Add love.data module.

- Moved love.math.compress / decompress / decode / encode / hash to love.data.
- Changed love.data.compress/decompress to take the format argument first instead of second.
- Added love.data.newDataView. Returns a read-only subsection of an existing Data object.
- Added love.data.newByteData. Mostly useful in combination with LuaJIT's FFI as it has no extra methods currently.
- Added implementations of Lua 5.3's data packing APIs: love.data.packString / packData / unpack / getPackedSize.

Resolves issue #1336.
Resolves issue #1331.

--HG--
branch : minor

src/modules/data/DataView.cpp

@@ -0,0 +1,71 @@
+/**
+ * Copyright (c) 2006-2017 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#include "DataView.h"
+#include "common/Exception.h"
+#include "common/int.h"
+
+namespace love
+{
+namespace data
+{
+
+love::Type DataView::type("DataView", &Data::type);
+
+DataView::DataView(Data *data, size_t offset, size_t size)
+	: data(data)
+	, offset(offset)
+	, size(size)
+{
+	if (offset >= data->getSize() || size > data->getSize() || offset > data->getSize() - size)
+		throw love::Exception("Offset and size of Data View must fit within the original Data's size.");
+
+	if (size == 0)
+		throw love::Exception("DataView size must be greater than 0.");
+}
+
+DataView::DataView(const DataView &d)
+	: data(d.data)
+	, offset(d.offset)
+	, size(d.size)
+{
+}
+
+DataView::~DataView()
+{
+}
+
+DataView *DataView::clone() const
+{
+	return new DataView(*this);
+}
+
+void *DataView::getData() const
+{
+	return (uint8 *) data->getData() + offset;
+}
+
+size_t DataView::getSize() const
+{
+	return size;
+}
+
+} // data
+} // love