Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php  | 
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| 10 | class Comparator  | 
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| 11 | { | 
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| 12 | /**  | 
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| 13 | * The version is equal to another.  | 
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| 14 | */  | 
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| 15 | const EQUAL_TO = 0;  | 
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| 16 | |||
| 17 | /**  | 
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| 18 | * The version is greater than another.  | 
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| 19 | */  | 
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| 20 | const GREATER_THAN = 1;  | 
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| 21 | |||
| 22 | /**  | 
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| 23 | * The version is less than another.  | 
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| 24 | */  | 
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| 25 | const LESS_THAN = -1;  | 
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| 26 | |||
| 27 | /**  | 
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| 28 | * Compares one version with another.  | 
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| 29 | *  | 
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| 30 | * @param Version $left The left version to compare.  | 
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| 31 | * @param Version $right The right version to compare.  | 
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| 32 | *  | 
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| 33 | * @return integer Returns Comparator::EQUAL_TO if the two versions are  | 
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| 34 | * equal. If the left version is less than the right  | 
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| 35 | * version, Comparator::LESS_THAN is returned. If the left  | 
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| 36 | * version is greater than the right version,  | 
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| 37 | * Comparator::GREATER_THAN is returned.  | 
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| 38 | */  | 
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| 39 | public static function compareTo(Version $left, Version $right)  | 
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| 63 | |||
| 64 | /**  | 
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| 65 | * Checks if the left version is equal to the right.  | 
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| 66 | *  | 
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| 67 | * @param Version $left The left version to compare.  | 
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| 68 | * @param Version $right The right version to compare.  | 
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| 69 | *  | 
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| 70 | * @return boolean TRUE if the left version is equal to the right, FALSE  | 
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| 71 | * if not.  | 
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| 72 | */  | 
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| 73 | public static function isEqualTo(Version $left, Version $right)  | 
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| 77 | |||
| 78 | /**  | 
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| 79 | * Checks if the left version is greater than the right.  | 
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| 80 | *  | 
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| 81 | * @param Version $left The left version to compare.  | 
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| 82 | * @param Version $right The right version to compare.  | 
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| 83 | *  | 
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| 84 | * @return boolean TRUE if the left version is greater than the right,  | 
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| 85 | * FALSE if not.  | 
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| 86 | */  | 
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| 87 | public static function isGreaterThan(Version $left, Version $right)  | 
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| 91 | |||
| 92 | /**  | 
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| 93 | * Checks if the left version is less than the right.  | 
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| 94 | *  | 
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| 95 | * @param Version $left The left version to compare.  | 
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| 96 | * @param Version $right The right version to compare.  | 
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| 97 | *  | 
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| 98 | * @return boolean TRUE if the left version is less than the right,  | 
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| 99 | * FALSE if not.  | 
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| 100 | */  | 
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| 101 | public static function isLessThan(Version $left, Version $right)  | 
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| 105 | |||
| 106 | /**  | 
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| 107 | * Compares the identifier components of the left and right versions.  | 
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| 108 | *  | 
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| 109 | * @param array $left The left identifiers.  | 
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| 110 | * @param array $right The right identifiers.  | 
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| 111 | *  | 
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| 112 | * @return integer Returns Comparator::EQUAL_TO if the two identifiers are  | 
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| 113 | * equal. If the left identifiers is less than the right  | 
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| 114 | * identifiers, Comparator::LESS_THAN is returned. If the  | 
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| 115 | * left identifiers is greater than the right identifiers,  | 
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| 116 | * Comparator::GREATER_THAN is returned.  | 
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| 117 | */  | 
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| 118 | public static function compareIdentifiers(array $left, array $right)  | 
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| 174 | }  | 
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| 175 | 
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.