BUFFER_TO_STRING.EXP

(* @NESTEDCOMMENTS := 'Yes' *)
(* @PATH := '\/Buffer Management' *)
(* @OBJECTFLAGS := '0, 8' *)
(* @SYMFILEFLAGS := '2048' *)
FUNCTION BUFFER_TO_STRING : STRING(STRING_LENGTH)
VAR_INPUT
	PT : POINTER TO ARRAY[0..32767] OF BYTE;
	SIZE : UINT;
	START : UINT;
	STOP : UINT;
END_VAR
VAR
	ps : POINTER TO BYTE;
	i : UINT;
	stp: UINT;
	sta: UINT;
END_VAR


(*
version 1.5	12. nov. 2009
programmer 	hugo
tested by		oscat

this function will retrieve a string from an array of byte starting at position start and stop at position stop.
the function needs to be called:	buffer_TO_String(adr("array"),sizeof("array"), start, stop);
because this function works with pointers its very time efficient and it needs no extra memory.

*)
(* @END_DECLARATION := '0' *)
ps := ADR(BUFFER_TO_STRING);
IF size = 0 THEN RETURN; END_IF;
sta := MIN(start, size -1);
stp := MIN(stop, size -1);

(* check for maximum string_length *)
IF UINT_TO_INT(stp - sta + 1) >= STRING_LENGTH THEN
	stp := sta + INT_TO_UINT(STRING_LENGTH) - 1;
END_IF;

FOR i := sta TO stp DO
	ps^ := pt^[i];
	ps := ps + 1;
END_FOR;

(* terminate the string *)

ps^ := 0;



(* revision History
hm 	5. mar. 2008	rev 1.0
	original version

hm	16. mar. 2008	rev 1.1
	changed type of input size to uint

hm	13. may. 2008	rev 1.2
	changed type of pointer to array[0..32767]
	changed size of string to STRING_LENGTH

hm	12. jun. 2008	rev 1.3
	check for pointer overrun
	change input start and stop to uint
	added type conversions to avoid warnings under codesys 3.0

hm	23. mar. 2009	rev 1.4
	avoid writing to input stop

hm	12. nov. 2009 rev 1.5
	limit start and stop to size -1

*)
END_FUNCTION