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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
This commit is contained in:
Xin Li 2017-05-19 10:13:08 -07:00
parent 2d36be5912
commit 4b1a3992de
3 changed files with 173 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

84
libc/upstream-freebsd/lib/libc/stdlib/qsort.c
View File

@ -41,15 +41,15 @@ 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) { \
long i = (n) / sizeof (TYPE); \
size_t i = (n) / sizeof (TYPE); \
TYPE *pi = (TYPE *) (parmi); \
TYPE *pj = (TYPE *) (parmj); \
do { \
@ -59,29 +59,35 @@ static inline void swapfunc(char *, char *, int, int);
} while (--i > 0); \
}
#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
#define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \
((char *)a - (char *)0) % sizeof(TYPE) || \
es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
static inline void
swapfunc(a, b, n, swaptype)
char *a, *b;
int n, swaptype;
swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
{
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) \
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)))
@ -111,11 +117,12 @@ 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);
vecswap(a, pb - r, r);
r = min(pd - pc, pn - pd - es);
vecswap(pb, pn - r, r);
if ((r = pb - pa) > es)
d1 = MIN(pa - (char *)a, pb - pa);
vecswap(a, pb - d1, d1);
d1 = MIN(pd - pc, pn - pd - es);
vecswap(pb, pn - d1, d1);
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) {
}
if (d2 > es) {
/* Iterate rather than recurse to save stack space */
a = pn - r;
n = r / es;
/* qsort(pn - d2, d2 / es, es, cmp); */
a = pn - d2;
n = d2 / es;
goto loop;
}
/* qsort(pn - r, r / es, es, cmp);*/
} 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;
}
}
}

1
tests/Android.bp
View File

@ -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",

106
tests/qsort_test.cpp Normal file
View File

@ -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]);
}