Simtel MSDOS 1992 June/SIMTEL_0692.cdr/msdos/msjournl/msjv24.arc/QBASIC.ALL

Text File | 1987-10-30 | 21KB | 644 lines

Microsoft Systems Journal
Volume 2; Issue 4; September, 1987

Code Listings For:

    DSEARCH.ASM
    DSEARCHT.BAS
    BROWSE.BAS
    pp. 63-76

Author(s): Dan Mick
Title:     Microsoft QuickBASIC: Everyone's First PC Language Gets Better



Figure 1
========



;;    DSEARCH.ASM
;;    Written by Dan Mick


        page    62,132

data    segment public 'data'
dta_ofs dw      ?               ;save area for BASIC's DTA
dta_seg dw      ?
fill    db      ?               ;"fill array" flag
selflg  db      ?               ;"selective search" flag
search_attr     db      ?       ;files' search attribute
filcnt  dw      ?               ;count of files found
path    db      64 dup (0)      ;search path, passed from BASIC

;DTA structure for findfirst, findnext calls (see DOS documentation)

dta     db      21 dup (0)      ;reserved area (used for findnext)
attrib  db      ?               ;attribute of file found
time    dw      ?               ;time of last write
date    dw      ?               ;date
fsize   dd      ?               ;filesize (32 bit integer)
fname   db      13 dup (0)      ;ASCIIZ filename: name.ext,00
data    ends

dgroup  group   data

code    segment byte public 'code'
        assume  cs:code, ds:dgroup
        .xlist
;
;CALL DSEARCH(path$, attr, count, selective, array ofs)
; path$ is a normal string variable with the path for the
; directory search.  It be a full pathname, including filename
; and extension fields.  To get all the files in the default
; directory on C:, for instance, path$="C:*.*", or all the files
; in subdir on the current drive, path$="subdir\*.*".
; attr is the MS-DOS file attribute for the search.  See below for
; a description.  Each bit represents a file attribute.
; count is an input and an output parameter.  On input, if it is
; zero, the files will not be put in the array, only counted.
; This is provided so that a dynamic array may be allocated after
; the size is determined by dsearch().  If count is non-zero on
; input, the filenames will be placed in the array.
; In either case, the count of filenames found is returned.
; selective is a flag indicating how to do the counting and
; searching process.  If the file attribute 10 is specified, for
; example, DOS will return all those filenames that have the
; subdir attribute as well as those that don't.  If selective is
; set nonzero, the non-subdir files will not be returned.  What
; this does, basically, is allow a "filter normal files" selection
; so that subdirs and volume labels may easily be found.
; array offset is a pointer (offset only for strings) to a string
; array big enough to hold all files found in path$.  The size
; required may be determined as described below.
;
; The attribute byte:
;
;           -------------------------------------
;           | X | X | X | A | D | V | S | H | R |
;           -------------------------------------
;
;  X is don't care, A = archive, D = subdirectory, V = volume label,
;  S = system, H = hidden, R = read-only.
;
        .list

stk     struc
bbp     dw      ?               ;BASIC's bp
retadd  dd      ?               ;return address
arrofs  dw      ?               ;param: array offset
select  dw      ?               ;param: filter normal files flag
count   dw      ?               ;param: count flag/count return
attr    dw      ?               ;param: search attr
path$   dw      ?               ;param: pathname to search
stk     ends

;calculate value to pop with RET n at end of proc (length of params)
popval  =       (offset path$) + (size path$) - (offset arrofs)

strdes  struc                   ;BASIC string descriptor structure
len     dw      ?               ;word length of string
strptr  dw      ?               ;pointer to string space
strdes  ends

dsearch proc    far             ;it's a far proc to BASIC
        public  dsearch         ;let LINK know about this one

        push    bp              ;save BASIC's bp
        mov     bp,sp           ;address stack as it exists now

        mov     [filcnt],0      ;initialize file count

        mov     si,path$[bp]    ;get pointer to string descriptor
        mov     cx,len[si]      ;cx = path length
        mov     si,strptr[si]   ;si -> path string data
        lea     di,path         ;di -> place to fill
        rep     movsb           ;move pathname to our data area
        mov     byte ptr es:[di],0 ;make sure it's an ASCIIZ string

        mov     si,count[bp]    ;get pointer to fill flag in di
        mov     cx,[si]         ;cx = fill flag
        mov     byte ptr [fill],0 ;set flag to "no" first
        or      cx,cx           ;nonzero?
        jz      nofill          ;nope
        mov     byte ptr [fill],0ffh ;yes, set flag

nofill: mov     di,select[bp]   ;get pointer to selective flag in di
        mov     cx,[di]         ;cx = selective flag
        mov     byte ptr [selflg],0 ;set flag to "no" first
        or      cx,cx           ;nonzero?
        jz      nosel           ;nope
        mov     byte ptr [selflg],0ffh ;yes, set flag

nosel:  mov     di,attr[bp]     ;point at search attribute param
        mov     cx,[di]         ;and get it

        mov     ah,2fh          ;get BASIC's DTA
        int     21h
        mov     [dta_ofs],bx
        mov     [dta_seg],es    ;and save it
        lea     dx,dta          ;set DTA to our area here
        mov     ah,1ah
        int     21h

        mov     di,arrofs[bp]   ;di -> first string descriptor
        mov     di,[di]         ;di = first string descriptor offset
        mov     bx,ds           ;set up es to string array segment
        mov     es,bx           ; (BASIC's data segment)
                                ;now es:di -> first string descriptor

        mov     ah,4eh          ;find first matching file
        xor     ch,ch           ;clear hi part of attribute
        lea     dx,path         ;ds:dx points to search path
        int     21h
        jnc     ok              ;if error, cy set
        cmp     ax,18           ;no files found?
        jz      exit            ;yes, don't report error
        mov     [filcnt],0ffffh ;set count to -1 to report path error
        jmp     short exit      ;and leave

ok:     call    countit         ;rets cy if should save, incs filcnt
        jz      findnext        ;no fill if zr set
        call    move_filename   ;do the move

findnext:
        mov     ah,4fh          ;find next function
        int     21h             ;do it
        jc      exit            ;if error, must be no more files
        call    countit         ;count, return cy if should save
        jz      findnext        ;if zr set, don't save name
        call    move_filename   ;move it
        jmp     short findnext  ;and keep hunting

exit:   push    ds
        lds     dx,dword ptr [dta_ofs] ;get BASIC's DTA
        mov     ah,1ah                 ;set DTA fn.
        int     21h
        pop     ds
        mov     di,count[bp]    ;di -> fattr for count return
        mov     ax,[filcnt]     ;get file count
        mov     [di],ax         ;put file count in fattr
        pop     bp              ;restore BASIC's BP
        ret     popval          ;return and pop parameter pointers
dsearch endp

countit         proc
;

;Check file attribute if selective, and update count or not based on
;result. Return flag saying whether or not to move filename, too,
;based on updated count and the "fill" flag.

;
         cmp     [selflg],0ffh  ;are we selective?
         jnz     bump           ;nope, count it
         cmp     [attrib],cl    ;is the attr just what we want?
         je      bump           ;yes, count this file
         cmp     cl,cl          ;nope, set ZF
         jmp     short dontfill ;and skip to exit
bump:    inc     [filcnt]       ;update counter
         cmp     [fill],0       ;now, are we filling?
dontfill:                       ;get here from jne, so NZ
         ret                    ; return with NZ if filling
countit         endp

move_filename   proc    near
;
;es:di points to string descriptor to fill with filename from DTA
;
        push    di              ;save pointer to descr. length part
        mov     di,es:strptr[di] ;and point instead to string data
        lea     si,fname        ;si -> filename (ASCIIZ)
moveloop:
        lodsb                   ;get filename character
        or      al,al           ;is it 0? (end of string?)
        jz      done            ;yes, quit moving data
        stosb                   ;no, store
        jmp     short moveloop  ;and continue
done:   test    byte ptr [attrib],10h ;is this a subdir?
        jz      notsub          ;no
        mov     al,'\'          ;yes, store a trailing backslash
        stosb
notsub: pop     di              ;di -> length in s.d. again
        add     di,4            ;move to next s.d. pointer
        ret
move_filename   endp

code    ends
        end     dsearch





Figure 2
========


"Test Program" for DSEARCH.


'dsearcht.bas
'simple program to check dsearch routine and make sure it's
'working.  The idea is to call it just enough to check out
'its capabilities, and perhaps vary its input by small
'amounts, so that you get a controlled test where there are
'no likely bugs in the BASIC code.


rem $dynamic
DIM A$(0)

start:
input "Path for directory? (wildcards allowed): ",path$
if instr("\:",right$(path$,1)) then path$=path$+"*.*"

'get number of filenames in path
attr%=&H10:arrofs%=0:count%=0:selective%=0
call dsearch(path$,attr%,count%,selective%,arrofs%)

'now count% has actual filename count for redim, or -1 if error
'(other than file not found, that is.)

if count%=-1 then print "Bad pathname":goto start
redim a$(count%)

print "There are "count%"filenames in path "path$"."
'set up a$ so that dsearch doesn't have to change length
for i=0 to count%-1:a$(i)=space$(12):next i

arrptr=varptr(a$(0))
arrofs%=int(arrptr)             'explicit conversion

call dsearch(path$,attr%,count%,selective%,arrofs%)

for i= 0 to count%-1:print i;":";a$(i):next i
goto start







Figure 3
========



BROWSE.BAS


'BROWSE.BAS - a file browser/directory maintenance routine
'To compile in the editor environment, make a user library by
'assembling DSEARCH.ASM, using BUILDLIB to add it and USERLIB.OBJ
'to a user library (call it MYLIB.EXE, for instance), and then
'use the /L switch to load QB, as in "QB BROWSE /L MYLIB.EXE".
'To compile standalone, use "LINK BROWSE+DSEARCH+USERLIB...."

defint a-z
dim winrec(8) 'holds window dimensions, colors for text and borders

'the following arrays and constants are used for int86()
dim inary(7), outary(7)
const ax = 0, bx = 1, cx = 2, dx = 3
const bp = 4, si = 5, di = 6, flag = 7

'actions returned by PageAndSelect
const disk.change = 1, delete.file = 2, type.file = 3, quit = 4
action.flag = 0  'set by PageAndSelect to one of the above

rem $dynamic
dim filename$(0)
dim shared ScreenData (0,0)

def fn.min(x,y)
   if x < y then fn.min = x else fn.min = y
end def

def fn.max(x,y)
   if x > y then fn.max = x else fn.max = y
end def

'************************ MAIN PROGRAM **************************

call GetCurrDisk(origdisk$)
call GetCurrPath(origdisk$,origpath$)

disk$ = origdisk$

'get a count of all normal and subdir files

Do
   call GetCurrPath(disk$,CurrPath$)
   searchpath$ = disk$ + ":" + CurrPath$ + "*.*"

   attr = &H10 : count  =  0 : selective = 0
   arrofs = int(varptr(filename$(0)))
   call dsearch (searchpath$,attr,count,selective,arrofs)

   ' This should never happen!...
   if count = -1 then
      locate 25,1:print "Invalid path: "searchpath$
      print "Strike a key...":a$ = input$(1):end
   end if

   redim filename$(count-1)
   for i = 0 to count-1:filename$(i) = space$(12):next i

   arrofs = int(varptr(filename$(0)))
   call dsearch (searchpath$,attr,count,selective,arrofs)

   'now filename$(0 to count-1) have all the files and subdirs
   winrec(1) = 1 : winrec(2) = 1    'upper left of window  (row,col)
   winrec(3) = 10 : winrec(4) = 80   'lower right of window
   winrec(5) = 0 : winrec(6) = 11    'fg/bg color
   winrec(7) = 10 : winrec(8) = 0    'border colors, fg/bg

   call makewindow (winrec())

   'do window/cursor/path manipulation.

   call PageAndSelect(winrec(),filename$(),action.flag,f$)

   'f$ comes back as fixed-length (12) string
   ' ...strip off trailing blanks
   i = instr(f$," ") : if i > 0 then f$ = left$(f$,i-1)

   select case action.flag
      case quit
         call SetCurrDisk(OrigDisk$)
         call SetCurrPath(OrigPath$)
         cls : end
      case disk.change
         cls : print "Enter new disk drive letter: ";
         disk$ = input$(1) : print disk$;
         if disk$ > "Z" then disk$ = chr$(asc(disk$) and &HDF)
         call SetCurrDisk(disk$)
         action.flag = 0
      case type.file
         if right$(f$,1) = "\" then
            CurrPath$ = CurrPath$ + f$
            call SetCurrPath(CurrPath$)
         else
            call ListIt (disk$+":"+CurrPath$+f$)
         end if
      case delete.file
         kill (disk$+":"+CurrPath$+f$)
   end select

   action.flag = 0
loop while (1)

'****************************************************************

sub makewindow (winrec(1)) static
y1 = winrec(1):x1 = winrec(2):y2 = winrec(3):x2 = winrec(4)
fc = winrec(5):bc = winrec(6):bfc = winrec(7):bbc = winrec(8)
wid  =  x2-x1+1 : height = y2-y1+1

const vert = 186,upright = 187,lowright = 188
const lowleft = 200,upleft = 201,horiz = 205

color bfc,bbc
locate y1,x1:print chr$(upleft);string$(wid-2,horiz);chr$(upright);
for i = 2 to height-1
   locate y1+i-1,x1:print chr$(vert);
   locate y1+i-1,x2:print chr$(vert);
next i
locate y2,x1:print chr$(lowleft);string$(wid-2,horiz);chr$(lowright);

call clearwindow(winrec())
end sub

'****************************************************************

sub clearwindow (winrec(1)) static
y1 = winrec(1):x1 = winrec(2):y2 = winrec(3):x2 = winrec(4)
fc = winrec(5):bc = winrec(6):bfc = winrec(7):bbc = winrec(8)
wid  =  x2-x1+1 : height = y2-y1+1

color fc,bc
for i = 2 to height-1
   locate y1+i-1,x1+1:print string$(wid-2," ");
next i
end sub

'****************************************************************

sub savewindow (winrec(1)) static
y1 = winrec(1):x1 = winrec(2):y2 = winrec(3):x2 = winrec(4)
fc = winrec(5):bc = winrec(6):bfc = winrec(7):bbc = winrec(8)
wid = x2-x1+1 : height = y2-y1+1

for i = x1 to x2
   for j = y1 to y2
      ScreenData(j-y1,i-x1) = screen(j,i,1) * 256 + screen (j,i,0)
   next j
next i
end sub

'****************************************************************

sub restorewindow (winrec(1)) static
y1 = winrec(1):x1 = winrec(2):y2 = winrec(3):x2 = winrec(4)
fc = winrec(5):bc = winrec(6):bfc = winrec(7):bbc = winrec(8)

for j = y1 to y2
   locate j,x1
   for i = x1 to x2
      d = ScreenData(j-y1,i-x1)
      bc = (d\256)\8 : fc = (d\256) mod 8 : color fc,bc
      print chr$(d and &hff);
   next i
next j
end sub

'****************************************************************

sub PageAndSelect_
  (winrec(1),file$(1),action.flag,FileSelected$) static

'This routine does all the work here.  It assumes MakeWindow
'has been called before entering, and does all key processing and
'subsequent window updates.  action.flag is returned as the action
'for the main program to take (see the constants in the main program
'for a list of possible actions).

shared disk$,CurrPath$,count

'second codes from extended keys used in PageAndSelect
const up = 72, down = 80, left = 75, right = 77
const f1 = 59, AltD = 32, AltX = 45

y1 = winrec(1):x1 = winrec(2):y2 = winrec(3):x2 = winrec(4)
fc = winrec(5):bc = winrec(6):bfc = winrec(7):bbc = winrec(8)
wid = x2-x1+1 : height = y2-y1+1

locate y1,x1+1:color bfc,bbc:print " ";disk$;":";CurrPath$;" "
locate y2,x1+1
print "RET-Type file  AltD - delete file  F1 - chg disk  AltX - quit"
locate y1,x2-1-9:print count;"files"

NamesPerLine = (wid-2)\15 'how many filenames on each line in window
lines = height-2          'how many usable lines inside window
FilesPerWindow = lines * NamesPerLine

StartIndex = 0 'first file$() to be displayed in window
CurrIndex = 0  'current file$() being highlighted
NewIndex = 0   'updated file$() index after moving cursor

do
   call clearwindow(winrec())
   limit = fn.min (ubound(file$) - StartIndex, FilesPerWindow - 1)
   color fc,bc : locate y1+1
   for i = 0 to limit step NamesPerLine
      for j = 0 to NamesPerLine-1
         locate ,x1 + 1 + j*15
         if StartIndex + i + j <= ubound(file$) then
            print file$(StartIndex+i+j);
         else
            print space$(15);
         end if
      next j
   print
   next i

   'initialize highlight bar position
   BarRow = y1+1 : BarCol = x1 + 1

   do
      color fc,bc : locate BarRow,BarCol : print file$(CurrIndex);
      CurrIndex = NewIndex
      BarRow = (CurrIndex-StartIndex)\NamesPerLine + y1 + 1
      BarCol = (CurrIndex mod NamesPerLine)*15 + x1 + 1
      color bc,fc : locate BarRow,BarCol : print file$(CurrIndex);

      'wait for extended character (look for cursor keys) or RETURN
      GetKey:
         a$ = "" : while a$ = "" : a$ = inkey$ : wend
         if a$ = chr$(13) then
            action.flag = type.file
            FileSelected$ = file$(CurrIndex)
            exit do
         end if
      if len(a$)<>2 then goto GetKey

      redraw = 0  'flag to indicate when window must be redrawn
                  'and in which direction the cursor was moving
      select case asc(right$(a$,1))
         case up
            NewIndex = fn.max (0,CurrIndex-NamesPerLine)
            if NewIndex < StartIndex then redraw = -1
         case down
            NewIndex = fn.min (ubound(file$), CurrIndex+NamesPerLine)
            if NewIndex > StartIndex + FilesPerWindow - 1 _
             then redraw = 1
         case left
            NewIndex = fn.max (0,CurrIndex-1)
            if NewIndex < StartIndex then redraw = -1
         case right
            NewIndex = fn.min (ubound(file$), CurrIndex + 1)
            if NewIndex > StartIndex + FilesPerWindow - 1 _
             then redraw = 1

         case f1
            action.flag = disk.change : file.selected = -1 : exit do
         case AltX
            action.flag = quit : file.selected = -1 : exit do
         case AltD
            action.flag = delete.file
            FileSelected$ = file$(CurrIndex) : exit do
         case else
            sound 440,2:sound 220,2
      end select
   loop while redraw = 0

   if action.flag then exit do
   'otherwise, fall through and redo the entire "do" loop
   select case sgn(redraw)
      case -1
        StartIndex = fn.max (StartIndex - FilesPerWindow , 0)
      case 1
        StartIndex = fn.min (StartIndex + FilesPerWindow , _
                             ubound(file$))
   end select
   CurrIndex = StartIndex
loop while not action.flag

end sub

'****************************************************************

sub     GetCurrPath(disk$,CurrPath$) static
shared inary(),outary()

'first set up 64-byte work area for Int 21h Function 47h
' (get current directory)
CurrPath$ = space$(64) : pathptr = sadd(CurrPath$)

inary(dx)=asc(disk$)-65+1
inary(si)=pathptr 'pointer to area to fill
inary(ax)=&H4700  'function number
call int86(&H21,varptr(inary(0)),varptr(outary(0)))

'strip off trailing NUL, rest of blanks
CurrPath$=left$(CurrPath$,instr(CurrPath$,chr$(0))-1)
CurrPath$="\"+CurrPath$
if CurrPath$ <> "\" then CurrPath$=CurrPath$+"\"
end sub

'****************************************************************

sub GetCurrDisk(disk$) static
shared inary(),outary()
inary(ax) = &H1900
call int86(&H21,varptr(inary(0)),varptr(outary(0)))
disk$ = chr$(65 + (outary(ax) and 255))
end sub

'****************************************************************

sub SetCurrDisk(disk$) static
shared inary(),outary()

inary(ax) = &H0E00
inary(dx) = asc(disk$) - 65
call int86(&H21,varptr(inary(0)),varptr(outary(0)))

end sub

'****************************************************************

sub SetCurrPath(path$) static
shared inary(),outary()

newpath$=path$
if newpath$<>"\" then newpath$=left$(newpath$,len(newpath$)-1)
newpath$=newpath$+chr$(0)

inary(ax) = &H3B00
inary(dx) = sadd(newpath$)
call int86(&H21,varptr(inary(0)),varptr(outary(0)))

end sub

'****************************************************************

sub TypeIt (path$) static
   cls
   shell ("type "+path$+" | more")
   locate 25,1:print "Any key to continue...";
   a$=input$(1):cls
end sub

'****************************************************************

sub ListIt (path$) static
   shell ("list "+path$)
   cls
end sub