Wanted MVS Assembler program to read any flat file

[dallasdino]

Does anyone have source to read any file into a general purpose program?

I have a COBOL smart compare but want to make it general purpose smart compare program.

Does anyone have an Assembler program or another way to do this?

I am only talking about simple flat files here.

 

[kevinf2349]

I am not really sure what it is you are looking for the assembler to do. IBM have IEBGENER (or ICEGENER) that will read a flat file, but then your program would still have to read in the file in order to process it so I am unsure as to what it is you actually want.

Reading an input file in assembler is very easy, but then again it is easy in Cobol too so I am not sure what benefit writing the routine in assembler will achieve.

 

[dallasdino]

I think the key will be examining the OPEN and perhaps the GET and PUT macro. Has anyone examined this to know it well? I want to find the length and if it is variable or fixed when I open the file.

This is for a MVS mainframe OS/390 system. I forgot COBOL was on so many platforms but most COBOL is still on the mainframe so I assumed. Sorry.

I am interested in reading any size flat file either fixed or variable length and getting the DCB parameters from the program. I do have mainframe assembler skills but I have yet to venture too far down this path. After the file is opened it can be determined what type of file it is.

SYNCSORT, EDSs Waapdsut, DYL280, Easytrieve and many other utilities can process files without knowing the attributes first.

I have written a smart compare COBOL program that works but I must define the COBOL with some length. This does work but I must copy the OLD and NEW files to match the input format for COBOL and then supply the real attributes by a parm or card input. I could make the file variable but I would still have to copy the old fixed and new file using a SORT or something to the standard format for the COBOL progam. I want to bypass these extra steps copying the input to a certain format first. An assembler subprogram with a GL returning the file with a pointer might do the trick. I wish COBOL could.

Below is some basic assembler GET logic with a pointer.
I have seen sample code for after the open to test for a fixed or variable file as below but I am not sure it works yet. Also can I get other information like the LRECL supplied by the JCL when the file is opened? All I really need is the LRECL and if it is a fixed or variable file.
LA 1,FILEIN POINT TO DCB
TM 36(1),X'40' CHECK IF FIXED OR VARIABLE FILE
BZ FIXED
B VARIABLE

Basic 370 Assembler code:
USING NEWDSECT,4 REGISTER 4 POINTS TO NEW
************************************************************************
* READ THE NEWFILE *
************************************************************************
READNEW DS 0H
ST 14,READNEWS
CLI SNEWEOF,C'Y' IF NEW FILE NOT EOF
BE READNEWX
GET NEWFILE READ NEWFILE
LR 4,1 POINT TO NEW DSECT
B READNEWX ELSE
EOFNEW MVI SNEWEOF,C'Y' SET EOF SWITCH TO YES
READNEWX DS 0H END-IF
L 14,READNEWS
BR 14
SNEWEOF DC CL1'N'
NEWFILE DCB DSORG=PS,MACRF=GL,DDNAME=NEWFILE,EODAD=EOFNEW

 

[kevinf2349]

Now I see what you are wanting.

What you need to do is issue a RDJFCB (Read JFCB) from there you can get all the information that you need about the input file. Here is a much trimmed sample.

RDJFCB (INPUT2) Now read the JFCB
LTR R15,R15 Did it work?
BNZ RDJFCB_FAILED No - Skip to error out
LA R7,JFCBAREA Load R7 with JFCB area
USING INFMJFCB,R7 Addressability to JFCB
LH R1,JFCLRECL Get record length into R1
ST R1,MYLRECL Save record length
DROP R7
GETMAIN RC,LV=(R1),LOC=(RES,ANY) Get storage
LTR R15,R15 Did the GETMAIN work?
BNZ GETMAIN_FAILED No - Skip to error out

:::::::: more program code

INPUT2 DCB DDNAME=INPUT,DSORG=PS,MACRF=(GL),EXLST=EXLST
JFCBAREA DS 176X'00'
DS 0F
EXLST DC X'87',AL3(JFCBAREA)
JFCB DSECT
IEFJFCBN ,


Details on the JFCB can be found in the DATA AREAS Manual (Volume 3) (IBM Manual number SY28-1166-11)

Good luck

 

[dallasdino]

Thanks Kevin.

I will give this a try. Yak at me if you think of anything else I should know.

Thanks again.

 

[dallasdino]

Here is the code needed for getting the input file attirbutes and setting an output file to the same attributes as an input file.

         OPEN  (IFILE,INPUT)           OPEN INPUT TO GET ATTRIBUTES
         MVC   OFILE+36(1),IFILE+36    MOVE THE FORMAT INPUT TO OUTPUT
*                                      V=X'40',VB=X'50,F=X'80',FB=X'90'
         MVC   OFILE+82(2),IFILE+82    MOVE THE LRECL  INPUT TO OUTPUT
*                                      (RECORD LENGTH IS A HALF WORD)
         OPEN  (OFILE,OUTPUT)          OPEN OUPUT WITH INPUT ATTRIBUTES

IFILE    DCB   DSORG=PS,MACRF=GL,DDNAME=IFILE,EODAD=EOFI
OFILE    DCB   DSORG=PS,MACRF=PL,DDNAME=OFILE

Thanks for everyone pointing me in the right direction. Yak back if you want a copy of the finished program.