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Cream of the Crop 1
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Cream of the Crop 1.iso
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PROGRAM
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UCRASM25.ARJ
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FILEIO.ASM
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Assembly Source File
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1991-10-12
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18KB
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639 lines
;******************************************************************************
;
; New routines and functions
; for the Stdlib package
;
; Featuring:
; - Opening and closing files
; - Creating new files
; - Blocked I/O:
; -Reading from files using getc
; -Writing to files using putc and puts
; - File-Buffer Flushing
; - File Seeking
; - File Deleting
; - File Renaming
;
;******************************************************************************
;
; Written by:
;
; Mark Radleigh
; &
; Brian Harvey
;
; (CS 13)
;
;******************************************************************************
;
;
;******************************************************************************
; These externs are needed for this demonstration program.
;******************************************************************************
;
;
StdGrp group StdLib, StdData
;
StdData segment para public 'sldata'
;
; Some useful constants:
;
cr equ 13
lf equ 10
eos equ 0
EOF equ 04h
;
true equ 1
false equ 0
NIL equ 0
;
;******************************************************************************
; The following is a Struct that contains all necessary information to
; handle multiple files opened or closed.
;******************************************************************************
;
ftype struc
fbuffptr dd ? ;Buffer pointer that holds the Data
fhandle dw ? ;DOS FileHandle
findex dw ? ;Index into Buffer
fcounter dw ?
fflush_flag db ? ;Says if you can flush the buffer or not
ftype ends
;
;******************************************************************************
; The Folowing declares neccessary variables for the library.
; FILES is the base struct for the alloted number of files opened.
;******************************************************************************
;
FILES ftype 10 dup (<NIL,NIL,NIL,NIL,NIL>)
Old_out_addrss dd 0 ;Keep the old address of output
Old_in_addrss dd 0 ;Keep the old address of input
current_fwrite dw ? ;Keep the current index of writing
current_fread dw ? ;Keep the current index of reading
;
;******************************************************************************
; The following are variables used by the demonstration program.
;******************************************************************************
;
fileptr dw ?
fileptr2 dw ?
fileptr3 dw ?
;
StdData ends
;
stdlib segment para public 'slcode'
assume cs:StdGrp, ds:nothing
;
extrn sl_SetOutAdrs:far, sl_GetOutAdrs:far
extrn sl_SetInAdrs:far, sl_GetInAdrs:far
extrn sl_malloc:far, sl_free:far
;
;
;----------------------------------------------------------------------------
; Fcreate -> A procedure that creates a file for writing (Deletes any previous
; file of the same name.)
; INPUT-> ES:DI Contains the address of the filename for the new file.
; OUTPUT-> CARRY Flag is set if error occurs.
; OUTPUT-> AX contains the error code if carry flag is set, else AX
; contains the STDLIB FileHandle.
;
public sl_fcreate
sl_fcreate proc far
push ds
push dx
push cx
push si
;
fcreate_read: xor si, si
fcreate_test: cmp word ptr StdGrp:FILES[si].fbuffptr + 2, NIL
jne fcreate_test2
cmp word ptr StdGrp:FILES[si].fbuffptr, NIL
je Fcreate_file
fcreate_test2: add si, size ftype
cmp si, length FILES * size ftype
jbe fcreate_test
stc
mov ax, 10 ;No more file buffer ->error
jmp fcreate_done
Fcreate_file:
mov dx, es
mov ds, dx ;get the segment adrs ready
;for DOS
mov dx, di ;get the offset adrs ready
;for DOS
mov ah, 3ch ;command for CREATE
mov cx, 0 ;Tells DOS file is ARCHIVED.
int 21h
jc fcreate_done
mov StdGrp:FILES[si].fflush_flag, true ;So we can flush
;the buffer!
mov StdGrp:FILES[si].fhandle, ax
mov ax, si
call fmalloc_this ;Malloc space for the buffer
;
fcreate_done: pop si
pop cx
pop dx
pop ds
ret
sl_fcreate endp
;
;-----------------------------------------------------------------------------
; Fopen -> A procedure that opens a file for reading/writing.
; INPUT-> ES:DI Contains the address of the filename for the new file.
; OUTPUT-> CARRY Flag is set if error occurs.
; OUTPUT-> AX contains the error code if carry flag is set, else AX
; contains the STDLIB FileHandle.
;
;
public sl_fopen
sl_fopen proc far
push cx
push dx
push si
push di
push ds
push es
cmp al, 1 ;Want to open for writing?
je fopen_write
cmp al, 0 ;Want to open for reading?
je fopen_read
stc
mov ax, 5 ;Incorrect sub function passed in al
jmp fopen_done
;
;--------------------------------------------------
; Here we open the file for reading..
; We first test to see if there is an open buffer, then we open the file,
; and if everything is ok, we Malloc space for the buffer.
;
fopen_read: xor si, si
fread_test: cmp word ptr StdGrp:FILES[si].fbuffptr + 2, NIL
jne fread_test2
cmp word ptr StdGrp:FILES[si].fbuffptr, NIL
je Open_file_r
fread_test2: add si, size ftype
cmp si, length FILES * size ftype
jbe fread_test
stc
mov ax, 10 ;No more file buffers ->error
jmp fopen_done
;
Open_file_r: mov dx, es
mov ds, dx
mov dx, di
mov ah, 3dh ; Code for opening for reading
int 21h
jc fopen_done
mov StdGrp:FILES[si].fflush_flag, false ;so we don't flush the
;buffer
mov StdGrp:FILES[si].fhandle, ax
mov ax, si
call fmalloc_this ;Get some buffer space
jmp fopen_done
;
;--------------------------------------------------
; Here we open the file for writing..
; We first test to see if there is an open buffer, then we open the file,
; and if everything is ok, we Malloc space for the buffer.
;
fopen_write: mov si, 0
fwrite_test: cmp word ptr StdGrp:FILES[si].fbuffptr + 2, NIL
jne fwrite_test2
cmp word ptr StdGrp:FILES[si].fbuffptr, NIL
je Open_file_w
;
fwrite_test2: add si, size ftype
cmp si, length FILES * size ftype
jbe fwrite_test
stc
mov ax, 10
jmp fopen_done
;
Open_file_w: mov dx, es
mov ds, dx
mov dx, di
mov ah, 3dh ;Code for open for writing
int 21h
jc fopen_done
mov StdGrp:FILES[si].fflush_flag, true ;So we do flush
;File buffer
mov StdGrp:FILES[si].fhandle, ax
mov ax, si
call fmalloc_this ;Get some buffer space!
;
fopen_done:
pop es
pop ds
pop di
pop si
pop dx
pop cx
ret
sl_fopen endp
;
;*****************************************************************************
; This small procedure Mallocs some space for our FILES buffer pointers,
; so we can read in and write out blocks at a time.
;*****************************************************************************
;
fmalloc_this proc near
mov cx, 256
call sl_malloc
jnc FMalloc_it
mov ax, 10
FMalloc_it:
mov bx, es
mov word ptr StdGrp:FILES[si].fbuffptr + 2, bx
mov word ptr StdGrp:FILES[si].fbuffptr, di
mov StdGrp:FILES[si].findex, 0
ret
fmalloc_this endp
;
;
;---------------------------------------------------------------------------
; Readon -> A procedure that changes the stdlib fuctions of character
; and string input to a specified file.
; -INPUT -> AX contains the FileHandle variable.
;
public sl_freadon
sl_freadon proc far
push es
push di
push bx
;The following cmp instructions
;See if we have already set
;READON
mov bx, word ptr StdGrp:Old_in_addrss + 2
cmp bx, 0
jne freadon_done
mov di, word ptr StdGrp:Old_in_addrss
cmp di, 0
jne freadon_done
;
mov current_fread, ax
call sl_GetInAdrs ;Get the origonal input adrs
mov bx, es
mov word ptr StdGrp:Old_in_addrss + 2, bx
mov word ptr StdGrp:Old_in_addrss, di
mov bx, cs ;Now we load in our fgetc
mov es, bx
lea di, sl_fgetc
call sl_SetInAdrs ;Set to the new input adrs
freadon_done:
pop bx
pop di
pop es
ret
sl_freadon endp
;
;---------------------------------------------------------------------------
; Readoff -> A procedure that resets the stdlib functions of character
; and string input.
;
public sl_freadoff
sl_freadoff proc far
push es
push di
les di, StdGrp:Old_In_Addrss
call sl_SetInAdrs
mov word ptr StdGrp:Old_In_Addrss + 2, 0
mov word ptr StdGrp:Old_In_Addrss, 0
pop di
pop es
ret
sl_freadoff endp
;
;----------------------------------------------------------------------------
; Fgetc -> A procedure that is called whenever GETC is called and
; READON was called previously.
; NOTE: CARRY FLAG IS SET and AX contains 8 if it encounters EOF.
;
public sl_fgetc
sl_fgetc proc far
push si
push di
push ds
push dx
push cx
push bx
;
mov si, StdGrp:current_fread ;Get the current
;Readfile index
;-----------------
;The following 4 instruc
;see if we have an
;available buffer...
cmp word ptr StdGrp:FILES[si].fbuffptr + 2, NIL
jne fgetc_getchar
cmp word ptr StdGrp:FILES[si].fbuffptr, NIL
je fgetc_nada
fgetc_getchar:
cmp StdGrp:FILES[si].fcounter, 0
je fget_new_block
les di, StdGrp:FILES[si].fbuffptr
add di, StdGrp:FILES[si].findex
mov al, es:[di]
inc StdGrp:FILES[si].findex
dec StdGrp:FILES[si].fcounter
jmp fgetc_done
fget_new_block:
lds dx, StdGrp:FILES[si].fbuffptr
mov bx, StdGrp:FILES[si].fhandle
mov cx, 256
mov ah, 3fh
int 21h
jc fgetc_done
cmp ax, 0 ;How many bytes did it read in?
je EOF_error
mov StdGrp:FILES[si].fcounter, ax
mov StdGrp:FILES[si].findex, 0
jmp fgetc_getchar
fgetc_nada: stc
mov ax, 6 ;Invalid FileHandle
;(Just a safeguard)
EOF_error: stc
mov ax, 8 ;End of file...
;
fgetc_done:
pop bx
pop cx
pop dx
pop ds
pop di
pop si
ret
sl_fgetc endp
;
;
;
;------------------------------------------------------------------------------
;
; Fclose - A procedure that closes an open file.
; - INPUT -> AX contains the FileHandle variable of the file to close.
; - OUTPUT -> Carry flag is set if error occurs.
; - OUTPUT -> Ax contains 6 which is invalid file handle error (if
; carry flag is set) or AX contains 7 if trouble with FREE.
;
public sl_fclose
sl_fclose proc far
push bx
push si
mov si, ax
mov bx, StdGrp:FILES[si].fhandle ;Move file handle into bx
cmp StdGrp:FILES[si].fflush_flag, true
jne fclose_it
call far ptr sl_fflush ;Make sure the buffer is empty
fclose_it:
mov ah, 3eh
int 21h
les di, StdGrp:FILES[si].fbuffptr
call sl_free ;Conserve space!!!!!
jnc fclose_cont
mov ax, 7 ;Trouble with FREE
fclose_cont:
mov word ptr StdGrp:FILES[si].fbuffptr + 2, 0
mov word ptr StdGrp:FILES[si].fbuffptr, 0
mov StdGrp:FILES[si].findex, 0
mov StdGrp:FILES[si].fcounter, 0
pop si
pop bx
ret
sl_fclose endp
;
;
;------------------------------------------------------------------------------
; Fflush -> A procedure that flushes the write buffer into the file.
; Usefull if user didn't read in 256 blocks
; INPUT -> AX contains the STDLIB FileHandle
;
public sl_fflush
sl_fflush proc far
push di
push si
push ds
push dx
push cx
push bx
mov di, ax
mov si, StdGrp:FILES[di].findex
cmp si, 0 ;Is the buffer empty?
je fwbuffempty
mov cx, si ;The number of bytes to write
lds dx, StdGrp:FILES[di].fbuffptr
mov ah, 40h
int 21h
fwbuffempty:
pop bx
pop cx
pop dx
pop ds
pop si
pop di
ret
sl_fflush endp
;------------------------------------------------------------------------------
;
; Writeon - A procedure that changes stdlib functions of character and string
; output to a specified file instead.
; -INPUT -> AX contains the FileHandle variable.
;
public sl_fwriteon
sl_fwriteon proc far
push es
push di
push bx
;The following cmp instructions
;See if we have already set
;WRITEON
;
mov bx, word ptr StdGrp:Old_out_addrss + 2
cmp bx, 0
jne fwriteon_done
mov di, word ptr StdGrp:Old_out_addrss
cmp di, 0
jne fwriteon_done
;
mov StdGrp:current_fwrite, ax
call sl_GetOutAdrs ;Get the original ouput address
mov bx, es
mov word ptr StdGrp:Old_out_addrss + 2, bx
mov word ptr StdGrp:Old_out_addrss, di
mov bx, cs ;Load in our fputc
mov es, bx
lea di, StdGrp:sl_fputc
call sl_SetOutAdrs ;sets the ouput address to file
fwriteon_done:
pop bx
pop di
pop es
ret
sl_fwriteon endp
;
;
;------------------------------------------------------------------------------
; Fputc -> A procedure that is called whenever PUTC is called and
; WRITEON was called previously.
;
public sl_fputc
sl_fputc proc far
push si
push di
push ds
push dx
push cx
push bx
;
mov si, StdGrp:current_fwrite ;gets the current index of FILES
;The following comparisons see
;If we have a valid buffer..
cmp word ptr StdGrp:FILES[si].fbuffptr + 2, NIL
jne fputc_do_this
cmp word ptr StdGrp:FILES[si].fbuffptr, NIL
je no_such_thing
fputc_do_this:
les di, StdGrp:FILES[si].fbuffptr
add di, StdGrp:FILES[si].findex
mov es:[di], al ;Stick that char in the buffer
inc byte ptr StdGrp:FILES[si].findex
jne fwrite_done ;If we hit 0, write the buffer!
lds dx, StdGrp:FILES[si].fbuffptr
mov bx, StdGrp:FILES[si].fhandle
mov cx, 256
mov ah, 40h
int 21h
;
fwrite_done:
pop bx
pop cx
pop dx
pop ds
pop di
pop si
ret
no_such_thing: stc
mov ax, 6 ;invalid filehandle
;(Safe guard - shouldn't happen)
jmp fwrite_done
sl_fputc endp
;
;
;---------------------------------------------------------------------------
; Writeoff -> A procedure that resets the stdlib functions of character
; and string output.
;
public sl_fwriteOff
sl_fwriteOff proc far
push es
push di
mov es, word ptr StdGrp:Old_out_addrss + 2
mov di, word ptr StdGrp:Old_out_addrss
call sl_SetOutAdrs
mov word ptr StdGrp:Old_out_addrss + 2, 0
mov word ptr StdGrp:Old_out_addrss, 0
pop di
pop es
ret
sl_fwriteOff endp
;
;
;
;
;------------------------------------------------------------------------
; Fseek -> Moves the File Pointer a specified # of Bytes..
; INPUT-> AL contains the offset from where to start the file seeking.
; AL=0; Seek from the begining of the file.
; AL=1; Seek from the current pointer possition.
; AL=2; Seek backwards from the end of the file.
; INPUT-> SI contains the Unique FileHandle given by these procedures.
; INPUT-> CX:DX contains the number of bytes to seek (Unsigned number).
; OUTPUT -> Carry flag is set if error..
; OUTPUT -> AX contains the error code.
; OUTPUT -> DX:AX contains the new file positoin if no error.
;
public sl_fseek
sl_fseek proc far
push bx
mov ah, 42h
mov bx, StdGrp:FILES[si].fhandle ;Get the FileHandle
int 21h
pop bx
sl_fseek endp
;
;-----------------------------------------------------------------------
; DOSHandle -> A procedure that returns the DOS given FileHandle.
; INPUT-> AX contains the stdlib given FileHandle.
; OUTPUT->Carry is set if error.
; OUTPUT->AX contains error code.
; AX=1; Invalid user input FileIndex.
; OUTPUT->AX contains the DOS FileHandle.
;
public sl_DOSHandle
sl_DOSHandle proc far
push si
mov si, ax
cmp si, length FILES * size ftype
ja Handle_error
cmp si, 0
jb Handle_error
clc
mov ax, StdGrp:FILES[si].fhandle
jmp DOS_Done
Handle_error: stc
mov ax, 1
DOS_Done:
pop si
ret
sl_DOSHandle endp
;
;--------------------------------------------------------------------------
; Fdel -> A procedure that deletes a file.
; INPUT->ES:DI contains the address of zero terminated pathname of file.
; OUTPUT -> CARRY Flag is set if error and
; AX=2 File not found
; AX=5 Access denied
;
public sl_fdel
sl_fdel proc far
push ds
push dx
mov dx, es
mov ds, dx
mov dx, di
mov ah, 41h
int 21h
pop dx
pop ds
ret
sl_fdel endp
;
;--------------------------------------------------------------------------
; Frename -> A procedure that renames one file to another.
; INPUT -> DX:SI contains the origonal pathname of the file.
; INPUT -> ES:DI contains the new pathname of the file.
; OUTPUT -> CARRY Flag is set if error and:
; AX=2 File not found
; AX=5 Access denied
; AX=17 Not the Same device
;
public sl_frename
sl_frename proc far
push ds
mov ds, dx
mov dx, si
mov ah, 56h
int 21h
pop ds
ret
sl_frename endp
;
;
stdlib ends
;
;
end
