ComputePad returns pad's count and space's count(less than len(pad)) will be need to pad s to len n padCount = (n-len(s))/len(pad) spaceCount = (n-len(s))%len(pad).

CountIndex counts the number of non-overlapping instances of sep in s.

PadLeft returns s padded to length n, padded left with repeated pad return s directly if pad is empty padding s with {{pad}} and spaces(less than len(pad)) as a prefix, as [pad]...[pad][space]...[space][s].

PadRight returns s padded to length n, padded right with repeated pad return s directly if pad is empty padding s with {{pad}} and spaces(less than len(pad)) as a suffix, as [s][space]...[space][pad]...[pad].

Reverse returns bytes in reverse order.

Truncate shrinks s's len to n at most.