Made love.data.newDataView size arg optional

[EngineerSmith]

I got annoyed that I had to keep calculating the size lua side when making a new dataview. So, this change makes the 3rd arg [size], optional and is calculated as love.data.newByteData calculates the default size when calling love.data.newByteData(someData) this line

I made this change on github directly; and so I haven't tested the change. I'll add a comment once I've tested the build to ensure it works as expected.

Example usage:

local data = love.data.newByteData(200)
local offset = 100

-- Change:
local dataview = love.data.newDataView(data, offset)
-- Previously:
local dataview = love.data.newDataView(data, offset, data:getSize() - offset)

[slime73]

The change seems reasonable to me, but I'm curious what sort of situations you were running into where you wanted to use all the remaining size after an offset

[EngineerSmith]

Right now I'm making a chunk of a save file; I precalculated the chunk size/length for all the data I have to insert into the chunk; so I'm treating it like a write to a file which moves the cursor/position along. I've ran into this previously when working with dataviews. So, I thought it would be a "nice to have" than having to store the offset in a different variable.

-- When quickly prototyping, I don't want to come back and fix this mess. When I can add the source change to handle it for me as I add more to the offset
love.data.newDataView(data, foo + x + y + z, data:getSize() - (foo + x + y + z))

I tested it; with this code and looks good.

local data = love.data.newByteData(200)
local offset = 50

local dv = love.data.newDataView(data, offset)

print(tostring(dv:getSize() == 150), dv:getSize()) -- true   150

[slime73]

Makes sense, thanks!