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lib/writable_file.cpp

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+///////////////////////////////////////////////////////////////////////////////
+// Copyright (c) Lewis Baker
+// Licenced under MIT license. See LICENSE.txt for details.
+///////////////////////////////////////////////////////////////////////////////
+
+#include <cppcoro/writable_file.hpp>
+
+#include <system_error>
+
+#if CPPCORO_OS_WINNT
+# ifndef WIN32_LEAN_AND_MEAN
+#  define WIN32_LEAN_AND_MEAN
+# endif
+# include <Windows.h>
+
+void cppcoro::writable_file::set_size(
+	std::uint64_t fileSize)
+{
+	LARGE_INTEGER position;
+	position.QuadPart = fileSize;
+
+	BOOL ok = ::SetFilePointerEx(m_fileHandle.handle(), position, nullptr, FILE_BEGIN);
+	if (!ok)
+	{
+		DWORD errorCode = ::GetLastError();
+		throw std::system_error
+		{
+			static_cast<int>(errorCode),
+			std::system_category(),
+			"error setting file size: SetFilePointerEx"
+		};
+	}
+
+	ok = ::SetEndOfFile(m_fileHandle.handle());
+	if (!ok)
+	{
+		DWORD errorCode = ::GetLastError();
+		throw std::system_error
+		{
+			static_cast<int>(errorCode),
+			std::system_category(),
+			"error setting file size: SetEndOfFile"
+		};
+	}
+}
+
+cppcoro::file_write_operation cppcoro::writable_file::write(
+	std::uint64_t offset,
+	const void* buffer,
+	std::size_t byteCount) noexcept
+{
+	return file_write_operation{
+		m_fileHandle.handle(),
+		offset,
+		buffer,
+		byteCount
+	};
+}
+
+cppcoro::file_write_operation_cancellable cppcoro::writable_file::write(
+	std::uint64_t offset,
+	const void* buffer,
+	std::size_t byteCount,
+	cancellation_token ct) noexcept
+{
+	return file_write_operation_cancellable{
+		m_fileHandle.handle(),
+		offset,
+		buffer,
+		byteCount,
+		std::move(ct)
+	};
+}
+
+#endif