DEFINT A-Z
'----------------------------------------------------------------
'Routines to manage a table of values in RAM
'----------------------------------------------------------------

'$INCLUDE: 'TABLMNGR.BI'

'Fixed-length table manager

  CONST True = -1, False = 0, MaxTblSize = 32767

'----------------------------------------------------------------
'Create a symbol based on parameters for table
'----------------------------------------------------------------
FUNCTION SymCreate$ (Sym$, Parms AS SymbolTableParameters)
    SymCreate$ = Parms.Delim + SymPad$(UCASE$(Sym$), Parms)
END FUNCTION

'----------------------------------------------------------------
'Create a table based on the parameters
'----------------------------------------------------------------
FUNCTION SymCreateTbl (Tbl$, Parms AS SymbolTableParameters, Nbr)
  IF Nbr < 1 THEN Nbr = 1
  Parms.TblLength = ((Parms.SWidth + LEN(Parms.Delim)) * Nbr)
  IF Parms.TblLength <= MaxTblSize THEN
    Tbl$ = SPACE$(Parms.TblLength)
    FOR I = 0 TO Nbr - 1
      TblOffset = (Parms.SWidth + LEN(Parms.Delim))
      MID$(Tbl$, I * TblOffset + 1, 1) = Parms.Delim
    NEXT I
    Parms.NbrEntries = 0
    Parms.NbrEmpty = Nbr
    SymCreateTbl = True
  ELSE
    Parms.NbrEntries = 0
    Parms.NbrEmpty = 0
    Parms.TblLength = 0
    SymCreateTbl = False
  END IF
END FUNCTION

'----------------------------------------------------------------
'Define a symbol for the table
'----------------------------------------------------------------
FUNCTION SymDefine (Tbl$, Sym$, Parms AS SymbolTableParameters)

'If Symbol$ not blank and not previously defined and
'it doesn't contain the delimiter then add symbol

  SymDefine = False

  IF INSTR(Sym$, Parms.Delim) = 0 THEN
    SymTest = SymDefined(Tbl$, Sym$, Parms)  'Check if defined
    IF LEN(LTRIM$(RTRIM$(Sym$))) <> 0 AND NOT SymTest THEN
      S$ = SymCreate(Sym$, Parms)
      SymEmptyEntry$ = SymCreate$("", Parms)
      SymLen = Parms.SWidth + 1
        'Find an empty table entry or
        'Adds entry to end of table
      SPos = SymPos(Tbl$, "", Parms)  'Find first empty entry
      IF SPos = 0 THEN                     'Add to end of string
        IF Parms.TblLength + SymLen > MaxTblSize THEN
          EXIT FUNCTION
        END IF
        Tbl$ = Tbl$ + S$
        Parms.TblLength = Parms.TblLength + SymLen
      ELSE
        MID$(Tbl$, SPos, SymLen) = S$  'Set entry
        Parms.NbrEmpty = Parms.NbrEmpty - 1
      END IF
      Parms.NbrEntries = Parms.NbrEntries + 1
      SymDefine = True
    END IF
  END IF
END FUNCTION

'----------------------------------------------------------------
'Check to see if symbol defined in the table
'----------------------------------------------------------------
FUNCTION SymDefined (Tbl$, Sym$, Parms AS SymbolTableParameters)
  IF SymPos(Tbl$, Sym$, Parms) = 0 THEN
    SymDefined = False
  ELSE
    SymDefined = True
  END IF
END FUNCTION

'----------------------------------------------------------------
'Display a table on the screen
'----------------------------------------------------------------
SUB SymDisplayTbl (Tbl$, Parms AS SymbolTableParameters)
  PRINT "  Number of active symbol entries  = "; Parms.NbrEntries
  PRINT "  Number of empty symbol entries   = "; Parms.NbrEmpty
  PRINT "Press any key to see the table"
  WHILE INKEY$ = "": WEND
  PRINT
  NbrSyms = Parms.TblLength \ (Parms.SWidth + 1)
  FOR SymNbr = 1 TO NbrSyms
    Sym$ = SymGet(Tbl$, SymNbr, Parms)
    IF Sym$ <> "" THEN PRINT SymNbr, "|"; Sym$; "|"
    IF INKEY$ <> "" THEN EXIT SUB
  NEXT SymNbr
END SUB

'----------------------------------------------------------------
'Get a symbol based on the position number from table
'----------------------------------------------------------------
FUNCTION SymGet$ (Tbl$, SymNbr, Parms AS SymbolTableParameters)
  SymGet$ = ""
  IF SymNbr > 0 THEN
    BegPos = (Parms.SWidth + 1) * (SymNbr - 1) + 2
    SymGet$ = LTRIM$(RTRIM$(MID$(Tbl$, BegPos, Parms.SWidth)))
  END IF
END FUNCTION

'----------------------------------------------------------------
'Pad a symbol with spaces on the end for maximum symbol length
'----------------------------------------------------------------
FUNCTION SymPad$ (Sym$, Parms AS SymbolTableParameters)
  SymPad$ = LEFT$(Sym$ + SPACE$(Parms.SWidth), Parms.SWidth)
END FUNCTION

'----------------------------------------------------------------
'Find the position of symbol in the string table
'----------------------------------------------------------------
FUNCTION SymPos (Tbl$, Sym$, Parms AS SymbolTableParameters)
  IF INSTR(Sym$, Parms.Delim) = 0 THEN
    SymPos = INSTR(Tbl$, SymCreate$(Sym$, Parms))
  ELSE
    SymPos = 0  'Cannot have delimiter in symbol
  END IF
END FUNCTION

'----------------------------------------------------------------
'Remove a symbol from the table
'----------------------------------------------------------------
FUNCTION SymUnDefine (Tbl$, Sym$, Parms AS SymbolTableParameters)
  SymUnDefine = False
  IF INSTR(Sym$, Parms.Delim) = 0 THEN    'Check this first
    IF SymDefined(Tbl$, Sym$, Parms) THEN
      SymEmptyEntry$ = SymCreate$("", Parms)
  'Find the table location for Symbol$
      SPos = SymPos(Tbl$, Sym$, Parms)  'Find empty entry
      MID$(Tbl$, SPos) = SymEmptyEntry$        'Clear entry
      SymUnDefine = True
      Parms.NbrEntries = Parms.NbrEntries - 1
      Parms.NbrEmpty = Parms.NbrEmpty + 1
    END IF
  END IF
END FUNCTION