import winlean

type
  PROCESS_MEMORY_COUNTERS = object
    cb: int32
    PageFaultCount: int32
    PeakWorkingSetSize: uint
    WorkingSetSize: uint
    QuotaPeakPagedPoolUsage: uint
    QuotaPagedPoolUsage: uint
    QuotaPeakNonPagedPoolUsage: uint
    QuotaNonPagedPoolUsage: uint
    PagefileUsage: uint
    PeakPagefileUsage: uint

# Only works on Windows - https://docs.microsoft.com/en-us/windows/win32/api/psapi/nf-psapi-getprocessmemoryinfo
proc getProcessMemoryInfo*(process: Handle, ppsmemCounters: var PROCESS_MEMORY_COUNTERS, cb: DWORD): WINBOOL {.stdcall, dynlib: "Psapi", importc: "GetProcessMemoryInfo".}

proc fillSeq(y: int, x: var seq[seq[int8]]) =
  var
    w: seq[int8] = @[1i8, 2, 3, 4, 5, 6]
    z = 1

  while z <= y:
    add(x, w)
    inc(z)

var
  c = getCurrentProcess()
  p: PROCESS_MEMORY_COUNTERS
  cap = 1310720
  ram1, ram2, ram3: uint


echo "Ram usage by process before creating sequence"
discard getProcessMemoryInfo(c, p, sizeof(p).DWORD)
ram1 = p.WorkingSetSize
echo ram1, " bytes\n"

var x = newSeqOfCap[seq[int8]](cap) # sizeof(seq[seq[int8]]) = 8 -> 8 * 1310720 = 10485760

echo "Ram usage by process after creating sequence with length 0 and capacity ", cap
discard getProcessMemoryInfo(c, p, sizeof(p).DWORD)
ram2 = p.WorkingSetSize
echo ram2, " bytes\n"

fillSeq(cap, x)

echo "Ram usage by process after filling sequence"
discard getProcessMemoryInfo(c, p, sizeof(p).DWORD)
ram3 = p.WorkingSetSize
echo ram3, " bytes\n"

echo len(x), " len seq\n"

echo "ram2 - ram1 = ", ram2 - ram1
echo "ram3 - (ram1 + ram2) = ", ram3 - (ram1 + ram2)