#######################################################################################
#-- This PERL script creates a 114-GIG Flat File containing 233+ million Bible verses,
#-- for 7500 complete copies of the KJV Bible (31,102 verses/copy).
#--  
#-- One copy of the Bible is used as input, and is of variable-length record format, 
#-- with CR/LF (newline) record terminator. Output file will be formatted to 528 byte
#-- fixed-length records, with no record terminator. 
#-- 
#-- Fixed-length records are used to demonstrate capacity requirements for a READ/WRITE
#-- database where the records are edited in-place at reliable byte offset locations.
#-- 
#-- A similar READ ONLY database with variable-length records would have the capacity
#-- to hold 4 times as many Bible verses i.e. almost 1 Billion records/verses. 
#--
#-- This Flat File is being created for RANDOM ACCESS of its records, where the byte
#-- offset locations are stored persistently in a PERL SDBM database file of key/value
#-- pairs tied to an in-memory PERL program hash table at run-time. 
#--
#-- Tested on Windows 7 Home Premium with NT File System (NTFS). 
#-- Tested with ActiveState ActivePerl for Windows version/release 5.26.1
#-- Tested using unbuffered File I/O syntax:  sysopen, sysseek, sysread, syswrite,
#-- and close. 
#######################################################################################

use File::Basename;
use Fcntl; 

$cwd=dirname($0);   #-- this application program directory

print "Processing... Please wait..." . "\n";
   
$total_verses = 0;
@nbr_verses = ();

open(IN, "< $cwd\\BibleVerses1Copy.txt") or
   do {print "Error on open input: $!\n"; sleep 5; die};  
 
while (<IN>) {   
   chomp;   #-- remove CR/LF
   push @nbr_verses, $_;   #-- load 31,102 verses to an array in memory
   
}

sysopen(OUT,"$cwd\\KJV_BIBLE_SDBM_528_31102_7500.dat", O_WRONLY|O_CREAT) or
     do {print "Error on open output: $!\n"; sleep 5; die};  

$tell = sysseek(OUT, 0, 0);  #-- top of file

for ($tran_nbr=1; $tran_nbr<=7500; $tran_nbr++) {  
   
   print "$tran_nbr of 7500\n"; 

   foreach $verse (@nbr_verses) {
      
      $total_verses++;
      $line=sprintf("%-528s", $verse); 
      syswrite(OUT, $line);
   }
}

print "Total verses written = $total_verses \n";
exit;

END {
   close(IN);
   close(OUT);
   sleep 5;
}