What language is that? Is this what's in the dat file or the source code?
Did you mean length(quad_i) ?
wat does the length(quad.dat) give??
I'm not familiar with a function length from standard libraries.
Dat files are not 'standardized' as a format - they are a generic extension with little definition (and an old idea now).
dat files could contain binary data, text, mixtures - anything. Only the application that created it would 'understand' it - and, of course, you'd need documentation or reverse engineering of source (or nefarious means) to figure out what's really in it.