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LibC: Replace Berkley's qsort() with AK::dual_pivot_quick_sort() wrapper

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Sahan Fernando 2020-06-30 23:49:44 +10:00 • committed by Andreas Kling
parent 80d800e6d4
commit 0ba9651e6e
2 changed files with 160 additions and 84 deletions
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146
Libraries/LibC/qsort.cpp
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@ -24,103 +24,81 @@
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*-
* Copyright (c) 1980, 1983, 1990 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)qsort.c 5.9 (Berkeley) 2/23/91";
#endif /* LIBC_SCCS and not lint */
#include <AK/Assertions.h>
#include <AK/QuickSort.h>
#include <stdlib.h>
#include <sys/types.h>
static void insertion_sort(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*));
static void insertion_sort_r(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*, void*), void* arg);
class SizedObject {
public:
SizedObject() = delete;
SizedObject(void* data, size_t size)
: m_data(data)
, m_size(size)
{
}
void* data() const { return m_data; }
size_t size() const { return m_size; }
private:
void* m_data;
size_t m_size;
};
namespace AK {
template<>
inline void swap(const SizedObject& a, const SizedObject& b)
{
ASSERT(a.size() == b.size());
const size_t size = a.size();
const auto a_data = reinterpret_cast<char*>(a.data());
const auto b_data = reinterpret_cast<char*>(b.data());
for (auto i = 0u; i < size; ++i) {
swap(a_data[i], b_data[i]);
}
}
}
class SizedObjectSlice {
public:
SizedObjectSlice() = delete;
SizedObjectSlice(void* data, size_t num_elements, size_t element_size)
: m_data(data)
, m_num_elements(num_elements)
, m_element_size(element_size)
{
}
const SizedObject operator[](size_t index)
{
return { static_cast<char*>(m_data) + index * m_element_size, m_element_size };
}
private:
void* m_data;
size_t m_num_elements;
size_t m_element_size;
};
void qsort(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*))
{
if (nmemb <= 1)
if (nmemb <= 1) {
return;
}
insertion_sort(bot, nmemb, size, compar);
SizedObjectSlice slice { bot, nmemb, size };
AK::dual_pivot_quick_sort(slice, 0, nmemb - 1, [=](const SizedObject& a, const SizedObject& b) { return compar(a.data(), b.data()) < 0; });
}
void qsort_r(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*, void*), void* arg)
{
if (nmemb <= 1)
if (nmemb <= 1) {
return;
insertion_sort_r(bot, nmemb, size, compar, arg);
}
void insertion_sort(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*))
{
int cnt;
unsigned char ch;
char *s1, *s2, *t1, *t2, *top;
top = (char*)bot + nmemb * size;
for (t1 = (char*)bot + size; t1 < top;) {
for (t2 = t1; (t2 -= size) >= bot && compar(t1, t2) < 0;)
;
if (t1 != (t2 += size)) {
for (cnt = size; cnt--; ++t1) {
ch = *t1;
for (s1 = s2 = t1; (s2 -= size) >= t2; s1 = s2)
*s1 = *s2;
*s1 = ch;
}
} else
t1 += size;
}
}
void insertion_sort_r(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*, void*), void* arg)
{
int cnt;
unsigned char ch;
char *s1, *s2, *t1, *t2, *top;
top = (char*)bot + nmemb * size;
for (t1 = (char*)bot + size; t1 < top;) {
for (t2 = t1; (t2 -= size) >= bot && compar(t1, t2, arg) < 0;)
;
if (t1 != (t2 += size)) {
for (cnt = size; cnt--; ++t1) {
ch = *t1;
for (s1 = s2 = t1; (s2 -= size) >= t2; s1 = s2)
*s1 = *s2;
*s1 = ch;
}
} else
t1 += size;
}
SizedObjectSlice slice { bot, nmemb, size };
AK::dual_pivot_quick_sort(slice, 0, nmemb - 1, [=](const SizedObject& a, const SizedObject& b) { return compar(a.data(), b.data(), arg) < 0; });
}

98
Tests/LibC/qsort-sorts-and-copies.cpp Normal file
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@ -0,0 +1,98 @@
/*
* Copyright (c) 2020, Sahan Fernando <sahan.h.fernando@gmail.com>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <AK/QuickSort.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <stdio.h>
#include <stdlib.h>
const size_t NUM_RUNS = 100;
struct SortableObject {
int m_key;
int m_payload;
};
int compare_sortable_object(const void* a, const void* b) {
const int key1 = static_cast<const SortableObject*>(a)->m_key;
const int key2 = static_cast<const SortableObject*>(b)->m_key;
if (key1 < key2) {
return -1;
} else if (key1 == key2) {
return 0;
} else {
return 1;
}
}
int calc_payload_for_pos(size_t pos) {
pos *= 231;
return pos ^ (pos << 8) ^ (pos << 16) ^ (pos << 24);
}
void shuffle_vec(Vector<SortableObject> &test_objects)
{
for (size_t i = 0; i < test_objects.size() * 3; ++i) {
auto i1 = rand() % test_objects.size();
auto i2 = rand() % test_objects.size();
swap(test_objects[i1], test_objects[i2]);
}
}
int main()
{
// Generate vector of SortableObjects in sorted order, with payloads determined by their sorted positions
Vector<SortableObject> test_objects;
for (auto i = 0; i < 1024; ++i) {
test_objects.append({i * 137, calc_payload_for_pos(i)});
}
for (size_t i = 0; i < NUM_RUNS; i++) {
// Shuffle the vector, then sort it again
shuffle_vec(test_objects);
qsort(test_objects.data(), test_objects.size(), sizeof(SortableObject), compare_sortable_object);
// Check that the objects are sorted by key
for (auto i = 0u; i + 1 < test_objects.size(); ++i) {
const auto &key1 = test_objects[i].m_key;
const auto &key2 = test_objects[i + 1].m_key;
if (key1 > key2) {
printf("\x1b[01;35mTests failed: saw key %d before key %d\n", key1, key2);
return 1;
}
}
// Check that the object's payloads have not been corrupted
for (auto i = 0u; i < test_objects.size(); ++i) {
const auto expected = calc_payload_for_pos(i);
const auto payload = test_objects[i].m_payload;
if (payload != expected) {
printf("\x1b[01;35mTests failed: expected payload %d for pos %u, got payload %d\n", expected, i, payload);
return 1;
}
}
}
printf("Tests succeeded\n");
return 0;
}