ladybird/AK/Tests/TestBitmap.cpp
Andreas Kling bf7b77e252 AK: Fix Bitmap not finding unset ranges at the end of the map
When we switched the Bitmap code to operating 32 bits at a time,
we neglected to look in the trailing remainder bits after the last
full 32-bit word.

This patch fixes that and adds a couple of tests for Bitmap that I
hacked up while tracking down this bug.

I found this bug when noticing that the kernel would OOM while there
were still some pages left in the physical page allocator.
2020-05-06 22:28:23 +02:00

139 lines
4.3 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* 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/TestSuite.h>
#include <AK/Bitmap.h>
TEST_CASE(construct_empty)
{
Bitmap bitmap;
EXPECT_EQ(bitmap.size(), 0u);
}
TEST_CASE(find_first_set)
{
Bitmap bitmap(128, false);
bitmap.set(69, true);
EXPECT_EQ(bitmap.find_first_set().value(), 69u);
}
TEST_CASE(find_first_unset)
{
Bitmap bitmap(128, true);
bitmap.set(51, false);
EXPECT_EQ(bitmap.find_first_unset().value(), 51u);
}
TEST_CASE(find_first_range)
{
Bitmap bitmap(128, true);
bitmap.set(47, false);
bitmap.set(48, false);
bitmap.set(49, false);
bitmap.set(50, false);
bitmap.set(51, false);
size_t found_range_size = 0;
auto result = bitmap.find_longest_range_of_unset_bits(5, found_range_size);
EXPECT_EQ(result.has_value(), true);
EXPECT_EQ(found_range_size, 5u);
EXPECT_EQ(result.value(), 47u);
}
TEST_CASE(set_range)
{
Bitmap bitmap(128, false);
bitmap.set_range(41, 10, true);
EXPECT_EQ(bitmap.get(40), false);
EXPECT_EQ(bitmap.get(41), true);
EXPECT_EQ(bitmap.get(42), true);
EXPECT_EQ(bitmap.get(43), true);
EXPECT_EQ(bitmap.get(44), true);
EXPECT_EQ(bitmap.get(45), true);
EXPECT_EQ(bitmap.get(46), true);
EXPECT_EQ(bitmap.get(47), true);
EXPECT_EQ(bitmap.get(48), true);
EXPECT_EQ(bitmap.get(49), true);
EXPECT_EQ(bitmap.get(50), true);
EXPECT_EQ(bitmap.get(51), false);
}
TEST_CASE(find_first_fit)
{
{
Bitmap bitmap(32, true);
auto fit = bitmap.find_first_fit(1);
EXPECT_EQ(fit.has_value(), false);
}
{
Bitmap bitmap(32, true);
bitmap.set(31, false);
auto fit = bitmap.find_first_fit(1);
EXPECT_EQ(fit.has_value(), true);
EXPECT_EQ(fit.value(), 31u);
}
for (size_t i = 0; i < 128; ++i) {
Bitmap bitmap(128, true);
bitmap.set(i, false);
auto fit = bitmap.find_first_fit(1);
EXPECT_EQ(fit.has_value(), true);
EXPECT_EQ(fit.value(), i);
}
for (size_t i = 0; i < 127; ++i) {
Bitmap bitmap(128, true);
bitmap.set(i, false);
bitmap.set(i + 1, false);
auto fit = bitmap.find_first_fit(2);
EXPECT_EQ(fit.has_value(), true);
EXPECT_EQ(fit.value(), i);
}
size_t bitmap_size = 1024;
for (size_t chunk_size = 1; chunk_size < 64; ++chunk_size) {
for (size_t i = 0; i < bitmap_size - chunk_size; ++i) {
Bitmap bitmap(bitmap_size, true);
for (size_t c = 0; c < chunk_size; ++c)
bitmap.set(i + c, false);
auto fit = bitmap.find_first_fit(chunk_size);
EXPECT_EQ(fit.has_value(), true);
EXPECT_EQ(fit.value(), i);
}
}
}
TEST_CASE(find_longest_range_of_unset_bits_edge)
{
Bitmap bitmap(36, true);
bitmap.set_range(32, 4, false);
size_t found_range_size = 0;
auto result = bitmap.find_longest_range_of_unset_bits(1, found_range_size);
EXPECT_EQ(result.has_value(), true);
EXPECT_EQ(result.value(), 32u);
}
TEST_MAIN(Bitmap)