Access Log Parser

<?php
/**
 * Access Log Parser
 */
$handle = fopen( 'access.log', 'r' );

function display_column_report( $values, $total ) {
    foreach ( $values as $key => $quantity ) {
        $percent = round( 100 * $quantity / $total );
        echo "- $quantity ($percent%): $key\n";
    }

    echo "\n";
}

function increment_key_in_array( $array, $key ) {
    if ( ! isset( $array[ $key ] ) ) {
        $array[ $key ] = 0;
    }

    $array[ $key ]++;

    return $array;
}

$line_quantity = 0;
$codes = $files = $referrers = $user_agents = [];

while ( $line = fgetcsv( $handle, 0, ' ' ) ) {
    $line_quantity++;

    $codes = increment_key_in_array( $codes, $line[6] );

    $file  = preg_replace( '#^(?:POST|GET)\s([^\s]+).*#', '$1', $line[5] );
    $files = increment_key_in_array( $files, $file );

    $referrer  = in_array( $line[8], [ ' ', '-' ] ) ? 'Unknown' : $line[8];
    $referrers = increment_key_in_array( $referrers, $referrer );

    $user_agent  = in_array( $line[9], [ ' ', '-' ] ) ? 'Unknown' : $line[9];
    $user_agents = increment_key_in_array( $user_agents, $user_agent );
}

echo "####### LOG REPORT #######\n\n";

echo "Line quantity: $line_quantity\n\n";

echo "HTTP Codes:\n";
display_column_report( $codes, $line_quantity );

echo "Files:\n";
arsort( $files );
display_column_report( $files, $line_quantity );

echo "Referrers:\n";
arsort( $referrers );
display_column_report( $referrers, $line_quantity );

echo "User Agents:\n";
arsort( $user_agents );
display_column_report( $user_agents, $line_quantity );