/usr/share/php/Icinga/Chart/Unit/LogarithmicUnit.php is in php-icinga 2.1.0-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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/* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
namespace Icinga\Chart\Unit;
/**
* Logarithmic tick distribution over the axis
*
* This class does not use the actual logarithm, but a slightly altered version called the
* Log-Modulo transformation. This is necessary, since a regular logarithmic scale is not able to display negative
* values and zero-points. See <a href="http://blogs.sas.com/content/iml/2014/07/14/log-transformation-of-pos-neg>
* this article </a> for a more detailed description.
*/
class LogarithmicUnit implements AxisUnit
{
/**
* @var int
*/
protected $base;
/**
* @var
*/
protected $currentTick;
/**
* @var
*/
protected $minExp;
/**
* @var
*/
protected $maxExp;
/**
* True when the minimum value is static and isn't affected by the data set
*
* @var bool
*/
protected $staticMin = false;
/**
* True when the maximum value is static and isn't affected by the data set
*
* @var bool
*/
protected $staticMax = false;
/**
* Create and initialize this AxisUnit
*
* @param int $nrOfTicks The number of ticks to use
*/
public function __construct($base = 10)
{;
$this->base = $base;
$this->minExp = PHP_INT_MAX;
$this->maxExp = ~PHP_INT_MAX;
}
/**
* Add a dataset and calculate the minimum and maximum value for this AxisUnit
*
* @param array $dataset The dataset to add
* @param int $idx The idx (0 for x, 1 for y)
*
* @return $this Fluent interface
*/
public function addValues(array $dataset, $idx = 0)
{
$datapoints = array();
foreach ($dataset['data'] as $points) {
$datapoints[] = $points[$idx];
}
if (empty($datapoints)) {
return $this;
}
sort($datapoints);
if (!$this->staticMax) {
$this->maxExp = max($this->maxExp, $this->logCeil($datapoints[count($datapoints) - 1]));
}
if (!$this->staticMin) {
$this->minExp = min($this->minExp, $this->logFloor($datapoints[0]));
}
$this->currentTick = 0;
return $this;
}
/**
* Transform the absolute value to an axis relative value
*
* @param int $value The absolute coordinate from the data set
* @return float|int The axis relative coordinate (between 0 and 100)
*/
public function transform($value)
{
if ($value < $this->pow($this->minExp)) {
return 0;
} elseif ($value > $this->pow($this->maxExp)) {
return 100;
} else {
return 100 * ($this->log($value) - $this->minExp) / $this->getTicks();
}
}
/**
* Return the position of the current tick
*
* @return int
*/
public function current()
{
return $this->currentTick * (100 / $this->getTicks());
}
/**
* Calculate the next tick and tick value
*/
public function next()
{
++ $this->currentTick;
}
/**
* Return the label for the current tick
*
* @return string The label for the current tick
*/
public function key()
{
$currentBase = $this->currentTick + $this->minExp;
if (abs($currentBase) > 4) {
return $this->base . 'E' . $currentBase;
}
return (string) intval($this->pow($currentBase));
}
/**
* True when we're at a valid tick (iterator interface)
*
* @return bool
*/
public function valid()
{
return $this->currentTick >= 0 && $this->currentTick < $this->getTicks();
}
/**
* Reset the current tick and label value
*/
public function rewind()
{
$this->currentTick = 0;
}
/**
* Perform a log-modulo transformation
*
* @param $value The value to transform
*
* @return double The transformed value
*/
protected function log($value)
{
$sign = $value > 0 ? 1 : -1;
return $sign * log1p($sign * $value) / log($this->base);
}
/**
* Calculate the biggest exponent necessary to display the given data point
*
* @param $value
*
* @return float
*/
protected function logCeil($value)
{
return ceil($this->log($value)) + 1;
}
/**
* Calculate the smallest exponent necessary to display the given data point
*
* @param $value
*
* @return float
*/
protected function logFloor($value)
{
return floor($this->log($value));
}
/**
* Inverse function to the log-modulo transformation
*
* @param $value
*
* @return double
*/
protected function pow($value)
{
if ($value == 0) {
return 0;
}
$sign = $value > 0 ? 1 : -1;
return $sign * (pow($this->base, $sign * $value));
}
/**
* Set the axis minimum value to a fixed value
*
* @param int $min The new minimum value
*/
public function setMin($min)
{
$this->minExp = $this->logFloor($min);
$this->staticMin = true;
}
/**
* Set the axis maximum value to a fixed value
*
* @param int $max The new maximum value
*/
public function setMax($max)
{
$this->maxExp = $this->logCeil($max);
$this->staticMax = true;
}
/**
* Return the current minimum value of the axis
*
* @return int The minimum set for this axis
*/
public function getMin()
{
return $this->pow($this->minExp);
}
/**
* Return the current maximum value of the axis
*
* @return int The maximum set for this axis
*/
public function getMax()
{
return $this->pow($this->maxExp);
}
/**
* Get the amount of ticks necessary to display this AxisUnit
*
* @return int
*/
public function getTicks()
{
return $this->maxExp - $this->minExp;
}
}
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