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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| 11 | * Filters $value to a boolean strictly. |
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| 12 | * |
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| 13 | * $value must be a bool or 'true' or 'false' disregarding case and whitespace. |
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| 14 | * |
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| 15 | * The return value is the bool, as expected by the \TraderInteractive\Filterer class. |
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| 16 | * |
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| 17 | * @param string|bool $value the value to filter to a boolean |
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| 18 | * @param bool $allowNull Set to true if NULL values are allowed. The filtered result of a NULL value is NULL |
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| 19 | * @param array $trueValues Array of values which represent the boolean true value. Values should be lower cased |
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| 20 | * @param array $falseValues Array of values which represent the boolean false value. Values should be lower cased |
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| 21 | * |
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| 22 | * @return bool|null the filtered $value |
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| 23 | * |
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| 24 | * @throws Exception if $value is not a string |
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| 25 | * @throws Exception if $value is not 'true' or 'false' disregarding case and whitespace |
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| 26 | */ |
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| 27 | public static function filter( |
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| 28 | $value, |
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| 29 | bool $allowNull = false, |
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| 30 | array $trueValues = ['true'], |
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| 31 | array $falseValues = ['false'] |
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| 32 | ) { |
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| 33 | if ($allowNull === true && $value === null) { |
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| 34 | return null; |
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| 35 | } |
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| 36 | |||
| 37 | if (is_bool($value)) { |
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| 38 | return $value; |
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| 39 | } |
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| 40 | |||
| 41 | if (!is_string($value)) { |
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| 42 | throw new Exception('"' . var_export($value, true) . '" $value is not a string'); |
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| 43 | } |
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| 44 | |||
| 45 | $value = trim($value); |
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| 46 | |||
| 47 | $value = strtolower($value); |
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| 48 | |||
| 49 | if (in_array($value, $trueValues, true)) { |
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| 50 | return true; |
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| 51 | } |
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| 52 | |||
| 53 | if (in_array($value, $falseValues, true)) { |
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| 54 | return false; |
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| 55 | } |
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| 56 | |||
| 57 | throw new Exception( |
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| 58 | sprintf( |
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| 59 | "%s is not '%s' disregarding case and whitespace", |
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| 60 | $value, |
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| 61 | implode("' or '", array_merge($trueValues, $falseValues)) |
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| 62 | ) |
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| 63 | ); |
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| 64 | } |
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| 65 | |||
| 66 | /** |
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| 67 | * Filters the boolean $value to the given $true and $false cases |
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| 68 | * |
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| 69 | * @param boolean $value The boolean value to convert. |
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| 70 | * @param mixed $true The value to return on the true case. |
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| 71 | * @param mixed $false The value to return on the false case. |
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| 72 | * |
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| 73 | * @return mixed |
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| 74 | */ |
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| 75 | public static function convert(bool $value, $true = 'true', $false = 'false') |
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| 79 | } |
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| 80 |