OS & Memory

Buddy Block Allocator

Difficulty

Asked at Hudson River Trading, Jump Trading

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Language: C++23BuddyAllocator

#include <cstddef>
#include <set>
#include <vector>

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class BuddyAllocator {
public:
    explicit BuddyAllocator(int max_order)
        : max_order_(max_order), free_(static_cast<std::size_t>(max_order) + 1) {
        free_[static_cast<std::size_t>(max_order)].insert(0);
    }

    long long allocate(long long size) {
        // ...
        (void)size;
        return -1;
    }

    void deallocate(long long offset, long long size) {
        // ...
        (void)offset;
        (void)size;
    }

    long long largest_free() const {
        // ...
        return 0;
    }

    long long free_bytes() const {
        // ...
        return 0;
    }

private:
    int max_order_;
    std::vector<std::set<long long>> free_;
};

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