HP 3000 Manuals

SORT-MERGE/XL Programmer's Guide

Example of Core Merging Routine 

The following program merges the personnel files shown at the beginning
of the previous example.  The input files are already sorted by employee
number.

In this example, the files are merged by employee number.  The record
size is determined by the input files.  The status parameter is checked
after the calls to HPMERGEINIT and HPMERGEEND.

Example 2-2.  MERGEFILE Program 

     program MERGEFILE (input,output);

     {This program reads the files, TEMPEMP and PERMEMP, merges}
     {them by employee number, and outputs to the file, ALLEMP }

     var
        tempFileNum: INTEGER;
        permFileNum: INTEGER;
        outFileNum : INTEGER;
        status     : INTEGER;

     procedure HPFOPEN  ; intrinsic;
     procedure HPMERGEINIT; intrinsic;
     procedure HPMERGEERRORMESS; intrinsic;
     procedure HPMERGEEND; intrinsic;
     procedure FCLOSE; intrinsic;

     procedure OPEN_FILES;

     const
        designator  = 2;
        domain      = 3;
        access      = 11;
        record_size = 19;

     var
        tempFile  : packed array [1..10] of CHAR;
        permFile  : packed array [1..10] of CHAR;
        outFile   : packed array [1..10] of CHAR;
        permanent : INTEGER;
        new       : INTEGER;
        write     : INTEGER;
        size      : INTEGER;

Example 2-2.  MERGEFILE Program, continued 

        tempFile := '%TEMPEMP%';
        permanent := 1;
        HPFOPEN (tempFileNum, status, designator, tempFile, domain, permanent) ;

        permFile := '%PERMEMP%';
        HPFOPEN (permFileNum, status, designator, permFile, domain, permanent) ;
        new := 4;
        write := 1;
        size := 80;
        outFile := '%ALLEMP%';
        HPFOPEN (oOutFileNum, status, designator, outFile, domain, new, access,
                 write, record_size, size);
     end;

     procedure DO_MERGE;

     var
        inputfiles   : array [1..3] of INTEGER;
        outputfile   : array [1..2] of INTEGER;
        keysonly     : INTEGER;
        numKeys      : INTEGER;
        keys         : array [1..4] of INTEGER;
        altseq       : packed array [1..2] of CHAR;
        message      : packed array [1..80] of CHAR;
        length       : INTEGER;

     begin
        inputfiles [1] := tempFileNum;
        inputfiles [2] := permFileNum;
        inputfiles [3] := 0;

        outputfile [1] := outFileNum;                                 {from HPFOPEN}
        outputfile [2] := 0;

        keysonly := 0;           {output record format same as input record format }
        numKeys := 1;                                                      {one key}
        keys[1] := 41;                                                  {key begins}
        keys[2] := 20;                                                  {key length}
        keys[3] := 0;                                                    {byte data}
        keys[4] := 0;                                              {ascending order}

        altseq[1] := CHR(255);                      {data = ASCII; sequence = ASCII}
        altseq[2] := CHR(255);                             {256 characters in ASCII}

Example 2-2.  MERGEFILE Program, continued 

        HPMERGEINIT (status, inputfiles,, outputfile,, keysonly, numKeys, keys,
                     altseq,,,,,);
        if status <> 0 then                    {if error in HPMERGEINIT           }
        begin                                  {get message and print it to screen}
           message := ' ';
           HPMERGEERRORMESS (status, message, length);
           writeln (Message);
        end;

        HPMERGEEND (status, statistics);

        if status <> 0 then                    {if error in HPMERGEEND            }
        begin                                  {get message and print it to screen}
           message := ' ';
           HPMERGEERRORMESS (status, message, length);
           writeln (message)
        end;
     end;

     procedure CLOSE_FILES;

     var
        disposition : SHORTINT;
        securityCode : SHORTINT;

     begin
        disposition := 0;
        securityCode := 0;
        FCLOSE (tempFileNum, disposition, securityCode);
        FCLOSE (permFileNum, disposition, securityCode);
        disposition := 1;
        FCLOSE (outFileNum, disposition, securityCode);

     end;

     begin {main}
        OPEN_FILES;
        DO_MERGE;
        CLOSE_FILES;
     end.

When this program is executed, the output is written to ALLEMP. To view
ALLEMP:
_____________________________________________________________________________
|                                                                           |
|                                                                           |
|      :print allemp                                                        |
|                                                                           |
|      Jones,              Eliza               000001              06/06/87 |
|      Gangley,            Tomas               000003              06/06/87 |
|      Smith,              James               000005              06/06/87 |
|      Jackson,            Jonathan            000006              06/06/87 |
|      Rields,             Evelyn              000007              07/12/87 |
|      Washington,         Lois                000014              07/23/87 |
|      Jackson,            Rosa                000022              08/15/87 |
|      Everett,            Joyce               000029              10/19/87 |
|                                                                           |
_____________________________________________________________________________

MPE/iX 5.0 Documentation