Add MemMappedFile

openVulkanoCpp/IO/MemMappedFile.cpp

@@ -0,0 +1,127 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include "MemMappedFile.hpp"
+#include "Base/Logger.hpp"
+#ifdef _MSC_VER
+#include <windows.h>
+#else
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
+namespace OpenVulkano
+{
+	class MemMappedFile::Internal final
+	{
+	public:
+		void* address = nullptr;
+		size_t size = 0;
+#ifdef _MSC_VER
+		HANDLE fileHandle;
+		HANDLE fileMappingHandle;
+
+		Internal(const char* file, FileMode fileMode)
+		{ //TODO handle other file modes than read
+			fileHandle = CreateFile(
+				TEXT(file),   // file to open
+				GENERIC_READ,       // open for reading
+				0,                  // do not share
+				NULL,               // default security
+				OPEN_EXISTING,      // existing file only
+				FILE_ATTRIBUTE_NORMAL, // normal file
+				NULL);              // no attribute template
+			if (fileHandle == INVALID_HANDLE_VALUE)
+			{
+				Logger::FILESYS->critical("Failed to open file: {}", file);
+				return;
+			}
+
+			LARGE_INTEGER fileSize;
+			if (!GetFileSizeEx(fileHandle, &fileSize))
+			{
+				Logger::FILESYS->critical("Failed to get size of file: {}", file);
+				CloseHandle(fileHandle);
+				return;
+			}
+			size = fileSize;
+
+			fileMappingHandle = CreateFileMapping(
+				fileHandle,
+				NULL,               // default security
+				PAGE_READONLY,      // read-only access
+				0,                  // maximum object size (high-order)
+				0,                  // maximum object size (low-order)
+				NULL);              // name of the mapping object
+			if (fileMappingHandle == 0)
+			{
+				Logger::FILESYS->critical("Failed to create file mapping handle: {}", file);
+				CloseHandle(fileHandle);
+				size = 0;
+				return;
+			}
+
+			address = MapViewOfFile(
+				fileMappingHandle, // handle to the map object
+				FILE_MAP_READ,    // read access
+				0,                 // max. object size
+				0,                 // size of the hFile
+				0);                // map the entire file
+
+			if (address == nullptr)
+			{
+				Logger::FILESYS->critical("Failed to create file mapping: {}", file);
+				CloseHandle(fileMappingHandle);
+				CloseHandle(fileHandle);
+				size = 0;
+			}
+		}
+
+		~Internal()
+		{
+			UnmapViewOfFile(lpMapAddress);
+			CloseHandle(fileMappingHandle);
+			CloseHandle(fileHandle);
+		}
+#else
+		int fileHandle;
+		struct stat fileStat;
+
+		Internal(const char* file, FileMode fileMode)
+		{
+			fileHandle = open(file, fileMode);
+			if (fstat(fileHandle, &fileStat) == -1)
+			{
+				Logger::FILESYS->critical("Failed to query stats for file: {}", file);
+				return;
+			}
+			address = mmap(nullptr, fileStat.st_size, fileMode, MAP_PRIVATE, fileHandle, 0);
+			if (address == MAP_FAILED)
+			{
+				Logger::FILESYS->critical("Failed to memory map file: {}", file);
+				address = nullptr;
+			}
+			size = fileStat.st_size;
+		}
+
+		~Internal()
+		{
+			munmap(address, fileStat.st_size);
+			close(fileHandle);
+		}
+#endif
+	};
+
+	MemMappedFile::MemMappedFile(const std::filesystem::path& path, FileMode fileMode)
+	{
+		m_internal = std::make_shared<Internal>(path.c_str(), fileMode);
+		m_data = m_internal->address;
+		m_size = (m_data) ? m_internal->size : 0;
+	}
+}

openVulkanoCpp/IO/MemMappedFile.hpp

@@ -0,0 +1,34 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <filesystem>
+
+namespace OpenVulkano
+{
+	class MemMappedFile
+	{
+		class Internal;
+
+		std::shared_ptr<Internal> m_internal;
+		void* m_data;
+		size_t m_size;
+
+	public:
+		enum FileMode : int { READ_ONLY = 0, WRITE_ONLY, READ_WRITE };
+
+		MemMappedFile(const std::filesystem::path& path, FileMode fileMode = READ_ONLY);
+
+		[[nodiscard]] bool IsOpen() const { return m_data; }
+
+		[[nodiscard]] operator bool() const { return m_data; }
+
+		[[nodiscard]] size_t Size() const { return m_size; }
+
+		[[nodiscard]] void* Data() const { return m_data; }
+	};
+}