tasks a-s

Task/Queue-Definition/OxygenBasic/queue-definition.oxy

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+'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