DecimalMath::shiftLeft() - Code Metrics - Inspection of "Merge pull request #124 from DataValues/DecimalMat..." - DataValues/Number - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( c68256...8d64d8 )

by Leszek

created 2018-11-06 09:50 UTC

DecimalMath::shiftLeft() A

↳ Parent: DecimalMath

Complexity

Conditions	2
Paths	2

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	2

Importance

Changes

Metric	Value
dl	0
loc	10
ccs	5
cts	5
cp	1
rs	9.9332
c	0
b	0
f	0
cc	2
nc	2
nop	2
crap	2

<?php

namespace DataValues;

use InvalidArgumentException;

/**
 * Class for performing basic arithmetic and other transformations
 * on DecimalValues.
 *
 * This uses the bcmath library if available. Otherwise, it falls back on
 * using floating point operations.
 *
 * @note: this is not a genuine decimal arithmetics implementation,
 * and should not be used for financial computations, physical simulations, etc.
 *
 * @see DecimalValue
 *
 * @since 0.1
 *
 * @license GPL-2.0+
 * @author Daniel Kinzler
 */
class DecimalMath {

	/**
	 * Whether to use the bcmath library.
	 *
	 * @var bool
	 */
	private $useBC;

	/**
	 * @param bool|null $useBC Whether to use the bcmath library. If null,
	 *        bcmath will automatically be used if available.
	 */
	public function __construct( $useBC = null ) {
		if ( $useBC === null ) {
			$useBC = function_exists( 'bcscale' );
		}

		$this->useBC = $useBC;
	}

	/**
	 * Whether this is using the bcmath library.
	 *
	 * @return bool
	 */
	public function getUseBC() {
		return $this->useBC;
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	public function product( DecimalValue $a, DecimalValue $b ) {
		if ( $this->useBC ) {
			return $this->productWithBC( $a, $b );
		}
		return $this->productWithoutBC( $a, $b );
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	private function productWithBC( DecimalValue $a, DecimalValue $b ) {
		$scale = strlen( $a->getFractionalPart() ) + strlen( $b->getFractionalPart() );
		$product = bcmul( $a->getValue(), $b->getValue(), $scale );

		$sign = $product[0] === '-' ? '' : '+';

		// (Potentially) round so that the result fits into a DecimalValue
		// Note: Product might still be to long if a*b >= 10^126
		$product = $this->roundDigits( $sign . $product, 126 );

		return new DecimalValue( $product );
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	private function productWithoutBC( DecimalValue $a, DecimalValue $b ) {
		$product = $a->getValueFloat() * $b->getValueFloat();

		// Append .0 for consistency, if the result is a whole number,
		// but $a or $b were specified with decimal places.
		if (
			$product === floor( $product ) &&
			$a->getFractionalPart() . $b->getFractionalPart() !== ''
		) {
			$product = strval( $product ) . '.0';
		}

		return new DecimalValue( $product );
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	public function sum( DecimalValue $a, DecimalValue $b ) {
		if ( $this->useBC ) {
			$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
			$sum = bcadd( $a->getValue(), $b->getValue(), $scale );
		} else {
			$sum = $a->getValueFloat() + $b->getValueFloat();
		}

		return new DecimalValue( $sum );
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	public function min( DecimalValue $a, DecimalValue $b ) {
		if ( $this->useBC ) {
			$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
			$comp = bccomp( $a->getValue(), $b->getValue(), $scale );
			$min = $comp > 0 ? $b : $a;
		} else {
			$min = min( $a->getValueFloat(), $b->getValueFloat() );
			$min = new DecimalValue( $min );
		}

		return $min;
	}

	/**
	 * @param DecimalValue $a
	 * @param DecimalValue $b
	 *
	 * @return DecimalValue
	 */
	public function max( DecimalValue $a, DecimalValue $b ) {
		if ( $this->useBC ) {
			$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
			$comp = bccomp( $a->getValue(), $b->getValue(), $scale );
			$max = $comp > 0 ? $a : $b;
		} else {
			$max = max( $a->getValueFloat(), $b->getValueFloat() );
			$max = new DecimalValue( $max );
		}

		return $max;
	}

	/**
	 * Returns the given value, with any insignificant digits removed or zeroed.
	 *
	 * Rounding is applied  using the "round half away from zero" rule (that is, +0.5 is
	 * rounded to +1 and -0.5 is rounded to -1).
	 *
	 * @since 0.1
	 *
	 * @param DecimalValue $decimal
	 * @param int $significantDigits The number of digits to retain, counting the decimal point,
	 *        but not counting the leading sign.
	 *
	 * @throws InvalidArgumentException
	 * @return DecimalValue
	 */
	public function roundToDigit( DecimalValue $decimal, $significantDigits ) {
		$value = $decimal->getValue();
		$rounded = $this->roundDigits( $value, $significantDigits );
		return new DecimalValue( $rounded );
	}

	/**
	 * Returns the given value, with any insignificant digits removed or zeroed.
	 *
	 * Rounding is applied  using the "round half away from zero" rule (that is, +0.5 is
	 * rounded to +1 and -0.5 is rounded to -1).
	 *
	 * @since 0.1
	 *
	 * @param DecimalValue $decimal
	 * @param int $significantExponent 	 The exponent of the last significant digit,
	 *        e.g. -1 for "keep the first digit after the decimal point", or 2 for
	 *        "zero the last two digits before the decimal point".
	 *
	 * @throws InvalidArgumentException
	 * @return DecimalValue
	 */
	public function roundToExponent( DecimalValue $decimal, $significantExponent ) {
		//NOTE: the number of digits to keep (without the leading sign)
		//      is the same as the exponent's offset (with the leaqding sign).
		$digits = $this->getPositionForExponent( $significantExponent, $decimal );
		return $this->roundToDigit( $decimal, $digits );
	}

	/**
	 * Returns the (zero based) position for the given exponent in
	 * the given decimal string, counting the decimal point and the leading sign.
	 *
	 * @example: the position of exponent 0 in "+10.03" is 2.
	 * @example: the position of exponent 1 in "+210.03" is 2.
	 * @example: the position of exponent -2 in "+1.037" is 4.
	 *
	 * @param int $exponent
	 * @param DecimalValue $decimal
	 *
	 * @return int
	 */
	public function getPositionForExponent( $exponent, DecimalValue $decimal ) {
		$decimal = $decimal->getValue();

		$pointPos = strpos( $decimal, '.' );
		if ( $pointPos === false ) {
			$pointPos = strlen( $decimal );
		}

		// account for leading sign
		$pointPos--;

		if ( $exponent < 0 ) {
			// account for decimal point
			$position = $pointPos + 1 - $exponent;
		} else {
			// make sure we don't remove more digits than are there
			$position = max( 0, $pointPos - $exponent );
		}

		return $position;
	}

	/**
	 * Returns the given value, with any insignificant digits removed or zeroed.
	 *
	 * Rounding is applied using the "round half away from zero" rule (that is, +0.5 is
	 * rounded to +1 and -0.5 is rounded to -1).
	 *
	 * @see round()
	 *
	 * @param string $value
	 * @param int $significantDigits
	 *
	 * @throws InvalidArgumentException if $significantDigits is smaller than 0
	 * @return string
	 */
	private function roundDigits( $value, $significantDigits ) {
		if ( !is_int( $significantDigits ) || $significantDigits < 0 ) {
			throw new InvalidArgumentException( '$significantDigits must be a non-negative integer' );
		}

		// keeping no digits results in zero.
		if ( $significantDigits === 0 ) {
			return '+0';
		}

		$len = strlen( $value );

		// keeping all digits means no rounding
		if ( $significantDigits >= $len - 1 ) {
			return $value;
		}

		// whether the last character is already part of the integer part of the decimal value
		$i = min( $significantDigits + 1, $len ); // account for the sign
		$ch = $i < $len ? $value[$i] : '0';

		if ( $ch === '.' ) {
			// NOTE: we expect the input to be well formed, so it cannot end with a '.'
			$i++;
			$ch = $i < $len ? $value[$i] : '0';
		}

		// split in significant and insignificant part
		$rounded = substr( $value, 0, $i );

		if ( strpos( $rounded, '.' ) === false ) {
			$suffix = substr( $value, $i );

			// strip insignificant digits after the decimal point
			$ppos = strpos( $suffix, '.' );
			if ( $ppos !== false ) {
				$suffix = substr( $suffix, 0, $ppos );
			}

			// zero out insignificant digits
			$suffix = strtr( $suffix, '123456789', '000000000' );
		} else {
			// decimal point is in $rounded, so $suffix is insignificant
			$suffix = '';
		}

		if ( $ch >= '5' ) {
			$rounded = $this->bumpDigits( $rounded );
		}

		$rounded .= $suffix;

		if ( $significantDigits > strlen( $rounded ) - 1 ) {
			if ( strpos( $rounded, '.' ) !== false ) {
				$rounded = str_pad( $rounded, $significantDigits + 1, '0', STR_PAD_RIGHT );
			}
		}

		// strip trailing decimal point
		$rounded = rtrim( $rounded, '.' );

		return $rounded;
	}

	/**
	 * Increment the least significant digit by one if it is less than 9, and
	 * set it to zero and continue to the next more significant digit if it is 9.
	 * Exception: bump( 0 ) == 1;
	 *
	 * E.g.: bump( 0.2 ) == 0.3, bump( -0.09 ) == -0.10, bump( 9.99 ) == 10.00
	 *
	 * This is the inverse of @see slump()
	 *
	 * @since 0.1
	 *
	 * @param DecimalValue $decimal
	 *
	 * @return DecimalValue
	 */
	public function bump( DecimalValue $decimal ) {
		$value = $decimal->getValue();
		$bumped = $this->bumpDigits( $value );
		return new DecimalValue( $bumped );
	}

	/**
	 * Increment the least significant digit by one if it is less than 9, and
	 * set it to zero and continue to the next more significant digit if it is 9.
	 *
	 * @see bump()
	 *
	 * @param string $value
	 * @return string
	 */
	private function bumpDigits( $value ) {
		if ( $value === '+0' ) {
			return '+1';
		}

		$bumped = '';

		for ( $i = strlen( $value ) - 1; $i >= 0; $i-- ) {
			$ch = $value[$i];

			if ( $ch === '.' ) {
				$bumped = '.' . $bumped;
				continue;
			} elseif ( $ch === '9' ) {
				$bumped = '0' . $bumped;
				continue;
			} elseif ( $ch === '+' || $ch === '-' ) {
				$bumped = $ch . '1' . $bumped;
				break;
			} else {
				$bumped = chr( ord( $ch ) + 1 ) . $bumped;
				break;
			}
		}

		$bumped = substr( $value, 0, $i ) . $bumped;
		return $bumped;
	}

	/**
	 * Decrement the least significant digit by one if it is more than 0, and
	 * set it to 9 and continue to the next more significant digit if it is 0.
	 * Exception: slump( 0 ) == -1;
	 *
	 * E.g.: slump( 0.2 ) == 0.1, slump( -0.10 ) == -0.01, slump( 0.0 ) == -1.0
	 *
	 * This is the inverse of @see bump()
	 *
	 * @since 0.1
	 *
	 * @param DecimalValue $decimal
	 *
	 * @return DecimalValue
	 */
	public function slump( DecimalValue $decimal ) {
		$value = $decimal->getValue();
		$slumped = $this->slumpDigits( $value );
		return new DecimalValue( $slumped );
	}

	/**
	 * Decrement the least significant digit by one if it is more than 0, and
	 * set it to 9 and continue to the next more significant digit if it is 0.
	 *
	 * @see slump()
	 *
	 * @param string $value
	 * @return string
	 */
	private function slumpDigits( $value ) {
		if ( $value === '+0' ) {
			return '-1';
		}

		// a "precise zero" will become negative
		if ( preg_match( '/^\+0\.(0*)0$/', $value, $m ) ) {
			return '-0.' . $m[1] . '1';
		}

		$slumped = '';

		for ( $i = strlen( $value ) - 1; $i >= 0; $i-- ) {
			$ch = substr( $value, $i, 1 );

			if ( $ch === '.' ) {
				$slumped = '.' . $slumped;
				continue;
			} elseif ( $ch === '0' ) {
				$slumped = '9' . $slumped;
				continue;
			} elseif ( $ch === '+' || $ch === '-' ) {
				$slumped = '0';
				break;
			} else {
				$slumped = chr( ord( $ch ) - 1 ) . $slumped;
				break;
			}
		}

		// preserve prefix
		$slumped = substr( $value, 0, $i ) . $slumped;
		$slumped = $this->stripLeadingZeros( $slumped );

		if ( $slumped === '-0' ) {
			$slumped = '+0';
		}

		return $slumped;
	}

	/**
	 * @param string $digits
	 *
	 * @return string
	 */
	private function stripLeadingZeros( $digits ) {
		$digits = preg_replace( '/^([-+])0+(?=\d)/', '\1', $digits );
		return $digits;
	}

	/**
	 * Shift the decimal point according to the given exponent.
	 *
	 * @param DecimalValue $decimal
	 * @param int $exponent The exponent to apply (digits to shift by). A Positive exponent
	 * shifts the decimal point to the right, a negative exponent shifts to the left.
	 *
	 * @throws InvalidArgumentException
	 * @return DecimalValue
	 */
	public function shift( DecimalValue $decimal, $exponent ) {
		if ( !is_int( $exponent ) ) {
			throw new InvalidArgumentException( '$exponent must be an integer' );
		}

		if ( $exponent == 0 ) {
			return $decimal;
		}

		$sign = $decimal->getSign();
		$intPart = $decimal->getIntegerPart();
		$fractPart = $decimal->getFractionalPart();

		if ( $exponent < 0 ) {
			$intPart = $this->shiftLeft( $intPart, $exponent );
		} else {
			$fractPart = $this->shiftRight( $fractPart, $exponent );
		}

		$digits = $sign . $intPart . $fractPart;
		$digits = $this->stripLeadingZeros( $digits );

		return new DecimalValue( $digits );
	}

	/**
	 * @param string $intPart
	 * @param int $exponent must be negative
	 *
	 * @return string
	 */
	private function shiftLeft( $intPart, $exponent ) {
		//note: $exponent is negative!
		if ( -$exponent < strlen( $intPart ) ) {
			$intPart = substr( $intPart, 0, $exponent ) . '.' . substr( $intPart, $exponent );
		} else {
			$intPart = '0.' . str_pad( $intPart, -$exponent, '0', STR_PAD_LEFT );
		}

		return $intPart;
	}

	/**
	 * @param string $fractPart
	 * @param int $exponent must be positive
	 *
	 * @return string
	 */
	private function shiftRight( $fractPart, $exponent ) {
		//note: $exponent is positive.
		if ( $exponent < strlen( $fractPart ) ) {
			$fractPart = substr( $fractPart, 0, $exponent ) . '.' . substr( $fractPart, $exponent );
		} else {
			$fractPart = str_pad( $fractPart, $exponent, '0', STR_PAD_RIGHT );
		}

		return $fractPart;
	}

}


1		<?php
2
3		namespace DataValues;
4
5		use InvalidArgumentException;
6
7		/**
8		* Class for performing basic arithmetic and other transformations
9		* on DecimalValues.
10		*
11		* This uses the bcmath library if available. Otherwise, it falls back on
12		* using floating point operations.
13		*
14		* @note: this is not a genuine decimal arithmetics implementation,
15		* and should not be used for financial computations, physical simulations, etc.
16		*
17		* @see DecimalValue
18		*
19		* @since 0.1
20		*
21		* @license GPL-2.0+
22		* @author Daniel Kinzler
23		*/
24		class DecimalMath {
25
26		/**
27		* Whether to use the bcmath library.
28		*
29		* @var bool
30		*/
31		private $useBC;
32
33		/**
34		* @param bool\|null $useBC Whether to use the bcmath library. If null,
35		* bcmath will automatically be used if available.
36		*/
37	224	public function __construct( $useBC = null ) {
38	224	if ( $useBC === null ) {
39	200	$useBC = function_exists( 'bcscale' );
40		}
41
42	224	$this->useBC = $useBC;
43	224	}
44
45		/**
46		* Whether this is using the bcmath library.
47		*
48		* @return bool
49		*/
50		public function getUseBC() {
51		return $this->useBC;
52		}
53
54		/**
55		* @param DecimalValue $a
56		* @param DecimalValue $b
57		*
58		* @return DecimalValue
59		*/
60	28	public function product( DecimalValue $a, DecimalValue $b ) {
61	28	if ( $this->useBC ) {
62	16	return $this->productWithBC( $a, $b );
63		}
64	12	return $this->productWithoutBC( $a, $b );
65		}
66
67		/**
68		* @param DecimalValue $a
69		* @param DecimalValue $b
70		*
71		* @return DecimalValue
72		*/
73	16	private function productWithBC( DecimalValue $a, DecimalValue $b ) {
74	16	$scale = strlen( $a->getFractionalPart() ) + strlen( $b->getFractionalPart() );
75	16	$product = bcmul( $a->getValue(), $b->getValue(), $scale );
76
77	16	$sign = $product[0] === '-' ? '' : '+';
78
79		// (Potentially) round so that the result fits into a DecimalValue
80		// Note: Product might still be to long if a*b >= 10^126
81	16	$product = $this->roundDigits( $sign . $product, 126 );
82
83	16	return new DecimalValue( $product );
84		}
85
86		/**
87		* @param DecimalValue $a
88		* @param DecimalValue $b
89		*
90		* @return DecimalValue
91		*/
92	12	private function productWithoutBC( DecimalValue $a, DecimalValue $b ) {
93	12	$product = $a->getValueFloat() * $b->getValueFloat();
94
95		// Append .0 for consistency, if the result is a whole number,
96		// but $a or $b were specified with decimal places.
97		if (
98	12	$product === floor( $product ) &&
99	12	$a->getFractionalPart() . $b->getFractionalPart() !== ''
100		) {
101	2	$product = strval( $product ) . '.0';
102		}
103
104	12	return new DecimalValue( $product );
105		}
106
107		/**
108		* @param DecimalValue $a
109		* @param DecimalValue $b
110		*
111		* @return DecimalValue
112		*/
113	9	public function sum( DecimalValue $a, DecimalValue $b ) {
114	9	if ( $this->useBC ) {
115	9	$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
116	9	$sum = bcadd( $a->getValue(), $b->getValue(), $scale );
117		} else {
118		$sum = $a->getValueFloat() + $b->getValueFloat();
119		}
120
121	9	return new DecimalValue( $sum );
122		}
123
124		/**
125		* @param DecimalValue $a
126		* @param DecimalValue $b
127		*
128		* @return DecimalValue
129		*/
130	5	public function min( DecimalValue $a, DecimalValue $b ) {
131	5	if ( $this->useBC ) {
132	5	$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
133	5	$comp = bccomp( $a->getValue(), $b->getValue(), $scale );
134	5	$min = $comp > 0 ? $b : $a;
135		} else {
136		$min = min( $a->getValueFloat(), $b->getValueFloat() );
137		$min = new DecimalValue( $min );
138		}
139
140	5	return $min;
141		}
142
143		/**
144		* @param DecimalValue $a
145		* @param DecimalValue $b
146		*
147		* @return DecimalValue
148		*/
149	5	public function max( DecimalValue $a, DecimalValue $b ) {
150	5	if ( $this->useBC ) {
151	5	$scale = max( strlen( $a->getFractionalPart() ), strlen( $b->getFractionalPart() ) );
152	5	$comp = bccomp( $a->getValue(), $b->getValue(), $scale );
153	5	$max = $comp > 0 ? $a : $b;
154		} else {
155		$max = max( $a->getValueFloat(), $b->getValueFloat() );
156		$max = new DecimalValue( $max );
157		}
158
159	5	return $max;
160		}
161
162		/**
163		* Returns the given value, with any insignificant digits removed or zeroed.
164		*
165		* Rounding is applied using the "round half away from zero" rule (that is, +0.5 is
166		* rounded to +1 and -0.5 is rounded to -1).
167		*
168		* @since 0.1
169		*
170		* @param DecimalValue $decimal
171		* @param int $significantDigits The number of digits to retain, counting the decimal point,
172		* but not counting the leading sign.
173		*
174		* @throws InvalidArgumentException
175		* @return DecimalValue
176		*/
177	105	public function roundToDigit( DecimalValue $decimal, $significantDigits ) {
178	105	$value = $decimal->getValue();
179	105	$rounded = $this->roundDigits( $value, $significantDigits );
180	105	return new DecimalValue( $rounded );
181		}
182
183		/**
184		* Returns the given value, with any insignificant digits removed or zeroed.
185		*
186		* Rounding is applied using the "round half away from zero" rule (that is, +0.5 is
187		* rounded to +1 and -0.5 is rounded to -1).
188		*
189		* @since 0.1
190		*
191		* @param DecimalValue $decimal
192		* @param int $significantExponent The exponent of the last significant digit,
193		* e.g. -1 for "keep the first digit after the decimal point", or 2 for
194		* "zero the last two digits before the decimal point".
195		*
196		* @throws InvalidArgumentException
197		* @return DecimalValue
198		*/
199	47	public function roundToExponent( DecimalValue $decimal, $significantExponent ) {
200		//NOTE: the number of digits to keep (without the leading sign)
201		// is the same as the exponent's offset (with the leaqding sign).
202	47	$digits = $this->getPositionForExponent( $significantExponent, $decimal );
203	47	return $this->roundToDigit( $decimal, $digits );
204		}
205
206		/**
207		* Returns the (zero based) position for the given exponent in
208		* the given decimal string, counting the decimal point and the leading sign.
209		*
210		* @example: the position of exponent 0 in "+10.03" is 2.
211		* @example: the position of exponent 1 in "+210.03" is 2.
212		* @example: the position of exponent -2 in "+1.037" is 4.
213		*
214		* @param int $exponent
215		* @param DecimalValue $decimal
216		*
217		* @return int
218		*/
219	53	public function getPositionForExponent( $exponent, DecimalValue $decimal ) {
220	53	$decimal = $decimal->getValue();
221
222	53	$pointPos = strpos( $decimal, '.' );
223	53	if ( $pointPos === false ) {
224	16	$pointPos = strlen( $decimal );
225		}
226
227		// account for leading sign
228	53	$pointPos--;
229
230	53	if ( $exponent < 0 ) {
231		// account for decimal point
232	19	$position = $pointPos + 1 - $exponent;
233		} else {
234		// make sure we don't remove more digits than are there
235	34	$position = max( 0, $pointPos - $exponent );
236		}
237
238	53	return $position;
239		}
240
241		/**
242		* Returns the given value, with any insignificant digits removed or zeroed.
243		*
244		* Rounding is applied using the "round half away from zero" rule (that is, +0.5 is
245		* rounded to +1 and -0.5 is rounded to -1).
246		*
247		* @see round()
248		*
249		* @param string $value
250		* @param int $significantDigits
251		*
252		* @throws InvalidArgumentException if $significantDigits is smaller than 0
253		* @return string
254		*/
255	121	private function roundDigits( $value, $significantDigits ) {
256	121	if ( !is_int( $significantDigits ) \|\| $significantDigits < 0 ) {
257		throw new InvalidArgumentException( '$significantDigits must be a non-negative integer' );
258		}
259
260		// keeping no digits results in zero.
261	121	if ( $significantDigits === 0 ) {
262	7	return '+0';
263		}
264
265	114	$len = strlen( $value );
266
267		// keeping all digits means no rounding
268	114	if ( $significantDigits >= $len - 1 ) {
269	51	return $value;
270		}
271
272		// whether the last character is already part of the integer part of the decimal value
273	63	$i = min( $significantDigits + 1, $len ); // account for the sign
274	63	$ch = $i < $len ? $value[$i] : '0';
275
276	63	if ( $ch === '.' ) {
277		// NOTE: we expect the input to be well formed, so it cannot end with a '.'
278	27	$i++;
279	27	$ch = $i < $len ? $value[$i] : '0';
280		}
281
282		// split in significant and insignificant part
283	63	$rounded = substr( $value, 0, $i );
284
285	63	if ( strpos( $rounded, '.' ) === false ) {
286	13	$suffix = substr( $value, $i );
287
288		// strip insignificant digits after the decimal point
289	13	$ppos = strpos( $suffix, '.' );
290	13	if ( $ppos !== false ) {
291	3	$suffix = substr( $suffix, 0, $ppos );
292		}
293
294		// zero out insignificant digits
295	13	$suffix = strtr( $suffix, '123456789', '000000000' );
296		} else {
297		// decimal point is in $rounded, so $suffix is insignificant
298	50	$suffix = '';
299		}
300
301	63	if ( $ch >= '5' ) {
302	27	$rounded = $this->bumpDigits( $rounded );
303		}
304
305	63	$rounded .= $suffix;
306
307	63	if ( $significantDigits > strlen( $rounded ) - 1 ) {
308		if ( strpos( $rounded, '.' ) !== false ) {
309		$rounded = str_pad( $rounded, $significantDigits + 1, '0', STR_PAD_RIGHT );
310		}
311		}
312
313		// strip trailing decimal point
314	63	$rounded = rtrim( $rounded, '.' );
315
316	63	return $rounded;
317		}
318
319		/**
320		* Increment the least significant digit by one if it is less than 9, and
321		* set it to zero and continue to the next more significant digit if it is 9.
322		* Exception: bump( 0 ) == 1;
323		*
324		* E.g.: bump( 0.2 ) == 0.3, bump( -0.09 ) == -0.10, bump( 9.99 ) == 10.00
325		*
326		* This is the inverse of @see slump()
327		*
328		* @since 0.1
329		*
330		* @param DecimalValue $decimal
331		*
332		* @return DecimalValue
333		*/
334	16	public function bump( DecimalValue $decimal ) {
335	16	$value = $decimal->getValue();
336	16	$bumped = $this->bumpDigits( $value );
337	16	return new DecimalValue( $bumped );
338		}
339
340		/**
341		* Increment the least significant digit by one if it is less than 9, and
342		* set it to zero and continue to the next more significant digit if it is 9.
343		*
344		* @see bump()
345		*
346		* @param string $value
347		* @return string
348		*/
349	43	private function bumpDigits( $value ) {
350	43	if ( $value === '+0' ) {
351	2	return '+1';
352		}
353
354	41	$bumped = '';
355
356	41	for ( $i = strlen( $value ) - 1; $i >= 0; $i-- ) {
357	41	$ch = $value[$i];
358
359	41	if ( $ch === '.' ) {
360	14	$bumped = '.' . $bumped;
361	14	continue;
362	41	} elseif ( $ch === '9' ) {
363	18	$bumped = '0' . $bumped;
364	18	continue;
365	41	} elseif ( $ch === '+' \|\| $ch === '-' ) {
366	14	$bumped = $ch . '1' . $bumped;
367	14	break;
368		} else {
369	27	$bumped = chr( ord( $ch ) + 1 ) . $bumped;
370	27	break;
371		}
372		}
373
374	41	$bumped = substr( $value, 0, $i ) . $bumped;
375	41	return $bumped;
376		}
377
378		/**
379		* Decrement the least significant digit by one if it is more than 0, and
380		* set it to 9 and continue to the next more significant digit if it is 0.
381		* Exception: slump( 0 ) == -1;
382		*
383		* E.g.: slump( 0.2 ) == 0.1, slump( -0.10 ) == -0.01, slump( 0.0 ) == -1.0
384		*
385		* This is the inverse of @see bump()
386		*
387		* @since 0.1
388		*
389		* @param DecimalValue $decimal
390		*
391		* @return DecimalValue
392		*/
393	24	public function slump( DecimalValue $decimal ) {
394	24	$value = $decimal->getValue();
395	24	$slumped = $this->slumpDigits( $value );
396	24	return new DecimalValue( $slumped );
397		}
398
399		/**
400		* Decrement the least significant digit by one if it is more than 0, and
401		* set it to 9 and continue to the next more significant digit if it is 0.
402		*
403		* @see slump()
404		*
405		* @param string $value
406		* @return string
407		*/
408	24	private function slumpDigits( $value ) {
409	24	if ( $value === '+0' ) {
410	2	return '-1';
411		}
412
413		// a "precise zero" will become negative
414	22	if ( preg_match( '/^\+0\.(0*)0$/', $value, $m ) ) {
415	4	return '-0.' . $m[1] . '1';
416		}
417
418	18	$slumped = '';
419
420	18	for ( $i = strlen( $value ) - 1; $i >= 0; $i-- ) {
421	18	$ch = substr( $value, $i, 1 );
422
423	18	if ( $ch === '.' ) {
424	2	$slumped = '.' . $slumped;
425	2	continue;
426	18	} elseif ( $ch === '0' ) {
427	8	$slumped = '9' . $slumped;
428	8	continue;
429	18	} elseif ( $ch === '+' \|\| $ch === '-' ) {
430		$slumped = '0';
431		break;
432		} else {
433	18	$slumped = chr( ord( $ch ) - 1 ) . $slumped;
434	18	break;
435		}
436		}
437
438		// preserve prefix
439	18	$slumped = substr( $value, 0, $i ) . $slumped;
440	18	$slumped = $this->stripLeadingZeros( $slumped );
441
442	18	if ( $slumped === '-0' ) {
443	1	$slumped = '+0';
444		}
445
446	18	return $slumped;
447		}
448
449		/**
450		* @param string $digits
451		*
452		* @return string
453		*/
454	40	private function stripLeadingZeros( $digits ) {
455	40	$digits = preg_replace( '/^([-+])0+(?=\d)/', '\1', $digits );
456	40	return $digits;
457		}
458
459		/**
460		* Shift the decimal point according to the given exponent.
461		*
462		* @param DecimalValue $decimal
463		* @param int $exponent The exponent to apply (digits to shift by). A Positive exponent
464		* shifts the decimal point to the right, a negative exponent shifts to the left.
465		*
466		* @throws InvalidArgumentException
467		* @return DecimalValue
468		*/
469	26	public function shift( DecimalValue $decimal, $exponent ) {
470	26	if ( !is_int( $exponent ) ) {
471		throw new InvalidArgumentException( '$exponent must be an integer' );
472		}
473
474	26	if ( $exponent == 0 ) {
475	4	return $decimal;
476		}
477
478	22	$sign = $decimal->getSign();
479	22	$intPart = $decimal->getIntegerPart();
480	22	$fractPart = $decimal->getFractionalPart();
481
482	22	if ( $exponent < 0 ) {
483	14	$intPart = $this->shiftLeft( $intPart, $exponent );
484		} else {
485	8	$fractPart = $this->shiftRight( $fractPart, $exponent );
486		}
487
488	22	$digits = $sign . $intPart . $fractPart;
489	22	$digits = $this->stripLeadingZeros( $digits );
490
491	22	return new DecimalValue( $digits );
492		}
493
494		/**
495		* @param string $intPart
496		* @param int $exponent must be negative
497		*
498		* @return string
499		*/
500	14	private function shiftLeft( $intPart, $exponent ) {
501		//note: $exponent is negative!
502	14	if ( -$exponent < strlen( $intPart ) ) {
503	2	$intPart = substr( $intPart, 0, $exponent ) . '.' . substr( $intPart, $exponent );
504		} else {
505	12	$intPart = '0.' . str_pad( $intPart, -$exponent, '0', STR_PAD_LEFT );
506		}
507
508	14	return $intPart;
509		}
510
511		/**
512		* @param string $fractPart
513		* @param int $exponent must be positive
514		*
515		* @return string
516		*/
517	8	private function shiftRight( $fractPart, $exponent ) {
518		//note: $exponent is positive.
519	8	if ( $exponent < strlen( $fractPart ) ) {
520		$fractPart = substr( $fractPart, 0, $exponent ) . '.' . substr( $fractPart, $exponent );
521		} else {
522	8	$fractPart = str_pad( $fractPart, $exponent, '0', STR_PAD_RIGHT );
523		}
524
525	8	return $fractPart;
526		}
527
528		}
529

DataValues / Number

Push — master ( c68256...8d64d8 )

DecimalMath::shiftLeft() A

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