Question

I have a large text resource in my bundle. It’s a CSV containing lines like

0,1,100,2.2345

It’s over 9MB. What’s the best way to open and sequentially read it in so I can do something like:

myObject->initData(col0, col1, col2, col3);

(Which just stuffs the float value into one of a number of multidimensional arrays indexed by the integers in the file.)

I tried reading it into a string using [NSString stringWithContentsOfFile:] and using an NSScanner to loop over it, but I don’t want to double up my memory usage, even temporarily. It was also quite slow.

What’s the best way to do this?

Thanks

Answer 1

You can use NSFileHandle or C APIs to read incrementally, or you can use mmap with NSData.

The remainder is basic cstring buffer handling, or you could use NSString line-by-line.

Your life may be easier if you can export it as a sequence of binary floats, rather than CSV.