Commit 03ae07ab authored by Andreas Schmidt's avatar Andreas Schmidt
Browse files

Improve bitmap efficiency and tests

parent f10b2e3e

prrt/util/bitmap.c

+55 −16
Original line number Diff line number Diff line
@@ -28,32 +28,71 @@ Bitmap *Bitmap_create(bool initialValue, uint32_t elementCount) 


void Bitmap_set_range_0(Bitmap *bitmap, uint32_t start, uint32_t length)

{

    uint32_t i = 0;

    // TODO: highly inefficient - optimize

	for(i = 0; i < length; i++) {

		Bitmap_set_0(bitmap, start + i);

    uint32_t start_byte = start / 32;

    uint32_t start_bit = start % 32;

    uint32_t end_byte = (start + length) / 32;

    uint32_t end_bit = (start + length) % 32;

    uint32_t full_mask = ~0u;



    if (start_byte == end_byte) {

        uint32_t mask = (full_mask << end_bit) ^ (full_mask << start_bit);

        bitmap->data[start_byte] ^= (bitmap->data[start_byte] & mask);

    } else {

        uint32_t start_mask = full_mask << start_bit;

        bitmap->data[start_byte] ^= (bitmap->data[start_byte] & start_mask);

        for (uint32_t current_byte = start_byte + 1; current_byte < end_byte; ++current_byte) {

            bitmap->data[current_byte] = 0;

        }

        uint32_t end_mask = ~(full_mask << end_bit);

        bitmap->data[end_byte] ^= (bitmap->data[end_byte] & end_mask);

    }

}



void Bitmap_set_range_1(Bitmap *bitmap, uint32_t start, uint32_t length)

{

    uint32_t i = 0;

    // TODO: highly inefficient - optimize

	for(i = 0; i < length; i++) {

		Bitmap_set_1(bitmap, start + i);

    uint32_t start_byte = start / 32;

    uint32_t start_bit = start % 32;

    uint32_t end_byte = (start + length) / 32;

    uint32_t end_bit = (start + length) % 32;

    uint32_t full_mask = ~0u;



    if (start_byte == end_byte) {

        uint32_t mask = (full_mask << end_bit) ^ (full_mask << start_bit);

        bitmap->data[start_byte] |= mask;

    } else {

        uint32_t start_mask = full_mask << start_bit;

        bitmap->data[start_byte] |= start_mask;

        for (uint32_t current_byte = start_byte + 1; current_byte < end_byte; ++current_byte) {

            bitmap->data[current_byte] = full_mask;

        }

        uint32_t end_mask = ~(full_mask << end_bit);

        bitmap->data[end_byte] |= end_mask;

    }

}



uint32_t Bitmap_sum_ones(Bitmap *bitmap, uint32_t start, uint32_t length)

{

    uint32_t sum = 0;

    uint32_t i = 0;

    // TODO: highly inefficient - optimize

    for(i = 0; i < length; i++) {

        sum += (Bitmap_get(bitmap, start + i) == true);

    uint32_t start_byte = start / 32;

    uint32_t start_bit = start % 32;

    uint32_t end_byte = (start + length) / 32;

    uint32_t end_bit = (start + length) % 32;

    uint32_t full_mask = ~0u;



    if (start_byte == end_byte) {

        uint32_t mask = (full_mask << end_bit) ^ (full_mask << start_bit);

        return __builtin_popcount(bitmap->data[start_byte] & mask);

    } else {

        uint32_t start_mask = full_mask << start_bit;

        uint32_t sum = __builtin_popcount(bitmap->data[start_byte] & start_mask);

        for (uint32_t current_byte = start_byte + 1; current_byte < end_byte; ++current_byte) {

            sum += __builtin_popcount(bitmap->data[current_byte]);

        }

        uint32_t end_mask = ~(full_mask << end_bit);

        sum += __builtin_popcount(bitmap->data[end_byte] & end_mask);



        return sum;

    }

}



uint32_t Bitmap_sum_zeros(Bitmap *bitmap, uint32_t start, uint32_t length)

{

tests/bitmap_tests.cpp

+18 −8
Original line number Diff line number Diff line
@@ -54,12 +54,22 @@ TEST_F(BitmapTest, GetRange) 


TEST_F(BitmapTest, SetRange)

{

    ASSERT_EQ(5, Bitmap_sum_ones(bitmap, 1, 5));

    ASSERT_EQ(0, Bitmap_sum_zeros(bitmap, 1, 5));

    Bitmap_set_range(bitmap, 2, 2, false);

    ASSERT_FALSE(Bitmap_get(bitmap, 2));

    ASSERT_FALSE(Bitmap_get(bitmap, 3));

    ASSERT_TRUE(Bitmap_get(bitmap, 4));

    ASSERT_EQ(3, Bitmap_sum_ones(bitmap, 1, 5));

    ASSERT_EQ(2, Bitmap_sum_zeros(bitmap, 1, 5));

    ASSERT_EQ(500, Bitmap_sum_ones(bitmap, 17, 500));

    ASSERT_EQ(0, Bitmap_sum_zeros(bitmap, 17, 500));



    Bitmap_set_range(bitmap, 2, 300, false);

    ASSERT_TRUE(Bitmap_get(bitmap, 1));

    for (int i = 2; i < 302; ++i) {

        ASSERT_FALSE(Bitmap_get(bitmap, i));

    }

    ASSERT_TRUE(Bitmap_get(bitmap, 302));



    Bitmap_set_range(bitmap, 150, 100, true);

    ASSERT_FALSE(Bitmap_get(bitmap, 149));

    for (int i = 150; i < 250; ++i) {

        ASSERT_TRUE(Bitmap_get(bitmap, i));

    }

    ASSERT_FALSE(Bitmap_get(bitmap, 250));

    ASSERT_EQ(300, Bitmap_sum_ones(bitmap, 1, 500));

    ASSERT_EQ(200, Bitmap_sum_zeros(bitmap, 1, 500));

}