REM file: Rdvolbpb.bas - Public Domain DOS Utility
REM Version 1.0a created 09/12/1995
REM Version 1.1a created 04/15/2001

' default integer variables
DEFINT A-Z
REM $DYNAMIC

' define boolean values
CONST True = -1
CONST False = NOT True
CONST TrueD = -1#
CONST FalseD = NOT TrueD
CONST NUL = ""

' define color values
CONST Black = 0
CONST Cyan = 11
CONST Green = 10
CONST Plain = 7
CONST Red = 12
CONST White = 15
CONST Yellow = 14

' get include files
REM $INCLUDE: 'qbx.bi'
REM $INCLUDE: 'bpb.bi'

' declare functions
DECLARE FUNCTION ParseLine (S$)
DECLARE FUNCTION BreakIS()
DECLARE FUNCTION ClearBreak()
DECLARE FUNCTION KeyIS()

' initialize filename buffer
COMMON SHARED Drive.Search AS STRING * 1

' declare some structures
COMMON SHARED BPBfile AS BPBtype

' declare registers
COMMON SHARED InregsX AS RegTypeX, OutregsX AS RegTypeX

' declare work variables
COMMON SHARED Continuous.Display AS INTEGER, Display.Errors AS INTEGER

' declare command line work variables
COMMON SHARED Command.Line AS STRING, Command.Line.Redirect AS STRING
COMMON SHARED Command.Work AS STRING, Control.Break AS INTEGER

' declare external procedures
DECLARE SUB SetInt
DECLARE SUB RestInt

' backwards compatible for bc 7.1
REM $INCLUDE: 'bc7.inc'

' increase stack size
STACK STACK

' install new interrupt service routine
CALL SetInt

' declare standard error trap
ON ERROR GOTO Error.Routine

' command line parser
FUNCTION ParseLine (X$)
 Imbedded = INSTR(Command.Line, X$)
 IF Imbedded THEN
    Command.Line = LEFT$(Command.Line, Imbedded - 1) + MID$(Command.Line, Imbedded + LEN(X$))
    ParseLine = True
 ELSE
    ParseLine = False
 END IF
END FUNCTION 

' get current drive
InregsX.AX = &H1900
CALL InterruptX(&H21, InregsX, OutregsX)
Current.Drive$ = CHR$((OutregsX.AX AND &HFF) + 65)

' check command line
SELECT CASE COMMAND$
CASE "/?"
   GOTO Boot.Usage
END SELECT

' store and parse command line
Command.Line = COMMAND$
IF Command.Line = NUL THEN
   Command.Line = UCASE$(ENVIRON$("RDVOLBPB"))
END IF

' get switches from command line
Continuous.Display = ParseLine ("/C")
Display.Errors = ParseLine ("/Z")
Control.Break = ParseLine ("/~")

' recheck command line
IF INSTR(Command.Line, "/") THEN
   GOTO Boot.Usage
END IF

' remove blanks from command line
Command.Line = RTRIM$(Command.Line)
Command.Line = LTRIM$(Command.Line)
Command.Line.Redirect = Command.Line

' check break flag override
IF Control.Break THEN
   Var = ClearBreak
END IF

' search through all input filenames
Redirected.Input = False
DO
   ' check control break
   IF BreakIS THEN
      EXIT DO
   END IF

   ' get standard input
   Standard.Input$ = NUL
   InregsX.AX = &HB00
   CALL InterruptX(&H21, InregsX, OutregsX)
   DO WHILE (OutregsX.AX AND &HFF) = &HFF
      Redirected.Input = True
      InregsX.AX = &H800
      CALL InterruptX(&H21, InregsX, OutregsX)
      Char$ = CHR$(OutregsX.AX AND &HFF)
      SELECT CASE ASC(Char$)
      CASE 10, 26
      CASE 13
	 EXIT DO
      CASE ELSE
	 Standard.Input$ = Standard.Input$ + Char$
      END SELECT
      InregsX.AX = &HB00
      CALL InterruptX(&H21, InregsX, OutregsX)
   LOOP

   ' clear break flag
   IF Redirected.Input = False THEN
      IF Cleared = False THEN
         Cleared = True
         Var = ClearBreak
      END IF
   END IF

   ' check control break
   IF BreakIS THEN
      EXIT DO
   END IF

   ' check nul filename input
   IF Redirected.Input = False THEN
      IF Standard.Input$ = NUL THEN
         CALL RestInt ' restore Control-Break
         X$ = Inkey$ ' quits here
         CALL SetInt ' reset Control-Break
         IF X$ = CHR$(0) + CHR$(0) THEN
            EXIT DO
         END IF
      END IF
   END IF

   ' check standard input
   IF Redirected.Input THEN
      IF Standard.Input$ = NUL THEN
	 EXIT DO
      END IF
   END IF

   ' display header
   GOSUB Header

   ' store entire command
   Command.Work = Command.Line.Redirect

   DO
      ' store entire command
      Imbedded = INSTR(Command.Line, " ")
      IF Imbedded THEN
         Command.Work = Standard.Input$ + LEFT$(Command.Line, Imbedded - 1)
         Command.Line = MID$(Command.Line, Imbedded + 1)
      ELSE
         Command.Work = Standard.Input$ + Command.Line
         Command.Line = NUL
      END IF

      ' store current drive
      IF MID$(Command.Work, 2, 1) = ":" THEN
         Drive.Search = LEFT$(Command.Work, 1)
         Command.Work = MID$(Command.Work, 3)
      ELSE
	 Drive.Search = Current.Drive$
      END IF

      ' get volume info
      InregsX.AX = &H6900
      InregsX.BX = ASC(Drive.Search) - 64
      InregsX.DS = VARSEG(BPBfile)
      InregsX.DX = VARPTR(BPBfile)
      CALL InterruptX(&H21, InregsX, OutregsX)

      ' display any errors
      CALL DisplayError ("Error reading volume bpb.")

      ' check error flag
      IF (OutregsX.Flags AND &H1) = &H0 THEN

	 ' display search filename
         COLOR Yellow, Black
         IF Continuous.Display = False THEN
	    PRINT "Volume bpb: ";
	 END IF
	 PRINT BPBfile.Label
      END IF

      ' check search filename
      IF Command.Line = NUL THEN
	 EXIT DO
      END IF
   LOOP

   ' check search filename
   IF Standard.Input$ = NUL THEN
      EXIT DO
   END IF
LOOP

End.Rdvolbpb:

' display end program
IF Continuous.Display = False THEN
   Prompt$ = "Press <enter> to exit to DOS:"
   CALL MorePrompt(Prompt$, CHR$(13), Outpt$)
END IF
COLOR Plain, Black

' restore key trapping
CALL RestInt

END

' display program usage
Boot.Usage:
 ' restore key trapping
 CALL RestInt
 Var$=Inkey$
 ' make header
 COLOR White, Black
 PRINT "Rdvolbpb v1.1a: Volume bpb display utility; "
 COLOR Yellow, Black
 PRINT "Usage:"
 PRINT "   Rdvolbpb [d:][/cz]"
 PRINT "Where:"
 PRINT "   /c  continuous display"
 PRINT "   /z  suppress errors"
 COLOR Plain, Black
 END

' make header
Header:
 IF Header.Flag THEN
    RETURN
 END IF
 Header.Flag = True
 IF Continuous.Display = False THEN
    COLOR White, Black
    PRINT "Rdvolbpb v1.1a: Volume bpb display utility;"
 END IF
 RETURN
   
' critical error trap
Error.Routine:
 Data.Error = ERR
 IF Display.Errors THEN
    Error.Level = True
    OutregsX.Flags = &H1
    RESUME NEXT
 END IF
 SELECT CASE Data.Error
 CASE 53
    Temp.Outpt$ = "File not found."
 CASE 61
    Temp.Outpt$ = "Disk full."
 CASE 70
    Temp.Outpt$ = "Permission denied."
 CASE 71
    Temp.Outpt$ = "Disk not ready."
 CASE ELSE
    Temp.Outpt$ = "Untrapped error" + STR$(Data.Error) + "."
 END SELECT
 COLOR White, Black
 PRINT Temp.Outpt$
 Prompt$ = "Press R to retry, Q to quit, C to continue:"
 CALL MorePrompt(Prompt$, "rqc", Outpt$)
 IF BreakIS THEN
    Outpt$ = "q"
 END IF
 SELECT CASE Outpt$
 CASE "r"
    RESUME
 CASE "q"
    Error.Level = True
    RESUME End.Rdvolbpb
 CASE "c"
    OutregsX.Flags = &H1
    RESUME NEXT
 END SELECT
 COLOR Plain, Black
 ' restore key trapping
 CALL RestInt
 END 0

SUB MorePrompt (Input.String$, Input.Mask$, Output.String$)
 COLOR White, Black
 PRINT Input.String$ + " ";
 Input.Char$ = NUL
 DO
    LOCATE , , 1
    DO
       IF BreakIS THEN
          EXIT DO
       END IF
       IF KeyIS THEN
          IF OutregsX.AX <> 0 THEN
             InregsX.AX = &H0000
             CALL InterruptX(&H16, InregsX, OutregsX)
             Input.Char$=CHR$(OutregsX.AX AND &HFF)
             EXIT DO
          END IF
       END IF
    LOOP
    IF BreakIS THEN
       EXIT DO
    END IF
    IF LEN(Input.Char$) THEN
       Input.Char$ = LCASE$(Input.Char$)
       IF INSTR(Input.Mask$, Input.Char$) THEN
	  PRINT Input.Char$
	  Output.String$ = Input.Char$
	  EXIT DO
       END IF
    END IF
 LOOP
END SUB

' clears Control-Break flag
FUNCTION ClearBreak
 DEF SEG = &H40
 POKE &H71, &H0
 DEF SEG
 ClearBreak = True
END FUNCTION

' checks Control-Break flag
FUNCTION BreakIS
 STATIC Var AS INTEGER
 IF KeyIS THEN
    IF OutregsX.AX = 0 THEN
       Var = True
    END IF
 END IF
 IF Var THEN
    Continuous.Display = True
 END IF
 BreakIS = Var
END FUNCTION

' checks keyboard buffer
FUNCTION KeyIS
 InregsX.AX = &H0100
 CALL InterruptX(&H16, InregsX, OutregsX)
 IF (OutregsX.Flags AND &H40) = &H40 THEN
    KeyIS = False
 ELSE
    KeyIS = True
 END IF
END FUNCTION

' displays carry flag error
SUB DisplayError (Temp$)
 ' check carry flag error
 IF (OutregsX.Flags AND &H1) = &H1 THEN
    ' check display errors flag
    IF Display.Errors = False THEN
       ' display error
       COLOR Red, Black
       PRINT Temp$
    END IF
 END IF
END SUB
