!	crs_reserve_uparrow.scp			reb, 06-Oct-1989 09:56

.label begin
	display Selecting previous reservation . . . \force	

	decimal i
	get #cpref=$crs_last_used:8		
	get #fkey=""
	get #nkey=""
	get #dflag="N"

.label pre_loop

! get first record key for the date in the window; put it in #fkey
	for first crs_reserve with .crs_key beginning #cpref do -
		get #fkey=.crs_key
	.if #fkey eqs $crs_last_used then get #dflag="Y"
	.if #dflag eqs "Y" then .goto decrement

!++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.label loop
	get #nkey=crs_reserve:crs_key.%next[#fkey]
	.if #nkey:8 gts #cpref:8 and #dkey eqs "Y" then .goto first_of_date
	.if #nkey:8 gts #cpref:8 then .goto decrement
	.if #nkey eqs $crs_last_used then .goto found
	get #fkey=#nkey
	.goto loop


!++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

.label found
	get $crs_last_used=#fkey
	display The previous reservation has been selected.
	.goto exit_procedure

.label decrement

	date_convert #old_dt,#cpref,9
	get oa$display="Checking before " #old_dt " . . ."\force
!	display Checking previous date(s)...\force
	get #firstkey=crs_reserve:crs_key.%next[""]
	.if #cpref:8 lts #firstkey:8 then .goto top_of_file

	get #bday=#firstkey:8

	get #yyyy=#cpref:4
	get #mm=#cpref:2:4
	get #dd=#cpref:2:6
	compute #dd=#dd-1
	.if #dd:1:1 eqs "" then get #dd="0" #dd
	get #cpref=#yyyy #mm #dd
	.if #cpref:4:4 eqs "1200" then get #dd="1130"
	.if #cpref:4:4 eqs "1100" then get #dd="1031"
	.if #cpref:4:4 eqs "1000" then get #dd="0930"
	.if #cpref:4:4 eqs "0900" then get #dd="0831"
	.if #cpref:4:4 eqs "0800" then get #dd="0731"
	.if #cpref:4:4 eqs "0700" then get #dd="0630"
	.if #cpref:4:4 eqs "0600" then get #dd="0531"
	.if #cpref:4:4 eqs "0500" then get #dd="0430"
	.if #cpref:4:4 eqs "0400" then get #dd="0331"
	.if #cpref:4:4 eqs "0300" then get #dd="0229"
	.if #cpref:4:4 eqs "0200" then get #dd="0131"
	.if #cpref:4:4 eqs "0100" then get #dd="1231"\-
		compute #yyyy=#yyyy-1
	get #cpref = #yyyy #mm #dd
	.if #dflag eqs "Y" then .goto loop2
	.goto pre_loop

.label loop2

! get first record key for the date in the window; put it in #fkey
	for crs_reserve with .crs_key beginning #cpref do -
		get #fkey=.crs_key
	.if #fkey eqs $crs_last_used then .goto decrement
	.goto found

.label top_of_file
	get $crs_last_used=#fkey
	oa$msg_purge
	display You are at the top of the Reservations file.
	.goto exit_procedure

.label exit_procedure
	.exit