I would say that the first step is to find the length in bytes of the raw data block represented by  'i i f f f' (remembering that the data sizes of these template specifiers are implementation dependent). 

c:\@Work\Perl>perl -wMstrict -le
"my $template = 'i2 f3';
 ;;
 sub template_len {
   my ($template) = @_;
   ;;
   my $s = pack $template;
   return length $s;
   }
 ;;
 my $buf_size = template_len($template);
 print $buf_size;
 ;;
 print template_len('i i f f f');
 print template_len('i f3 i');
"
20
20
20

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Knowing the size of a single raw block allows reading n raw blocks of data at a time with, IIRC, read or sysread (or the appropriate buffered-read built-in) and then unpack-ing with a template like "($template)n" or just "($template)*".

In reply to Re: Iteratively unpack structure from binary file by AnomalousMonk
in thread Iteratively unpack structure from binary file by cMonkE

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