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tdutils/td/utils/port/MemoryMapping.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+#include "td/utils/common.h"
+#include "td/utils/port/FileFd.h"
+#include "td/utils/Slice.h"
+#include "td/utils/Status.h"
+
+namespace td {
+
+class MemoryMapping {
+ public:
+  struct Options {
+    int64 offset{0};
+    int64 size{-1};
+
+    Options() {
+    }
+    Options &with_offset(int64 new_offset) {
+      offset = new_offset;
+      return *this;
+    }
+    Options &with_size(int64 new_size) {
+      size = new_size;
+      return *this;
+    }
+  };
+
+  static Result<MemoryMapping> create_anonymous(const Options &options = {});
+  static Result<MemoryMapping> create_from_file(const FileFd &file, const Options &options = {});
+
+  Slice as_slice() const;
+  MutableSlice as_mutable_slice();  // returns empty slice if memory is read-only
+
+  MemoryMapping(const MemoryMapping &other) = delete;
+  const MemoryMapping &operator=(const MemoryMapping &other) = delete;
+  MemoryMapping(MemoryMapping &&other);
+  MemoryMapping &operator=(MemoryMapping &&other);
+  ~MemoryMapping();
+
+ private:
+  class Impl;
+  unique_ptr<Impl> impl_;
+  explicit MemoryMapping(unique_ptr<Impl> impl);
+};
+
+}  // namespace td