skia2/tests/HashTest.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkRefCnt.h"
#include "include/core/SkString.h"
#include "include/private/SkChecksum.h"
#include "include/private/SkTHash.h"
#include "tests/Test.h"

// Tests use of const foreach().  map.count() is of course the better way to do this.
static int count(const SkTHashMap<int, double>& map) {
    int n = 0;
    map.foreach([&n](int, double) { n++; });
    return n;
}

DEF_TEST(HashMap, r) {
    SkTHashMap<int, double> map;

    map.set(3, 4.0);
    REPORTER_ASSERT(r, map.count() == 1);

    REPORTER_ASSERT(r, map.approxBytesUsed() > 0);

    double* found = map.find(3);
    REPORTER_ASSERT(r, found);
    REPORTER_ASSERT(r, *found == 4.0);

    map.foreach([](int key, double* d){ *d = -key; });
    REPORTER_ASSERT(r, count(map) == 1);

    found = map.find(3);
    REPORTER_ASSERT(r, found);
    REPORTER_ASSERT(r, *found == -3.0);

    REPORTER_ASSERT(r, !map.find(2));

    const int N = 20;

    for (int i = 0; i < N; i++) {
        map.set(i, 2.0*i);
    }
    for (int i = 0; i < N; i++) {
        double* found = map.find(i);
        REPORTER_ASSERT(r, found);
        REPORTER_ASSERT(r, *found == i*2.0);
    }
    for (int i = N; i < 2*N; i++) {
        REPORTER_ASSERT(r, !map.find(i));
    }

    REPORTER_ASSERT(r, map.count() == N);

    for (int i = 0; i < N/2; i++) {
        map.remove(i);
    }
    for (int i = 0; i < N; i++) {
        double* found = map.find(i);
        REPORTER_ASSERT(r, (found == nullptr) ==  (i < N/2));
    }
    REPORTER_ASSERT(r, map.count() == N/2);

    map.reset();
    REPORTER_ASSERT(r, map.count() == 0);

    {
        // Test that we don't leave dangling values in empty slots.
        SkTHashMap<int, sk_sp<SkRefCnt>> refMap;
        auto ref = sk_make_sp<SkRefCnt>();
        REPORTER_ASSERT(r, ref->unique());

        refMap.set(0, ref);
        REPORTER_ASSERT(r, refMap.count() == 1);
        REPORTER_ASSERT(r, !ref->unique());

        refMap.remove(0);
        REPORTER_ASSERT(r, refMap.count() == 0);
        REPORTER_ASSERT(r, ref->unique());
    }
}

DEF_TEST(HashSet, r) {
    SkTHashSet<SkString> set;

    set.add(SkString("Hello"));
    set.add(SkString("World"));

    REPORTER_ASSERT(r, set.count() == 2);

    REPORTER_ASSERT(r, set.contains(SkString("Hello")));
    REPORTER_ASSERT(r, set.contains(SkString("World")));
    REPORTER_ASSERT(r, !set.contains(SkString("Goodbye")));

    REPORTER_ASSERT(r, set.find(SkString("Hello")));
    REPORTER_ASSERT(r, *set.find(SkString("Hello")) == SkString("Hello"));

    set.remove(SkString("Hello"));
    REPORTER_ASSERT(r, !set.contains(SkString("Hello")));
    REPORTER_ASSERT(r, set.count() == 1);

    set.reset();
    REPORTER_ASSERT(r, set.count() == 0);
}

namespace {

class CopyCounter {
public:
    CopyCounter() : fID(0), fCounter(nullptr) {}

    CopyCounter(uint32_t id, uint32_t* counter) : fID(id), fCounter(counter) {}

    CopyCounter(const CopyCounter& other)
        : fID(other.fID)
        , fCounter(other.fCounter) {
        SkASSERT(fCounter);
        *fCounter += 1;
    }

    void operator=(const CopyCounter& other) {
        fID = other.fID;
        fCounter = other.fCounter;
        *fCounter += 1;
    }

    CopyCounter(CopyCounter&& other) { *this = std::move(other); }
    void operator=(CopyCounter&& other) {
        fID = other.fID;
        fCounter = other.fCounter;
    }


    bool operator==(const CopyCounter& other) const {
        return fID == other.fID;
    }

private:
    uint32_t  fID;
    uint32_t* fCounter;
};

struct HashCopyCounter {
    uint32_t operator()(const CopyCounter&) const {
        return 0; // let them collide, what do we care?
    }
};

}  // namespace

DEF_TEST(HashSetCopyCounter, r) {
    SkTHashSet<CopyCounter, HashCopyCounter> set;

    uint32_t globalCounter = 0;
    CopyCounter copyCounter1(1, &globalCounter);
    CopyCounter copyCounter2(2, &globalCounter);
    REPORTER_ASSERT(r, globalCounter == 0);

    set.add(copyCounter1);
    REPORTER_ASSERT(r, globalCounter == 1);
    REPORTER_ASSERT(r, set.contains(copyCounter1));
    REPORTER_ASSERT(r, globalCounter == 1);
    set.add(copyCounter1);
    // We allow copies for same-value adds for now.
    REPORTER_ASSERT(r, globalCounter == 2);

    set.add(copyCounter2);
    REPORTER_ASSERT(r, globalCounter == 3);
    REPORTER_ASSERT(r, set.contains(copyCounter1));
    REPORTER_ASSERT(r, set.contains(copyCounter2));
    REPORTER_ASSERT(r, globalCounter == 3);
    set.add(copyCounter1);
    set.add(copyCounter2);
    // We allow copies for same-value adds for now.
    REPORTER_ASSERT(r, globalCounter == 5);
}


DEF_TEST(HashFindOrNull, r) {
    struct Entry {
        int key = 0;
        int val = 0;
    };

    struct HashTraits {
        static int GetKey(const Entry* e) { return e->key; }
        static uint32_t Hash(int key) { return key; }
    };

    SkTHashTable<Entry*, int, HashTraits> table;

    REPORTER_ASSERT(r, nullptr == table.findOrNull(7));

    Entry seven = { 7, 24 };
    table.set(&seven);

    REPORTER_ASSERT(r, &seven == table.findOrNull(7));
}

DEF_TEST(HashTableGrowsAndShrinks, r) {
    SkTHashSet<int> s;
    auto check_count_cap = [&](int count, int cap) {
        REPORTER_ASSERT(r, s.count() == count);
        REPORTER_ASSERT(r, s.approxBytesUsed() == (sizeof(int) + sizeof(uint32_t)) * cap);
    };

    // Add and remove some elements to test basic growth and shrink patterns.
                 check_count_cap(0,0);
    s.add(1);    check_count_cap(1,4);
    s.add(2);    check_count_cap(2,4);
    s.add(3);    check_count_cap(3,4);
    s.add(4);    check_count_cap(4,8);

    s.remove(4); check_count_cap(3,8);
    s.remove(3); check_count_cap(2,4);
    s.remove(2); check_count_cap(1,4);
    s.remove(1); check_count_cap(0,4);

    s.add(1);    check_count_cap(1,4);
    s.add(2);    check_count_cap(2,4);
    s.add(3);    check_count_cap(3,4);
    s.add(4);    check_count_cap(4,8);

    // Add and remove single elements repeatedly to test hysteresis
    // avoids reallocating these small tables all the time.
    for (int i = 0; i < 10; i++) {
        s.   add(5); check_count_cap(5,8);
        s.remove(5); check_count_cap(4,8);
    }

    s.remove(4);     check_count_cap(3,8);
    for (int i = 0; i < 10; i++) {
        s.   add(4); check_count_cap(4,8);
        s.remove(4); check_count_cap(3,8);
    }

    s.remove(3);     check_count_cap(2,4);
    for (int i = 0; i < 10; i++) {
        s.   add(4); check_count_cap(3,4);
        s.remove(4); check_count_cap(2,4);
    }

    s.remove(2);     check_count_cap(1,4);
    for (int i = 0; i < 10; i++) {
        s.   add(2); check_count_cap(2,4);
        s.remove(2); check_count_cap(1,4);
    }
}