// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ddk/phys-iter.h"

#include <utility>

#include <fbl/algorithm.h>
#include <unittest/unittest.h>

namespace {

bool EmptyIteratorTest() {
    BEGIN_TEST;
    ddk::PhysIter phys_iter(phys_iter_buffer_t{}, 0);
    EXPECT_TRUE(phys_iter.begin() == phys_iter.end());
    END_TEST;
}

bool SimpleIterationTest() {
    BEGIN_TEST;

    constexpr zx_paddr_t kPhysList[] = {
        2 * ZX_PAGE_SIZE,
    };

    const phys_iter_buffer_t kIterBuffer = {
        .phys = kPhysList,
        .phys_count = fbl::count_of(kPhysList),
        .length = ZX_PAGE_SIZE,
        .vmo_offset = 0,
        .sg_list = nullptr,
        .sg_count = 0,
    };

    ddk::PhysIter phys_iter(kIterBuffer, 0);
    auto iter = phys_iter.begin();
    const auto end = phys_iter.end();

    EXPECT_TRUE(iter != end);
    auto [paddr, size] = *iter;
    EXPECT_EQ(paddr, 2 * ZX_PAGE_SIZE);
    EXPECT_EQ(size, ZX_PAGE_SIZE);

    ++iter;
    EXPECT_TRUE(iter == end);

    size_t count = 0;
    for (auto [paddr, size] : phys_iter) {
        ++count;
        EXPECT_EQ(paddr, 2 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, ZX_PAGE_SIZE);
    }
    EXPECT_EQ(count, 1);

    END_TEST;
}

bool ContiguousTest() {
    BEGIN_TEST;

    constexpr zx_paddr_t kPhysList[] = {
        0 * ZX_PAGE_SIZE,
        1 * ZX_PAGE_SIZE,
        2 * ZX_PAGE_SIZE,
        3 * ZX_PAGE_SIZE,
    };

    const phys_iter_buffer_t kIterBuffer = {
        .phys = kPhysList,
        .phys_count = fbl::count_of(kPhysList),
        .length = 4 * ZX_PAGE_SIZE,
        .vmo_offset = 0,
        .sg_list = nullptr,
        .sg_count = 0,
    };

    ddk::PhysIter phys_iter(kIterBuffer, 0);
    auto iter = phys_iter.begin();
    const auto end = phys_iter.end();

    EXPECT_TRUE(iter != end);
    auto [paddr, size] = *iter;
    EXPECT_EQ(paddr, 0);
    EXPECT_EQ(size, 4 * ZX_PAGE_SIZE);

    ++iter;
    EXPECT_TRUE(iter == end);

    END_TEST;
}

bool DiscontiguousTest() {
    BEGIN_TEST;

    constexpr zx_paddr_t kPhysList[] = {
        1 * ZX_PAGE_SIZE,
        3 * ZX_PAGE_SIZE,
        4 * ZX_PAGE_SIZE,
        7 * ZX_PAGE_SIZE,
    };

    const phys_iter_buffer_t kIterBuffer = {
        .phys = kPhysList,
        .phys_count = fbl::count_of(kPhysList),
        .length = 4 * ZX_PAGE_SIZE,
        .vmo_offset = 0,
        .sg_list = nullptr,
        .sg_count = 0,
    };

    ddk::PhysIter phys_iter(kIterBuffer, 0);
    auto iter = phys_iter.begin();
    const auto end = phys_iter.end();

    {
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, ZX_PAGE_SIZE);
        EXPECT_EQ(size, ZX_PAGE_SIZE);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 3 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, 2 * ZX_PAGE_SIZE);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 7 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, ZX_PAGE_SIZE);
    }

    ++iter;
    EXPECT_TRUE(iter == end);

    END_TEST;
}

bool UnalignedTest() {
    BEGIN_TEST;

    constexpr zx_paddr_t kPhysList[] = {
        2 * ZX_PAGE_SIZE,
        4 * ZX_PAGE_SIZE,
    };

    const phys_iter_buffer_t kIterBuffer = {
        .phys = kPhysList,
        .phys_count = fbl::count_of(kPhysList),
        .length = 2 * ZX_PAGE_SIZE - 7,
        .vmo_offset = 7,
        .sg_list = nullptr,
        .sg_count = 0,
    };

    ddk::PhysIter phys_iter(kIterBuffer, 0);
    auto iter = phys_iter.begin();
    const auto end = phys_iter.end();

    {
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 2 * ZX_PAGE_SIZE + 7);
        EXPECT_EQ(size, ZX_PAGE_SIZE - 7);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 4 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, ZX_PAGE_SIZE);
    }

    ++iter;
    EXPECT_TRUE(iter == end);

    END_TEST;
}

bool ScatterGatherTest() {
    BEGIN_TEST;

    constexpr zx_paddr_t kPhysList[] = {
        1 * ZX_PAGE_SIZE,
        3 * ZX_PAGE_SIZE,
        4 * ZX_PAGE_SIZE,
        7 * ZX_PAGE_SIZE,
    };

    constexpr phys_iter_sg_entry_t kScatterGatherList[] = {
        {10, 1024},
        // Cross contiguous pages.
        {2 * ZX_PAGE_SIZE, ZX_PAGE_SIZE},
        // Cross contiguous pages with offset and non-page size.
        {ZX_PAGE_SIZE + 10, ZX_PAGE_SIZE + 10},
        // Cross nont-contiguous pages and overflow over end.
        {2 * ZX_PAGE_SIZE, 2 * ZX_PAGE_SIZE + 15},
    };

    const phys_iter_buffer_t kIterBuffer = {
        .phys = kPhysList,
        .phys_count = fbl::count_of(kPhysList),
        .length = 0,
        .vmo_offset = 0,
        .sg_list = kScatterGatherList,
        .sg_count = fbl::count_of(kScatterGatherList),
    };

    ddk::PhysIter phys_iter(kIterBuffer, 0);
    auto iter = phys_iter.begin();
    const auto end = phys_iter.end();

    {
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, ZX_PAGE_SIZE + 1024);
        EXPECT_EQ(size, 10);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 3 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, 2 * ZX_PAGE_SIZE);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 3 * ZX_PAGE_SIZE + 10);
        EXPECT_EQ(size, ZX_PAGE_SIZE + 10);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 4 * ZX_PAGE_SIZE + 15);
        EXPECT_EQ(size, ZX_PAGE_SIZE - 15);
    }

    {
        ++iter;
        EXPECT_TRUE(iter != end);
        auto [paddr, size] = *iter;
        EXPECT_EQ(paddr, 7 * ZX_PAGE_SIZE);
        EXPECT_EQ(size, ZX_PAGE_SIZE);
    }

    ++iter;
    EXPECT_TRUE(iter == end);

    END_TEST;
}

} // namespace

BEGIN_TEST_CASE(PhyIterTests)
RUN_TEST_SMALL(EmptyIteratorTest)
RUN_TEST_SMALL(SimpleIterationTest)
RUN_TEST_SMALL(ContiguousTest)
RUN_TEST_SMALL(DiscontiguousTest)
RUN_TEST_SMALL(UnalignedTest)
RUN_TEST_SMALL(ScatterGatherTest)
END_TEST_CASE(PhyIterTests)