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Omphaloskepsis/plugins/jetpack/modules/tiled-gallery/math/class-constrained-array-rounding.php
2018-03-21 18:19:20 +00:00

75 lines
2.4 KiB
PHP

<?php
/**
* Lets you round the numeric elements of an array to integers while preserving their sum.
*
* Usage:
*
* Jetpack_Constrained_Array_Rounding::get_rounded_constrained_array( $bound_array )
* if a specific sum doesn't need to be specified for the bound array
*
* Jetpack_Constrained_Array_Rounding::get_rounded_constrained_array( $bound_array, $sum )
* If the sum of $bound_array must equal $sum after rounding.
*
* If $sum is less than the sum of the floor of the elements of the array, the class defaults to using the sum of the array elements.
*/
class Jetpack_Constrained_Array_Rounding {
public static function get_rounded_constrained_array( $bound_array, $sum = false ) {
// Convert associative arrays before working with them and convert them back before returning the values
$keys = array_keys( $bound_array );
$bound_array = array_values( $bound_array );
$bound_array_int = self::get_int_floor_array( $bound_array );
$lower_sum = array_sum( wp_list_pluck( $bound_array_int, 'floor' ) );
if ( ! $sum || ( $sum < $lower_sum ) ) {
// If value of sum is not supplied or is invalid, calculate the sum that the returned array is constrained to match
$sum = array_sum( $bound_array );
}
$diff_sum = $sum - $lower_sum;
self::adjust_constrained_array( $bound_array_int, $diff_sum );
$bound_array_fin = wp_list_pluck( $bound_array_int, 'floor' );
return array_combine( $keys, $bound_array_fin );
}
private static function get_int_floor_array( $bound_array ) {
$bound_array_int_floor = array();
foreach ( $bound_array as $i => $value ){
$bound_array_int_floor[$i] = array(
'floor' => (int) floor( $value ),
'fraction' => $value - floor( $value ),
'index' => $i,
);
}
return $bound_array_int_floor;
}
private static function adjust_constrained_array( &$bound_array_int, $adjustment ) {
usort( $bound_array_int, array( 'self', 'cmp_desc_fraction' ) );
$start = 0;
$end = $adjustment - 1;
$length = count( $bound_array_int );
for ( $i = $start; $i <= $end; $i++ ) {
$bound_array_int[ $i % $length ]['floor']++;
}
usort( $bound_array_int, array( 'self', 'cmp_asc_index' ) );
}
private static function cmp_desc_fraction( $a, $b ) {
if ( $a['fraction'] == $b['fraction'] )
return 0;
return $a['fraction'] > $b['fraction'] ? -1 : 1;
}
private static function cmp_asc_index( $a, $b ) {
if ( $a['index'] == $b['index'] )
return 0;
return $a['index'] < $b['index'] ? -1 : 1;
}
}