This module implements two functions - an advanced binary search one and a function to merge a small sorted array into a larger sorted array. It was used until the newer hash or balanced binary tree storage were implemented, and may still be used if FCS_STATE_STORAGE_INDIRECT or FCS_STACK_STORAGE_INDIRECT are specified. [1]
[1] It is no longer recommended to use a sorted array as a state or stack storage, as they are much slower than using a hash or a balanced binary tree, both in asymptotic complexity (O(n2))) and in average performance.