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GetOctetCountByFirstOctet

Short summary​

This function returns octets amount by first octet

  • Return type: BYTE

Parameters​

NameTypeCommentKind
firstByteBYTEfirst byte of an octet sequenceinput

Code​

Declaration​

FUNCTION INTERNAL GetOctetCountByFirstOctet : BYTE(0..4)
VAR_INPUT
	(* first byte of an octet sequence *)
	firstByte : BYTE;
END_VAR

Implementation​

CASE firstByte OF
16#00..16#7F:	// ASCII, 1 byte
	GetOctetCountByFirstOctet := 1;	
16#C2..16#DF:	// 2-byte utf-8
	GetOctetCountByFirstOctet := 2;	
16#E0..16#EF:	// 3-byte utf-8
	GetOctetCountByFirstOctet := 3;	
16#F0..16#F4:	// 4-byte utf-8
	GetOctetCountByFirstOctet := 4;
ELSE			// not first byte or invalid utf-8 byte found
	GetOctetCountByFirstOctet := 0;
END_CASE