144 lines
4.2 KiB
PHP
144 lines
4.2 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Brick\Math;
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/**
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* Specifies rounding behavior by defining how discarded digits affect the returned result when an exact value cannot
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* be represented at the requested scale.
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*/
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enum RoundingMode
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{
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/**
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* Asserts that the requested operation has an exact result, hence no rounding is necessary.
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*
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* If this rounding mode is specified on an operation that yields a result that
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* cannot be represented at the requested scale, a RoundingNecessaryException is thrown.
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*/
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case Unnecessary;
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/**
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* Rounds away from zero.
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*
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* Always increments the digit prior to a nonzero discarded fraction.
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* Note that this rounding mode never decreases the magnitude of the calculated value.
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*/
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case Up;
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/**
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* Rounds towards zero.
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*
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* Never increments the digit prior to a discarded fraction (i.e., truncates).
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* Note that this rounding mode never increases the magnitude of the calculated value.
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*/
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case Down;
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/**
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* Rounds towards positive infinity.
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*
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* If the result is positive, behaves as for Up; if negative, behaves as for Down.
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* Note that this rounding mode never decreases the calculated value.
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*/
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case Ceiling;
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/**
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* Rounds towards negative infinity.
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*
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* If the result is positive, behaves as for Down; if negative, behaves as for Up.
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* Note that this rounding mode never increases the calculated value.
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*/
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case Floor;
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/**
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* Rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
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*
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* Behaves as for Up if the discarded fraction is >= 0.5; otherwise, behaves as for Down.
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* Note that this is the rounding mode commonly taught at school.
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*/
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case HalfUp;
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/**
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* Rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
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*
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* Behaves as for Up if the discarded fraction is > 0.5; otherwise, behaves as for Down.
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*/
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case HalfDown;
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/**
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* Rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round towards positive infinity.
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*
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* If the result is positive, behaves as for HalfUp; if negative, behaves as for HalfDown.
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*/
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case HalfCeiling;
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/**
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* Rounds towards "nearest neighbor" unless both neighbors are equidistant, in which case round towards negative infinity.
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*
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* If the result is positive, behaves as for HalfDown; if negative, behaves as for HalfUp.
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*/
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case HalfFloor;
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/**
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* Rounds towards the "nearest neighbor" unless both neighbors are equidistant, in which case rounds towards the even neighbor.
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*
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* Behaves as for HalfUp if the digit to the left of the discarded fraction is odd;
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* behaves as for HalfDown if it's even.
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*
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* Note that this is the rounding mode that statistically minimizes
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* cumulative error when applied repeatedly over a sequence of calculations.
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* It is sometimes known as "Banker's rounding", and is chiefly used in the USA.
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*/
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case HalfEven;
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/**
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* @deprecated Use RoundingMode::Unnecessary instead.
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*/
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public const UNNECESSARY = self::Unnecessary;
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/**
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* @deprecated Use RoundingMode::Up instead.
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*/
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public const UP = self::Up;
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/**
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* @deprecated Use RoundingMode::Down instead.
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*/
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public const DOWN = self::Down;
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/**
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* @deprecated Use RoundingMode::Ceiling instead.
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*/
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public const CEILING = self::Ceiling;
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/**
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* @deprecated Use RoundingMode::Floor instead.
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*/
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public const FLOOR = self::Floor;
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/**
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* @deprecated Use RoundingMode::HalfUp instead.
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*/
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public const HALF_UP = self::HalfUp;
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/**
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* @deprecated Use RoundingMode::HalfDown instead.
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*/
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public const HALF_DOWN = self::HalfDown;
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/**
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* @deprecated Use RoundingMode::HalfCeiling instead.
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*/
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public const HALF_CEILING = self::HalfCeiling;
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/**
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* @deprecated Use RoundingMode::HalfFloor instead.
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*/
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public const HALF_FLOOR = self::HalfFloor;
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/**
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* @deprecated Use RoundingMode::HalfEven instead.
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*/
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public const HALF_EVEN = self::HalfEven;
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}
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