dkstmt.asm

[随书类]Dos6.0源代码

	TITLE	DKSTMT - Disk I/O Interfaces
	page	56,132
;***
;DKSTMT - Disk I/O Interfaces
;
;	Copyright <C> 1986, Microsoft Corporation
;
;Purpose:
;	This module contains disk I/O interfaces for BASIC statements.
;
;	This module came from iodisk.asm, which had been split into three
;	modules, -- diskio.asm, dkopen.asm and fileio.asm.  Diskio.asm
;	contains all drivers for disk I/O except disk open and close.
;	Disk open is in dkopen.asm.  This module contains interfaces for
;	file I/O statements.
;
;BASIC Syntax mapping to included runtime entry points:
;
;- FILES Statement:
;
;     FILES Statement:
;
;     FILES [filespec]
;	 |
;     B$FILS
;
;- KILL Statement:
;
;     KILL filespec
;	 |
;     B$KILL
;
;- LOCK Statement:
;
;     LOCK [#]filenum [{, record} | [start] TO end]
;	 |
;     B$LOCK
;
;- NAME Statement:
;
;     NAME oldname AS newname
;	 |
;     B$NAME
;
;- RESET Statement:
;
;     RESET
;	 |
;     B$REST
;
;- UNLOCK Statement:
;
;     UNLOCK [#]filenum [{, record} | [start] TO end]
;	  |
;	B$LOCK
;
;******************************************************************************
	INCLUDE switch.inc
	INCLUDE rmacros.inc	;Runtime Macro Defintions

;Code segmetns
	useSeg	DK_TEXT
	useSeg	ER_TEXT
	useSeg	NH_TEXT
	useSeg	RT_TEXT		
;Data segments
	useSeg	CONST
	useSeg	_DATA
	useSeg	_BSS

	INCLUDE seg.inc

	INCLUDE ascii.inc
	INCLUDE baslibma.inc
	INCLUDE devdef.inc
	INCLUDE files.inc
	INCLUDE idmac.inc		
	INCLUDE messages.inc
	INCLUDE rtps.inc		
	INCLUDE string.inc		

	SUBTTL	local constant definitions
	page

sBegin	CONST

	externB	b$EightSpaces		; buffer of 8 spaces
	staticB DirStr,"<DIR> "

sEnd	CONST

sBegin	_DATA


sEnd	_DATA

sBegin	_BSS

	externB b$PATHNAM 		; defined in GWINI.ASM
	externB b$Buf2 		; defined in GWINI.ASM
	b$PATHNAM2 EQU b$Buf2		
	externW b$PN_NAME		



sEnd	_BSS

	SUBTTL	code externals
	page

sBegin	DK_TEXT


	externNP	B$GET_PATHNAME	
	externNP	B$GET_CUR_DIR	
	externFP	B$PSI4		
	externNP	B$PUTS		
	externNP	B$OUTCNT		
	externNP	B$$WCHT
	externNP	B$$TCR
	externNP	B$TTY_GPOS
	externNP	B$TTY_GWID
	externNP	B$CLOSF
	externNP	B$CHKFOPEN	
	externNP	B$DOS3CHECK	;check for >= DOS 3.00
	externNP	B$MUL32	

sEnd	DK_TEXT

sBegin	NH_TEXT

	externNP	B$STDALCTMP
	externNP	B$LHFDBLOC	

sEnd	NH_TEXT

sBegin	ER_TEXT

	externNP	B$PUTNUM	; output message

	externNP	B$ERR_FC
	externNP	B$ERR_BFN
	externNP	B$ERR_BRN
	externNP	B$ERR_FAE
	externNP	B$ERR_FNF
	externNP	B$ERR_IFN
	externNP	B$ERR_ACD
	externNP	B$ERR_FWP
	externNP	B$ERR_AFE
	externNP	B$ERR_PNF	
	externNP	B$ERR_RAD	

sEnd	ER_TEXT

sBegin	RT_TEXT				
sEnd	RT_TEXT				


	PAGE

	assumes CS,DK_TEXT

sBegin	DK_TEXT

;***
;B$KILL - KILL filename
;
;Purpose:
;
;Entry:
; fname = filename sdesc
;
;Exit:
;
;Uses:
; Per convention
;
;Exceptions:
;	B$ERR_FNF -- for file not found
;	B$ERR_ACD -- for access denied
;	B$ERR_FAO -- for file already open
;
;******************************************************************************
cProc	B$KILL,<FAR,PUBLIC>,<SI,DI,ES> 
parmSD	fname			
cbegin				


	PUSH	DS		; set ES=DS for string operations
	POP	ES		
	MOV	BX,fname	; get *sd of filename
	MOV	DI,OFFSET DGROUP:b$PATHNAM ; Where to put the pathname
	CALL	B$GET_PATHNAME	; generate pathname, checking for errors
				; sets ES = DS
	CALL	B$STDALCTMP	;delete temporaries
	CALL	SearchNoDir	; find first file, or give "file not found"

KILL_NEXT:
;	DI --> pointer to processed filename

	PUSH	DI		; save pathname buffer address
	MOV	DI,b$PN_NAME	; DI = address past last "\" in pathname
				; (filename.ext field of pathname)
	mov	si,offset dgroup:b$PATHNAM2+30 ; Where dos put the filename

				; store name into the name field of pathname
dkk22:
	lodsb			;get a byte from the filename
	stosb			;store it into the pathname
	or	al,al		;end ?
	jnz	dkk22		;no

	pop	di		;--> pathname
	CALL	B$CHKFOPEN	; Check for conflict with open files
				; (doesn't return if error)

				; delete the link
	mov	dx,di		; DX = address of pathname to delete
	CALLOS	unlink,,,,dx
	JB	KILL_ERR	; give proper error message
	CALLOS	FINDN		;find next
	JNB	KILL_NEXT	; found next, continue


cEnd				

KILL_ERR:
	CMP	AX,ERRACD	;test if access error
	JNE	ERFNF		; if not, then KILL defaults to file not
				; found error
	JMP	B$ERR_ACD	  ;treat as access error
ERFNF:				
	JMP	B$ERR_FNF	; File not found

;***
; B$NAME - Name statement
;
;Purpose:
; Rename a file
;
;Entry:
; oldname = Name of existing file
; newname = name to change to
;
;Exit:
;
;Uses:
; Per convention
;
;Exceptions:
; B$ERR_FAE if newname already exists.
;
;******************************************************************************
cProc	B$NAME,<FAR,PUBLIC>,<ES,SI,DI> 
parmSD	oldname 		
parmSD	newname 		
cBegin				


	PUSH	DS		; set ES=DS
	POP	ES		

	GetpSD	BX,newname	
	MOV	DI,OFFSET DGROUP:b$PATHNAM2 
	CALL	NAME_COMMON	; do common processing for second name

	GetpSD	BX,oldname	; source pathname sdesc
	MOV	DI,OFFSET DGROUP:b$PATHNAM 
	CALL	NAME_COMMON	; do common processing for first name

	MOV	DX,OFFSET DGROUP:b$PATHNAM ;source
	MOV	DI,OFFSET DGROUP:b$PATHNAM2 ;destination
	CALLOS	RENAME		
	JC	NAME_ERR	


cEnd				

NAME_ERR: 			
	CMP	AL,ERRFNF	; file not found?
	JE	ERFNF		; brif so
	CMP	AL,ERRPNF	; path not found?
	JE	ERPNF		; brif so
	CMP	AL,ERRACD	; access denied?
	JE	ERFAE		; brif so -- File already exists
	CMP	AL,ERRNSD	; not same device?
	JE	ERRAD		; brif so -- Rename across disks
				; default to Illegal function call error
				; for NAME if not one of the above.
ERFC:
	JMP	B$ERR_FC	; Illegal function call
ERFAE:				
	JMP	B$ERR_FAE	; File already exists
ERPNF:
	JMP	B$ERR_PNF	; Path not found
ERRAD:				
	JMP	B$ERR_RAD	; Rename across disks
ERBFN:				
	JMP	B$ERR_BFN	; Bad file name
ERCFNF2:			
	JMP	SHORT ERFNF	; give "file not found" error

;*** 
; NAME_COMMON - common processing.  Added as part of [14].
;
;Purpose:
;	Common processing for each filename of B$NAME.
;
;	Algorithm:
;		call B$GET_PATHNAME
;		if (wildcards in filename) then error		
;		deallocate the string temp
;		if (file already open) then error
;
;Entry:
;	DI =	*space for pathname
;	BX =	pointer to user-specified filename string descriptor
;
;Exit:
;	DI =	*processed pathname
;	CX =	length of pathname (including null byte)
;
;Uses:
;	per convention
;
;Preserves:
;
;Exceptions:
;	B$ERR_BFN -- for bad file name
;	B$ERR_FAO -- for file already open
;
;******************************************************************************
NAME_COMMON:
	CALL	B$GET_PATHNAME	; Scan file name
				; sets ES = DS
	cCall	B$STDALCTMP	; deallocate string temp
	TEST	AL,FN_WILD	; wildcards in filename?
	JNZ	ERBFN 		; brif so -- error
				; [DI] = processed pathname
				; [CX] = number of bytes in pathname
	JMP	B$CHKFOPEN	; check for file already open and return
				; (doesn't return if error)

;*** 
; Search/SearchNoDir - search for file
;
;Purpose:
;	Search for files
;Entry:
;	b$PATHNAM has pathname to search for
;Exit:
;	Conditions after DOS search function:
;		b$PATHNAM2 has directory entry for first matching file
;		DX -> b$PATHNAM
;	ZF ==> file found, NZ ==> error
;