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scylladb/utils/mutable_view.hh

79 lines
2.1 KiB
C++

/*
* Copyright (C) 2017-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 <string_view>
#include <seastar/core/sstring.hh>
#include "seastarx.hh"
template<typename CharT>
class basic_mutable_view {
CharT* _begin = nullptr;
CharT* _end = nullptr;
public:
using value_type = CharT;
using pointer = CharT*;
using iterator = CharT*;
using const_iterator = CharT*;
basic_mutable_view() = default;
template<typename U, U N>
basic_mutable_view(basic_sstring<CharT, U, N>& str)
: _begin(str.begin())
, _end(str.end())
{ }
basic_mutable_view(CharT* ptr, size_t length)
: _begin(ptr)
, _end(ptr + length)
{ }
operator std::basic_string_view<CharT>() const noexcept {
return std::basic_string_view<CharT>(begin(), size());
}
CharT& operator[](size_t idx) const { return _begin[idx]; }
iterator begin() const { return _begin; }
iterator end() const { return _end; }
CharT* data() const { return _begin; }
size_t size() const { return _end - _begin; }
bool empty() const { return _begin == _end; }
CharT& front() { return *_begin; }
const CharT& front() const { return *_begin; }
void remove_prefix(size_t n) {
_begin += n;
}
void remove_suffix(size_t n) {
_end -= n;
}
basic_mutable_view substr(size_t pos, size_t count) {
size_t n = std::min(count, (_end - _begin) - pos);
return basic_mutable_view{_begin + pos, n};
}
};