build-data.exchanges

#!/usr/local/bin/perl

use strict;
use warnings;
use Text::CSV_XS;
use Data::Dumper;

my $csv = Text::CSV_XS->new();

my %exch_ranges = ();
while(<STDIN>) {
    $csv->parse($_) || die("Bad data $_\n");
    my @fields = $csv->fields();
    $fields[1] =~ s/^0//;
    $fields[2] =~ s/^0//;
    my ($exchg, $min, $max) = @fields[0..2];
    print STDERR "$exchg: $min, $max\n";
    
    my @minprefixes = map { substr($min, 0, $_) } reverse 1..length($min);
    my @maxprefixes = map { substr($max, 0, $_) } reverse 1..length($max);
    my $longest_prefix;
    foreach(0 .. length($max) - 1) {
        if($minprefixes[$_] == $maxprefixes[$_]) {
            $longest_prefix = $minprefixes[$_];
            last;
        }
    }
    my @prefixes = break_prefix($longest_prefix, $min, $max);
    $exch_ranges{$_} = $exchg foreach(@prefixes);
    print STDERR "  [".join(', ', @prefixes)."]\n";
}
print Dumper(\%exch_ranges);

sub break_prefix {
    my($prefix, $min, $max) = @_;
    
    my $extradigits = length($min) - length($prefix);
    return () unless($extradigits);
    
    if(
        $prefix.('0' x $extradigits) >= $min &&
        $prefix.('9' x $extradigits) <= $max
    ) {
        return $prefix;
    } else {
        return map { break_prefix($prefix.$_, $min, $max) } (0 .. 9);
    }
}