base/AlignedBuf_unittest.cpp

// Copyright 2020 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 "base/AlignedBuf.h"
#include "base/ArraySize.h"

#include <gtest/gtest.h>

#include <vector>
#include <array>

using android::AlignedBuf;
using android::base::arraySize;
using android::aligned_buf_alloc;
using android::aligned_buf_free;

static void checkAligned(size_t align, void* ptr) {
    uintptr_t ptrVal = reinterpret_cast<uintptr_t>(ptr);
    EXPECT_EQ(0, ptrVal & (align - 1));
}

TEST(AlignedBuf, Basic) {
    const int numItems = 10;

    // Check that the buffers are aligned
    {
        AlignedBuf<uint32_t, 64> buf(numItems);
        checkAligned(64, buf.data());
        EXPECT_EQ(numItems, buf.size());
    }

    {
        AlignedBuf<uint32_t, 256> buf(numItems);
        checkAligned(256, buf.data());
        EXPECT_EQ(numItems, buf.size());
    }

    {
        AlignedBuf<uint32_t, 4096> buf(numItems);
        checkAligned(4096, buf.data());
        EXPECT_EQ(numItems, buf.size());
    }

    const int numManyItems = 100;
    const int numFewItems = 4;

    // Test read/write
    AlignedBuf<uint32_t, 64> buf(numManyItems);
    uint32_t* bufData = buf.data();
    for (int i = 0; i < numManyItems; i++) {
        bufData[i] = 0;
        EXPECT_EQ(0, bufData[i]);
    }

    AlignedBuf<uint32_t, 64> buf2(numFewItems);
    bufData = buf2.data();
    for (int i = 0; i < numFewItems; i++) {
        bufData[i] = 0;
        EXPECT_EQ(0, bufData[i]);
    }
}

// Tests that copy constructor copies underlying buffer.
TEST(AlignedBuf, Copy) {
    constexpr int align = 64;
    constexpr int size = 128;

    AlignedBuf<uint32_t, align> buf(size);
    AlignedBuf<uint32_t, align> buf2 = buf;

    EXPECT_EQ(buf2.size(), buf.size());
    EXPECT_NE(buf2.data(), buf.data());

    for (int i = 0; i < buf.size(); i++) {
        buf[i] = 0;
    }

    for (int i = 0; i < buf2.size(); i++) {
        buf2[i] = 1;
    }

    for (int i = 0; i < buf.size(); i++) {
        EXPECT_EQ(0, buf[i]);
    }
}

// Tests that move constructor preserves underlying buffer.
TEST(AlignedBuf, Move) {
    constexpr int align = 64;
    constexpr int size = 128;

    AlignedBuf<uint32_t, align> buf(size);

    for (int i = 0; i < buf.size(); i++) {
        buf[i] = 0;
        EXPECT_EQ(0, buf[i]);
    }

    AlignedBuf<uint32_t, align> buf2 = std::move(buf);

    EXPECT_EQ(0, buf.size());
    EXPECT_EQ(size, buf2.size());

    for (int i = 0; i < buf2.size(); i++) {
        EXPECT_EQ(0, buf2[i]);
        // Check that it is stil writable.
        buf2[i] = 0;
    }
}

// Tests that operator== is comparing raw bytes.
TEST(AlignedBuf, Compare) {
    constexpr int align = 64;
    constexpr int size = 128;

    AlignedBuf<uint32_t, align> buf(size);
    AlignedBuf<uint32_t, align> buf2 = buf;

    EXPECT_EQ(buf, buf2);
}

// Tests that resize preserves contents.
TEST(AlignedBuf, Resize) {
    std::array<char, 4> contents = { 0xa, 0xb, 0xc, 0xd };
    size_t initialSize = contents.size();
    AlignedBuf<char, 4096> buf(initialSize);

    auto check = [&]() {
        for (size_t i = 0; i < initialSize; i++) {
            EXPECT_EQ(contents[i], buf[i]);
        }
    };

    memcpy(buf.data(), contents.data(), initialSize);
    check();

    for (size_t i = 0; i < 10; i++) {
        buf.resize(initialSize + i * 4096);
        check();
    }
}

// Tests raw aligned alloc.
TEST(AlignedBuf, Raw) {
    constexpr size_t alignmentsToTest[] = {
        1, 2, 4, 8, 16, 256, 1024, 4096,
    };
    constexpr size_t sizesToTest[] = {
        1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
        16, 17, 256, 400, 500, 4000, 4096,
    };

    size_t numAlignmentCases = arraySize(alignmentsToTest);
    size_t numSizeCases = arraySize(sizesToTest);

    for (size_t i = 0; i < numAlignmentCases; ++i) {
        for (size_t j = 0; j < numSizeCases; ++j) {
            void* buf = aligned_buf_alloc(alignmentsToTest[i], sizesToTest[j]);
            EXPECT_NE(nullptr, buf);
            checkAligned(alignmentsToTest[i], buf);
            aligned_buf_free(buf);
        }
    }
}