my ($x, $y, $z, $n, $len) = ... # fill in these parameters

my $format = "V$x n$y n C$z ".("Z$len" x $n);
my $recsize = 4*$x + 2*$y + 2 + $z + ($n*$len);

open B, '<', 'binary_file.bin' or die ...;

while (read(B, $buf, $recsize) == $recsize) {
  my @values = unpack($format, $buf);

  my @x = splice(@values, 0, $x);   # snip off the 4-byte ints
  my @y = splice(@values, 0, $y);   # the 2-byte ints
  my $bits = splice(@values, 0, 1);
  my @z = splice(@values, 0, $z);   # the 1-byte ints
  # @values now contain just the null-terminated strings

  # manually fix up signed vs. unsigned shorts in @y:
  $y[1] -= 65536 if ($y[1] > 32767); # repeat for each signed valued

  ...process the record...
}