LeftOfAnyString

Short summary

This function edits an AnyString, so only the count of length leftmost characters of the string remain. If length is greater than the length of the string, the string is unchanged.

It returns the new size of the string (Utf8: in byte, Utf16: in words).

Attention: All strings are handled as null-terminated byte streams

Example:

myString 			:WString(10) := "Test";
lengthOfMyString	:UDINT		:= 	4;
------------------
LeftOfAnyString(
	stringAdress 		:= ADR(myString),
	length		 		:= 3,
	newStringLength		=> lengthOfMyString
); // myString will be "Tes" with length 3

• Return type: UDINT

Parameters

Name	Type	Comment	Kind
stringToHandle	ANY_STRING	string to get the left chars of	input
length	UDINT	count of characters in in new substring	input
normalizeString	BOOL	normalize the string before creating subtring	input
newStringLength	UDINT	new length of the string in bytes	output

Code

Declaration

FUNCTION LeftOfAnyString: UDINT
VAR_INPUT
	(* string to get the left chars of *)
	stringToHandle		:ANY_STRING;
	(* count of characters in in new substring *)
	length				:UDINT;
	(* normalize the string before creating subtring *)
	normalizeString 	:BOOL := TRUE;
END_VAR
VAR_OUTPUT
	(* new length of the string in bytes *)
	newStringLength 	:UDINT := 0;
END_VAR

Implementation

RETURN((stringToHandle.pValue = 0) OR stringToHandle.diSize <= 0);

CASE stringToHandle.TypeClass OF
__SYSTEM.TYPE_CLASS.TYPE_STRING:
	LeftOfUtf8String(
		stringAddress 	:= stringToHandle.pValue,
		length			:= length,
		normalizeString	:= normalizeString,
		newStringLength	=> newStringLength
	);
	LeftOfAnyString := newStringLength;
__SYSTEM.TYPE_CLASS.TYPE_WSTRING:
	LeftOfUtf16String(
		stringAddress 	:= stringToHandle.pValue,
		length			:= length,
		normalizeString	:= normalizeString,
		newStringLength	=> newStringLength
	);
	LeftOfAnyString := newStringLength;
ELSE
	; // do nothing
END_CASE