I need to read a line of numbers separated by spaces and ending with a 0, like this:

1 2 3 4 7 20 12334 0

Each number needs to only be processed individually, so I don't have to keep them all in memory. The problem is, input lines can be very long and reading them with <> and splitting consumes a lot of memory.

I tried setting a space as the input record separator, but it doesn't get the last number correctly.

use strict;
use warnings;

sub do_something { print '{', $_[0], "}\n" }

local $/ = ' ';
while (<>) {
    do_something($_);
}

[download]

I also tried to simulate C++ cin behaviour with the following function:

sub cin_read {
    my $inchar = getc;
    $inchar = getc while $inchar =~ /^\s$/;
    my $result = '';
    while ($inchar =~ /^\S$/) {
        $result .= $inchar;
        $inchar = getc;
    }
    return $result;
}

[download]

However, it's overly complicated and slow.

How else could I go about doing this?

EDIT: Updated sample input to include multi-digit numbers

In reply to Reading a huge input line in parts by kroach

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