A method of either of these types obtains or calculates the offset/size of the next protocol layer and stores it into the variable called iOutput as in this example:
NEXT_PROTOCOL_SIZE
METHOD FromField__
/* obtains the size from a given field */
CODE
iOutput = (int)ai64Field[fldParam1] + iParam2;
ENDCODE
PARAM "Field that contains the next protocol size" field