and in situations where execution speed is more important than minimal memory
usage, something along these lines might come in handy:
type
ExpandingArray*[T] = object
chunks: array[65536, ptr UncheckedArray[T]]
len: int64
proc `[]=`*[T](e: var ExpandingArray[T], index: int64, elem: sink T) =
if unlikely(e.chunks[index.shr(16)] == nil):
e.chunks[index.shr(16)] = cast[ptr
UncheckedArray[char]](alloc0(T.sizeof*65536))
e.chunks[index.shr(16)][index and 0x0000FFFF] = elem
if index >= e.len: e.len = index + 1
proc add*[T](e: var ExpandingArray[T], elem: sink T) = e[e.len] = elem
proc `[]`*[T](e: ExpandingArray[T], index: int64): var T =
if likely(e.chunks[index.shr(16)] != nil): return
e.chunks[index.shr(16)][index and 0x0000FFFF]
else: raise newException(IndexDefect, "index out of bounds")
Run
