Stream Cache - Flexible moving window buffer any objects

stream_cache.pm

package stream_cache;

use strict;
use warnings;

sub new{
    my $get_next_chunk_data = shift;
    my $next_chunk_id = shift;
    $next_chunk_id = 0 unless $next_chunk_id;
    return {
        stored_chunks=>{},
        oldest_stored_chunk=>undef,
        next_chunk_id => 0,
        get_next_chunk_data=>$get_next_chunk_data,
    };
}

sub get_chunk {
    my $self=shift;
    my $chunk_id =shift;

    if($chunk_id == $self->{next_chunk_id}){
        my $chunk_data = $self->{get_next_chunk_data}->();
        $self->{next_chunk_id}++;
        $self->{stored_chunks}{$chunk_id}=$chunk_data;
        $self->{oldest_stored_chunk}=$chunk_id if !defined($self->{oldest_stored_chunk});
        return $chunk_data;
    }

    if(exists $self->{stored_chunks}{$chunk_id}){
        return $self->{stored_chunks}{$chunk_id};
    }

    if($chunk_id > $self->{next_chunk_id}){
        warn "uhh, are you asking me to skip a chunk???";
        return undef;
    }
    if($chunk_id < $self->{oldest_stored_chunk}){
        warn "uhh you are asking for a chunk I already deleted, wtf?";
        return undef;
    }
    warn "I have no explaination for why I can't provide you with the chunk. I just can't";
    return undef;
}
sub calc_oldest_stored_chunk{
	my $self=shift;
    $self->{oldest_stored_chunk} = undef;
    my @chunkids = keys %{$self->{stored_chunks}};
    if(@chunkids){
    	@chunkids = sort {$a <=> $b} @chunkids;
    	$self->{oldest_stored_chunk} = $chunkids[0];
    }   	
}

sub delete_chunks_older_than {
    my $self = shift;
    my $chunk_id = shift;
    for my $old_id( keys %{$self->{stored_chunks}}){
        delete $self->{stored_chunks}{$old_id} if $old_id < $chunk_id;
    }
	calc_oldest_stored_chunk();
}

sub rewind{
	my $self=shift;
	my $new_next_id=shift;
    for my $old_id( keys %{$self->{stored_chunks}}){
        delete $self->{stored_chunks}{$old_id} if $old_id >= $new_next_id;
    }
    calc_oldest_stored_chunk();
    
}	


1;