cleanup and refactoring

raytracer/nvpro_core/nvh/filemapping.hpp

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2020-2021 NVIDIA CORPORATION
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/// @DOC_SKIP (keyword to exclude this file from automatic README.md generation)
+
+#pragma once
+
+#include <cstddef>
+#include <utility>
+
+namespace nvh {
+
+class FileMapping
+{
+public:
+  FileMapping(FileMapping&& other) noexcept { this->operator=(std::move(other)); };
+
+  FileMapping& operator=(FileMapping&& other) noexcept
+  {
+    m_isValid     = other.m_isValid;
+    m_fileSize    = other.m_fileSize;
+    m_mappingType = other.m_mappingType;
+    m_mappingPtr  = other.m_mappingPtr;
+    m_mappingSize = other.m_mappingSize;
+#ifdef _WIN32
+    m_win32.file              = other.m_win32.file;
+    m_win32.fileMapping       = other.m_win32.fileMapping;
+    other.m_win32.file        = nullptr;
+    other.m_win32.fileMapping = nullptr;
+#else
+    m_unix.file       = other.m_unix.file;
+    other.m_unix.file = -1;
+#endif
+    other.m_isValid    = false;
+    other.m_mappingPtr = nullptr;
+
+    return *this;
+  }
+
+  FileMapping(const FileMapping&)                  = delete;
+  FileMapping& operator=(const FileMapping& other) = delete;
+  FileMapping() {}
+
+  ~FileMapping() { close(); }
+
+  enum MappingType
+  {
+    MAPPING_READONLY,       // opens existing file for read-only access
+    MAPPING_READOVERWRITE,  // creates new file with read/write access, overwriting existing files
+  };
+
+  // fileSize only for write access
+  bool open(const char* filename, MappingType mappingType, size_t fileSize = 0);
+  void close();
+
+  const void* data() const { return m_mappingPtr; }
+  void*       data() { return m_mappingPtr; }
+  size_t      size() const { return m_mappingSize; }
+  bool        valid() const { return m_isValid; }
+
+protected:
+  static size_t g_pageSize;
+
+#ifdef _WIN32
+  struct
+  {
+    void* file        = nullptr;
+    void* fileMapping = nullptr;
+  } m_win32;
+#else
+  struct
+  {
+    int file = -1;
+  } m_unix;
+#endif
+
+  bool        m_isValid     = false;
+  size_t      m_fileSize    = 0;
+  MappingType m_mappingType = MappingType::MAPPING_READONLY;
+  void*       m_mappingPtr  = nullptr;
+  size_t      m_mappingSize = 0;
+};
+
+// convenience types
+class FileReadMapping : private FileMapping
+{
+public:
+  bool        open(const char* filename) { return FileMapping::open(filename, MAPPING_READONLY, 0); }
+  void        close() { FileMapping::close(); }
+  const void* data() const { return m_mappingPtr; }
+  size_t      size() const { return m_fileSize; }
+  bool        valid() const { return m_isValid; }
+};
+
+class FileReadOverWriteMapping : private FileMapping
+{
+public:
+  bool open(const char* filename, size_t fileSize)
+  {
+    return FileMapping::open(filename, MAPPING_READOVERWRITE, fileSize);
+  }
+  void   close() { FileMapping::close(); }
+  void*  data() { return m_mappingPtr; }
+  size_t size() const { return m_fileSize; }
+  bool   valid() const { return m_isValid; }
+};
+}  // namespace nvh