38 lines
719 B
C++
38 lines
719 B
C++
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#pragma once
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// TODO: implement better hash function
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/**
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* Class calculates hash of the data dynamically.
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*/
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class Hasher {
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public:
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Hasher() = default;
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/**
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* Sets hash to 0.
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*/
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void Reset() { hash_ = 0; }
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/**
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* Updates hash from given data.
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* @param data data from which hash will be updated
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* @param n length of the data
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*/
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void Update(const uint8_t *data, size_t n) {
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for (int i = 0; i < n; ++i) hash_ = hash_ * kPrime + data[i] + 1;
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}
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/**
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* Returns current hash value.
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*/
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uint64_t hash() const { return hash_; }
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private:
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/**
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* Prime number used in calculating hash.
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*/
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const uint64_t kPrime = 3137;
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/**
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* Hash of data.
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*/
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uint64_t hash_ = 0;
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};
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