Complex classes like Script often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Script, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 14 | class Script extends Serializable implements ScriptInterface  | 
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| 15 | { | 
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| 16 | |||
| 17 | /**  | 
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| 18 | * @var Opcodes  | 
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| 19 | */  | 
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| 20 | protected $opCodes;  | 
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| 21 | |||
| 22 | /**  | 
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| 23 | * @var string  | 
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| 24 | */  | 
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| 25 | protected $script;  | 
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| 26 | |||
| 27 | /**  | 
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| 28 | * @param BufferInterface $script  | 
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| 29 | 1666 | * @param Opcodes|null $opCodes  | 
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| 30 | */  | 
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| 31 | 1666 | public function __construct(BufferInterface $script = null, Opcodes $opCodes = null)  | 
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| 36 | |||
| 37 | /**  | 
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| 38 | 1444 | * @return BufferInterface  | 
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| 39 | */  | 
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| 40 | 1444 | public function getBuffer()  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | 1114 | * @return Parser  | 
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| 47 | */  | 
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| 48 | 1114 | public function getScriptParser()  | 
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| 52 | |||
| 53 | /**  | 
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| 54 | * Get all opcodes  | 
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| 55 | *  | 
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| 56 | 672 | * @return Opcodes  | 
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| 57 | */  | 
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| 58 | 672 | public function getOpCodes()  | 
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| 62 | |||
| 63 | /**  | 
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| 64 | * Return a buffer containing the hash of this script.  | 
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| 65 | *  | 
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| 66 | 162 | * @return BufferInterface  | 
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| 67 | */  | 
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| 68 | 162 | public function getScriptHash()  | 
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| 72 | |||
| 73 | /**  | 
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| 74 | * @param bool|true $accurate  | 
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| 75 | 48 | * @return int  | 
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| 76 | */  | 
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| 77 | 48 | public function countSigOps($accurate = true)  | 
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| 108 | |||
| 109 | /**  | 
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| 110 | * @param WitnessProgram $program  | 
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| 111 | 18 | * @return int  | 
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| 112 | */  | 
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| 113 | 18 | private function witnessSigOps(WitnessProgram $program, ScriptWitnessInterface $scriptWitness)  | 
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| 129 | 12 | ||
| 130 | 12 | /**  | 
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| 131 | 18 | * @param ScriptInterface $scriptSig  | 
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| 132 | * @param ScriptWitnessInterface $scriptWitness  | 
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| 133 | 18 | * @param int $flags  | 
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| 134 | 6 | * @return int  | 
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| 135 | */  | 
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| 136 | public function countWitnessSigOps(ScriptInterface $scriptSig, ScriptWitnessInterface $scriptWitness, $flags)  | 
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| 157 | |||
| 158 | /**  | 
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| 159 | * @param ScriptInterface $scriptSig  | 
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| 160 | * @return int  | 
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| 161 | */  | 
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| 162 | public function countP2shSigOps(ScriptInterface $scriptSig)  | 
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| 190 | |||
| 191 | /**  | 
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| 192 | * @return bool  | 
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| 193 | */  | 
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| 194 | public function isPushOnly()  | 
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| 202 | |||
| 203 | /**  | 
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| 204 | * @param WitnessProgram|null $program  | 
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| 205 | * @return bool  | 
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| 206 | */  | 
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| 207 | public function isWitness(WitnessProgram & $program = null)  | 
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| 234 | }  | 
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| 235 | 
Unless you are absolutely sure that the expression can never be null because of other conditions, we strongly recommend to add an additional type check to your code: