Files
scylladb/xx_hasher.hh
Avi Kivity fcb8d040e8 treewide: use Software Package Data Exchange (SPDX) license identifiers
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.

Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.

The changes we applied mechanically with a script, except to
licenses/README.md.

Closes #9937
2022-01-18 12:15:18 +01:00

64 lines
1.4 KiB
C++

/*
* Copyright (C) 2018-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#pragma once
#include "bytes.hh"
#include "utils/serialization.hh"
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Warray-bounds"
#include <xxhash.h>
#pragma GCC diagnostic pop
#include <array>
class xx_hasher {
static constexpr size_t digest_size = 16;
XXH64_state_t _state;
public:
explicit xx_hasher(uint64_t seed = 0) noexcept {
XXH64_reset(&_state, seed);
}
void update(const char* ptr, size_t length) noexcept {
XXH64_update(&_state, ptr, length);
}
bytes finalize() {
bytes digest{bytes::initialized_later(), digest_size};
serialize_to(digest.begin());
return digest;
}
std::array<uint8_t, digest_size> finalize_array() {
std::array<uint8_t, digest_size> digest;
serialize_to(digest.begin());
return digest;
}
uint64_t finalize_uint64() {
return XXH64_digest(&_state);
}
private:
template<typename OutIterator>
void serialize_to(OutIterator&& out) {
serialize_int64(out, 0);
serialize_int64(out, finalize_uint64());
}
};
// Used to specialize templates in order to fix a bug
// in handling null values: #4567
class legacy_xx_hasher_without_null_digest : public xx_hasher {
public:
explicit legacy_xx_hasher_without_null_digest(uint64_t seed = 0) noexcept : xx_hasher(seed) {}
};