utl.asm

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; UTL.ASM
; (c) 1989, 1990 Ashok P. Nadkarni
;
; General utility functions for CMDEDIT. SMALL model only. Also assume 
; ES == DS. 
;

	INCLUDE common.inc
	INCLUDE	general.inc
	INCLUDE	ascii.inc
	INCLUDE dos.inc
	INCLUDE buffers.inc

	PUBLIC	stre_cmp
	PUBLIC	tolower
	PUBLIC	xlate_lower
	PUBLIC	getargs
	PUBLIC	isalphnum
	PUBLIC	iscntrl
	PUBLIC	isspace
	PUBLIC	isdelim
	PUBLIC	bell
	PUBLIC	push_string
	PUBLIC	push_word
	PUBLIC	skip_nonwhite
	PUBLIC	skip_whitespace
	PUBLIC	skip_nondelim
	PUBLIC	output_newline
	PUBLIC	output_counted_string
	
	EXTRN	silent:BYTE
	EXTRN	lastchar:WORD
	EXTRN	linebuf:BYTE


CSEG	SEGMENT	PARA PUBLIC 'CODE'

DGROUP	GROUP	CSEG

	ASSUME	CS:DGROUP,DS:DGROUP,ES:DGROUP,SS:DGROUP

;+
; FUNCTION : stre_cmp
;
;	Does a case-insensitve comparison of two strings of equal length.
;
; Parameters:
;	DS:SI :=	Address of string 1.
;	ES:DI :=	Address of string 2.
;	CX    :=	Length.
;
; Returns:
;	If string 1 = string 2, ZF = 1, CF = 0.
;	If string 1 < string 2, ZF = 0, CF = 1.
;	If string 1 > string 2, ZF = 0, CF = 0.
; Registers AX,CX destroyed.
;-
stre_cmp proc near
	@save	si,di,dx
	dec	si		;Prime for loop
	dec	di
	xor	ax,ax		;Clear flags
	jcxz	@stre_cmp_99
@stre_cmp_10:
	cmpsb			;Point SI,DI to next byte
	mov	al,[si]		;String 1 byte
	call	near ptr tolower ;al := Uppercase version
	xchg	al,dl		;Save it.
	mov	al,ES:[di]	;Ditto for string 2
	call	near ptr tolower ;al := Uppercase version
	cmp	dl,al		;Compare string 1 with string 2
@stre_cmp_20:
	loope	@stre_cmp_10	;Keep looping as long as equal
@stre_cmp_99:
	@restore
	ret
stre_cmp endp


;+
; FUNCTION : tolower
;
;	Converts the character in AL to lower case if it is a upper case
;	character, else leaves it unchanged.
;
; Parameters:
;	Al :=	character
;
; Returns:
;	AL :=	lowercase version or unchanged
;-
tolower	proc near
	cmp	al,'A'
	jb	@tolower_99
	cmp	al,'Z'
	ja	@tolower_99
	add	al,20h
@tolower_99:
	ret
tolower	endp



;+
; FUNCTION : xlate_lower
;
;	Converts the passed string to lower case.
;
; Parameters:
;	AX :=	length of string
;	SI :=	address of string
;
; Returns:
;	Nothing.
;
; Registers destroyed:
;	AX,CX
;-
xlate_lower proc near
	@save	si,di
	mov	di,si
	mov	cx,ax
	jcxz	@xlate_lower_99

@xlate_lower_10:
	lodsb
	call	near ptr tolower
	stosb
	loop	@xlate_lower_10
	
@xlate_lower_99:
	@restore
	ret
xlate_lower endp



;+ FUNCTION : getargs
;
;	getargs does one of two functions depending on the value in AX.
;	If AX = 0, returns count of arguments in the line,
;	else if AX = n, returns the nth argument.
;
;	The argument separators are tab and space. Note that a
;	carraige return (0Dh) terminates a line even if the byte
;	count indicates otherwise.  Arguments containing a SPACE or
;	TAB separator may be specified by enclosing them in a pair of
;	quotes ("). The quotes do NOT act as argument delimiters. For
;	example the following line
;		this"is a single "arg
;	contains exactly one argument. An unmatched quote causes the
;	remaining characters in the line to be treated as a single
;	argument. A quote character can be included as part of an
;	argument by preceding it with a ESCARG character. An ESCARG preceding
;	any other character does not have any special meaning.
;	  Note that all other characters including the NUL char (00h)
;	have no special significance.
;
; Parameters:
;	DS:SI points to the line
;	AX = argument number n
;	CX = Length of line
;	If parameter n != 0,
;	then BX = address of user buffer where the returned argument is to
;		be stored. This param need not be present if n is 0.
;	     DX = length of user buffer.
;
;
; Returns:
;	If parameter n was 0,
;		return argument count in AX (CF is undefined),
;	else
;		Store n'th argument in the buffer pointed to by BX and
;		return the number of chars in the argument in AX.
;		The returned argument has quotes and ESCARGes stripped
;		out where appropriate. If the buffer is too small, CF
;		is set to 1, else it is 0. In this case the user buffer
;		contents are undefined.
;	BX is explicitly unchanged.
;
; Registers CX,DX are destroyed.
;-
getargs	proc	near
ESCARG	EQU	PERCENT
	@save	si,di
	push	bp
	mov	bp,sp
	sub	sp,2
userbuf_len EQU <word ptr [bp-2]>
	mov	di,ax		;save argument number

	xor	ax,ax		;al will hold char, ah will hold state
	mov	userbuf_len,dx	;Save size of user buffer
	xor	dx,dx		;dx counts arguments
				;CX = line length
	or	cx,cx		;Check if CX is 0 (jump too far for jcxz)
	jne	@getargs_2
	jmp	@getargs_99	;0 length, jump around ajnup
@getargs_2:
;	At the start of this loop, the following hold :
;	(1) CX >= 1. CX holds count of remaining characters.
;	(2) ah holds the current "state" with the following encoding -
;		When Bit 1 is 0, bit 0=0 indicates we're outside an argument
;		and bit0=1 indicates we are inside an arg.
;		When Bit 1 is 1, we are inside a quoted argument. In this
;		case, bit 0 "remembers" the state we were in before the
;		quotes so that it can be restored upon reaching the closing
;		quotes.
;		Bit 2 remembers if prev char was a ESCARG (=1) or not (=0)
;		Bit 3 = 1 indicates this argument is to be copied into the
;			  user buffer

in_arg		equ	01h
in_quote 	equ	02h
saw_ESCARG	equ	04h
	lodsb				;Get next char
	cmp	al,CR			;If carraige-return
	je	@getargs_50		;  then terminate processing.
	call	near ptr isspace	;Check if space or tab
	jne	@getargs_10		;No, jump
;	Process separator
	and	ah,NOT saw_ESCARG ;Remember char is not a ESCARG
	test	ah,in_quote	;Are we inside quotes ?
	jnz	@getargs_49		;If so go onto next char
	and	ah,NOT in_arg	;else reset the inside arg flag
	jmp	short @getargs_49	;and go onto next char


@getargs_10:			;Not a separator
	test	ah,in_arg OR in_quote ;Were we inside an arg or quoted arg ?
	jnz	@getargs_11		;Yes, then skip the increment
				;else entering an arg, so
	inc	dx		;	increment arg count
	or	di,di		;	If function is return arg count
	je	@getargs_11		;	then go on
	cmp	di,dx		;	else check if this is the arg we want
	jne	@getargs_11		;	Nope, keep on
				;	Yep, this be the one
	mov	di,bx		;di = destination buf, ES assumed = DS
	xor	dx,dx		;Zero the character count
	jmp	short @getargs_80	;Go to the copy loop
@getargs_11:
	cmp	al,QUOTE	;Is this a quote ?
	jne	@getargs_15		;No, normal processing
	test	ah,saw_ESCARG	;Found quote, was prev char a ESCARG ?
	jnz	@getargs_15		;Yes, normal processing
	xor	ah,in_quote	;else toggle the quote flag
	jmp	short @getargs_49	;go onto next char
@getargs_15:			;Normal processing
	and	ah,NOT saw_ESCARG ;assume char is not a ESCARG
	cmp	al,ESCARG	;Is this a ESCARG ?
	jnz	@getargs_20		;No
	or	ah,saw_ESCARG	;Set ESCARG flag
@getargs_20:
	test	ah,in_quote	;Are we inside quotes ?
	jnz	@getargs_49		;If so go onto next char
	or	ah,in_arg	;else set the inside arg flag

@getargs_49:
	loop	@getargs_2		;Go onto next char if any

@getargs_50:			;Finished with the line
	or	di,di		;Were we supposed to return an argument ?
	je	@getargs_99		;No, so go on
	xor	dx,dx		;Yes, but arg num was > number of args
				; so return a 0 count
	jmp	short @getargs_99	;Skip over copy arg section



;Copy argument loop begins.

@getargs_70:
	lodsb				;Get next char
	cmp	al,CR			;If carraige-return
	je	@getargs_99		;  then terminate processing.

	call	near ptr isspace	;Check if space or tab
	jne	@getargs_80		;No, jump

;	Process separator
	test	ah,in_quote	;Are we inside quotes ?
	jz	@getargs_99		;No, terminate processing
	jmp	short @getargs_85	;Treat like any other char

@getargs_80:			;Not a separator
	;At this point CX = num of bytes remaining in the line including the
	;one in AL.

	cmp	al,QUOTE	;Is this a quote ?
	jne	@getargs_85		;No, normal processing
	test	ah,saw_ESCARG	;Found quote, was prev char a ESCARG ?
	jnz	@getargs_84		;Yes, jump
	xor	ah,in_quote	;else toggle the quote flag
	jmp	short @getargs_89	;go onto next char

@getargs_84:			;Found a \" combination
	dec	di		;Previous \ shouldn't have been written
	dec	dx		;or counted.
				;fall thru for normal processing

@getargs_85:			;Normal processing
	sub	userbuf_len,1	;Decrement space remaining in buffer. Do
;				 NOT use DEC here since CF needs to be set
	jb	@getargs_100	;No more space, exit with CF set
	stosb			;Store the char
	inc	dx		;and incr count

	and	ah,NOT saw_ESCARG ;assume char is not a ESCARG
	cmp	al,ESCARG	;Is this a ESCARG ?
	jnz	@getargs_89	;No
	or	ah,saw_ESCARG	;Set ESCARG flag

@getargs_89:
	loop	@getargs_70	;Go onto next char if any

@getargs_99:
	xchg	ax,dx		;AX<-arg count or num chars in returned arg
	clc			;Clear CF for no error
@getargs_100:
	mov	sp,bp
	pop	bp
	@restore
	ret
getargs	endp




;+
; FUNCTION : isalphnum
;
;	Test if the character is alphanumeric.
;
; Parameters:
;	AL	= character
;
; Returns:
;	CF	= 0 if alphanumeric
;		  1 if not
; Register(s) destroyed:
;-
isalphnum proc near