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Source/Engine/Serialization/FileWriteStream.cpp

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+#include "FileWriteStream.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Platform/File.h"
+
+FileWriteStream* FileWriteStream::Open(const StringView& path)
+{
+    auto file = File::Open(path, FileMode::CreateAlways, FileAccess::Write, FileShare::Read);
+    if (file == nullptr)
+    {
+        LOG(Warning, "Cannot open file '{0}'", path);
+        return nullptr;
+    }
+    return New<FileWriteStream>(file);
+}
+
+void FileWriteStream::Unlink()
+{
+    _file = nullptr;
+}
+
+FileWriteStream::FileWriteStream(File* file)
+    : _file(file)
+    , _virtualPosInBuffer(0)
+{
+    ASSERT_LOW_LAYER(_file);
+}
+
+FileWriteStream::~FileWriteStream()
+{
+    // Ensure to be file flushed, closed and deleted
+    if (_file)
+    {
+        Flush();
+        Delete(_file);
+    }
+}
+
+void FileWriteStream::Flush()
+{
+    // Check if need to flush
+    if (_virtualPosInBuffer > 0)
+    {
+        // Update buffer
+        uint32 bytesWritten;
+        _hasError |= _file->Write(_buffer, _virtualPosInBuffer, &bytesWritten) != 0;
+        _virtualPosInBuffer = 0;
+    }
+}
+
+void FileWriteStream::Close()
+{
+    if (_file)
+    {
+        Flush();
+        _file->Close();
+    }
+}
+
+uint32 FileWriteStream::GetLength()
+{
+    Flush();
+    return _file->GetSize();
+}
+
+uint32 FileWriteStream::GetPosition()
+{
+    Flush();
+    return _file->GetPosition();
+}
+
+void FileWriteStream::SetPosition(uint32 seek)
+{
+    Flush();
+    _file->SetPosition(seek);
+}
+
+void FileWriteStream::WriteBytes(const void* data, uint32 bytes)
+{
+    const uint32 bufferBytesLeft = FILESTREAM_BUFFER_SIZE - _virtualPosInBuffer;
+    if (bytes <= bufferBytesLeft)
+    {
+        Platform::MemoryCopy(_buffer + _virtualPosInBuffer, data, bytes);
+        _virtualPosInBuffer += bytes;
+    }
+    else
+    {
+        uint32 bytesWritten;
+
+        // Flush already written bytes and write more it the buffer (reduce amount of flushes)
+        if (_virtualPosInBuffer > 0)
+        {
+            Platform::MemoryCopy(_buffer + _virtualPosInBuffer, data, bufferBytesLeft);
+            data = (byte*)data + bufferBytesLeft;
+            bytes -= bufferBytesLeft;
+            _virtualPosInBuffer = 0;
+            _hasError |= _file->Write(_buffer, FILESTREAM_BUFFER_SIZE, &bytesWritten) != 0;
+        }
+
+        // Write as much as can using whole buffer
+        while (bytes >= FILESTREAM_BUFFER_SIZE)
+        {
+            Platform::MemoryCopy(_buffer, data, FILESTREAM_BUFFER_SIZE);
+            data = (byte*)data + FILESTREAM_BUFFER_SIZE;
+            bytes -= FILESTREAM_BUFFER_SIZE;
+            _hasError |= _file->Write(_buffer, FILESTREAM_BUFFER_SIZE, &bytesWritten) != 0;
+        }
+
+        // Write the rest of the buffer but without flushing its data
+        if (bytes > 0)
+        {
+            Platform::MemoryCopy(_buffer, data, bytes);
+            _virtualPosInBuffer = bytes;
+        }
+    }
+}