Suffix array construction algorithm linear complexity constant

Question

A non-recursive linear Suffix Array construction algorithm is presented in this thesis: Linear-time Suffix Sorting. The author claims that, overall, the algorithm runs at $O(n)$. While it is well explained, there are only hints that this is case. The implementation of the algorithm is in this GitHub repository written in C.

My question is: What are the complexity constants (say $O(\alpha n + \beta)$ where $\alpha$ and $\beta$ are constants) for C code between lines 92 and 186?