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Add constexpr rsync_hash::repeating_window()

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This commit is contained in:
Marcus Holland-Moritz 2023-08-18 21:49:49 +02:00
parent db4499847e
commit c903f6b265
1 changed files with 7 additions and 0 deletions
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7
include/dwarfs/cyclic_hash.h
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@ -50,6 +50,13 @@ class rsync_hash {
len_ = 0;
}
static constexpr uint32_t repeating_window(uint8_t byte, size_t length) {
uint16_t v = static_cast<uint16_t>(byte);
uint16_t a{static_cast<uint16_t>(v * length)};
uint16_t b{static_cast<uint16_t>(v * (length * (length + 1)) / 2)};
return static_cast<uint32_t>(a) | (static_cast<uint32_t>(b) << 16);
}
private:
uint16_t a_{0};
uint16_t b_{0};