc(a, b, n, swaptype)
+swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
-	char *a, *b;
-	int n, swaptype;
 {
-	if(swaptype <= 1)
+	if (swaptype_long <= 1)
 		swapcode(long, a, b, n)
+	else if (swaptype_int <= 1)
+		swapcode(int, a, b, n)
 	else
 		swapcode(char, a, b, n)
 }
 
-#define swap(a, b)					\
+#define	swap(a, b)					\
-	if (swaptype == 0) {				\
+	if (swaptype_long == 0) {			\
 		long t = *(long *)(a);			\
 		*(long *)(a) = *(long *)(b);		\
 		*(long *)(b) = t;			\
+	} else if (swaptype_int == 0) {			\
+		int t = *(int *)(a);			\
+		*(int *)(a) = *(int *)(b);		\
+		*(int *)(b) = t;			\
 	} else						\
-		swapfunc(a, b, es, swaptype)
+		swapfunc(a, b, es, swaptype_long, swaptype_int)
 
-#define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
+#define	vecswap(a, b, n)				\
+	if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int)
 
 #ifdef I_AM_QSORT_R
 #define	CMP(t, x, y) (cmp((t), (x), (y)))
@@ -98,24 +104,25 @@ __unused
 {
 	return CMP(thunk, a, b) < 0 ?
 	       (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
-              :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
+	      :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
 }
 
 #ifdef I_AM_QSORT_R
 void
 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
 #else
-#define thunk NULL
+#define	thunk NULL
 void
 qsort(void *a, size_t n, size_t es, cmp_t *cmp)
 #endif
 {
 	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
-	size_t d, r;
+	size_t d1, d2;
 	int cmp_result;
-	int swaptype, swap_cnt;
+	int swaptype_long, swaptype_int, swap_cnt;
 
-loop:	SWAPINIT(a, es);
+loop:	SWAPINIT(long, a, es);
+	SWAPINIT(int, a, es);
 	swap_cnt = 0;
 	if (n < 7) {
 		for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
@@ -130,7 +137,8 @@ loop:	SWAPINIT(a, es);
 		pl = a;
 		pn = (char *)a + (n - 1) * es;
 		if (n > 40) {
-			d = (n / 8) * es;
+			size_t d = (n / 8) * es;
+
 			pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
 			pm = med3(pm - d, pm, pm + d, cmp, thunk);
 			pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
@@ -175,21 +183,43 @@ loop:	SWAPINIT(a, es);
 	}
 
 	pn = (char *)a + n * es;
-	r = min(pa - (char *)a, pb - pa);
+	d1 = MIN(pa - (char *)a, pb - pa);
-	vecswap(a, pb - r, r);
+	vecswap(a, pb - d1, d1);
-	r = min(pd - pc, pn - pd - es);
+	d1 = MIN(pd - pc, pn - pd - es);
-	vecswap(pb, pn - r, r);
+	vecswap(pb, pn - d1, d1);
-	if ((r = pb - pa) > es)
+
+	d1 = pb - pa;
+	d2 = pd - pc;
+	if (d1 <= d2) {
+		/* Recurse on left partition, then iterate on right partition */
+		if (d1 > es) {
 #ifdef I_AM_QSORT_R
-		qsort_r(a, r / es, es, thunk, cmp);
+			qsort_r(a, d1 / es, es, thunk, cmp);
 #else
-		qsort(a, r / es, es, cmp);
+			qsort(a, d1 / es, es, cmp);
 #endif
-	if ((r = pd - pc) > es) {
+		}
-		/* Iterate rather than recurse to save stack space */
+		if (d2 > es) {
-		a = pn - r;
+			/* Iterate rather than recurse to save stack space */
-		n = r / es;
+			/* qsort(pn - d2, d2 / es, es, cmp); */
-		goto loop;
+			a = pn - d2;
+			n = d2 / es;
+			goto loop;
+		}
+	} else {
+		/* Recurse on right partition, then iterate on left partition */
+		if (d2 > es) {
+#ifdef I_AM_QSORT_R
+			qsort_r(pn - d2, d2 / es, es, thunk, cmp);
+#else
+			qsort(pn - d2, d2 / es, es, cmp);
+#endif
+		}
+		if (d1 > es) {
+			/* Iterate rather than recurse to save stack space */
+			/* qsort(a, d1 / es, es, cmp); */
+			n = d1 / es;
+			goto loop;
+		}
 	}
-/*		qsort(pn - r, r / es, es, cmp);*/
 }

tests/Android.bp

@@ -88,6 +88,7 @@ cc_test_library {
         "nl_types_test.cpp",
         "pthread_test.cpp",
         "pty_test.cpp",
+        "qsort_test.cpp",
         "regex_test.cpp",
         "resolv_test.cpp",
         "sched_test.cpp",

tests/qsort_test.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <sys/types.h>
+
+#include <gtest/gtest.h>
+
+#include "gtest_globals.h"
+
+#define BUFFER_SIZE 1024
+
+static int cmp_long(const void *l, const void *r)
+{
+
+  return (*(long *)l - *(long *)r);
+}
+
+static int cmp_int(const void *l, const void *r)
+{
+
+  return (*(int *)l - *(int *)r);
+}
+
+#ifndef arc4random_uniform
+static bool seeded;
+
+u_int32_t arc4random_uniform(uint32_t upper_bound)
+{
+  if (!seeded) {
+    srandom((int)time(NULL));
+    seeded = true;
+  }
+
+  return (random() % upper_bound);
+}
+#endif
+
+TEST(qsort_test, long_test) {
+  long buf[BUFFER_SIZE];
+  long i;
+
+  /* Initialize buffer with known numbers */
+  for (i=0; i<BUFFER_SIZE; i++)
+    buf[i] = i;
+
+  /* Stir 1/4 pairs in the buffer */
+  for (i=0; i<BUFFER_SIZE/4; i++) {
+    u_int32_t pos1, pos2;
+    long t;
+
+    pos1 = arc4random_uniform(BUFFER_SIZE);
+    pos2 = arc4random_uniform(BUFFER_SIZE);
+
+    t = buf[pos1];
+    buf[pos1] = buf[pos2];
+    buf[pos2] = t;
+  }
+
+  /* Sort */
+  qsort(buf, BUFFER_SIZE, sizeof(buf[0]), &cmp_long);
+
+  for (i=0; i<BUFFER_SIZE; i++)
+    EXPECT_EQ(i, buf[i]);
+}
+
+TEST(qsort_test, int_test) {
+  int buf[BUFFER_SIZE];
+  int i;
+
+  /* Initialize buffer with known numbers */
+  for (i=0; i<BUFFER_SIZE; i++)
+    buf[i] = i;
+
+  /* Stir 1/4 pairs in the buffer */
+  for (i=0; i<BUFFER_SIZE/4; i++) {
+    u_int32_t pos1, pos2;
+    int t;
+
+    pos1 = arc4random_uniform(BUFFER_SIZE);
+    pos2 = arc4random_uniform(BUFFER_SIZE);
+
+    t = buf[pos1];
+    buf[pos1] = buf[pos2];
+    buf[pos2] = t;
+  }
+
+  /* Sort */
+  qsort(buf, BUFFER_SIZE, sizeof(buf[0]), &cmp_int);
+
+  for (i=0; i<BUFFER_SIZE; i++)
+    EXPECT_EQ(i, buf[i]);
+}