Tutorial - Turn a QB64 interpreter into a compiler

Code: (Select All)

'===============

'MarkExeSize.bas

'===============

'Marks QB64 compiled EXE's with its EXE data size.

'Coded by Dav, JAN/2021



'WINDOWS ONLY!



'This helps facilitate using appended data on the EXE.

'It saves the compiled EXE size to the EXE file, so

'the program can read that info and jump to its data.



'It does this by borrowing some space near the top of

'the EXE file.  It shortens 'This program cannot be run

'in DOS mode.' to 'This program can't run in DOS mode.' and

'uses those 4 gained spaces to save EXE file size instead.



'=======================================================

'Example...after you mark your EXE file, it can do this:

'=======

'OPEN COMMAND$(0) FOR BINARY AS 1  'Open itself up...

'test$ = INPUT$(200, 1) 'grab a little info

'place = INSTR(1, test$, "This program can't") 'look for words

'IF place = 0 THEN PRINT "No data found.": CLOSE: END

'grab exesize info...

'SEEK 1, place + 35: ExeSize& = CVL(INPUT$(4, 1))

'Go there....

'SEEK 1, ExeSize& + 1   'where appended data begins

'=======================================================



'NOTE: Always mark the EXE before appending data to it.

'      If you use EXE compressors, like UPX, mark the EXE

'      AFTER using UPX, not before, otherwise the info won't

'      be read correctly by your program.





SCREEN Pete



PRINT

PRINT "================"

PRINT "MarkExeSize v1.0 - by Dav"

PRINT "================"

PRINT



IF COMMAND$ = "" THEN

    INPUT "EXE to Mark -->", exe$

    PRINT

ELSE

    exe$ = COMMAND$

END IF



IF exe$ = "" THEN END

IF NOT _FILEEXISTS(exe$) THEN

    PRINT "File not found.": END

END IF



OPEN exe$ FOR BINARY AS 1



'find location of place to mark

test$ = INPUT$(200, 1)

place = INSTR(1, test$, "This program can")

IF place = 0 THEN

    PRINT "This file is not markable."

    CLOSE: END

END IF



'jump to location

SEEK 1, place

look$ = INPUT$(19, 1) 'grab a little info



SELECT CASE look$

    CASE IS = "This program cannot"

        'mark/overwrite exe file info file with new info

        PRINT "Marking file "; exe$

        PRINT

        PRINT "EXE files size:"; LOF(1)

        PRINT "Data start loc:"; LOF(1) + 1

        new$ = "This program can't run in DOS mode." + MKL$(LOF(1))

        PUT 1, place, new$

        PRINT: PRINT "Done."

    CASE IS = "This program can't "

        PRINT "EXE already appears to be marked."

        PRINT

        SEEK 1, place + 35: datastart& = CVL(INPUT$(4, 1))

        PRINT "EXE files size:"; LOF(1)

        PRINT "Data start loc:"; datastart& + 1

        PRINT "Size of data  :"; LOF(1) - datastart&

    CASE ELSE

        PRINT "EXE is not markable."

END SELECT



CLOSE

Code: (Select All)

    'Mini Interpreter runtime.

    'A compiled EXE of this runs BAS code attached to it.

     

    DIM Code$(100) 'space for 100 lines

     

    '==========================================================

    OPEN COMMAND$(0) FOR BINARY AS 1

    place = INSTR(1, INPUT$(200, 1), "This program can't")

    IF place = 0 THEN

        CLOSE: END

    ELSE

        SEEK 1, place + 35: ExeSize& = CVL(INPUT$(4, 1))

    END IF

    '==========================================================

     

    'Make sure something is attached to exe...

    IF ExeSize& + 1 > LOF(1) THEN END

     

    SEEK 1, ExeSize& + 1

     

    Lines = 1

    WHILE NOT EOF(1)

        LINE INPUT #1, c$

        Code$(Lines) = c$

        Lines = Lines + 1

    WEND

    CLOSE 1

     

     

    FOR t = 1 TO Lines

        ExecuteLine Code$(t)

    NEXT

     

    SUB ExecuteLine (cmd$)

        cmd$ = LTRIM$(RTRIM$(cmd$))

        IF LEFT$(cmd$, 1) = "'" THEN EXIT SUB

        IF UCASE$(LEFT$(cmd$, 3)) = "REM" THEN EXIT SUB

        IF UCASE$(LEFT$(cmd$, 5)) = "SLEEP" THEN SLEEP

        IF UCASE$(cmd$) = "BEEP" THEN BEEP

        IF UCASE$(LEFT$(cmd$, 6)) = "COLOR " THEN

            COLOR VAL(RIGHT$(cmd$, LEN(cmd$) - 6))

        END IF

        IF UCASE$(cmd$) = "PRINT" THEN PRINT

        IF UCASE$(LEFT$(cmd$, 7)) = "PRINT " + CHR$(34) THEN

            PRINT MID$(cmd$, 8, LEN(cmd$) - 8)

        END IF

        IF UCASE$(LEFT$(cmd$, 3)) = "CLS" THEN CLS

        IF UCASE$(LEFT$(cmd$, 3)) = "END" THEN END

    END SUB

Code: (Select All)

    'Mini Compiler example

     

    PRINT

    PRINT "A Mini .BAS Compiler"

    PRINT "Compile .BAS to .EXE"

    PRINT

    INPUT "BAS to open ->", in$: IF in$ = "" THEN END

    INPUT "EXE to make ->", out$: IF out$ = "" THEN END

     

    'First see if this EXE is marked...

    OPEN COMMAND$(0) FOR BINARY AS 1

    place = INSTR(1, INPUT$(200, 1), "This program can't")

    IF place = 0 THEN CLOSE: END

     

    'Grab EXE size info

    SEEK 1, place + 35: ExeSize& = CVL(INPUT$(4, 1))

    'Make sure data attached...

    IF ExeSize& + 1 > LOF(1) THEN END

     

    'Jump to data

    SEEK 1, ExeSize& + 1

     

    'Extract data, make EXE file...

    OPEN out$ FOR OUTPUT AS 2

    outdata$ = INPUT$(LOF(1) - ExeSize&, 1)

    PRINT #2, outdata$;: outdata$ = ""

     

    'Add/attach BAS code to EXE

    OPEN in$ FOR BINARY AS 3

    outdata$ = INPUT$(LOF(3), 3)

    PRINT #2, outdata$;

     

    CLOSE

     

    PRINT "Made "; out$

     

    END