glibc/stdlib/tst-qsort4.c
Kuan-Wei Chiu 1bb28b7b4f stdlib: Verify heapsort for two-element cases
Adjust the testing approach to start from scenarios with only 2
elements, as insertion sort no longer handles such cases.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-01-16 11:00:51 -03:00

110 lines
3.1 KiB
C

/* Test the heapsort implementation behind qsort.
Copyright (C) 2023-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include "qsort.c"
#include <stdio.h>
#include <support/check.h>
#include <support/support.h>
static int
cmp (const void *a1, const void *b1, void *closure)
{
const signed char *a = a1;
const signed char *b = b1;
return *a - *b;
}
static void
check_one_sort (signed char *array, int length)
{
signed char *copy = xmalloc (length);
memcpy (copy, array, length);
heapsort_r (copy, length - 1, 1, cmp, NULL);
/* Verify that the result is sorted. */
for (int i = 1; i < length; ++i)
if (copy[i] < copy[i - 1])
{
support_record_failure ();
printf ("error: sorting failure for length %d at offset %d\n",
length, i - 1);
printf ("input:");
for (int i = 0; i < length; ++i)
printf (" %d", array[i]);
printf ("\noutput:");
for (int i = 0; i < length; ++i)
printf (" %d", copy[i]);
putchar ('\n');
break;
}
/* Verify that no elements went away or were added. */
{
int expected_counts[256];
for (int i = 0; i < length; ++i)
++expected_counts[array[i] & 0xff];
int actual_counts[256];
for (int i = 0; i < length; ++i)
++actual_counts[copy[i] & 0xff];
for (int i = 0; i < 256; ++i)
TEST_COMPARE (expected_counts[i], expected_counts[i]);
}
free (copy);
}
/* Enumerate all possible combinations of LENGTH elements. */
static void
check_combinations (int length, signed char *start, int offset)
{
if (offset == length)
check_one_sort (start, length);
else
for (int i = 0; i < length; ++i)
{
start[offset] = i;
check_combinations(length, start, offset + 1);
}
}
static int
do_test (void)
{
/* A random permutation of 20 values. */
check_one_sort ((signed char[20]) {5, 12, 16, 10, 14, 11, 9, 13, 8, 15,
0, 17, 3, 7, 1, 18, 2, 19, 4, 6}, 20);
/* A permutation that appeared during adversarial testing for the
quicksort pass. */
check_one_sort ((signed char[16]) {15, 3, 4, 2, 1, 0, 8, 7, 6, 5, 14,
13, 12, 11, 10, 9}, 16);
for (int i = 2; i <= 8; ++i)
{
signed char *buf = xmalloc (i);
check_combinations (i, buf, 0);
free (buf);
}
return 0;
}
#include <support/test-driver.c>