Files
scylladb/bytes.hh
Avi Kivity 1b64b1a628 bytes: compare_unsigned(): change to std::strong_ordering
Note that the previous implementation was broken for blobs
larger than 4GB. Luckily that can't happen.

Ref #1449.
2021-07-28 13:21:01 +03:00

126 lines
3.4 KiB
C++

/*
* Copyright (C) 2015-present ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "seastarx.hh"
#include <seastar/core/sstring.hh>
#include "hashing.hh"
#include <optional>
#include <iosfwd>
#include <functional>
#include <compare>
#include "utils/mutable_view.hh"
#include <xxhash.h>
using bytes = basic_sstring<int8_t, uint32_t, 31, false>;
using bytes_view = std::basic_string_view<int8_t>;
using bytes_mutable_view = basic_mutable_view<bytes_view::value_type>;
using bytes_opt = std::optional<bytes>;
using sstring_view = std::string_view;
inline bytes to_bytes(bytes&& b) {
return std::move(b);
}
inline sstring_view to_sstring_view(bytes_view view) {
return {reinterpret_cast<const char*>(view.data()), view.size()};
}
inline bytes_view to_bytes_view(sstring_view view) {
return {reinterpret_cast<const int8_t*>(view.data()), view.size()};
}
struct fmt_hex {
bytes_view& v;
fmt_hex(bytes_view& v) noexcept : v(v) {}
};
std::ostream& operator<<(std::ostream& os, const fmt_hex& hex);
bytes from_hex(sstring_view s);
sstring to_hex(bytes_view b);
sstring to_hex(const bytes& b);
sstring to_hex(const bytes_opt& b);
std::ostream& operator<<(std::ostream& os, const bytes& b);
std::ostream& operator<<(std::ostream& os, const bytes_opt& b);
namespace std {
// Must be in std:: namespace, or ADL fails
std::ostream& operator<<(std::ostream& os, const bytes_view& b);
}
template<>
struct appending_hash<bytes> {
template<typename Hasher>
void operator()(Hasher& h, const bytes& v) const {
feed_hash(h, v.size());
h.update(reinterpret_cast<const char*>(v.cbegin()), v.size() * sizeof(bytes::value_type));
}
};
template<>
struct appending_hash<bytes_view> {
template<typename Hasher>
void operator()(Hasher& h, bytes_view v) const {
feed_hash(h, v.size());
h.update(reinterpret_cast<const char*>(v.begin()), v.size() * sizeof(bytes_view::value_type));
}
};
struct bytes_view_hasher : public hasher {
XXH64_state_t _state;
bytes_view_hasher(uint64_t seed = 0) noexcept {
XXH64_reset(&_state, seed);
}
void update(const char* ptr, size_t length) noexcept {
XXH64_update(&_state, ptr, length);
}
size_t finalize() {
return static_cast<size_t>(XXH64_digest(&_state));
}
};
namespace std {
template <>
struct hash<bytes_view> {
size_t operator()(bytes_view v) const {
bytes_view_hasher h;
appending_hash<bytes_view>{}(h, v);
return h.finalize();
}
};
} // namespace std
inline std::strong_ordering compare_unsigned(bytes_view v1, bytes_view v2) {
auto size = std::min(v1.size(), v2.size());
if (size) {
auto n = memcmp(v1.begin(), v2.begin(), size);
if (n) {
return n <=> 0;
}
}
return v1.size() <=> v2.size();
}