ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/UTILITY/KEYBOARD/CMDED2E5.ZIP/DIRS.ASM

Assembly Source File | 1990-04-29 | 11.3 KB | 485 lines

; DIRS.ASM
; (c) 1989, 1990 Ashok P. Nadkarni
;
;This module implements the directory stack feature of the cmdedit program.

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

    PUBLIC    dirs_init
    PUBLIC    execute_popd
    PUBLIC    execute_pushd
    PUBLIC    execute_chd
    PUBLIC    execute_rstdir
    PUBLIC    enable_dircmds

PATHBUF_SIZE EQU 68

CSEG    SEGMENT    PARA PUBLIC 'CODE'

    EXTRN    user_command:BYTE
    EXTRN    in_appl:BYTE
    EXTRN    linebuf:BYTE        ;line buffer
    EXTRN    lastchar:WORD
    EXTRN    dirstk_error:BYTE
    EXTRN    resident:BYTE
    EXTRN    abort_install:PROC
    EXTRN    abort_processing:PROC
    EXTRN    skip_whitespace:PROC
    EXTRN    skip_nonwhite:PROC
    EXTRN    tolower:PROC

dir_stk    $string_stack   <>        ;Buffer descriptors
enable_dircmds    db    1        ;If 1, enables directory commands
;                     even if caller is not DOS

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


;+
; FUNCTION : dirs_init
;
; Initializes the various data structures associated with the
; directory stack buffer. CALLER MUST ENSURE PASSED ADDRESSES ARE VALID
; AND BUFFER IS LARGE ENOUGH.
;
; Parameters:
;    AX     - length of buffer in bytes
;    BX    - address of buffer
;
; Returns:
;    AX =    0 if no errors
;        -1 otherwise
; Registers destroyed : BX
;-
dirs_init proc    near
    push    bx
    mov    bx,offset DGROUP:dir_stk ;bx := address of buffer descriptors
    xchg    ax,cx            ;CX = buffer size
    pop    ax            ;AX = Buffer address
                    ;BX points to appropriate descriptor
    call    near ptr strstk_init    ;Initialize buffer and descriptor
    ret
dirs_init    endp


;+
; FUNCTION: execute_rstdir
;
;    Called to reset the directory stack.
;
; Parameters:
;    None.
;-
execute_rstdir proc near
    mov    bx,offset DGROUP:dir_stk
    call    near ptr strstk_reset
    ret
execute_rstdir endp

;+
; FUNCTION : dir_push
;
;    Called to push a drive and path onto the directory stack. The
;    string must end in a 0 byte.
;
; Parameters:
;    DX    ->string to push
;
; Returns:
;    CF    = 1 if errors
;          0 no errors
;
; Register(s) destroyed:
;    AX,BX,CX,DX
;-
dir_push proc    near
    @save    di
    mov    di,dx                ;di->string
    mov    cx,0ffffh
    xor    al,al
    repne    scasb
    mov    ax,cx
    not    ax                ;AX<-length of string
;                         including null terminator
    mov    bx,offset DGROUP:dir_stk
    xor    cx,cx                ;Don't force push
    call    near ptr strstk_push        ;Params AX,BX,CX,DX
    ; strstk_push sets/resets CF
    @restore
    ret
dir_push endp

;+
; FUNCTION : abort_dir_op
;
;    Called to abort a directory stack operation. Action taken
;    depends on whether the program is already resident or is being
;    installed. This routine does NOT return to caller.
;
; Parameters:
;    AX    = code to pass to abort_processing
;
; Returns:
;    Nothing.
; Register(s) destroyed:
;-
abort_dir_op proc near
    mov    dx,offset DGROUP:abort_processing
    cmp    resident,0
    jne    @abort_dir_op_90        ;Jump if resident
    @DispStr dirstk_error
    mov    dx,offset DGROUP:abort_install
@abort_dir_op_90:
    jmp    dx
abort_dir_op endp




;+
; FUNCTION : check_dircmd_allowed
;
;    Makes sure DOS is the caller or directory commands have been
;    enabled for all applications and returns. Else aborts.
;
; Parameters:
;    None.
;
; Returns:
;    Nothing.
; Register(s) destroyed:
;     AX
;-
check_dircmd_allowed proc near
    cmp    enable_dircmds,1
    je    @check_dircmd_allowed_99
    mov    ax,E_DIRSTK_DOS            ;Assume error
    cmp    in_appl,1            ;In application ?
    je    abort_dir_op            ;Yes, abort
@check_dircmd_allowed_99:                    ;Else return
    ret
check_dircmd_allowed endp


;+
; FUNCTION : save_drv_path
;
;    Saves the current drive and path in the specified buffer in the
;    form `D:\dir1....' where the current drive letter. The buffer
;    MUST be long enough.
;
; Parameters:
;    AX    = address of save buffer
;
; Returns:
;    Nothing.
;
; Register(s) destroyed:
;    AX,DX
;-
save_drv_path    proc near
    @save    si,di
    mov    di,ax                ;DI->save buffer
    @GetDrv                    ;AL<-drive number
    add    al,'a'                ;AL<-drive letter
    stosb                    ;Remember current drive
    mov    al,':'
    stosb
    mov    al,'\'
    stosb
    @GetDir di                ;Remember current path
    @restore
    ret
save_drv_path    endp



;+
; FUNCTION : change_drv_path
;
;    Changes the current drive and directory to the one specified.
;
; Parameters:
;    AX    ->path in the form `D:\dir1\dir2\...' terminated
;          with a 0 byte where D is the drive letter. Entire
;          path name need no be given. It is OK if the last
;          directory in the path is followed by a '\'.
;
; Returns:
;    CF    = 0 if current drive and directory succesfully changed,
;          1 if any errors (drive and path both unchanged)
; Register(s) destroyed:
;-
change_drv_path proc near
    @save    si,di
    push    bp
    mov    bp,sp
    sub    sp,PATHBUF_SIZE
cur_path    equ <byte ptr [bp-PATHBUF_SIZE]>
    push    ax                ;Remember new path
    lea    ax,cur_path            ;AX->current path save buf
    call    near ptr save_drv_path        ;Save current disk/dir
    pop    dx                ;DX->new path
    mov    si,dx                ;SI->new path
    mov    di,dx
    xor    al,al                ;Search for terminator
    mov    cx,0ffffh
    repne    scasb                ;DI->byte after NULL
    cmp    byte ptr [di-2],'\'        ;Extra '\' char ?
    jne    @change_drv_path_10        ;No
    ;If '\' at the end, make sure it is not of the form d:\ or just \
    cmp    byte ptr [di-3],':'
    je    @change_drv_path_10
    dec    di
    dec    di                ;DI->'\' character
    cmp    di,dx                ;Solitary '\' ?
    je    @change_drv_path_10        ;Yes
    mov    [di],al                ;No, replace '\' with 0
@change_drv_path_10:
    @ChDir    dx
    jnc    @change_drv_path_80        ;No error
;     Check if error was because drive was specified but not the path.
;    In this case, we should only change the drive.
    cmp    byte ptr 2[si],0        ;third byte nust be null
    jne    @change_drv_path_85        ;Nope
    cmp    byte ptr 1[si],':'        ;Drive specified ?
    jne    @change_drv_path_85        ;Nope
    jmp    short @change_drv_path_82
@change_drv_path_80:
    cmp    byte ptr 1[si],':'        ;Drive spec ?
    clc                    ;To indicate success
    jne    @change_drv_path_99        ;No, all done
@change_drv_path_82:
    lodsb                    ;AL<-drive
    call    near ptr tolower
    sub    al,'a'                ;AL<-drive number
    @SetDrv al                ;Change the drive
    jnc    @change_drv_path_99        ;No error
;     Error, restore path, drive would not have been changed
@change_drv_path_85:
    lea    dx,cur_path
    @ChDir    dx
    stc                    ;Indicate error to caller
@change_drv_path_99:
    mov    sp,bp
    pop    bp
    @restore
    ret
change_drv_path endp



;+
; FUNCTION : execute_popd
;
;    Pops the topmost element off the directory stack and makes it
;    the current drive/directory.
;
; Parameters:
;    None.
;
; Returns:
;    Nothing.
;
; Register(s) destroyed:
;    AX,BX,CX,DX
;-
execute_popd proc near
    call    near ptr check_dircmd_allowed
    @save    si,di
    push    bp
    mov    bp,sp
    sub    sp,PATHBUF_SIZE
topdir    equ    PATHBUF_SIZE
    mov    bx,offset DGROUP:dir_stk    ;BX->dir stack descriptor
    call    near ptr strstk_settop
    lea    ax,[bp-topdir]
    mov    cx,PATHBUF_SIZE
    call    near ptr strstk_copy        ;Get top of stack
;                         String is terminated
;                         by a 0 byte
    jc    @execute_popd_90
    or    ax,ax                ;Empty stack ?
    jz    @execute_popd_90        ;Yes, error
    lea    ax,[bp-topdir]            ;AX->new path
    call    near ptr change_drv_path    ;Change drive and path
    jc    @execute_popd_90
    call    near ptr strstk_kill        ;Delete top of stack
    mov    sp,bp
    pop    bp
    @restore
; Klugery - return a zero length string to DOS in order to set prompt properly.
    mov    lastchar,offset DGROUP:linebuf
    mov    user_command,1            ;indicate line to be
;                         returned to DOS
    ret

@execute_popd_90:
    mov    ax,E_DIRSTK_EMPTY
    jmp    near ptr abort_dir_op
execute_popd    endp



;+
; FUNCTION : execute_pushd
;
;    If a parameter is given, pushes current directory/disk onto the
;    dir stack and changes to the parameter. If no parameter,
;    exchange the top of directory stack with current disk-directory.
;
; Parameters:
;    SI    -> first char in linebuf following this command
;    CX    = remaining num chars in line
;
; Returns:
;    Nothing.
;
; Register(s) destroyed:
;    AX,BX,CX,DX
;-
execute_pushd    proc    near
    @save    si,di
    push    bp
    mov    bp,sp
    sub    sp,2*PATHBUF_SIZE
cur_path    equ <byte ptr [bp-PATHBUF_SIZE]>
new_path    equ <byte ptr [bp-(2*PATHBUF_SIZE)]>
    call    near ptr check_dircmd_allowed
;                         Will return only if so
    push    cx                ;Save line length
    lea    ax,cur_path
    call    near ptr save_drv_path        ;Save current drive and path

    pop    cx                ;CX<-restored line length
    call    near ptr skip_whitespace
    ; SI->first non blank, CX<-num remaining chars
    jcxz    @execute_pushd_50        ;Exchange directory
;                         with top of stack
    push    si                ;SI->path to change to
    call    near ptr skip_nonwhite
    ; SI->first non-blank
    mov    byte ptr [si],0            ;Terminating 0 byte
;    We are guaranteed place for a 0 because of the dummy byte after linebuf
    pop    ax                ;AX->dir to change to
    call    near ptr change_drv_path    ;Change path and drive
    jc    @execute_pushd_32        ;Error
@execute_pushd_25:
    lea    dx,cur_path
    call    near ptr dir_push        ;Push onto stack
    jnc    @execute_pushd_100        ;No error
@execute_pushd_30:
; Error. Restore original directory and display error message.
    lea    ax,cur_path
    call    near ptr change_drv_path
@execute_pushd_32:
    mov    ax,E_DIRSTK
    jmp    abort_dir_op

@execute_pushd_50:
; Exhange current directory with the directory at the top of the stack
    mov    bx,offset DGROUP:dir_stk    ;BX->dir stack descriptor
    call    near ptr strstk_settop
    lea    ax,new_path
    mov    cx,PATHBUF_SIZE
    call    near ptr strstk_copy        ;Get top of stack
;                         String is terminated
;                         by a 0 byte
    jnc    @execute_pushd_60
@execute_pushd_55:
    lea    ax,cur_path
    call    near ptr change_drv_path
    mov    ax,E_DIRSTK_EMPTY
    jmp    abort_dir_op
@execute_pushd_60:
    or    ax,ax                ;Empty stack ?
    jz    @execute_pushd_55        ;Yes, error
    lea    ax,new_path            ;AX->new path
    call    near ptr change_drv_path    ;Change drive and path
    jc    @execute_pushd_30
    call    near ptr strstk_kill        ;Delete top of stack
    lea    dx,cur_path
    call    near ptr dir_push
    jnc    @execute_pushd_100            ;All set
;    Error. Restore original top of stack
    lea    dx,new_path
    call    near ptr dir_push        ;Push must succeed
    jmp    short @execute_pushd_30

@execute_pushd_100:
    mov    sp,bp
    pop    bp
    @restore
; Klugery - return a zero length string to DOS in order to set prompt properly.
    mov    lastchar,offset DGROUP:linebuf
    mov    user_command,1            ;indicate line to be
;                         returned to DOS
    ret
execute_pushd    endp




;+
; FUNCTION : execute_chd
;
;    Changes to the disk and directory specified as parameter.
;
; Parameters:
;    SI    -> first char in linebuf following this command
;    CX    = remaining num chars in line
;
; Returns:
;    Nothing.
;
; Register(s) destroyed:
;    AX,BX,CX,DX
;-
execute_chd    proc    near
    @save    si,di
    push    bp
    mov    bp,sp
    sub    sp,PATHBUF_SIZE
new_path    equ <byte ptr [bp-PATHBUF_SIZE]>
    call    near ptr check_dircmd_allowed
;                         Will return only if so
    push    cx                ;Save line length
    call    near ptr skip_whitespace
    ; SI->first non blank, CX<-num remaining chars
    jcxz    @execute_chd_100        ;No args
;                         with top of stack
    push    si                ;SI->path to change to
    call    near ptr skip_nonwhite
    ; SI->first non-blank
    mov    byte ptr [si],0            ;Terminating 0 byte
;    We are guaranteed place for a 0 because of the dummy byte after linebuf
    pop    ax                ;AX->dir to change to
    call    near ptr change_drv_path    ;Change path and drive
    jnc    @execute_chd_100            ;No error
    mov    ax,E_DIRSTK
    jmp    abort_dir_op

@execute_chd_100:
    mov    sp,bp
    pop    bp
    @restore
; Klugery - return a zero length string to DOS in order to set prompt properly.
    mov    lastchar,offset DGROUP:linebuf
    mov    user_command,1            ;indicate line to be
;                         returned to DOS
    ret
execute_chd endp





CSEG    ENDS

    END