World of Shareware - Software Farm 2/wosw_2.zip/wosw_2/CPROG/CMDSRC.ZIP/UTL.ASM

Assembly Source File | 1990-04-29 | 15KB | 686 lines

; 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
    cmp    al,'0'
    jc    @isalphnum_99        ;Not alphanumeric
    cmp    al,'9'+1
    cmc
    jnc    @isalphnum_99        ;Number
    cmp    al,'A'
    jc    @isalphnum_99        ;Not alphanumeric
    cmp    al,'Z'+1
    cmc
    jnc    @isalphnum_99        ;Uppercase letter
    cmp    al,'a'
    jc    @isalphnum_99        ;Not alphanumeric
    cmp    al,'z'+1
    cmc
@isalphnum_99:
    ret
isalphnum endp



;+
; FUNCTION : iscntrl
;
;    Check if control character and DEL (00h-1Fh and 0FFh).
;
; Parameters:
;    AL    = character to be checked
;
; Returns:
;    CF    = 0 if AL is a control character or DEL
;          1 not a control char or DEL
; Register(s) destroyed:
;-
iscntrl    proc    near
    cmp    al,DEL
    jne    @iscntrl_99
    cmp    al,' '
    cmc
@iscntrl_99:
    ret
iscntrl    endp



;+
; FUNCTION : isspace
;
;    Check if a character is a SPACE or a TAB
;
; Parameters:
;    AL    = character to check
;
; Returns:
;    ZF    = 1 if AL is a space or a tab
;          0 otherwise
; Register(s) destroyed:
;
;-
isspace    proc    near
    cmp    al,TAB
    je    @isspace_99
    cmp    al,SPACE
@isspace_99:
    ret
isspace    endp



;+
; FUNCTION : isdelim
;
;    Check if a character is an MSDOS delimiter.
;
; Parameters:
;    AL    = character to check
;
; Returns:
;    ZF    = 1 if AL is a delimiter
;          0 otherwise
; Register(s) destroyed:
;
;-
isdelim    proc    near
    call    near ptr isspace    ;Check if space or tab
    je    @isdelim_99        ;Yes, go return
    cmp    al,'/'
    je    @isdelim_99        ;Yes, go return
    cmp    al,'|'
    je    @isdelim_99        ;Yes, go return
    cmp    al,'<'
    je    @isdelim_99        ;Yes, go return
    cmp    al,'>'
@isdelim_99:
    ret
isdelim    endp



;+
; FUNCTION : skip_whitespace
;
;    Searches for the next non-whitespace character in a given string.
;
; Parameters:
;    SI    -> pointer to string
;    CX    == num chars in the string
;
; Returns:
;    CF    = 1 if end-of string reached else 0
;    SI    ->next non-whitespace character or end-of-string
;    CX    <-num remaining characters including one pointed to by SI
;
; Register(s) destroyed:
;    AX
;-
skip_whitespace proc near
    jcxz    @skip_whitespace_98        ;Empty string
@skip_whitespace_10:
    lodsb                    ;AL<-next char
    call    near ptr isspace        ;Whitespace character ?
    loope    @skip_whitespace_10        ;Repeat until
;                         non-whitespace or string ends
    je    @skip_whitespace_98        ;End-of-string
; Non-whitespace char found
    dec    si                ;SI->non-whitespace char
    inc    cx                ;CX<-remaining number of bytes
    clc                    ;CF<-0 (char found)
    jmp    short @skip_whitespace_99

@skip_whitespace_98:
; End of string reached.
    stc                    ;Set CF

@skip_whitespace_99:
    ret
skip_whitespace endp




;+ FUNCTION : skip_nonwhite, skip_nondelim
;
;    Searches for the next whitespace character / delimiter in a given
;    string.
;
; Parameters:
;    SI    -> pointer to string
;    CX    == num chars in the string
;
; Returns:
;    CF    = 1 if end-of string reached else 0
;    SI    ->next whitespace character or end-of-string
;    CX    <-num remaining characters including one pointed to by SI
;
; Register(s) destroyed:
;    AX
;-
skip_non proc near
skip_nonwhite LABEL near
    push    dx
    mov    dx,offset DGROUP:isspace
    jmp    short @skip_non

skip_nondelim LABEL near
    push    dx
    mov    dx,offset DGROUP:isdelim
@skip_non:
    jcxz    @skip_non_98            ;Empty string
@skip_non_10:
    lodsb                    ;AL<-next char
    call    dx                ;nonwhite / delimiter
;                         character ?
    loopne    @skip_non_10            ;Repeat until
;                         whitespace or string ends
    jne    @skip_non_98            ;End-of-string
; whitespace char found
    dec    si                ;SI->whitespace char
    inc    cx                ;CX<-remaining number of bytes
    clc                    ;CF<-0 (char found)
    jmp    short @skip_non_99

@skip_non_98:
; End of string reached.
    stc                    ;Set CF

@skip_non_99:
    pop    dx
    ret
skip_non endp






;+
; FUNCTION : push_word
;
;    Looks for the next word (delimited by whitespace) and pushes it
;    onto the specified string stack.
;
; Parameters:
;    BX    -> strstack descriptor
;    SI    -> string
;    CX    == length of string (< 256)
;
; Returns:
;    AX    <- 0 if no errors
;          -1 if no room in stack
;          +1 if no word in string
;    SI    -> char after first word (or end-of-string)
;    CX    <- num remaining characters
;
; Register(s) destroyed:
;    DX
;-
push_word proc    near
; Skip forward to first word
    call    near ptr skip_whitespace    ;Returns
;                         SI->start of word
;                         CX<-remaining chars
    jcxz    @push_word_98            ;No words in line
    mov    dx,si                ;DX->start of word
    push    cx                ;Save count
    call    near ptr skip_nonwhite        ;Find end of word
;                         SI->beyond word
;                         CX<-remaining chars
    pop    ax
    sub    ax,cx                ;AX<-length of word
    push    cx                ;Save remaining char count
    xor    cx,cx                ;CX<-0 (don't force push)
    call    near ptr strstk_push        ;Store macro name into
;                         macro stack. Params
;                         AX,BX,CX,DX
;                         Returns Cf = 0 or 1
    pop    cx                ;CX<-remaining character
;    Assume no error
    mov    ax,0    ;DON'T DO xor ax,ax SINCE CF to be preserved
    jnc    @push_word_99            ;Jump if no error
    dec    ax                ;Error AX <- -1
    jmp    short @push_word_99        ;Exit

@push_word_98:
; No words found in line. Set return codes.
    mov    ax,1                ;Code for blank line

@push_word_99:
    ret
push_word    endp





;+
; FUNCTION : push_string
;
;    Pushed the specified string onto the specified stack.
;
; Parameters:
;    BX    -> strstack descriptor
;    SI    -> string
;    CX    == length of string must be < 256
;
; Returns:
;    CF    <- 0 if no errors
;           1 if no room in stack
;
; Register(s) destroyed:
;    AX,CX,DX
;-
push_string proc    near
    mov    dx,si                ;DX->start of string
    mov    ax,cx                ;AX<-length of string
    xor    cx,cx                ;CX<-0 (don't force push)
    call    near ptr strstk_push        ;Store macro name into
;                         macro stack. Params
;                         AX,BX,CX,DX
;                         Returns Cf = 0 or 1
    ret
push_string    endp



;+
; FUNCTION : bell
;
;    Called to ring the bell.
;
; Parameters:
;    None.
;
; Returns:
;    Nothing.
; Register(s) destroyed:
;    AX
;-
bell    proc    near
    cmp    silent,1
    je    @bell_99
    @DispCh    BEL
@bell_99:
    ret
bell    endp


;+
; FUNCTION : output_counted_string
;
; Parameters :
;    CX - Number of bytes to display
;    DX - address of string
; Registers destroyed:
;    AX,BX,CX,DX
output_counted_string proc near
    mov    ah,40h
    mov    bx,1                ;stdout handle
    int    21h                ;Params ax,bx,cx,dx
    ret
output_counted_string endp

;+
; FUNCTION: output_newline
;
; Registers destroyed:
;    AX,BX,CX,DX
;-
output_newline proc near
    @DispCh    CR
    @DispCh    LF
    ret
output_newline endp






CSEG    ENDS

    END