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Assembly Source File | 1986-05-27 | 14.4 KB | 444 lines

;=================================================== ; PROGRAM DUP Version 1.0 by Dave Whitman ; ; Filter to remove adjacent duplicate lines. ; Reads StdIn and writes non-duplicated lines to StdOut. ; Duplicate lines must be adjacent to be detected. ; ; Syntax: DUP [?] [/nn] [<infile] [>outfile] ; ; The ? option prints a help message. ; If option /nn is used, comparision is based on ; the first nn characters only. ; ; Requires DOS 2.0, will abort under earlier versions. ;==================================================== ;============ ; Equates ;============ @read equ 3FH ;read file/device @write equ 40H ;write file/device @dosver equ 30H ;get dos version @prnstr equ 09H ;print string cr equ 0DH ;carriage return character lf equ 0AH ;line feed character stdin equ 0000H ;standard input stdout equ 0001H ;standard output u equ 01H ;upper case option selected buf_size equ 8192 ;size of input and output buffers param_count equ [80H] param_area equ [81H] mem_avail equ [06H] ;PSP field: memory available in segment up_mask equ 11011111B ;mask for lowercase conversion (with AND) low_mask equ 00100000B ;mask for uppercase conversion (with OR) main proc far call setup ;check dos, parse options call process ;count w, l, c from std i/o int 20H ;and return to dos endp ;====================================== ; SUBROUTINE SETUP ; Checks for proper DOS, parses options ;====================================== setup proc near mov ah, @dosver ;what dos are we under? int 21H cmp al, 2 ;2.0 or over? jae a_mem ;yes, skip mov ah, @write ;no, bitch mov bx, 2 ;on stderror mov cx, dosend-baddos mov dx, offset(baddos) int 21H pop ax ;reset stack int 20H ;and exit a_mem mov ax, mem_avail ;do we have room for the buffers? cmp ax, (buf_size*2)+200H jae a_help ;yes mov ah, @write ;no, bitch mov bx, 2 ;on stderror mov cx, memend-nomem mov dx, offset(nomem) int 21H pop ax ;reset stack int 20H ;and exit a_help xor ch,ch ;cx <== param count mov cl, param_count ; " cmp cl, 00H ;any params? je aexit ;return if none mov di, offset(param_area) ;scan for help request mov al, '?' repnz ;repeat until matched or end scasb jnz a_par ;reached end, no match? skip mov ah, @write ;founc ?, so print help mov bx, 2 ;on stderror mov cx, helpend-help mov dx, offset(help) int 21H pop ax ;pop stack int 20H ;and exit a_par xor ch, ch ;cx <== param count mov cl, param_count ; " mov di, offset(param_area) ;scan for options a_loop mov al, '/' ;will be marked with / repnz ;repeat until matched or end scasb jnz aexit ;reached end, no match? skip xor ax,ax ;will hold building number jmps enter ;convert string to binary s2bin mov bl, 10 ;multiply running total by 10 mul al,bl jo bad_num ;overflow? error exit enter xor bx,bx ;clear out top half mov bl, [di] ;get a digit into al inc di ;bump pointer cmp bl, ' ' ;if space, done je aexit cmp bl, '0' ;must be between 0 jb bad_num cmp bl, '9' ;and 9 ja bad_num sub bl, '0' ;convert to binary add ax, bx ;add to running total jo bad_num ;overflow? error exit loop s2bin cmp ax, 0FFH ;too long? jg bad_num ;abort mov comp_length, al ;else store converted number aexit ret ;normal return bad_num mov ah, @write ;print error message mov bx, 2 ;on stderror mov cx, numend-nummsg mov dx, offset(nummsg) int 21H ;and use default ret baddos db cr lf 'This program requires DOS 2.0!' cr, lf dosend nomem db cr lf 'Insufficient memory, program aborted' cr lf memend nummsg db cr lf 'Length parameter non-numeric or greater than 255' db cr lf numend help db cr lf db 'DUP version 1.0 by D. Whitman' cr lf db cr lf db 'Reads stdin and writes all non-duplicated lines to stdout.' db cr lf db 'Duplicates must be adjacent to be detected.' cr lf db 'DUP will normally be used in a pipeline, following SORT.' db cr lf cr lf db 'Syntax: DUP [?] [/nn] [<infile] [>outfile]' cr lf db cr lf db 'Options:' cr lf db ' ? = print this help message' cr lf db ' /nn = base comparision on first nn chars only' cr lf db cr lf db 'This program is in the public domain.' cr lf db cr lf helpend endp ;========================================= ; SUBROUTINE PROCESS ; ; while not(EOF) do ; begin ; get next line ; if curr_line <> last_line ; then begin ; write(curr_line) ; last_line := curr_line ; end ; end ;========================================== ;================== ; Register assignments: ; ; SI ^buf_in ; DI ^buf_out ; CX # of chars left in buf_in ;=================== process proc near movw outnum, 0000H ;output buffer is empty mov si, offset(buf_in) mov di, offset(buf_out) call fillbuf ;get 1st buffer's worth cmp cx, 0000H ;any chars? je p_done ;if not, quit call read_line ;read 1st line call save_line ;save as "old_line" call put_line ;and output it ;=========== ; Main loop ;=========== p_loop call read_line ;get next line jc p_done ;none available? done call compare ;is it unique? jc p_loop ;if not, bit bucket, and try again call put_line ;if so, output it call save_line ;and save as new template jmps p_loop ;and continue til EOF p_done call dumpbuf ;flush output buffer ret endp ;======================================================= ; SUBROUTINE READLINE ; ; Reads the next line from the input buffer into string ; CURR_LINE. If sucessful, clears the carry flag. ; If not sucessful, sets the carry flag ;======================================================= read_line proc near push bx push dx xor dx, dx mov bx, offset(curr_line) call getchar jc r_fail r_loop mov [bx], al ;put char in string inc bx ;bump string pointer inc dl ;bump char count cmp al, lf ;newline? je r_exit ;done if so cmp dl, 0FFH ;string too long? je r_exit ;abort if so call getchar ;get next character jc r_exit ;none available? exit jmps r_loop ;otherwise continue r_exit mov [offset(curr_length)], dl ;save length pop dx pop bx clc ret r_fail pop dx pop bx stc ret endp ;================================== ; SUBROUTINE SAVE_LINE ; ; Copies CURR_LINE into LAST_LINE. ;================================== save_line proc near push si push di push cx mov si, offset(curr_line) mov di, offset(last_line) xor cx, cx mov cl, [offset(curr_length)] mov [offset(last_length)], cl cld ;autoincrement mode rep movsb pop cx pop di pop si ret endp ;================================================== ; SUBROUTINE COMPARE ; ; Compares CURR_LINE and LAST_LINE. If identical, ; sets carry flag, otherwise carry is cleared. ;================================================== compare proc near push si push di push cx xor cx, cx mov cl, [offset(curr_length)] ;set comparison length cmp cl, comp_length ja c_trunc ;longer than compare length? truncate jmps c_doit c_trunc mov cl, comp_length c_doit mov di, offset(curr_line) mov si, offset(last_line) repe ;repeat until different or end cmpsb je c_match ;matched clc ;not identical jmps c_exit c_match stc c_exit pop cx pop di pop si ret endp ;================================================ ; SUBROUTINE PUT_LINE ; ; Moves the current line into the output buffer. ;================================================ put_line proc near push bx push dx mov bx, offset(curr_line) xor dx, dx mov dl, [offset(curr_length)] cmp dl, 0 je pl_done pl_loop mov al, [bx] ;get char call putchar ;output it inc bx ;bump string pointer dec dl ;used one char jnz pl_loop ;loop til done pl_done pop dx pop bx ret endp ;====================================================== ; SUBROUTINE GETCHAR ; ; Trys to get a character from the input buffer. ; If sucessful, returns with character in AL, and carry ; flag clear. If unsucessful, sets carry flag. ;====================================================== getchar proc near cmp cx, 0000 ;is the buffer empty? jne g1 ;nope, skip call fillbuf ;if so, try to refill it cmp cx, 0000 ;still empty? je g_abort ;then return failure g1 lodsb ;get character from [si] dec cx ;used up one char clc ;clear flag to indicate sucess ret ;and return g_abort stc ;set flag for failure ret endp ;====================================================== ; SUBROUTINE FILLBUF ; ; Fills the input buffer from StdIn. The number of ; available characters is stored in CX, and SI is reset ; to the beginning of the buffer. ;====================================================== fillbuf proc near push bx push dx mov ah, @read ;read mov bx, stdin ;from stdin mov cx, buf_size ;one buffer's worth mov dx, offset(buf_in) ;into the input buffer int 21H mov cx, ax ;save number of chars read mov si, offset(buf_in) ;reset buffer pop dx pop bx ret endp ;=================================================== ; SUBROUTINE PUTCHAR ; ; Moves the character in AL into the output buffer. ; If the buffer is now full, it is dumped to disk. ;=================================================== putchar proc near stosb ;move character into buffer incw outnum ;bump count of chars in buffer cmpw outnum, buf_size ;is buffer full? jl pu_exit ;no, skip call dumpbuf ;yes, dump buffer to disk pu_exit ret endp ;================================================== ; SUBROUTINE DUMPBUF ; ; Dumps the output buffer to StdOut. ;================================================== dumpbuf proc near push ax ;save active registers push bx ; " " " push cx ; " " " push dx ; " " " mov ah, @write ;write mov bx, stdout ;to stdout mov cx, outnum ;number of chars for output mov dx, offset(buf_out) ;from output buffer int 21H movw outnum, 0 ;reset buffer mov di, offset(buf_out) ; " " pop dx ;restore active registers pop cx ; " " " pop bx ; " " " pop ax ; " " " ret endp ;===================================================== ;BUFFERS ; ; No space is actually allocated for the buffers. ; At run time, the program checks to ensure there ; is suffcient free memory, then uses the memory ; immediately after itself for buffers. ; ; This stratagy minimizes the size of the object file, ; and lets the program load quicker. ;====================================================== outnum dw 0000H comp_length db 0FFH last_length org offset($+1) last_line org offset($+0FFH) curr_length org offset($+1) curr_line org offset($+0FFH) buf_in org offset($+buf_size) buf_out