'FIRST IN FIRST OUT

'==========
Class Queue
'==========

string buf
sys    bg,i,le

method Encodelength(sys ls)
int p at (i+strptr buf)
p=ls
i+=sizeof int
end method

method push(string s)
ls=len s
if i+ls+8>le then
  buf+=nuls 8000+ls*2 : le=len buf 'expand buf
end if
EncodeLength ls
mid buf,i+1,s
i+=ls
'EncodeLength ls
end method

method GetLength() as sys
  if bg>=i then return -1 'buffer empty
  int p at (bg+strptr buf)
  bg+=sizeof int
  return p
end method

method pop(string *s) as sys
sys ls=GetLength
if ls<0 then s="" : return ls 'empty buffer
s=mid buf,bg+1,ls
bg+=ls
if bg>1e6 then
  buf=mid buf,bg+1 : bg=0 : le=len buf : i-=bg 'shrink buf
end if
end method

method clear()
  buf="" : le="" : bg=0 : i=0
end method

end class

'====
'TEST
'====

Queue fifo
string     s
'
fifo.push "HumptyDumpty"
fifo.push "Sat on a wall"
'
sys er
do
  er=fifo.pop s
  if er then print "(buffer empty)" : exit do
  print s
end do