Part-DB-server/src/Services/SIFormatter.php
Jan Böhmer e557bdedd5 Added an PHP CS fixer config file and applied it to files.
We now use the same the same style as the symfony project, and it allows us to simply fix the style by executing php_cs_fixer fix in the project root.
2019-11-09 00:47:20 +01:00

108 lines
3.6 KiB
PHP

<?php
/**
* This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
*
* Copyright (C) 2019 Jan Böhmer (https://github.com/jbtronics)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
namespace App\Services;
/**
* A service that helps you to format values using the SI prefixes.
*/
class SIFormatter
{
/**
* Returns the magnitude of a value (the count of decimal place of the highest decimal place).
* For example, for 100 (=10^2) this function returns 2. For -2500 (=-2.5*10^3) this function returns 3.
*
* @param float $value The value of which the magnitude should be determined.
*
* @return int The magnitude of the value
*/
public function getMagnitude(float $value): int
{
return (int) floor(log10(abs($value)));
}
/**
* Returns the best SI prefix (and its corresponding divisor) for the given magnitude.
*
* @param int $magnitude The magnitude for which the prefix should be determined.
*
* @return array A array, containing the divisor in first element, and the prefix symbol in second. For example, [1000, "k"].
*/
public function getPrefixByMagnitude(int $magnitude): array
{
$prefixes_pos = ['', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
$prefixes_neg = ['', 'm', 'μ', 'n', 'p', 'f', 'a', 'z', 'y'];
if ($magnitude >= 0) {
$nearest = (int) floor(abs($magnitude) / 3);
$symbol = $prefixes_pos[$nearest];
} else {
$nearest = (int) round(abs($magnitude) / 3);
$symbol = $prefixes_neg[$nearest];
}
if ($magnitude < 0) {
$nearest *= -1;
}
return [10 ** (3 * $nearest), $symbol];
}
/**
* @return array
*/
public function convertValue(float $value): array
{
//Choose the prefix to use
$tmp = $this->getPrefixByMagnitude($this->getMagnitude($value));
$ret = [
'value' => $value / $tmp[0],
'prefix_magnitude' => log10($tmp[0]),
'prefix' => $tmp[1],
];
return $ret;
}
/**
* Formats the given value to a string, using the given options.
*
* @param float $value The value that should be converted
* @param string $unit The unit that should be appended after the prefix
* @param int $decimals The number of decimals (after decimal dot) that should be outputed.
*
* @return string
*/
public function format(float $value, string $unit = '', int $decimals = 2): string
{
[$divisor, $symbol] = $this->getPrefixByMagnitude($this->getMagnitude($value));
$value /= $divisor;
//Build the format string, e.g.: %.2d km
if ('' !== $unit || '' !== $symbol) {
$format_string = '%.'.$decimals.'f '.$symbol.$unit;
} else {
$format_string = '%.'.$decimals.'f';
}
return sprintf($format_string, $value);
}
}