Completed
Branch master (c5ffc1)
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02:29
created

SizeEstimation::estimateUtxoFromScripts()   C

Complexity

Conditions 7
Paths 15

Size

Total Lines 39
Code Lines 27

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 20
CRAP Score 7.1086

Importance

Changes 0
Metric Value
cc 7
eloc 27
nc 15
nop 3
dl 0
loc 39
ccs 20
cts 23
cp 0.8696
crap 7.1086
rs 6.7272
c 0
b 0
f 0
1
<?php
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namespace Blocktrail\SDK;
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use BitWasp\Bitcoin\Script\ScriptFactory;
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use BitWasp\Bitcoin\Script\ScriptType;
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use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PublicKeyInterface;
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use \BitWasp\Bitcoin\Script\ScriptInfo\Multisig;
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use \BitWasp\Bitcoin\Script\ScriptInfo\PayToPubKey;
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use \BitWasp\Bitcoin\Script\Classifier\OutputClassifier;
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use BitWasp\Bitcoin\Script\ScriptInterface;
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use BitWasp\Bitcoin\Transaction\TransactionOutputInterface;
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class SizeEstimation
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{
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    const SIZE_DER_SIGNATURE = 72;
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    const SIZE_V0_P2WSH = 36;
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19
    /**
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     * @param bool $compressed
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     * @return int
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     */
23 3
    public static function getPublicKeySize($compressed = true) {
24 3
        return $compressed ? PublicKeyInterface::LENGTH_COMPRESSED : PublicKeyInterface::LENGTH_UNCOMPRESSED;
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    }
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    /**
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     * @param int $length
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     * @return int
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     */
31 30
    public static function getLengthOfScriptLengthElement($length) {
32 30
        if ($length < 75) {
33 22
            return 1;
34 19
        } else if ($length <= 0xff) {
35 15
            return 2;
36 4
        } else if ($length <= 0xffff) {
37 3
            return 3;
38 1
        } else if ($length <= 0xffffffff) {
39 1
            return 5;
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        } else {
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            throw new \RuntimeException('Size of pushdata too large');
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        }
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    }
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    /**
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     * @param int $length
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     * @return int
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     */
49 37
    public static function getLengthOfVarInt($length) {
50 37
        if ($length < 253) {
51 24
            return 1;
52 21
        } else if ($length < 65535) {
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            $num_bytes = 2;
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        } else if ($length < 4294967295) {
55 4
            $num_bytes = 4;
56 3
        } else if ($length < 18446744073709551615) {
57 3
            $num_bytes = 8;
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        } else {
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            throw new \InvalidArgumentException("Invalid decimal");
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        }
61 21
        return 1 + $num_bytes;
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    }
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    /**
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     * @param array $vectorSizes
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     * @return int|mixed
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     */
68 13
    public static function getLengthOfVector(array $vectorSizes) {
69 13
        $vectorSize = self::getLengthOfVarInt(count($vectorSizes));
70 13
        foreach ($vectorSizes as $size) {
71 13
            $vectorSize += self::getLengthOfVarInt($size) + $size;
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        }
73 13
        return $vectorSize;
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    }
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    /**
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     * @param Multisig $multisig
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     * @return array - first is array of stack sizes, second is script len
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     */
80 24
    public static function estimateMultisigStackSize(Multisig $multisig) {
81 24
        $stackSizes = [0];
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        for ($i = 0; $i < $multisig->getRequiredSigCount(); $i++) {
83 24
            $stackSizes[] = self::SIZE_DER_SIGNATURE;
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        }
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86 24
        $scriptSize = 1; // OP_$m
87 24
        $keys = $multisig->getKeyBuffers();
88 24
        for ($i = 0, $n = $multisig->getKeyCount(); $i < $n; $i++) {
89 24
            $scriptSize += 1 + $keys[$i]->getSize();
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        }
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92 24
        $scriptSize += 1 + 1; // OP_$n OP_CHECKMULTISIG
93 24
        return [$stackSizes, $scriptSize];
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    }
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    /**
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     * @param PayToPubKey $info
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     * @return array - first is array of stack sizes, second is script len
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     */
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    public static function estimateP2PKStackSize(PayToPubKey $info) {
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        $stackSizes = [self::SIZE_DER_SIGNATURE];
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        $scriptSize = 1 + $info->getKeyBuffer()->getSize(); // PUSHDATA[<75] PUBLICKEY
0 ignored issues
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Unused Code Comprehensibility introduced by
38% of this comment could be valid code. Did you maybe forget this after debugging?

Sometimes obsolete code just ends up commented out instead of removed. In this case it is better to remove the code once you have checked you do not need it.

The code might also have been commented out for debugging purposes. In this case it is vital that someone uncomments it again or your project may behave in very unexpected ways in production.

This check looks for comments that seem to be mostly valid code and reports them.

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104
        $scriptSize += 1; // OP_CHECKSIG
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        return [$stackSizes, $scriptSize];
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    }
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    /**
109
     * @param bool $isCompressed
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     * @return array - first is array of stack sizes, second is script len
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     */
112 3
    public static function estimateP2PKHStackSize($isCompressed = true) {
113 3
        $pubKeySize = self::getPublicKeySize($isCompressed);
114 3
        $stackSizes = [self::SIZE_DER_SIGNATURE, $pubKeySize];
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116 3
        $scriptSize = 1 + 1 + 1 + 20 + 1 + 1;
117 3
        return [$stackSizes, $scriptSize];
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    }
119
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    /**
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     * @param array $stackSizes - array of integer size of a value (for scriptSig or witness)
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     * @param bool $isWitness
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     * @param ScriptInterface $redeemScript
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     * @param ScriptInterface $witnessScript
125
     * @return array
126
     */
127 24
    public static function estimateSizeForStack(array $stackSizes, $isWitness, ScriptInterface $redeemScript = null, ScriptInterface $witnessScript = null) {
128 24
        assert(($witnessScript === null) || $isWitness);
129
130 24
        if ($isWitness) {
131 13
            $scriptSigSizes = [];
132 13
            $witnessSizes = $stackSizes;
133 13
            if ($witnessScript instanceof ScriptInterface) {
134 13
                $witnessSizes[] = $witnessScript->getBuffer()->getSize();
135
            }
136
        } else {
137 13
            $scriptSigSizes = $stackSizes;
138 13
            $witnessSizes = [];
139
        }
140
141 24
        if ($redeemScript instanceof ScriptInterface) {
142 17
            $scriptSigSizes[] = $redeemScript->getBuffer()->getSize();
143
        }
144
145 24
        $scriptSigSize = 0;
146 24
        foreach ($scriptSigSizes as $size) {
147 19
            $len = self::getLengthOfScriptLengthElement($size);
148 19
            $scriptSigSize += $len;
149 19
            $scriptSigSize += $size;
150
        }
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        // Make sure to count the CScriptBase length prefix..
153 24
        $scriptSigSize += self::getLengthOfVarInt($scriptSigSize);
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        // make sure this is set to 0 when not used.
156
        // Summing WitnessSize is used in addition to $withWitness
157
        // because a tx without witnesses _cannot_ use witness serialization
158
        // total witnessSize = 0 means don't use that format
159 24
        $witnessSize = 0;
160 24
        if (count($witnessSizes) > 0) {
161
            // witness has a prefix indicating `n` elements in vector
162 13
            $witnessSize = self::getLengthOfVector($witnessSizes);
163
        }
164 24
        return [$scriptSigSize, $witnessSize];
165
    }
166
167
    /**
168
     * @param ScriptInterface $script - not the scriptPubKey, might be SPK,RS,WS
169
     * @param ScriptInterface|null $redeemScript
170
     * @param ScriptInterface $witnessScript
171
     * @param bool $isWitness
172
     * @return array
173
     */
174 20
    public static function estimateInputFromScripts(ScriptInterface $script, ScriptInterface $redeemScript = null, ScriptInterface $witnessScript = null, $isWitness) {
175 20
        assert($witnessScript === null || $isWitness);
176 20
        $classifier = new OutputClassifier();
177 20
        if ($classifier->isMultisig($script)) {
178 17
            list ($stackSizes, ) = SizeEstimation::estimateMultisigStackSize(new Multisig($script));
179 3
        } else if ($classifier->isPayToPublicKey($script)) {
180
            list ($stackSizes, ) = SizeEstimation::estimateP2PKStackSize(new PayToPubKey($script));
181 3
        } else if ($classifier->isPayToPublicKeyHash($script)) {
182
            // defaults to compressed, tough luck
183 3
            list ($stackSizes, ) = SizeEstimation::estimateP2PKHStackSize();
184
        } else {
185
            throw new \InvalidArgumentException("Unsupported script type");
186
        }
187
188 20
        return self::estimateSizeForStack($stackSizes, $isWitness, $redeemScript, $witnessScript);
189
    }
190
191
    /**
192
     * @param UTXO $utxo
193
     * @return array
194
     */
195 20
    public static function estimateUtxo(UTXO $utxo) {
196 20
        return self::estimateUtxoFromScripts($utxo->scriptPubKey, $utxo->redeemScript, $utxo->witnessScript);
197
    }
198
199
    /**
200
     * @param ScriptInterface $scriptPubKey
201
     * @param ScriptInterface $redeemScript
202
     * @param ScriptInterface $witnessScript
203
     * @return array
204
     */
205 20
    public static function estimateUtxoFromScripts(
206
        ScriptInterface $scriptPubKey,
207
        ScriptInterface $redeemScript = null,
208
        ScriptInterface $witnessScript = null
209
    ) {
210 20
        $classifier = new OutputClassifier();
211 20
        $decodePK = $classifier->decode($scriptPubKey);
212 20
        $witness = false;
213 20
        if ($decodePK->getType() === ScriptType::P2SH) {
214 15
            if (null === $redeemScript) {
215
                throw new \RuntimeException("Can't estimate, missing redeem script");
216
            }
217 15
            $decodePK = $classifier->decode($redeemScript);
218
        }
219
220 20
        if ($decodePK->getType() === ScriptType::P2WKH) {
221 3
            $scriptSitu = ScriptFactory::scriptPubKey()->p2pkh($decodePK->getSolution());
222 3
            $decodePK = $classifier->decode($scriptSitu);
223 3
            $witness = true;
224 17
        } else if ($decodePK->getType() === ScriptType::P2WSH) {
225 8
            if (null === $witnessScript) {
226
                throw new \RuntimeException("Can't estimate, missing witness script");
227
            }
228 8
            $decodePK = $classifier->decode($witnessScript);
229 8
            $witness = true;
230
        }
231
232 20
        if (!in_array($decodePK->getType(), [ScriptType::MULTISIG, ScriptType::P2PKH, ScriptType::P2PK])) {
233
            throw new \RuntimeException("Unsupported script type");
234
        }
235
236 20
        $script = $decodePK->getScript();
237 20
        list ($scriptSig, $witness) = SizeEstimation::estimateInputFromScripts($script, $redeemScript, $witnessScript, $witness);
238
239
        return [
240 20
            "scriptSig" => $scriptSig,
241 20
            "witness" => $witness,
242
        ];
243
    }
244
245
    /**
246
     * @param UTXO[] $utxos
247
     * @param bool $withWitness
248
     * @return integer
249
     */
250 15
    public static function estimateInputsSize(array $utxos, $withWitness) {
251 15
        $inputSize = 0;
252 15
        $witnessSize = 0;
253 15
        foreach ($utxos as $utxo) {
254 15
            $estimate = SizeEstimation::estimateUtxo($utxo);
255 15
            $inputSize += 32 + 4 + 4;
256 15
            $inputSize += $estimate['scriptSig'];
257 15
            if ($withWitness) {
258 15
                $witnessSize += $estimate['witness'];
259
            }
260
        }
261
262 15
        if ($withWitness && $witnessSize != 0) {
263 9
            $inputSize += $witnessSize;
264 9
            $inputSize += 2; // flag bytes
265
        }
266
267 15
        return $inputSize;
268
    }
269
270
    /**
271
     * @param array $outputs
272
     * @return int
273
     */
274 15
    public static function estimateOutputsSize(array $outputs) {
275 15
        $outputSize = 0;
276 15
        foreach ($outputs as $output) {
277 13
            $size = 8;
278
279 13
            $scriptSize = null;
0 ignored issues
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Unused Code introduced by
$scriptSize is not used, you could remove the assignment.

This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.

$myVar = 'Value';
$higher = false;

if (rand(1, 6) > 3) {
    $higher = true;
} else {
    $higher = false;
}

Both the $myVar assignment in line 1 and the $higher assignment in line 2 are dead. The first because $myVar is never used and the second because $higher is always overwritten for every possible time line.

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280 13
            if ($output instanceof TransactionOutputInterface) {
281 6
                $scriptSize = $output->getScript()->getBuffer()->getSize();
282
            } else {
283 11
                if (isset($output['scriptPubKey'])) {
284 11
                    if ($output['scriptPubKey'] instanceof ScriptInterface) {
285 11
                        $scriptSize = $output['scriptPubKey']->getBuffer()->getSize();
286
                    } else {
287 11
                        $scriptSize = strlen($output['scriptPubKey']) / 2;
288
                    }
289
                } else {
290 6
                    $scriptSize = 25;
291
                }
292
            }
293
294 13
            $size += SizeEstimation::getLengthOfVarInt($scriptSize) + $scriptSize;
295 13
            $outputSize += $size;
296
        }
297 15
        return $outputSize;
298
    }
299
300
    /**
301
     * @param UTXO[] $utxos
302
     * @param array $outputs
303
     * @return int
304
     */
305 15
    public static function estimateVsize(array $utxos, array $outputs) {
306 15
        return (int)ceil(self::estimateWeight($utxos, $outputs) / 4);
307
    }
308
309
    /**
310
     * @param UTXO[] $utxos
311
     * @param array $outputs
312
     * @return int
313
     */
314 15
    public static function estimateWeight(array $utxos, array $outputs) {
315 15
        $outputsSize = SizeEstimation::estimateOutputsSize($outputs);
316 15
        $outputsSize += SizeEstimation::getLengthOfVarInt(count($outputs));
317
318
        $baseSize = 4 +
319 15
            SizeEstimation::getLengthOfVarInt(count($utxos)) + SizeEstimation::estimateInputsSize($utxos, false) +
320 15
            $outputsSize + 4;
321
322
        $witnessSize = 4 +
323 15
            SizeEstimation::getLengthOfVarInt(count($utxos)) + SizeEstimation::estimateInputsSize($utxos, true) +
324 15
            $outputsSize + 4;
325
326 15
        return ($baseSize * 3) + $witnessSize;
327
    }
328
}
329