#! /bin/sh

# This is a shell archive.  Type 'sh <file>' to unpack.

echo x - README.1st
cat >README.1st <<'MKSHAR_EOF'

		Multiple Report Interleaved Output Processing

This presents a sample of 4GL code which writes interleaved sections of
multiple reports to a single output stream.  In the case of the sample it is a
detail report and a summary report which would be difficult to implement as a
single 4GL report module.  The user requirement is that the summary page for a
client appear immediately following the detail page.  The solution presented is
to write both reports to a pipe and have the pipe filter handle interleaving
the reports properly using UNIX file locking functions.  The indicator to the
sample filter, append.c, that a logical report page is complete is the FormFeed
(^L or \f) character at the end of each physical page accomplished using the
4GL END OF PAGE option in the OUTPUT section or the page length passed on the
command line.

The method requires that a separate report be started and finished for each
grouping that causes an alternation in the output from one report type to the
other (ie from summary to detail).  The order in which the reports are FINISHed
is the order in which their pages will be flushed as 4GL itself buffers the
report lines in a temp table until the report is FINISHed.

To allow for logical report pages or sections that span physical pages a
semaphore character or string can be printed from the REPORT HEADER section as
appropriate and the filter modified to recognize that semaphore string as the
point at which to flush buffered output, optionally not printing the semaphore.

The current version uses a fixed array of 100 strings 1024 characters each to
buffer the report.  Modifiing this to use a dynamically growing array is
trivial and left to the user as an exercise.

Files included:

README.1st	- This file.
append.c	- The sample output filter program.
sample.4gl	- The sample 4GL module.
sample.sql	- Table structure for the sample program.
sample.dat	- Sample data for the sample program.

MKSHAR_EOF


echo x - append.c
cat >append.c <<'MKSHAR_EOF'
/* append.c - buffer one page at a time (up to 100 lines) and flush locking 
   the output file to permit multiple writers to the file without interference.
   This could be implemented as a Perl script if "C" is not available. 

   Author: Art S. Kagel
 */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

#define ARRSIZE 100

int main( int argc, char **argv )
{
    FILE *out;
    char line[ARRSIZE][1024];
    long ln=0, i, fd, pgln;

    /* Arg 1 is output file name */
    out = fopen( argv[1], "a" );
    fd = fileno( out );

    /* Arg 2 is output page length */
    pgln = atol( argv[2] );
    if (!pgln)
	pgln = ARRSIZE;

    /* Buffer one page of data and then output. */
    for (;;) {
        if (fgets( line[ln], 1024, stdin ) == (char *)NULL)
	    break;
        if (strstr( line[ln], "\f" ) || (ln + 1) >= pgln) {
	    lockf( fd, F_LOCK, 0 );
	    for (i=0; i<=ln; i++)
		fputs( line[i], out );
	    fflush( out );
	    lockf( fd, F_ULOCK, 0 );
	    ln = 0;
	} else
	    ln++;
    }
    if (ln) {
	lockf( fd, F_LOCK, 0 );
	for (i=0; i<ln; i++)
	    fputs( line[i], out );
	fflush( out );
	lockf( fd, F_ULOCK, 0 );
    }
}
MKSHAR_EOF


echo x - sample.4gl
cat >sample.4gl <<'MKSHAR_EOF'
# 
# Sample of a 4GL program that produces multiple interleaved reports using 
# append.c to filter and flush the output
#
database flintstones

main 
define cust, ocust     char(6),
       rn_no    char(10),
       type     char(2),
       amt      decimal(9,2),
       first	integer

   declare summ cursor for
	select * from tm_rental order by cust, type

   let ocust = ""
   let first = TRUE

   run "rm inv.all"  -- delete any old output file -ASK

   -- Start the report the first time -ASK
   -- The append program buffers one report page and locks the output file
   -- before flushing to avoid clashes between the two reports.  See source.
   start report summary to pipe "append inv.all 59" -ASK
   start report detail to pipe "append inv.all 59" -ASK
   foreach summ into cust, rn_no, type, amt
      if (first) then
	  -- So the first row does not trigger an empty report -ASK
	  let ocust = cust
	  let first = FALSE
      end if
      if (ocust != cust) then
	  -- If customer changes, close summary and detail reports and restart
	  finish report summary
	  finish report detail
	  start report summary to pipe "append inv.all 59"
	  start report detail to pipe "append inv.all 59"
      end if
      output to report summary (cust, rn_no, type, amt)
      output to report detail (cust, rn_no, type, amt)
      let ocust = cust  -- Detects change in customer
   end foreach
   -- Don't forget to finish for last customer -ASK
   finish report summary
   finish report detail

   run "lp inv.all" without waiting

end main

# layout for summary invoice
report summary (cust, rn_no, type, amt)
define cust     char(6),
       rn_no    char(10),
       type     char(2),
       amt      decimal(9,2)

OUTPUT               -- I added this section, if nothing else it documents -ASK
   PAGE LENGTH 59    -- Set the page length -ASK
   LEFT MARGIN 5     -- This is default anyway -ASK
   TOP OF PAGE "^L"  -- This uses form feed char instead of blank lines -ASK
 
ORDER EXTERNAL BY cust, type  -- Need this so report knows data is sorted - ASK

format
   page header
      print "Summary Invoice"
      print "Bill To : ", cust
      print
      print "Type     Amt (RM)"
      print "-----------------"
   
   before group of cust
      skip to top of page

   after group of type
      print type, column 8, group sum(amt) using "##,##&.&&"

   after group of cust
      print "-----------------"
      print "TOTAL", column 8, group sum(amt) using "##,##&.&&"
      print "-----------------"
end report


# layout for detail invoice
report detail (cust, rn_no, type, amt)
define cust   char(6),
       rn_no    char(10),
       type     char(2),
       amt      decimal(9,2)

OUTPUT               -- I added this section, if nothing else it documents -ASK
   PAGE LENGTH 59    -- Set the page length -ASK
   LEFT MARGIN 5     -- This is default anyway -ASK
   TOP OF PAGE "^L"  -- This uses form feed char instead of blank lines -ASK
 
ORDER EXTERNAL BY cust, type  -- Need this so report knows data is sorted -ASK

format
   page header
      print "Detail Invoice"
      print "Bill To : ", cust
		print
      print "Rental No  Type     Amt (RM)"
      print "----------------------------"
   
   on every row
      print rn_no, column 12, type, column 19, amt using "##,##&.&&"

   before group of cust
      skip to top of page

   after group of cust
      print "----------------------------"
      print "TOTAL", column 19, group sum(amt) using "##,##&.&&"
      print "----------------------------"
end report
MKSHAR_EOF


echo x - sample.sql
cat >sample.sql <<'MKSHAR_EOF'
create table TM_RENTAL
(
	 CUST                CHAR(6)       ,
	 RN_NO               CHAR(10)      ,
	 TYPE                CHAR(2)       ,
	 AMT                 DECIMAL(9,2)
);
MKSHAR_EOF


echo x - sample.dat
cat >sample.dat <<'MKSHAR_EOF'
ABAA02|98000680|TT|343.9|
ACAA09|98000014|DT|216.15|
ACAA09|98000421|RT|67.08|
ACAA09|98000548|RT|67.76|
AHAA06|97000159|RT|901.0|
AHAA06|98000392|RT|77.64|
AHAA06|98000395|RT|70.08|
ACAA09|98000004|DT|201.9|
ACAA09|98000012|DT|509.18|
ACAA09|98000376|TT|288.0|
ABAA02|98000539|RT|175.6|
ABAA02|98000659|RT|171.0|
ABAA02|98000393|TT|96.03|
AFAA08|98000665|RT|176.0|
AFAA08|98000365|TT|117.71|
AFAA08|98000402|TT|781.28|
ABAA02|98000440|RT|125.7|
ABAA02|98000511|TT|184.69|
ABAA02|98000512|TT|196.44|
AFAA08|98000721|TT|100.08|
AFAA08|98000741|TT|120.47|
AHAA06|98000400|RT|60.54|
ABAA02|98000694|TT|522.95|
ACAA09|98000002|DT|249.35|
AHAA06|98000013|DT|450.45|
ACAA09|98000017|DT|218.84|
AHAA06|98000436|RT|55.34|
AHAA06|98000437|RT|70.55|
AHAA06|98000444|RT|79.0|
MKSHAR_EOF