Libris Britannia 4/science library(b).zip/science library(b)/PROGRAMM/BASIC/0006.ZIP/COVER.DOC

Text File | 1983-06-16 | 13KB | 265 lines

                   SORTED DISKETTE DIRECTORY LISTING - IBM PC

             Just what you always needed!   Yet another redundant, dupli-
        cative,  and space occupying utility...  Hopefully,  this fills a
        nitch left open in the array of PC-DOS utilities.  This one sorts
        and formats the directory data and prints it so its "just  right"
        to  fit inside the diskette envelope.   You have to provide  your
        own paper cutter... the utility does the rest.

             The program runs under PC-DOS Versions 1.x or 2.0,  and will
        operate  on any normal configuration.   It does expect the IBM or
        Epson MX80 printer (or equivalent), but should be easily modified
        to apply to any printer that offers "condensed" print and 8 lines
        per inch line spacing.   It is written in Assembler,  but uses no
        macros,  so either ASM or MASM can be used to assemble the source
        code.  LINK and EXE2BIN are required.

             It has two known limitations.   It ignores hidden files, and
        if  you're  a Version 2.0 user and have  implemented  the  "tree"
        directory  paths  with mulitple directories on  a  diskette,  the
        subordinate  directories will also be ignored.   Since the "path"
        logic  seems primarily aimed at fixed disk,  and this utility  is
        directed towards diskettes,  these limitations should not  effect
        most  users.   Someday I'll get rich,  and get a fixed disk,  but
        till then....

             The utility resulted from a scenario in which I found myself
        a frequent player.   I hope I'm alone in the world, but I suspect
        I'm not.   The scenario goes like this...  Phone rings.  Voice on
        the line says, "Say Dan, you know that program that puts a double
        whammy  on the singlefritz when you've juiced  the  slobert?   My
        only copy got clobbered, so would you check and see if you've got
        a  backup?"  Well,  I've got something in excess of 200 diskettes
        neatly filed in boxes,  labeled correctly, etc.  The only problem
        is that a label which says "Miscelaneous Junk Utilities" may have
        meant  something when I wrote it,  but it sure doesn't mean  much
        now.   Next step is to break in to what ever is currently running
        on the PC, and start sticking in diskettes to do a DIR to check.

             Actually  this  kind of event led to my writing a  "Catalog"
        facility (which does everything but cook) for the PC,  but  after
        some  months  of use,  I found that the part of  this  relatively
        large  and  complex package that I really used,  was this  simple
        print utility.   So I "extracted" that portion of the big  system
        to  pass on to the rest of the world.   I'm placing this code  in
        "Public Domain", so use it as you will.

             The  program  is  called "COVER" and is  composed  of  seven
        separately  assembled modules:  COVER,  COTITL,  COFREE,  COSCAN,
        COSORT, COPRNT, and COENDP.  The listings are commented, but I'll
        include a few words on each of the modules.

             COVER  is  the main control module,  and contains the  major
        loop.   Its first action is to preset the printer to 8 lines  per
        inch,  condensed  print,  and  a  44 line page.   If you  have  a


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        "different"  printer,  you may need to change the control  stream
        defined at SETPRT.   The final zero in the control stream is  not
        sent to the printer, but marks the end of string for DOPRT.

             Next, COVER checks for the DOS Version.  The return from the
        30H  call  (which is valid on release 1.x),  is the  release  and
        version numbers under V2.0 of DOS.   On prior releases it returns
        a  zero.   This  code  simply sets a switch that will  be  tested
        later.   The  "default" drive is then determined and  saved,  and
        finally, the number of drives on the configuration is determined.

             COVER  then  prompts  for the drive  letter  for  the  drive
        containing the diskette to be listed.  The single character input
        is first checked for an "Escape" (all done, so get off), and then
        the  drive character is verified for a "legal" drive  designator.
        The prompt starts the main loop,  which ends after all processing
        is  done for one diskette.   COVER then calls GETTTL (Get Title),
        GETFRE  (Determine  free  space  on  diskette),  SCAN  (Load  all
        directory  entries into an internal stack),  SORT  (Sequence  the
        stacked entries), and PRINT (which formats and prints the stacked
        entries).   Each  of the called routines will be mentioned in the
        following paragraphs.

             When  the Escape character is sensed,  COVER forces  a  page
        restore  to  complete the current listing,  resets the  "default"
        drive  to its value on entry,  conditionally forces out one  more
        "page"  to restore the paper to the true top of forms,  and  then
        resets the printer to "power up" status.   The control string for
        the  latter  is at RESPRT so the "different"  printer  users  may
        modify that string if required.

             GETTTL  is a primitive module which solicits a "title"  from
        the  user.   Forty characters are allowed,  and the standard  DOS
        function is used to get this string.  Nul titles are permissable.
        The DOS function is also used to get the system date.   DECMAL is
        a  local  subroutine  that coverts the content of the AL  to  two
        decimal digits in the AH and AL and then stores them in the  area
        defined by the DI register.

             GETFRE  computes the "free" space available on the  diskette
        and  places  the ASCII decimal result in the  title  line.   This
        program  is the reason COVER checked for the DOS  Version.   V2.0
        provides  a  "nice"  function  that  will  give  the  free  space
        directly,  but  does not allow you to gain addressability to  the
        File Allocation Table (FAT).  V1.x did not have this feature, but
        did provide addressability to the FAT.  Since this program was to
        be used in both environments,  this code has two paths.  The code
        following  the version test is for V2.0.   Code starting  at  the
        label  VERS1  is that process necessary to determine  free  space
        under the older versions of DOS.   VCOM marks the point where the
        two paths re-join.  If you're only running V2.0, you can decrease
        the size of the utility by removing the code from the instruction
        "JMP VCOM" to the instruction before that labeled VCOM.  Finally,
        CONVRT  is a public subroutine that converts the AX/DX content to
        a max of a six digit number,  leading zero surpressed, and places


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        the result at the area pointed to by the DI register.

             SCAN  does  the normal DOS function calls to "find"  an  all
        "wild  card" file name.   This process repeats until  the  entire
        directory has been scanned.   The result is placed in a stack and
        a  pointer to the start of the entry is placed in a pointer list.
        The format of the stack entries is the file-name.typ followed  by
        a  zero  byte,  and then the four byte file size field  from  the
        directory.  Since the data transfer area (DTA) has not been reset
        this  module  finds  it input in the default DTA at  80H  in  the
        program prefix.

             SORT  is a simple "bubble" sort of the stacked entries,  but
        is  driven from the pointer list.   Yes,  I know a shell sort  is
        faster,  but  for a max of 112 entries,  an old fashioned  bubble
        uses less memory!

             PRINT  simply  uses the sorted pointers to  form  the  final
        output.   The  title  line has already been formed by  the  prior
        modules.   The  local subroutine PRTENT uses CONVRT to format the
        file  sizes.   Four  columns  will "fit" within  the  print  size
        required,  so PRINT initially computes column length.   An inner
        and  an outer loop controls the print process.   The  inner  loop
        prints  one entry each execution,  and is executed four times per
        line.   The  outer  loop  is cycled once per entry  in  a  single
        column.

             The  source  module COENDP includes no  code.   This  module
        simply  provides  addressability to the memory above the  program
        code.   V2.0  provides this function in a much "cleaner"  manner,
        but  since  this  utility  is to  run  on  either  Version,  this
        subterfuge is necessary.

             That's  a  very  quick "walk  through"  for  the  code,  but
        together  with the source comments,  it should provide  sufficent
        information for any extensions or modifications you may choose to
        make.   Key the source in,  and assemble the seven modules.   The
        Link  control stream is also included in the listings.   Be  very
        sure that the module COENDP occurs last in the control stream, as
        shown  in  the listing.   Otherwise you'll be stacking  directory
        entries over some of the code.

             For those of you who are not familiar with "COM" files,  ALL
        segment  registers are preset by the operating system to the same
        value,  so  although  you see no code for setting the DS  and  ES
        segment registers,  they contain the same value as the CS and  SS
        at  program initiation so change is not required.   The stack  is
        automatically  allocated  at the "top" of the segment  (64K)  the
        program  is  loaded to,  so no stack establishment  is  required.
        Finally,  the  established stack is initialized so that a  "NEAR"
        return  at  end of program will return you to DOS  correctly,  so
        long as the CS register has not been changed.   This program uses
        the 20H termination call, but could do a simple near RET with the
        same result.



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             Link  will provide console messages saying that there is  no
        stack segment (that's right), and that there is one error (that's
        false).   This  response is normal when you're preparing a  "COM"
        file.   If you get more errors or other indications, you'd better
        re-check your work.

             Now  you're  ready  to  run EXE2BIN,  and  then  rename  the
        resultant  file (COVER.BIN) to COVER.COM.   That's all it  takes.
        The utility will prompt with a console message asking which drive
        contains the diskette to be listed, so enter the single character
        drive designator appropriate (A-G).   No colon or carriage return
        will be required.  The program will then prompt for the title you
        wish  to appear on the top line of the list.   A forty  character
        field is provided.   If you do not want the title, simply hit the
        "Enter" key, and the top line of the listing will be blank except
        for the date.   When the first listing is complete,  the  utility
        will loop back and ask for another drive.  This iterative process
        will  continue until you repond with an "Escape" key to the drive
        request prompt.  Exit is then made to the DOS.

             Note  that although the utility prints two  envelope  covers
        per page, forms will be advanced to the "top of form" position in
        effect  when the utility was started.   The printer will also  be
        restored to "power up" status.   If you use Control-Break to exit
        the  utility,  this will not be true,  so you'll have to manually
        re-aline and reset your printer.

             There's not that much code in this utility,  but as  always,
        if you don't want to "poke" this in yourself, send me a diskette,
        with mailer and postage, and I'll copy my source and return it to
        you,  or  if you prefer,  send me a check for $7.50 and I'll send
        you a new diskette (single surface - 8 sector).   You can contact
        me at the address or phone given below:

                  Dan Daetwyler
                  Route 5, Box 518A
                  Springdale, Arkansas 72764
                  501-756-0212



















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