# out.ludic - the reply stream: lines written into a buffer made once and grown when a frame needs
# more, then written and flushed whole, so a draw list makes no string per primitive
property PvOut {
  p: pointer = null
  n: int = 0
  cap: int = 0
}
extern function fflush(f: pointer) -> int = "fflush"
function pv_room(o: PvOut, more: int) -> void {
  if o.n + more + 1 <= o.cap { return }
  var cap = o.cap * 2
  if cap < 65536 { cap = 65536 }
  while cap < o.n + more + 1 { cap = cap * 2 }
  var q: pointer = null
  unsafe {
    q = bytes(cap)
    for i in 0 .. o.n { q[i] = o.p[i] }
    if o.p != null { free(o.p) }
  }
  o.p = q
  o.cap = cap
}
function pv_byte(o: PvOut, c: int) -> void {
  pv_room(o, 1)
  unsafe { o.p[o.n] = c }
  o.n += 1
}
# text as it is (a word of the protocol)
function pv_s(o: PvOut, s: string) -> void {
  let k = len(s)
  pv_room(o, k)
  unsafe {
    for i in 0 .. k { o.p[o.n + i] = s[i] }
  }
  o.n += k
}
# a space, then a word
function pv_w(o: PvOut, s: string) -> void {
  pv_byte(o, 32)
  pv_s(o, s)
}
# a space, then text as a JSON string: " and \ escaped, control bytes as \n \r \t or \u00XX, UTF-8 as is
function pv_q(o: PvOut, s: string) -> void {
  pv_byte(o, 32)
  pv_byte(o, 34)
  for i in 0 .. len(s) {
    let c = s[i] & 255
    if c == 34 or c == 92 {
      pv_byte(o, 92)
      pv_byte(o, c)
    } else if c == 10 {
      pv_s(o, "\\n")
    } else if c == 13 {
      pv_s(o, "\\r")
    } else if c == 9 {
      pv_s(o, "\\t")
    } else if c < 32 {
      pv_s(o, "\\u00")
      pv_byte(o, pv_hexch(c / 16))
      pv_byte(o, pv_hexch(c % 16))
    } else { pv_byte(o, c) }
  }
  pv_byte(o, 34)
}
function pv_hexch(d: int) -> int {
  if d < 10 { return 48 + d }
  return 87 + d
}
# the line so far ends
function pv_nl(o: PvOut) -> void { pv_byte(o, 10) }
# everything buffered goes to stdout now, and the buffer is empty again
function pv_flush(o: PvOut) -> void {
  if o.n == 0 { return }
  let f = file_stdout()
  unsafe { file_write(f, o.p, o.n) }
  fflush(f)
  o.n = 0
}