Routine: HLCSDL1

HLCSDL1 ;ALB/MTC/JC - X3.28 LOWER LAYER PROTOCOL 2.2 - 2/28/95 ;08/19/97

 ;;1.6;HEALTH LEVEL SEVEN;**2,34**;Oct 13, 1995

 ;This is an implemetation of the X3.28 LLP

START ;

 N HLIND0,HLIND1,HLNXST,HLTRANS,HLCHK,HLACKBLK,HLDOUT0,HLDOUT1,X,HLRETRY

 N HLNXST,HLLINE,HLXOR,HLTOUT,HLLINE,HLC1,HLC2

 N HLDLX,HLM

 ;S X=10 X ^%ZOSF("PRIORITY")

 S HLM=0,HLNXST=1

 ;-- enter loop for polling for i/o

 D POLL

 ;-- exit and clean-up

 D EXIT

POLL ;-- This function will check if any messages should be sent

 ;   then if anything is in the buffer to read in. If there is data

 ;   to write out then the system will bid for master status and if

 ;   successful x-mit the message. If the system receives a request to

 ;   receive data, then it will attemp to enter a slave mode and read

 ;   data in.

 N HLFLAG

 S HLFLAG=1

 D TRACE^HLCSDL2("Logging IO to ^XTMP('HL',N")

 ;-- enter loop

 F  D MONITOR^HLCSDR2("POLLING",5,HLDP) Q:'HLFLAG  D

 .; should we still be running

 . I '$$RUN^HLCSDL2 D MONITOR^HLCSDR2("SHUTDOWN",5,HLDP) S HLFLAG=0 Q

 .;-- check for data to read in

 . D TRACE^HLCSDL2("Slave Check"),SLAVE

 . I '$$RUN^HLCSDL2 D MONITOR^HLCSDR2("SHUTDOWN",5,HLDP) S HLFLAG=0 Q

 .;-- check for out going data

 . D TRACE^HLCSDL2("Master Check"),MASTER

SLAVE ;-- this function will check if anything is ready to read in from

 ;   the port. If nothing is ready then return to polling, else

 ;   start slave process.

 N HLX

 ;-- check if anything is ready to read in.

 D TRACE^HLCSDL2("Slave Request")

 ;-- read for enq (request for slave)

 I '$$READENQ^HLCSDL2 G SLAVEQ

 ;-- ack0

 D TRACE^HLCSDL2("Slave Ack0")

 D SENDACK^HLCSDL2(0)

 ;-- read data

 D TRACE^HLCSDL2("Slave Read Data")

 D READ

 ;-- exit and return to polling

SLAVEQ ;

READ ;-- This function will take the incoming data from the device and

 ;   store in file 870. After each read an ack will be sent to the

 ;   client application. Once an EOT has been received, return to

 ;   polling.

 N HLX,HLI,HLBK,HLETXB,HLLINE,HLDATA,BTERM

 ;-- prepare for incoming data

 S HLLINE=1,HLI=0

LOOP ;-- main loop for reading in message

 ;-- update status

 D MONITOR^HLCSDR2("READING",5,HLDP)

 ;-- read block of data

 S HLX=$$READBK^HLCSDL2("HLDATA",.HLLEN,.HLBK,.HLCK,.BTERM)

 ;-- check for TIMEOUT

 I $G(HLDATA)["TIMEOUT" G READQ

 ;-- check for EOT

 I $G(HLDATA)=HLEOT G READQ

 ;-- check if vaild data

 I '$$VALID^HLCSDL2("HLDATA",HLLINE#8,HLLEN,HLBK,HLCK,BTERM) D  G LOOP

 .;-- update status

 . D TRACE^HLCSDL2("Slave Write NAK")

 . D MONITOR^HLCSDR2("SEND NAK",5,HLDP)

 .;-- send nak

 . D SENDNAK^HLCSDL2

 ;-- write data to file 870

 S HLDOUT0=$$ENQUEUE^HLCSQUE(HLDP,"IN"),HLDOUT1=$P(HLDOUT0,U,2),HLDOUT0=+HLDOUT0

 D APPEND^HLCSUTL("HLDATA",HLDOUT0,HLDOUT1)

 S HLLINE=HLLINE+1

 ;-- If end of text set status

 I +BTERM=+HLETX D

 . D MONITOR^HLCSDR2("P",2,HLDOUT0,HLDOUT1,"IN")

 . D MONITOR^HLCSDR2("A",3,HLDOUT0,HLDOUT1,"IN")

 ;-- ack

 D SENDACK^HLCSDL2(HLBK)

 ;-- read next line of data

 G LOOP

READQ Q

MASTER ;-- if outgoing messages are present then establish m/s and begin

 ;   transmission of message.

 N HLBID,HLDOUT0,HLDOUT1

 ;-- check queue

 D TRACE^HLCSDL2("Master Check Queue")

 S HLDOUT0=$$DEQUEUE^HLCSQUE(HLDP,"OUT")

 ;-- nothing on queue quit

 I +HLDOUT0<0 D TRACE^HLCSDL2("*Out Queue Empty") G MASTERQ

 S HLDOUT1=$P(HLDOUT0,U,2),HLDOUT0=+HLDOUT0

 ;-- have item in queue to write, bid for master status

 S HLBID=$$BID(5)

 ;-- if attemp fails quit

 I 'HLBID D PUSH^HLCSQUE(HLDOUT0,HLDOUT1) G MASTERQ

 ;-- if successful goto write state

 I HLBID D

 . D WRITE(HLDOUT0,HLDOUT1)

 . D EOT^HLCSDL2

MASTERQ Q

BID(MAXTRY) ;-- This function will bid for Master status MAXTRY times

 ;  and return a 1 if succesful, 0 if fails

 ;  INPUT - MAXTRY - Maximum number of attemps before failing

 ; OUTPUT -  1 for ok; 0 fails

 N RESULT,HLTRIES,HLDLX

 S RESULT=0,HLTRIES=0

 ;-- update status

 D MONITOR^HLCSDR2("BIDDING",5,HLDP)

BIDRET ;-- bid for master status

 D TRACE^HLCSDL2("Master Bid")

 D ENQ^HLCSDL2

 ;-- update status

 D TRACE^HLCSDL2("Master Bid Wait Ack0")

 D MONITOR^HLCSDR2("WAIT ACK",5,HLDP)

 ;-- if read ack if block 0 OK else fail

 I $$READACK^HLCSDL2(0) S RESULT=1 G BIDQ

 ;-- if nak or timeout

 S HLTRIES=HLTRIES+1

 I HLTRIES>(MAXTRY-1) G BIDQ

 G BIDRET

BIDQ ;-- exit

 Q RESULT

WRITE(HLDOUT0,HLDOUT1) ;-- This function will take the message contained

 ;  in file 870 specified by HLDOUT0 and HLDOUT1 and write the data out.

 ;  after each write the system will wait for an ack.

 ;  INPUT : HLDOUT0 - IEN of file #870

 ;          HLDOUT1 - IEN of out queue multiple

 N HLHEAD,HLTEXT1,HLFOOT,HLX1,HLX2,HLX3,HLTEMP

 ;-- loop to process message

 S HLX1="",HLX2="HLTEXT1"

 F HLI=1:1 K HLTEXT1 S HLX1=$$NEXTLINE^HLCSUTL(HLDOUT0,HLDOUT1,HLX1,HLX2,"OUT") Q:'HLX1  D  I '$$SEND(HLX2,HLHEAD,HLFOOT,5,HLI#8) Q

 . S HLX3=$$NEXTLINE^HLCSUTL(HLDOUT0,HLDOUT1,HLX1,"HLTEMP","OUT")

 . D BUILD^HLCSDL2(HLX2,HLI,$S(HLX3:HLETB,1:HLETX),.HLHEAD,.HLFOOT)

WRITEQ Q

SEND(HLTEXT,HLHEAD,HLFOOT,HLRETRY,HLBK) ;-- This function will write the X3.28 formatted

 ; string out the port and wait for an ack. If this function fails

 ; 0 will be returned, else 1.

 ; Input - HLTEXT - Array containing segment to send

 ;       - HLHEAD - Block header <STX><BLK><LEN>

 ;       - HLFOOT - Block footer <ETX or ETB><BCC><TERM>

 ;       - HLRETRY- Maximum retries before failure

 ;       - HLBK   - Current block 0-7

 ; Output- 0 Fails, 1 = OK

 N RESULT,HLTRY,X

 S RESULT=1,HLTRY=0

RETRY ;-- write data

 ;-- update status

 D TRACE^HLCSDL2("Master Write")

 D MONITOR^HLCSDR2("WRITING",5,HLDP)

 U IO

 ;-- write header

 W HLHEAD

 D LOG(HLHEAD,"WRITE: ")

 S X="" F  S X=$O(@HLTEXT@(X)) Q:'X  W @HLTEXT@(X) D LOG(@HLTEXT@(X),"Write: ")

 ;-- write footer

 W HLFOOT D LOG(HLFOOT,"WRITE: ")

 ;-- Wait for ack

 D TRACE^HLCSDL2("Master Wait for Ack"_HLBK)

 D MONITOR^HLCSDR2("WAITING ACK",5,HLDP)

 ;-- if ack

 I $$READACK^HLCSDL2(HLBK) S RESULT=1 D MONITOR^HLCSDR2("D",2,HLDP,HLDOUT1,"OUT") G SENDQ

 ;-- if nak then retry

 S HLTRY=HLTRY+1

 I HLTRY>(HLRETRY-1) S RESULT=0 G SENDQ

 G RETRY

SENDQ ;-- exit

 Q RESULT

EXIT ;-- Cleanup

LOG(ST1,OP) ;Log reads/writes (translates ctrls)

 ;ST1=string to file

 ;OP=operation "read" or "write"

 I $G(HLTRACE) D

 .N X S X=$G(^XTMP("HL",0)),$P(X,U)=DT+1,$P(X,U,2)=DT

 .S $P(X,U,3)="HL7 Debug Log",HLLOG=$P(X,U,4)

 .S HLN=$$TRANS(ST1)

 .S HLLOG=HLLOG+1,^XTMP("HL",HLLOG)=OP_HLN,$P(X,U,4)=HLLOG

 .S ^XTMP("HL",0)=X

TRANS(ST) ;Translate controls in string

 ;ST=String containing embedded x3.28 control characters

 S ST2="" F I=1:1:$L(ST) S J=$E(ST,I) D

 .I $D(HLCTRL($A(J))) S J=HLCTRL($A(J))

 .S ST2=$G(ST2)_J

 Q ST2

HLCSDL1.m