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Assembly Source File | 1987-05-05 | 11.5 KB | 518 lines

name whereis title 'WHEREIS -- find file' page 55,132 ; ; WHEREIS -- find file in directory structure ; by John Scotia, first published in Softalk/IBM ; modified by Ray Duncan ; lf equ 0ah ;ASCII line feed cr equ 0dh ;ASCII carriage return ff equ 0ch ;ASCII form feed tab equ 09h eom equ '$' ;end of message flag ; ;Program Segment Prefix default_fcb equ 05ch command equ 80h default_dta equ 080h ; ; ; This is the format for the DOS Data Transfer Area used when DOS 2.0 ; searches for a file match in directories. DTA STRUC RESERVED DB 21 DUP (?) ATTRIBUTE DB 0 TIME DW 0 DATE DW 0 SIZE DD 0 NAME_FOUND DB 13 DUP (?) DTA ENDS cseg segment para public 'CODE' assume cs:cseg,ds:data,es:data,ss:stack page ; This is the main program that sets up the initial conditions for ; SDIR which, in turn, does a recursive search. ; ; Reads: PATH_NAME ; Writes: FILE_NAME ; Calls: SDIR whereis proc far push ds ;save final return xor ax,ax push ax mov bp,sp ;save pointer to final return ; in case we want to exit ; inside recursive routine mov ax,data ;make data segment addressable mov es,ax ;via ES call infile ;get name of search target mov ax,data ;make data segment addressable mov ds,ax ;via DS jnc whereis1 ;jump if filename was ok ;filename was missing, mov dx,offset msg1 ;print error message and exit mov ah,9 int 21h ret whereis1: mov ah,30h ;check DOS version int 21h cmp al,2 jae whereis2 ;proceed, DOS 2.0 or greater mov dx,offset msg3 ;DOS 1.1 --- print message mov ah,9 ;and exit int 21h ret whereis2: MOV DI,OFFSET PATH_NAME XOR AL,AL ;Search for the zero at the end CLD ; of PATH_NAME MOV CX,64 ;Max. length of scan for 0 REPNZ SCASB MOV BX,DI DEC BX ;DS:BX points to end of PATH_NAME MOV DX,0 ;Tell SDIR this is first CALL SDIR ;Now do the recursive search mov ax,match_count ;were any matches found? or ax,ax jz whereis8 ;no,jump ret ;yes,just exit whereis8: mov dx,offset msg2 ;no,print "no match" mov ah,9 int 21h ret ;this is a special crash ;exit, which may be taken ;from inside recursed proc. whereis9: mov sp,bp ret whereis endp page ; This procedure searches all the files in the current directory ; looking for a match. It also prints the full name for each match. ; ; DS:BX Pointer to end of current path name ; DS:DX Old disk transfer area (DTA) ; ; Reads: Disk Transfer Area (DTA) ; Writes: Disk Transfer Area (DTA) ; Calls: BUILD_NAME, FMATCH, PNAME ; NMATCH, BUILD_STAR_NAME, SSUB SDIR PROC NEAR PUSH SI ;Need to restore on exit PUSH DX CALL BUILD_NAME ;Build the absolute search name CALL FMATCH ;See if there is a match here JC sdir2 ;No match, check subdirectories CALL PNAME ;Write name of match. sdir1: CALL NMATCH ;Find the next match JC sdir2 ;No match, search sub-directories CALL PNAME ;Match, write absolute name JMP sdir1 ;Look for the next matching name sdir2: ;No match, so try sub-directories. POP DX ;Restore DTA PUSH DX CALL BUILD_STAR_NAME ;Search for all directories CALL FMATCH ;Get first entry JC SDIR5 ;There are no entries MOV SI,DX ;Put address of DTA into SI TEST [SI].ATTRIBUTE,10H ;Is it a directory entry? JNZ SDIR4 ;Yes, then search sub-directory SDIR3: CALL NMATCH ;No, then find the next match JC SDIR5 ;There are no more entries TEST [SI].ATTRIBUTE,10H ;Is this a directory? JZ SDIR3 ;No, then try again SDIR4: CMP [SI].NAME_FOUND,'.' ;Is this a . or .. directory? JE SDIR3 ;Yes, skip to next directory CALL SSUB ;Search the sub-directory PUSH AX ;Now reset the DTA MOV AH,1AH INT 21H POP AX JMP SDIR3 SDIR5: POP DX POP SI RET SDIR ENDP page ; This procedure searches the subdirectory whos name is in the DTA ; ; DS:BX End of the current path name ; DS:[DX].NAME_FOUND Name of subdirectory for search ; Reads: PATH_NAME ; Writes: PATH_NAME ; Calls: SDIR SSUB PROC NEAR PUSH DI PUSH SI PUSH AX PUSH BX CLD ;Set for increment MOV SI,DX ;Put address of DTA into SI ADD SI,OFFSET NAME_FOUND ;Set to start of sub-directory name MOV DI,BX ;DS:DI -- 0 at end of path name ssub1: ;Copy sub-directory to path name LODSB ;Copy one character STOSB OR AL,AL ;Was it a 0? JNZ ssub1 ;No, keep copying MOV BX,DI ;Set BX to end of new path name STD ;Set flag for decrement STOSB ;Store a 0 at end of string MOV AL,'\' STOSB ;Place '\' at end of path name CALL SDIR ;Search this new path POP BX ;Restore the old end-of-path MOV BYTE PTR [BX],0 ;And store a zero here POP AX POP SI POP DI RET SSUB ENDP page ; This procedure prints the matched name after the path name ; ; DS:DX Pointer to current disk transfer area ; ; Reads: PATH_NAME, NAME_FOUND (in DTA) ; Calls: pasciiz, CRLF PNAME PROC NEAR PUSH AX PUSH DX MOV DX,OFFSET PATH_NAME MOV AL,[BX] ;Save character at end of path MOV BYTE PTR [BX],0 ;Set for end of string CALL pasciiz MOV [BX],AL ;Restore character POP DX ;Recover old pointer PUSH DX ADD DX,OFFSET NAME_FOUND CALL pasciiz cmp byte ptr switch,'g' ;global switch set? je pname2 ;yes,keep searching ;no, check if user wants ;to keep looking. push dx ;save current DTA mov dx,offset msg4 ;print 'More? ' mov ah,9 int 21h mov ah,7 ;read console without echo int 21h or al,20h ;fold to lower case cmp al,'y' ;must be y, anything else exits je pname1 jmp whereis9 ;take crash exit pname1: mov dl,al ;if Y,echo it mov ah,2 int 21h pop dx ;restore pointer to DTA pname2: CALL CRLF inc match_count ;count names displayed POP DX POP AX RET PNAME ENDP page ; This procedure builds an absolute search name from PATH_NAME ; followed by FILE_NAME. ; ; Reads: FILE_NAME ; Calls: BUILD to build the name BUILD_NAME PROC NEAR PUSH SI MOV SI,OFFSET FILE_NAME CALL BUILD POP SI RET BUILD_NAME ENDP BUILD_STAR_NAME PROC NEAR PUSH SI MOV SI,OFFSET STAR_NAME CALL BUILD POP SI RET BUILD_STAR_NAME ENDP ; This procedure appends the string at DS:SI to PATH_NAME in ; PATH_NAME. It knows where the path name ends from knowing how ; long PATH_NAME is. ; ; DS:SI Name of file ; DS:BX End of PATH_NAME ; ; Reads: DS:SI ; Writes: PATH_NAME BUILD PROC NEAR PUSH AX PUSH DI MOV DI,BX CLD ;Set direction for increment build1: LODSB ;Copy one character of name STOSB OR AL,AL ;End of string yet? JNZ build1 ;No, keep copying POP DI POP AX RET BUILD ENDP page ; This procedure finds the first match between the name given by ; DS:DX and the directory entries found in the directory PATH_NAME. ; ; DS:DX Pointer to current disk transfer area ; Returns: ; CF 0 A match was found ; 1 No match found ; AX Error code returned: ; 2 File not found ; 18 No more files ; DS:DX Pointer to new disk transfer area ; ; Reads: PATH_NAME ; Writes: dbuff FMATCH PROC NEAR PUSH CX CMP DX,0 ;First one? JA ALLOCATE ;No, then allocate space MOV DX,OFFSET dbuff-TYPE DTA allocate: add dx,type dta ;no, then allocate room for new DTA MOV CX,10H ;Search attribute for files and dirs. MOV AH,1AH ;Set disk transfer address INT 21H PUSH DX ;Need DX for address of search name MOV DX,OFFSET PATH_NAME MOV AH,4EH ;Call for "find first match" INT 21H POP DX POP CX RET ;Return with carry flag info FMATCH ENDP page ; Get next match for filename ; (very similar to Get first match routine) ; Returns: ; CF 0 A match was found ; 1 No match found ; AX Error code returned: ; 2 File not found ; 18 No more files ; ; Reads: PATH_NAME ; Writes: dbuff NMATCH PROC NEAR PUSH CX PUSH DX MOV DX,OFFSET PATH_NAME MOV CX,10H ;Attribute for files and directories MOV AH,4FH ;Call for "Find next match" INT 21H POP DX POP CX RET ;Return with carry flag intact NMATCH ENDP page ; Send CRLF sequence to the screen. CRLF PROC NEAR PUSH AX PUSH DX MOV AH,02 MOV DL,0AH INT 21H MOV DL,0DH INT 21H POP DX POP AX RET CRLF ENDP page ; Display ASCIIZ string ; Call with DS:DX = string addr pasciiz PROC NEAR PUSH AX PUSH DX PUSH SI CLD ;Set direction for increment MOV SI,DX ;Set up pointer to string MOV AH,2 pasciiz1: LODSB ;Get character or al,al ;if zero,all done jz pasciiz2 MOV DL,AL INT 21H ;Write one character jmp pasciiz1 ;loop till string exhausted pasciiz2: POP SI POP DX POP AX RET pasciiz ENDP page infile proc near ;process name of input file ;DS:SI <- addr command line mov si,offset command ;ES:DI <- addr filespec buffer mov di,offset file_name cld lodsb ;any command line present? or al,al ;return error status if not. jz infile4 infile1: ;scan over leading blanks lodsb ;to file name cmp al,cr ;if we hit carriage return jz infile4 ;filename is missing. cmp al,20h ;is this a blank? jz infile1 ;if so keep scanning. xor ah,ah ;reset "." found flag ;found first char of name infile2: cmp al,'\' ;if slash,reset "." flag jne infile22 xor ah,ah infile22: ;check if extension specified cmp al,'.' jne infile24 inc ah infile24: ; stosb ;move last char. to output ;file name buffer. lodsb ;check next character, found cmp al,cr ;carriage return yet? je infile3 ;yes,exit with success code cmp al,'/' ;or if we hit a switch delimiter jne infile26 infile25: lodsb ;get the switch char and save it or al,20h ;force to lower case mov byte ptr es:switch,al jmp infile3 ;then jump to finish up infile26: cmp al,20h ;is this a blank? jne infile2 ;if not keep moving chars. infile27: lodsb ;search up to end, in case of switch cmp al,'/' je infile25 ;found switch,go save it cmp al,cr jne infile27 ;otherwise, fscan until CR found infile3: ;found end of input name or ah,ah ;was "." found? jnz infile35 ;yes,jump mov al,'.' ;no,force ext to wildcard stosb mov al,'*' stosb infile35: xor al,al ;store trailing null byte stosb ;exit with CY=0 as success flag clc ret infile4: ;exit with carry =1 stc ;for error flag ret infile endp cseg ends page data segment para public 'DATA' STAR_NAME DB '*.*',0 PATH_NAME DB '\',0 DB 80 DUP (0) ;Space for 64 character path name ; and 13 character file name FILE_NAME DB 13 DUP (0) ;Save room for full DOS file name msg1 db cr,lf db 'Missing file name.' db cr,lf,eom msg2 db cr,lf db 'No match found.' db cr,lf,eom msg3 db cr,lf db 'Requires DOS version 2.0 or greater.' db cr,lf,eom msg4 db tab,' More (y/n) ? ',eom match_count dw 0 ;number of filenames matching ;input filespec switch db 0 ;char following / saved here dbuff equ $ ;this starts the scratch area ;which will be used as search ;buffers. It is right under ;the stack, which is made very ;large to give it room. data ends stack segment para stack 'STACK' db 32768 dup (?) stack ends end whereis