include compiler.inc
	ttl	$STRHAND, 1.01, 08-03-86 clr

; internal routine to convert stream pointer to handle.  If bad handle, returns
; AX=-1; else returns handle in AX.  Returns state of MODE BIT (offset 2 in _ftb
; in BL register, state of UGC (word) in CX


	dseg
	exterr
	extrn	_ftb:byte

	cseg

	procdef $strhand <<stream,ptr>>
	pushreg
	pushds

	mov	si,offset _ftb
	ldptr	ax,stream,ds
	mov	dx,ds
	or	dx,ax
	jz	invalid

	mov	di,ax		;save stream pointer
	sub	ax,si		;convert to handle
	jz	nodiv
	mov	si,5
	cwd
	div	si
nodiv:	xor	dx,dx		;clear error code
	moverr	dx
	cmp	ax,0		;check range
	jl	seterr
	cmp	ax,19		;20 handles is DOS max
	jl	ok

seterr:
	or	byte ptr 2[di],10h	; set error code
	mov	ax,-1		;and return ERROR
ok:
	mov	bl,byte ptr 2[di]	; return MODE BIT
	mov	cx,word ptr [di]	; return UGC BYTE
out1:
	pret
invalid:
	mov	ax,-1
	jmp	short out1
	pend	$strhand
	finish