sub getholes(whole as snippet, occupied() as snippet, free() as snippet)
redim free(0)
dim tmp as snippet
occupied=qsort(occupied) ' сортировка по началу
redim free(0)
if whole.start <> occupied(0).start then
  free(0).start = whole.start 
  free(0).end = occupied(0).start 
  redim preserve free(1+ubound(free))
end if
tmp.start = occupied(0).start 
tmp.end = occupied(0).end 
for i = 1 to ubound(occupied)
  if occupied(i).start <= tmp.end then
    tmp.end = max(occupied(i).end, tmp.end)
  else
    free(ubound(free)).start = tmp.end 
    free(ubound(free)).end = occupied(i).start 
    redim preserve free(1+ubound(free))    
  end if
next
if tmp.end < whole.end then
  free(ubound(free)).start = tmp.end 
  free(ubound(free)).end = whole.end  
endif
end sub

Type snippet
start as double
end as double
end type