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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| 15 | class Script extends Serializable implements ScriptInterface |
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| 16 | { |
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| 17 | |||
| 18 | /** |
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| 19 | * @var Opcodes |
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| 20 | */ |
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| 21 | protected $opCodes; |
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| 22 | |||
| 23 | /** |
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| 24 | * @var string |
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| 25 | */ |
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| 26 | protected $script; |
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| 27 | |||
| 28 | /** |
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| 29 | * @var BufferInterface|null |
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| 30 | */ |
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| 31 | protected $scriptHash; |
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| 32 | |||
| 33 | /** |
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| 34 | * @var BufferInterface|null |
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| 35 | */ |
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| 36 | protected $witnessScriptHash; |
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| 37 | |||
| 38 | /** |
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| 39 | * @param BufferInterface $script |
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| 40 | * @param Opcodes|null $opCodes |
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| 41 | */ |
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| 42 | 2674 | public function __construct(BufferInterface $script = null, Opcodes $opCodes = null) |
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| 43 | { |
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| 44 | 2674 | $this->script = $script instanceof BufferInterface ? $script->getBinary() : ''; |
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| 45 | 2674 | $this->opCodes = $opCodes ?: new Opcodes(); |
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| 46 | 2674 | } |
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| 47 | |||
| 48 | /** |
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| 49 | * @return BufferInterface |
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| 50 | */ |
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| 51 | 2692 | public function getBuffer() |
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| 52 | { |
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| 53 | 2692 | return new Buffer($this->script); |
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| 54 | } |
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| 55 | |||
| 56 | /** |
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| 57 | * @return Parser |
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| 58 | */ |
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| 59 | 2575 | public function getScriptParser() |
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| 60 | { |
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| 61 | 2575 | return new Parser(Bitcoin::getMath(), $this); |
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| 62 | } |
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| 63 | |||
| 64 | /** |
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| 65 | * Get all opcodes |
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| 66 | * |
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| 67 | * @return Opcodes |
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| 68 | */ |
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| 69 | 5 | public function getOpCodes() |
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| 70 | { |
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| 71 | 5 | return $this->opCodes; |
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| 72 | } |
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| 73 | |||
| 74 | /** |
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| 75 | * Return a buffer containing the HASH160 of this script. |
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| 76 | * |
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| 77 | * @return BufferInterface |
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| 78 | */ |
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| 79 | 57 | public function getScriptHash() |
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| 80 | { |
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| 81 | 57 | if (null === $this->scriptHash) { |
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| 82 | 55 | $this->scriptHash = Hash::sha256ripe160($this->getBuffer()); |
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| 83 | } |
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| 84 | |||
| 85 | 57 | return $this->scriptHash; |
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| 86 | } |
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| 87 | |||
| 88 | /** |
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| 89 | * Return a buffer containing the SHA256 of this script. |
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| 90 | * |
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| 91 | * @return BufferInterface |
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| 92 | */ |
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| 93 | 147 | public function getWitnessScriptHash() |
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| 94 | { |
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| 95 | 147 | if (null === $this->witnessScriptHash) { |
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| 96 | 147 | $this->witnessScriptHash = Hash::sha256($this->getBuffer()); |
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| 97 | } |
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| 98 | |||
| 99 | 147 | return $this->witnessScriptHash; |
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| 100 | } |
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| 101 | |||
| 102 | /** |
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| 103 | * @param bool|true $accurate |
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| 104 | * @return int |
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| 105 | */ |
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| 106 | 9 | public function countSigOps($accurate = true) |
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| 107 | { |
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| 108 | 9 | $count = 0; |
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| 109 | 9 | $parser = $this->getScriptParser(); |
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| 110 | |||
| 111 | 9 | $lastOp = 0xff; |
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| 112 | try { |
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| 113 | 9 | foreach ($parser as $exec) { |
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| 114 | 6 | $op = $exec->getOp(); |
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| 115 | |||
| 116 | // None of these are pushdatas, so just an opcode |
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| 117 | 6 | if ($op === Opcodes::OP_CHECKSIG || $op === Opcodes::OP_CHECKSIGVERIFY) { |
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| 118 | 3 | $count++; |
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| 119 | 6 | } elseif ($op === Opcodes::OP_CHECKMULTISIG || $op === Opcodes::OP_CHECKMULTISIGVERIFY) { |
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| 120 | 5 | if ($accurate && ($lastOp >= Opcodes::OP_1 && $lastOp <= Opcodes::OP_16)) { |
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| 121 | 4 | $count += decodeOpN($lastOp); |
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| 122 | } else { |
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| 123 | 2 | $count += 20; |
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| 124 | } |
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| 125 | } |
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| 126 | |||
| 127 | 8 | $lastOp = $op; |
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| 128 | } |
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| 129 | 1 | } catch (\Exception $e) { |
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| 130 | /* Script parsing failures don't count, and terminate the loop */ |
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| 131 | } |
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| 132 | |||
| 133 | 9 | return $count; |
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| 134 | } |
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| 135 | |||
| 136 | /** |
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| 137 | * @param WitnessProgram $program |
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| 138 | * @param ScriptWitnessInterface $scriptWitness |
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| 139 | * @return int |
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| 140 | */ |
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| 141 | 1 | private function witnessSigOps(WitnessProgram $program, ScriptWitnessInterface $scriptWitness) |
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| 142 | { |
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| 143 | 1 | if ($program->getVersion() === 0) { |
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| 144 | 1 | $size = $program->getProgram()->getSize(); |
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| 145 | 1 | if ($size === 32 && count($scriptWitness) > 0) { |
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| 146 | 1 | $script = new Script($scriptWitness->bottom()); |
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| 147 | 1 | return $script->countSigOps(true); |
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| 148 | } |
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| 149 | |||
| 150 | if ($size === 20) { |
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| 151 | return 1; |
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| 152 | } |
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| 153 | } |
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| 154 | |||
| 155 | return 0; |
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| 156 | } |
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| 157 | |||
| 158 | /** |
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| 159 | * @param ScriptInterface $scriptSig |
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| 160 | * @param ScriptWitnessInterface $scriptWitness |
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| 161 | * @param int $flags |
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| 162 | * @return int |
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| 163 | */ |
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| 164 | 1 | public function countWitnessSigOps(ScriptInterface $scriptSig, ScriptWitnessInterface $scriptWitness, $flags) |
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| 165 | { |
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| 166 | 1 | if ($flags & InterpreterInterface::VERIFY_WITNESS === 0) { |
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| 167 | return 0; |
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| 168 | } |
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| 169 | |||
| 170 | 1 | $program = null; |
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| 171 | 1 | if ($this->isWitness($program)) { |
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| 172 | /** @var WitnessProgram $program */ |
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| 173 | 1 | return $this->witnessSigOps($program, $scriptWitness); |
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| 174 | } |
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| 175 | |||
| 176 | if ((new OutputClassifier())->isPayToScriptHash($this)) { |
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| 177 | $parsed = $scriptSig->getScriptParser()->decode(); |
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| 178 | $subscript = new Script(end($parsed)->getData()); |
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| 179 | if ($subscript->isWitness($program)) { |
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| 180 | /** @var WitnessProgram $program */ |
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| 181 | return $this->witnessSigOps($program, $scriptWitness); |
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| 182 | } |
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| 183 | } |
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| 184 | |||
| 185 | return 0; |
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| 186 | } |
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| 187 | |||
| 188 | /** |
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| 189 | * @param ScriptInterface $scriptSig |
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| 190 | * @return int |
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| 191 | */ |
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| 192 | 4 | public function countP2shSigOps(ScriptInterface $scriptSig) |
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| 193 | { |
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| 194 | 4 | if (!(new OutputClassifier())->isPayToScriptHash($this)) { |
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| 195 | 2 | return $this->countSigOps(true); |
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| 196 | } |
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| 197 | |||
| 198 | try { |
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| 199 | 4 | $data = null; |
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| 200 | 4 | foreach ($scriptSig->getScriptParser() as $exec) { |
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| 201 | 4 | if ($exec->getOp() > Opcodes::OP_16) { |
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| 202 | 1 | return 0; |
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| 203 | } |
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| 204 | |||
| 205 | 3 | if ($exec->isPush()) { |
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| 206 | 3 | $data = $exec->getData(); |
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| 207 | } |
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| 208 | } |
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| 209 | |||
| 210 | 4 | if (!$data instanceof BufferInterface) { |
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| 211 | 1 | return 0; |
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| 212 | } |
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| 213 | |||
| 214 | 3 | return (new Script($data))->countSigOps(true); |
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| 215 | } catch (\Exception $e) { |
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| 216 | return 0; |
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| 217 | } |
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| 218 | } |
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| 219 | |||
| 220 | /** |
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| 221 | * @param array|null $ops |
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| 222 | * @return bool |
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| 223 | */ |
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| 224 | 230 | public function isPushOnly(array&$ops = null) |
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| 225 | { |
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| 226 | 230 | $decoded = $this->getScriptParser()->decode(); |
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| 227 | 230 | $data = []; |
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| 228 | 230 | foreach ($decoded as $entity) { |
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| 229 | 192 | if ($entity->getOp() > Opcodes::OP_16) { |
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| 230 | 12 | return false; |
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| 231 | } |
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| 232 | |||
| 233 | 186 | if ($entity->getOp() === 0) { |
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| 234 | 44 | $data[] = new Buffer(); |
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| 235 | 44 | continue; |
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| 236 | } |
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| 237 | |||
| 238 | 184 | $op = $entity->getOp(); |
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| 239 | 184 | if ($op >= Opcodes::OP_1 && $op <= Opcodes::OP_16) { |
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| 240 | 23 | $data[] = Number::int(decodeOpN($op))->getBuffer(); |
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| 241 | } else { |
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| 242 | 184 | $data[] = $entity->getData(); |
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| 243 | } |
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| 244 | } |
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| 245 | 218 | $ops = $data; |
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| 246 | 218 | return true; |
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| 247 | } |
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| 248 | |||
| 249 | /** |
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| 250 | * @param WitnessProgram|null $program |
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| 251 | * @return bool |
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| 252 | */ |
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| 253 | 257 | public function isWitness(& $program = null) |
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| 254 | { |
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| 255 | 257 | $buffer = $this->getBuffer(); |
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| 256 | 257 | $size = $buffer->getSize(); |
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| 257 | 257 | if ($size < 4 || $size > 42) { |
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| 258 | 42 | return false; |
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| 259 | } |
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| 260 | |||
| 261 | 225 | $script = $this->getScriptParser()->decode(); |
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| 262 | 225 | if (!isset($script[0]) || !isset($script[1])) { |
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| 263 | 1 | return false; |
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| 264 | } |
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| 265 | |||
| 266 | 224 | $version = $script[0]->getOp(); |
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| 267 | 224 | if ($version !== Opcodes::OP_0 && ($version < Opcodes::OP_1 || $version > Opcodes::OP_16)) { |
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| 268 | 131 | return false; |
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| 269 | } |
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| 270 | |||
| 271 | 168 | $witness = $script[1]; |
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| 272 | 168 | if ($script[1]->isPush() && $size === $witness->getDataSize() + 2) { |
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| 273 | 165 | $program = new WitnessProgram(decodeOpN($version), $witness->getData()); |
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| 274 | 165 | return true; |
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| 275 | } |
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| 276 | |||
| 277 | 3 | return false; |
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| 278 | } |
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| 279 | |||
| 280 | /** |
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| 281 | * @param BufferInterface $scriptHash |
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| 282 | * @return bool |
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| 283 | */ |
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| 284 | 7 | public function isP2SH(& $scriptHash) |
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| 285 | { |
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| 286 | 7 | if (strlen($this->script) === 23 |
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| 287 | 1 | && $this->script[0] = Opcodes::OP_HASH160 |
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| 288 | 1 | && $this->script[1] = 20 |
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| 289 | 7 | && $this->script[22] = Opcodes::OP_EQUAL |
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| 290 | ) { |
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| 291 | 1 | $scriptHash = new Buffer(substr($this->script, 2, 20)); |
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| 292 | 1 | return true; |
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| 293 | } |
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| 294 | |||
| 295 | 6 | return false; |
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| 296 | } |
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| 297 | |||
| 298 | /** |
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| 299 | * @param ScriptInterface $script |
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| 300 | * @return bool |
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| 301 | */ |
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| 302 | 171 | public function equals(ScriptInterface $script) |
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| 306 | |||
| 307 | /** |
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| 308 | * @return string |
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| 309 | */ |
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| 310 | 1 | public function __debugInfo() |
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| 311 | { |
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| 312 | try { |
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| 313 | 1 | $decoded = $this->getScriptParser()->getHumanReadable(); |
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| 314 | } catch (\Exception $e) { |
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| 315 | $decoded = 'decode failed'; |
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| 316 | } |
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| 317 | return [ |
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| 318 | 1 | 'hex' => bin2hex($this->script), |
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| 319 | 1 | 'asm' => $decoded |
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| 322 | } |
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| 323 |