core: add FileBuffer

src/core/filesystem/file.h

@@ -15,7 +15,10 @@ namespace crown
 /// @ingroup Filesystem
 struct File
 {
+	///
 	File() {}
+
+	///
 	virtual ~File() {}
 
 	/// Opens the file at @a path with specified @a mode

src/core/filesystem/file_buffer.inl

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2012-2020 Daniele Bartolini and individual contributors.
+ * License: https://github.com/dbartolini/crown/blob/master/LICENSE
+ */
+
+#pragma once
+
+#include "core/containers/array.inl"
+#include "core/filesystem/file.h"
+
+namespace crown
+{
+/// File interface for Buffer.
+///
+/// @ingroup Filesystem
+struct FileBuffer : public File
+{
+	Buffer* _buffer;
+	u32 _position;
+
+	explicit FileBuffer(Buffer& buffer)
+		: _buffer(&buffer)
+		, _position(0)
+	{
+	}
+
+	virtual ~FileBuffer()
+	{
+		CE_NOOP();
+	}
+
+	virtual void open(const char* path, FileOpenMode::Enum mode)
+	{
+		CE_UNUSED(path);
+		CE_UNUSED(mode);
+		CE_NOOP();
+	}
+
+	virtual void close()
+	{
+		_buffer = NULL;
+		_position = 0;
+	}
+
+	virtual bool is_open()
+	{
+		return _buffer != NULL;
+	}
+
+	virtual u32 size()
+	{
+		return array::size(*_buffer);
+	}
+
+	virtual u32 position()
+	{
+		return _position;
+	}
+
+	virtual bool end_of_file()
+	{
+		return _position == array::size(*_buffer);
+	}
+
+	virtual void seek(u32 position)
+	{
+		_position = min(array::size(*_buffer), position);
+	}
+
+	virtual void seek_to_end()
+	{
+		_position = array::size(*_buffer);
+	}
+
+	virtual void skip(u32 bytes)
+	{
+		seek(_position + bytes);
+	}
+
+	virtual u32 read(void* data, u32 size)
+	{
+		const u32 rest = array::size(*_buffer) - _position;
+		const u32 num = min(size, rest);
+		memcpy(data, array::begin(*_buffer) + _position, num);
+		_position += num;
+		return num;
+	}
+
+	virtual u32 write(const void* data, u32 size)
+	{
+		_buffer->_size = _position;
+		array::push(*_buffer, (const char*)data, size);
+		_position += size;
+		return size;
+	}
+
+	virtual void flush()
+	{
+		CE_NOOP();
+	}
+};
+
+} // namespace crown