6 files changed, 422 insertions, 349 deletions

diff --git a/source/core/slang-io.cpp b/source/core/slang-io.cpp
index caa45c8f4..6cff8e1c9 100644
--- a/source/core/slang-io.cpp
+++ b/source/core/slang-io.cpp
@@ -660,10 +660,10 @@ namespace Slang
 	{
 		RefPtr<FileStream> fs = new FileStream(fileName, FileMode::Open, FileAccess::Read, FileShare::ReadWrite);
 		List<unsigned char> buffer;
-		while (!fs->IsEnd())
+		while (!fs->isEnd())
 		{
 			unsigned char ch;
-			int read = (int)fs->Read(&ch, 1);
+			int read = (int)fs->read(&ch, 1);
 			if (read)
 				buffer.add(ch);
 			else
diff --git a/source/core/slang-riff.cpp b/source/core/slang-riff.cpp
index df2076013..ce8b7129b 100644
--- a/source/core/slang-riff.cpp
+++ b/source/core/slang-riff.cpp
@@ -20,7 +20,7 @@ namespace Slang
     }
 
     // Skip the payload (we don't need to skip the Chunk because that was already read
-    stream->Seek(SeekOrigin::Current, chunkSize - sizeof(RiffChunk));
+    stream->seek(SeekOrigin::Current, chunkSize - sizeof(RiffChunk));
     return SLANG_OK;
 }
 
@@ -29,7 +29,7 @@ namespace Slang
 {
     try
     {
-        stream->Read(&outChunk, sizeof(RiffChunk));
+        stream->read(&outChunk, sizeof(RiffChunk));
     }
     catch (IOException&)
     {
@@ -53,13 +53,13 @@ namespace Slang
 
     try
     {
-        out->Write(&chunk, sizeof(chunk));
-        out->Write(data, size);
+        out->write(&chunk, sizeof(chunk));
+        out->write(data, size);
         size_t remaining = size & 3;
         if (remaining)
         {
             uint8_t end[4] = { 0, 0, 0, 0};
-            out->Write(end, 4 - remaining);
+            out->write(end, 4 - remaining);
         }
     }
     catch (IOException&)
@@ -79,13 +79,13 @@ namespace Slang
 
     try
     {
-        stream->Read(data.getBuffer(), outChunk.m_size);
+        stream->read(data.getBuffer(), outChunk.m_size);
 
         // Skip to the alignment
         uint32_t remaining = outChunk.m_size & 3;
         if (remaining)
         {
-            stream->Seek(SeekOrigin::Current, 4 - remaining);
+            stream->seek(SeekOrigin::Current, 4 - remaining);
         }
     }
     catch (IOException&)
diff --git a/source/core/slang-stream.cpp b/source/core/slang-stream.cpp
index ee194c451..b5eef1d9b 100644
--- a/source/core/slang-stream.cpp
+++ b/source/core/slang-stream.cpp
@@ -6,289 +6,301 @@
 
 namespace Slang
 {
-	FileStream::FileStream(const Slang::String & fileName, FileMode fileMode)
-	{
-		Init(fileName, fileMode, fileMode==FileMode::Open?FileAccess::Read:FileAccess::Write, FileShare::None);
-	}
-	FileStream::FileStream(const Slang::String & fileName, FileMode fileMode, FileAccess access, FileShare share)
-	{
-		Init(fileName, fileMode, access, share);
-	}
-	void FileStream::Init(const Slang::String & fileName, FileMode fileMode, FileAccess access, FileShare share)
+
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! FileStream !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+FileStream::FileStream(const String& fileName, FileMode fileMode)
+{
+	_init(fileName, fileMode, fileMode==FileMode::Open?FileAccess::Read:FileAccess::Write, FileShare::None);
+}
+
+FileStream::FileStream(const String& fileName, FileMode fileMode, FileAccess access, FileShare share)
+{
+	_init(fileName, fileMode, access, share);
+}
+
+void FileStream::_init(const String& fileName, FileMode fileMode, FileAccess access, FileShare share)
+{
+	const wchar_t * mode = L"rt";
+	const char* modeMBCS = "rt";
+	switch (fileMode)
 	{
-		const wchar_t * mode = L"rt";
-		const char* modeMBCS = "rt";
-		switch (fileMode)
+	case FileMode::Create:
+		if (access == FileAccess::Read)
+			throw ArgumentException("Read-only access is incompatible with Create mode.");
+		else if (access == FileAccess::ReadWrite)
 		{
-		case Slang::FileMode::Create:
-			if (access == FileAccess::Read)
-				throw ArgumentException("Read-only access is incompatible with Create mode.");
-			else if (access == FileAccess::ReadWrite)
-			{
-				mode = L"w+b";
-				modeMBCS = "w+b";
-				this->fileAccess = FileAccess::ReadWrite;
-			}
-			else
-			{
-				mode = L"wb";
-				modeMBCS = "wb";
-				this->fileAccess = FileAccess::Write;
-			}
-			break;
-		case Slang::FileMode::Open:
-			if (access == FileAccess::Read)
-			{
-				mode = L"rb";
-				modeMBCS = "rb";
-				this->fileAccess = FileAccess::Read;
-			}
-			else if (access == FileAccess::ReadWrite)
-			{
-				mode = L"r+b";
-				modeMBCS = "r+b";
-				this->fileAccess = FileAccess::ReadWrite;
-			}
-			else
-			{
-				mode = L"wb";
-				modeMBCS = "wb";
-				this->fileAccess = FileAccess::Write;
-			}
-			break;
-		case Slang::FileMode::CreateNew:
-			if (File::exists(fileName))
-			{
-				throw IOException("Failed opening '" + fileName + "', file already exists.");
-			}
-			if (access == FileAccess::Read)
-				throw ArgumentException("Read-only access is incompatible with Create mode.");
-			else if (access == FileAccess::ReadWrite)
-			{
-				mode = L"w+b";
-				this->fileAccess = FileAccess::ReadWrite;
-			}
-			else
-			{
-				mode = L"wb";
-				this->fileAccess = FileAccess::Write;
-			}
-			break;
-		case Slang::FileMode::Append:
-			if (access == FileAccess::Read)
-				throw ArgumentException("Read-only access is incompatible with Append mode.");
-			else if (access == FileAccess::ReadWrite)
-			{
-				mode = L"a+b";
-				this->fileAccess = FileAccess::ReadWrite;
-			}
-			else
-			{
-				mode = L"ab";
-				this->fileAccess = FileAccess::Write;
-			}
-			break;
-		default:
-			break;
+			mode = L"w+b";
+			modeMBCS = "w+b";
+			this->m_fileAccess = FileAccess::ReadWrite;
 		}
-#ifdef _WIN32
-        int shFlag = _SH_DENYRW;
-        switch (share)
+		else
 		{
-		case Slang::FileShare::None:
-			shFlag = _SH_DENYRW;
-			break;
-		case Slang::FileShare::ReadOnly:
-			shFlag = _SH_DENYWR;
-			break;
-		case Slang::FileShare::WriteOnly:
-			shFlag = _SH_DENYRD;
-			break;
-		case Slang::FileShare::ReadWrite:
-			shFlag = _SH_DENYNO;
-			break;
-		default:
-			throw ArgumentException("Invalid file share mode.");
-			break;
+			mode = L"wb";
+			modeMBCS = "wb";
+			this->m_fileAccess = FileAccess::Write;
 		}
-        if (share == Slang::FileShare::None)
-#pragma warning(suppress:4996)
-            handle = _wfopen(fileName.toWString(), mode);
-        else
-			handle = _wfsopen(fileName.toWString(), mode, shFlag);
-#else
-		handle = fopen(fileName.getBuffer(), modeMBCS);
-#endif
-		if (!handle)
+		break;
+	case FileMode::Open:
+		if (access == FileAccess::Read)
+		{
+			mode = L"rb";
+			modeMBCS = "rb";
+			this->m_fileAccess = FileAccess::Read;
+		}
+		else if (access == FileAccess::ReadWrite)
+		{
+			mode = L"r+b";
+			modeMBCS = "r+b";
+			this->m_fileAccess = FileAccess::ReadWrite;
+		}
+		else
 		{
-			throw IOException("Cannot open file '" + fileName + "'");
+			mode = L"wb";
+			modeMBCS = "wb";
+			this->m_fileAccess = FileAccess::Write;
 		}
+		break;
+	case FileMode::CreateNew:
+		if (File::exists(fileName))
+		{
+			throw IOException("Failed opening '" + fileName + "', file already exists.");
+		}
+		if (access == FileAccess::Read)
+			throw ArgumentException("Read-only access is incompatible with Create mode.");
+		else if (access == FileAccess::ReadWrite)
+		{
+			mode = L"w+b";
+			this->m_fileAccess = FileAccess::ReadWrite;
+		}
+		else
+		{
+			mode = L"wb";
+			this->m_fileAccess = FileAccess::Write;
+		}
+		break;
+	case FileMode::Append:
+		if (access == FileAccess::Read)
+			throw ArgumentException("Read-only access is incompatible with Append mode.");
+		else if (access == FileAccess::ReadWrite)
+		{
+			mode = L"a+b";
+			this->m_fileAccess = FileAccess::ReadWrite;
+		}
+		else
+		{
+			mode = L"ab";
+			this->m_fileAccess = FileAccess::Write;
+		}
+		break;
+	default:
+		break;
 	}
-	FileStream::~FileStream()
+#ifdef _WIN32
+    int shFlag = _SH_DENYRW;
+    switch (share)
 	{
-		Close();
+	case FileShare::None:
+		shFlag = _SH_DENYRW;
+		break;
+	case FileShare::ReadOnly:
+		shFlag = _SH_DENYWR;
+		break;
+	case FileShare::WriteOnly:
+		shFlag = _SH_DENYRD;
+		break;
+	case FileShare::ReadWrite:
+		shFlag = _SH_DENYNO;
+		break;
+	default:
+		throw ArgumentException("Invalid file share mode.");
+		break;
 	}
-	Int64 FileStream::GetPosition()
+    if (share == FileShare::None)
+#pragma warning(suppress:4996)
+        m_handle = _wfopen(fileName.toWString(), mode);
+    else
+		m_handle = _wfsopen(fileName.toWString(), mode, shFlag);
+#else
+	m_handle = fopen(fileName.getBuffer(), modeMBCS);
+#endif
+	if (!m_handle)
 	{
+		throw IOException("Cannot open file '" + fileName + "'");
+	}
+}
+
+FileStream::~FileStream()
+{
+	close();
+}
+
+Int64 FileStream::getPosition()
+{
 #if defined(_WIN32) || defined(__CYGWIN__)
-		fpos_t pos;
-		fgetpos(handle, &pos);
-		return pos;
+	fpos_t pos;
+	fgetpos(m_handle, &pos);
+	return pos;
 #elif defined(__APPLE__)
-		return ftell(handle);
+	return ftell(m_handle);
 #else 
-		fpos64_t pos;
-		fgetpos64(handle, &pos);
-		return *(Int64*)(&pos);
+	fpos64_t pos;
+	fgetpos64(m_handle, &pos);
+	return *(Int64*)(&pos);
 #endif
-	}
-	void FileStream::Seek(SeekOrigin origin, Int64 offset)
+}
+void FileStream::seek(SeekOrigin origin, Int64 offset)
+{
+	int _origin;
+	switch (origin)
 	{
-		int _origin;
-		switch (origin)
-		{
-		case Slang::SeekOrigin::Start:
-			_origin = SEEK_SET;
-			endReached = false;
-			break;
-		case Slang::SeekOrigin::End:
-			_origin = SEEK_END;
-            // JS TODO: This doesn't seem right, the offset can mean it's not at the end
-			endReached = true;
-			break;
-		case Slang::SeekOrigin::Current:
-			_origin = SEEK_CUR;
-			endReached = false;
-			break;
-		default:
-			throw NotSupportedException("Unsupported seek origin.");
-			break;
-		}
+	case SeekOrigin::Start:
+		_origin = SEEK_SET;
+		m_endReached = false;
+		break;
+	case SeekOrigin::End:
+		_origin = SEEK_END;
+        // JS TODO: This doesn't seem right, the offset can mean it's not at the end
+		m_endReached = true;
+		break;
+	case SeekOrigin::Current:
+		_origin = SEEK_CUR;
+		m_endReached = false;
+		break;
+	default:
+		throw NotSupportedException("Unsupported seek origin.");
+		break;
+	}
 #ifdef _WIN32
-		int rs = _fseeki64(handle, offset, _origin);
+	int rs = _fseeki64(m_handle, offset, _origin);
 #else
-		int rs = fseek(handle, (int)offset, _origin);
+	int rs = fseek(m_handle, (int)offset, _origin);
 #endif
-		if (rs != 0)
-		{
-			throw IOException("FileStream seek failed.");
-		}
-	}
-	Int64 FileStream::Read(void * buffer, Int64 length)
-	{
-		auto bytes = fread_s(buffer, (size_t)length, 1, (size_t)length, handle);
-		if (bytes == 0 && length > 0)
-		{
-			if (!feof(handle))
-				throw IOException("FileStream read failed.");
-			else if (endReached)
-				throw EndOfStreamException("End of file is reached.");
-			endReached = true;
-		}
-		return (int)bytes;
-	}
-	Int64 FileStream::Write(const void * buffer, Int64 length)
-	{
-		auto bytes = (Int64)fwrite(buffer, 1, (size_t)length, handle);
-		if (bytes < length)
-		{
-			throw IOException("FileStream write failed.");
-		}
-		return bytes;
-	}
-	bool FileStream::CanRead()
+	if (rs != 0)
 	{
-		return ((int)fileAccess & (int)FileAccess::Read) != 0;
+		throw IOException("FileStream seek failed.");
 	}
-	bool FileStream::CanWrite()
+}
+Int64 FileStream::read(void* buffer, Int64 length)
+{
+	auto bytes = fread_s(buffer, (size_t)length, 1, (size_t)length, m_handle);
+	if (bytes == 0 && length > 0)
 	{
-		return ((int)fileAccess & (int)FileAccess::Write) != 0;
+		if (!feof(m_handle))
+			throw IOException("FileStream read failed.");
+		else if (m_endReached)
+			throw EndOfStreamException("End of file is reached.");
+		m_endReached = true;
 	}
-	void FileStream::Close()
+	return (int)bytes;
+}
+Int64 FileStream::write(const void* buffer, Int64 length)
+{
+	auto bytes = (Int64)fwrite(buffer, 1, (size_t)length, m_handle);
+	if (bytes < length)
 	{
-		if (handle)
-		{
-			fclose(handle);
-			handle = 0;
-		}
+		throw IOException("FileStream write failed.");
 	}
-	bool FileStream::IsEnd()
+	return bytes;
+}
+bool FileStream::canRead()
+{
+	return ((int)m_fileAccess & (int)FileAccess::Read) != 0;
+}
+bool FileStream::canWrite()
+{
+	return ((int)m_fileAccess & (int)FileAccess::Write) != 0;
+}
+void FileStream::close()
+{
+	if (m_handle)
 	{
-		return endReached;
+		fclose(m_handle);
+		m_handle = 0;
 	}
+}
+bool FileStream::isEnd()
+{
+	return m_endReached;
+}
 
-    // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! MemoryStream !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! MemoryStreamBase !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
-    void MemoryStream::Seek(SeekOrigin origin, Int64 offset)
+void MemoryStreamBase::seek(SeekOrigin origin, Int64 offset)
+{
+    Int64 pos = 0;
+    switch (origin)
     {
-        Int64 pos = 0;
-        switch (origin)
-        {
-        case Slang::SeekOrigin::Start:
+        case SeekOrigin::Start:
             pos = offset;
             break;
-        case Slang::SeekOrigin::End:
-            pos = Int64(m_contents.getCount()) + offset;
+        case SeekOrigin::End:
+            pos = Int64(m_contentsSize) + offset;
             break;
-        case Slang::SeekOrigin::Current:
+        case SeekOrigin::Current:
             pos = Int64(m_position) + offset;
             break;
         default:
             throw NotSupportedException("Unsupported seek origin.");
             break;
-        }
+    }
 
-        m_atEnd = false;
+    m_atEnd = false;
 
-        // Clamp to the valid range
-        pos = (pos < 0) ? 0 : pos;
-        pos = (pos > Int64(m_contents.getCount())) ? Int64(m_contents.getCount()) : pos;
+    // Clamp to the valid range
+    pos = (pos < 0) ? 0 : pos;
+    pos = (pos > Int64(m_contentsSize)) ? Int64(m_contentsSize) : pos;
 
-        m_position = UInt(pos);
+    m_position = UInt(pos);
+}
+
+Int64 MemoryStreamBase::read(void* buffer, Int64 length)
+{
+    if (!canRead())
+    {
+        throw IOException("Cannot read this stream.");
     }
 
-    Int64 MemoryStream::Read(void * buffer, Int64 length)
+    const Int64 maxRead = Int64(m_contentsSize - m_position);
+
+    if (maxRead == 0 && length > 0)
     {
-        if (!CanRead())
-        {
-            throw IOException("Cannot read this stream.");
-        }
+        m_atEnd = true;
+        throw EndOfStreamException("End of file is reached.");
+    }
 
-        const Int64 maxRead = Int64(m_contents.getCount() - m_position);
-        
-        if (maxRead == 0 && length > 0)
-        {
-            m_atEnd = true;
-            throw EndOfStreamException("End of file is reached.");
-        }
+    length = length > maxRead ? maxRead : length;
 
-        length = length > maxRead ? maxRead : length;
+    ::memcpy(buffer, m_contents + m_position, size_t(length));
+    m_position += UInt(length);
+    return maxRead;
+}
 
-        ::memcpy(buffer, m_contents.begin() + m_position, size_t(length));
-        m_position += UInt(length);
-        return maxRead;
-    }
-    
-    Int64 MemoryStream::Write(const void * buffer, Int64 length)
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!! OwnedMemoryStream !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+Int64 OwnedMemoryStream::write(const void * buffer, Int64 length)
+{
+    if (!canWrite())
     {
-        if (!CanWrite())
-        {
-            throw IOException("Cannot write this stream.");
-        }
+        throw IOException("Cannot write this stream.");
+    }
 
-        if (m_position == m_contents.getCount())
-        {
-            m_contents.addRange((const uint8_t*)buffer, UInt(length));
-        }
-        else
-        {
-            m_contents.insertRange(m_position, (const uint8_t*)buffer, UInt(length));
-        }
+    if (m_position == m_ownedContents.getCount())
+    {
+        m_ownedContents.addRange((const uint8_t*)buffer, UInt(length));
+    }
+    else
+    {
+        m_ownedContents.insertRange(m_position, (const uint8_t*)buffer, UInt(length));
+    }
 
-        m_atEnd = false;
+    m_contents = m_ownedContents.getBuffer();
+    m_contentsSize = ptrdiff_t(m_ownedContents.getCount());
 
-        m_position += UInt(length);
-        return length;
-    }
+    m_atEnd = false;
 
+    m_position += ptrdiff_t(length);
+    return length;
 }
+
+} // namespace Slang
diff --git a/source/core/slang-stream.h b/source/core/slang-stream.h
index 67e04fa6a..8b8a6decf 100644
--- a/source/core/slang-stream.h
+++ b/source/core/slang-stream.h
@@ -5,109 +5,170 @@
 
 namespace Slang
 {
-	class IOException : public Exception
-	{
-	public:
-		IOException()
-		{}
-		IOException(const String & message)
-			: Slang::Exception(message)
-		{
-		}
-	};
-
-	class EndOfStreamException : public IOException
-	{
-	public:
-		EndOfStreamException()
-		{}
-		EndOfStreamException(const String & message)
-			: IOException(message)
-		{
-		}
-	};
-
-	enum class SeekOrigin
-	{
-		Start, End, Current
-	};
 
-	class Stream : public RefObject
-	{
-	public:
-        virtual ~Stream() {}
-		virtual Int64 GetPosition()=0;
-		virtual void Seek(SeekOrigin origin, Int64 offset)=0;
-		virtual Int64 Read(void * buffer, Int64 length) = 0;
-		virtual Int64 Write(const void * buffer, Int64 length) = 0;
-		virtual bool IsEnd() = 0;
-		virtual bool CanRead() = 0;
-		virtual bool CanWrite() = 0;
-		virtual void Close() = 0;
-	};
-
-	enum class FileMode
+class IOException : public Exception
+{
+public:
+	IOException()
+	{}
+	IOException(const String & message)
+		: Slang::Exception(message)
 	{
-		Create, Open, CreateNew, Append
-	};
+	}
+};
 
-	enum class FileAccess
+class EndOfStreamException : public IOException
+{
+public:
+	EndOfStreamException()
+	{}
+	EndOfStreamException(const String & message)
+		: IOException(message)
 	{
-		None = 0, Read = 1, Write = 2, ReadWrite = 3
-	};
+	}
+};
 
-	enum class FileShare
-	{
-		None, ReadOnly, WriteOnly, ReadWrite
-	};
+enum class SeekOrigin
+{
+	Start, End, Current
+};
+
+class Stream : public RefObject
+{
+public:
+    virtual ~Stream() {}
+	virtual Int64 getPosition()=0;
+	virtual void seek(SeekOrigin origin, Int64 offset)=0;
+	virtual Int64 read(void * buffer, Int64 length) = 0;
+	virtual Int64 write(const void * buffer, Int64 length) = 0;
+	virtual bool isEnd() = 0;
+	virtual bool canRead() = 0;
+	virtual bool canWrite() = 0;
+	virtual void close() = 0;
+};
+
+enum class FileMode
+{
+	Create, Open, CreateNew, Append
+};
+
+enum class FileAccess
+{
+	None = 0, Read = 1, Write = 2, ReadWrite = 3
+};
 
-    class MemoryStream : public Stream
+enum class FileShare
+{
+	None, ReadOnly, WriteOnly, ReadWrite
+};
+
+/// Base class for memory streams. Only supports reading and does NOT own contained data.
+class MemoryStreamBase : public Stream
+{
+public:
+    typedef Stream Super;
+
+    virtual Int64 getPosition() SLANG_OVERRIDE { return m_position; }
+    virtual void seek(SeekOrigin origin, Int64 offset) SLANG_OVERRIDE;
+    virtual Int64 read(void * buffer, Int64 length) SLANG_OVERRIDE;
+    virtual Int64 write(const void * buffer, Int64 length) SLANG_OVERRIDE { SLANG_UNUSED(buffer); SLANG_UNUSED(length); return 0; }
+    virtual bool isEnd() SLANG_OVERRIDE { return m_atEnd; }
+    virtual bool canRead() SLANG_OVERRIDE { return (int(m_access) & int(FileAccess::Read)) != 0; }
+    virtual bool canWrite() SLANG_OVERRIDE { return (int(m_access) & int(FileAccess::Write)) != 0; }
+    virtual void close() SLANG_OVERRIDE { m_access = FileAccess::None; }
+
+    MemoryStreamBase(FileAccess access = FileAccess::Read, const void* contents = nullptr, size_t contentsSize = 0):
+        m_access(access)
     {
-    public:
-        virtual Int64 GetPosition() SLANG_OVERRIDE { return m_position;  }
-        virtual void Seek(SeekOrigin origin, Int64 offset) SLANG_OVERRIDE;
-        virtual Int64 Read(void * buffer, Int64 length) SLANG_OVERRIDE;
-        virtual Int64 Write(const void * buffer, Int64 length) SLANG_OVERRIDE;
-        virtual bool IsEnd() SLANG_OVERRIDE { return m_atEnd; }
-        virtual bool CanRead() SLANG_OVERRIDE { return (int(m_access) & int(FileAccess::Read)) != 0;  }
-        virtual bool CanWrite() SLANG_OVERRIDE { return (int(m_access) & int(FileAccess::Write)) != 0; }
-        virtual void Close() SLANG_OVERRIDE { m_access = FileAccess::None;  }
-
-        MemoryStream(FileAccess access) :
-            m_access(access),
-            m_position(0),
-            m_atEnd(false)
-        {}
-
-        Index m_position;
-
-        bool m_atEnd;           ///< Happens when a read is done and nothing can be returned because already at end
-
-        FileAccess m_access;
-        List<uint8_t> m_contents;
-    };
-
-	class FileStream : public Stream
-	{
-	private:
-		FILE * handle;
-		FileAccess fileAccess;
-		bool endReached = false;
-		void Init(const Slang::String & fileName, FileMode fileMode, FileAccess access, FileShare share);
-	public:
-		FileStream(const Slang::String & fileName, FileMode fileMode = FileMode::Open);
-		FileStream(const Slang::String & fileName, FileMode fileMode, FileAccess access, FileShare share);
-		~FileStream();
-	public:
-		virtual Int64 GetPosition();
-		virtual void Seek(SeekOrigin origin, Int64 offset);
-		virtual Int64 Read(void * buffer, Int64 length);
-		virtual Int64 Write(const void * buffer, Int64 length);
-		virtual bool CanRead();
-		virtual bool CanWrite();
-		virtual void Close();
-		virtual bool IsEnd();
-	};
-}
+        _setContents(contents, contentsSize);
+    }
+
+protected:
+        /// Set to replace wholly current content with specified content
+    void _setContents(const void* contents, size_t contentsSize)
+    {
+        m_contents = (const uint8_t*)contents;
+        m_contentsSize = ptrdiff_t(contentsSize);
+        m_position = 0;
+        m_atEnd = false;    
+    }
+        /// Update means that the content has changed, but position should be maintained
+    void _updateContents(const void* contents, size_t contentsSize)
+    {
+        const ptrdiff_t newPosition = (m_position > ptrdiff_t(contentsSize)) ? ptrdiff_t(contentsSize) : m_position;
+        _setContents(contents, contentsSize);
+        m_position = newPosition;
+    }
+
+    const uint8_t* m_contents;   ///< The content held in the stream
+
+    // Using ptrdiff_t (as opposed to size_t) as makes maths simpler
+    ptrdiff_t m_contentsSize;    ///< Total size of the content in bytes
+    ptrdiff_t m_position;       ///< The current position within content (valid values can only be between 0 and m_contentSize)
+
+    bool m_atEnd;               ///< Happens when a read is done and nothing can be returned because already at end
+
+    FileAccess m_access;
+};
+
+/// Memory stream that owns it's contents
+class OwnedMemoryStream : public MemoryStreamBase
+{
+public:
+    typedef MemoryStreamBase Super;
+
+    virtual Int64 write(const void* buffer, Int64 length) SLANG_OVERRIDE;
+
+        /// Set the contents
+    void setContent(const void* contents, size_t contentsSize)
+    {
+        m_ownedContents.setCount(contentsSize);
+        ::memcpy(m_ownedContents.getBuffer(), contents, contentsSize);
+        _setContents(m_ownedContents.getBuffer(), m_ownedContents.getCount());
+    }
+
+    void swapContents(List<uint8_t>& rhs)
+    {
+        rhs.swapWith(m_ownedContents);
+        _setContents(m_ownedContents.getBuffer(), m_ownedContents.getCount());
+    }
+
+    OwnedMemoryStream(FileAccess access) :
+        Super(access)
+    {}
+
+protected:
+     
+    List<uint8_t> m_ownedContents;
+};
+
+class FileStream : public Stream
+{
+public:
+    typedef Stream Super;
+
+    // Stream interface
+	virtual Int64 getPosition();
+	virtual void seek(SeekOrigin origin, Int64 offset);
+	virtual Int64 read(void* buffer, Int64 length);
+	virtual Int64 write(const void* buffer, Int64 length);
+	virtual bool canRead();
+	virtual bool canWrite();
+	virtual void close();
+	virtual bool isEnd();
+
+    FileStream(const String& fileName, FileMode fileMode = FileMode::Open);
+    FileStream(const String& fileName, FileMode fileMode, FileAccess access, FileShare share);
+    ~FileStream();
+
+private:
+    void _init(const String& fileName, FileMode fileMode, FileAccess access, FileShare share);
+
+    FILE* m_handle;
+    FileAccess m_fileAccess;
+    bool m_endReached = false;
+};
+
+} // namespace Slang
 
 #endif
diff --git a/source/core/slang-text-io.cpp b/source/core/slang-text-io.cpp
index 18039e41b..4e989b627 100644
--- a/source/core/slang-text-io.cpp
+++ b/source/core/slang-text-io.cpp
@@ -126,11 +126,11 @@ namespace Slang
 		this->encoding = encoding;
 		if (encoding == Encoding::UTF16)
 		{
-			this->stream->Write(&Utf16Header, 2);
+			this->stream->write(&Utf16Header, 2);
 		}
 		else if (encoding == Encoding::UTF16Reversed)
 		{
-			this->stream->Write(&Utf16ReversedHeader, 2);
+			this->stream->write(&Utf16ReversedHeader, 2);
 		}
 	}
 	StreamWriter::StreamWriter(RefPtr<Stream> stream, Encoding * encoding)
@@ -139,11 +139,11 @@ namespace Slang
 		this->encoding = encoding;
 		if (encoding == Encoding::UTF16)
 		{
-			this->stream->Write(&Utf16Header, 2);
+			this->stream->write(&Utf16Header, 2);
 		}
 		else if (encoding == Encoding::UTF16Reversed)
 		{
-			this->stream->Write(&Utf16ReversedHeader, 2);
+			this->stream->write(&Utf16ReversedHeader, 2);
 		}
 	}
 	void StreamWriter::Write(const String & str)
@@ -169,7 +169,7 @@ namespace Slang
 				sb << str[i];
 		}
 		encoding->GetBytes(encodingBuffer, sb.ProduceString());
-		stream->Write(encodingBuffer.getBuffer(), encodingBuffer.getCount());
+		stream->write(encodingBuffer.getBuffer(), encodingBuffer.getCount());
 	}
 	void StreamWriter::Write(const char * str)
 	{
@@ -237,7 +237,7 @@ namespace Slang
 	{
 		buffer.setCount(4096);
         memset(buffer.getBuffer(), 0, buffer.getCount() * sizeof(buffer[0]));
-		auto len = stream->Read(buffer.getBuffer(), buffer.getCount());
+		auto len = stream->read(buffer.getBuffer(), buffer.getCount());
 		buffer.setCount((int)len);
 		ptr = 0;
 	}
@@ -248,7 +248,7 @@ namespace Slang
 		{
 			return buffer[ptr++];
 		}
-		if (!stream->IsEnd())
+		if (!stream->isEnd())
 			ReadBuffer();
 		if (ptr<buffer.getCount())
 		{
diff --git a/source/core/slang-text-io.h b/source/core/slang-text-io.h
index ac9a4f5dc..b5a9ad0e1 100644
--- a/source/core/slang-text-io.h
+++ b/source/core/slang-text-io.h
@@ -259,7 +259,7 @@ namespace Slang
 		virtual void Write(const char * str);
 		virtual void Close()
 		{
-			stream->Close();
+			stream->close();
 		}
         void ReleaseStream()
         {
@@ -300,11 +300,11 @@ namespace Slang
 		virtual String ReadToEnd();
 		virtual bool IsEnd()
 		{
-			return ptr == buffer.getCount() && stream->IsEnd();
+			return ptr == buffer.getCount() && stream->isEnd();
 		}
 		virtual void Close()
 		{
-			stream->Close();
+			stream->close();
 		}
         void ReleaseStream()
         {