Completed
Pull Request — master (#99)
by thomas
42:14 queued 39:21
created

SizeEstimation::estimateVsize()   A

Complexity

Conditions 1
Paths 1

Size

Total Lines 3
Code Lines 2

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 2
CRAP Score 1

Importance

Changes 0
Metric Value
cc 1
eloc 2
nc 1
nop 2
dl 0
loc 3
ccs 2
cts 2
cp 1
crap 1
rs 10
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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    /**
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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 $length
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     * @return int
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     */
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    public static function getLengthOfScriptLengthElement($length) {
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        if ($length < 75) {
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            return 1;
34 19
        } else if ($length <= 0xff) {
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            return 2;
36 4
        } else if ($length <= 0xffff) {
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            return 3;
38 1
        } else if ($length <= 0xffffffff) {
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            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 $length
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     * @return int
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     */
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    public static function getLengthOfVarInt($length) {
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        if ($length < 253) {
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            return 1;
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        } else if ($length < 65535) {
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            $num_bytes = 2;
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        } else if ($length < 4294967295) {
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            $num_bytes = 4;
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        } else if ($length < 18446744073709551615) {
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            $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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     */
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    public static function getLengthOfVector(array $vectorSizes) {
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        $vectorSize = self::getLengthOfVarInt(count($vectorSizes));
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        foreach ($vectorSizes as $size) {
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            $vectorSize += self::getLengthOfVarInt($size) + $size;
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        }
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        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) {
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        $stackSizes = [0];
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        for ($i = 0; $i < $multisig->getRequiredSigCount(); $i++) {
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            $stackSizes[] = self::SIZE_DER_SIGNATURE;
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        }
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86 24
        $scriptSize = 1; // OP_$m
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        $keys = $multisig->getKeyBuffers();
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        for ($i = 0, $n = $multisig->getKeyCount(); $i < $n; $i++) {
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            $scriptSize += 1 + $keys[$i]->getSize();
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        }
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        $scriptSize += 1 + 1; // OP_$n OP_CHECKMULTISIG
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        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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    /**
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     * @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) {
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        $pubKeySize = self::getPublicKeySize($isCompressed);
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        $stackSizes = [self::SIZE_DER_SIGNATURE, $pubKeySize];
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        $scriptSize = 1 + 1 + 1 + 20 + 1 + 1;
117 3
        return [$stackSizes, $scriptSize];
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    }
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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
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     * @return array
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     */
127 24
    public static function estimateSizeForStack(array $stackSizes, $isWitness, ScriptInterface $redeemScript = null, ScriptInterface $witnessScript = null) {
128 24
        assert(($witnessScript === null) || $isWitness);
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        if ($isWitness) {
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            $scriptSigSizes = [];
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            $witnessSizes = $stackSizes;
133 12
            if ($witnessScript instanceof ScriptInterface) {
134 12
                $witnessSizes[] = $witnessScript->getBuffer()->getSize();
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            }
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        } else {
137 13
            $scriptSigSizes = $stackSizes;
138 13
            $witnessSizes = [];
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        }
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141 24
        if ($redeemScript instanceof ScriptInterface) {
142 17
            $scriptSigSizes[] = $redeemScript->getBuffer()->getSize();
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        }
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145 24
        $scriptSigSize = 0;
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        foreach ($scriptSigSizes as $size) {
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            $len = self::getLengthOfScriptLengthElement($size);
148 19
            $scriptSigSize += $len;
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            $scriptSigSize += $size;
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        }
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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.
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        // Summing WitnessSize is used in addition to $withWitness
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        // because a tx without witnesses _cannot_ use witness serialization
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        // total witnessSize = 0 means don't use that format
159 24
        $witnessSize = 0;
160 24
        if (count($witnessSizes) > 0) {
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            // witness has a prefix indicating `n` elements in vector
162 12
            $witnessSize = self::getLengthOfVector($witnessSizes);
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        }
164 24
        return [$scriptSigSize, $witnessSize];
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    }
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    /**
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     * @param ScriptInterface $script - not the scriptPubKey, might be SPK,RS,WS
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     * @param ScriptInterface|null $redeemScript
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     * @param ScriptInterface $witnessScript
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     * @param bool $isWitness
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     * @return array
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     */
174 20
    public static function estimateInputFromScripts(ScriptInterface $script, ScriptInterface $redeemScript = null, ScriptInterface $witnessScript = null, $isWitness) {
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        assert($witnessScript === null || $isWitness);
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        $classifier = new OutputClassifier();
177 20
        if ($classifier->isMultisig($script)) {
178 17
            list ($stackSizes, ) = SizeEstimation::estimateMultisigStackSize(new Multisig($script));
179 3
        } else if ($classifier->isPayToPublicKey($script)) {
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            list ($stackSizes, ) = SizeEstimation::estimateP2PKStackSize(new PayToPubKey($script));
181 3
        } else if ($classifier->isPayToPublicKeyHash($script)) {
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            // defaults to compressed, tough luck
183 3
            list ($stackSizes, ) = SizeEstimation::estimateP2PKHStackSize();
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        } else {
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            throw new \InvalidArgumentException("Unsupported script type");
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        }
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188 20
        return self::estimateSizeForStack($stackSizes, $isWitness, $redeemScript, $witnessScript);
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    }
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    /**
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     * @param UTXO $utxo
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     * @return array
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     */
195 20
    public static function estimateUtxo(UTXO $utxo) {
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        $classifier = new OutputClassifier();
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        $decodePK = $classifier->decode($utxo->scriptPubKey);
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        $witness = false;
199 20
        if ($decodePK->getType() === ScriptType::P2SH) {
200 15
            if (null === $utxo->redeemScript) {
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                throw new \RuntimeException("Can't estimate, missing redeem script");
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            }
203 15
            $decodePK = $classifier->decode($utxo->redeemScript);
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        }
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206 20
        if ($decodePK->getType() === ScriptType::P2WKH) {
207 3
            $scriptSitu = ScriptFactory::scriptPubKey()->p2pkh($decodePK->getSolution());
208 3
            $decodePK = $classifier->decode($scriptSitu);
209 3
            $witness = true;
210 17
        } else if ($decodePK->getType() === ScriptType::P2WSH) {
211 7
            if (null === $utxo->witnessScript) {
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                throw new \RuntimeException("Can't estimate, missing witness script");
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            }
214 7
            $decodePK = $classifier->decode($utxo->witnessScript);
215 7
            $witness = true;
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        }
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218 20
        if (!in_array($decodePK->getType(), [ScriptType::MULTISIG, ScriptType::P2PKH, ScriptType::P2PK])) {
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            throw new \RuntimeException("Unsupported script type");
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        }
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222 20
        $script = $decodePK->getScript();
223 20
        list ($scriptSig, $witness) = SizeEstimation::estimateInputFromScripts($script, $utxo->redeemScript, $utxo->witnessScript, $witness);
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        return [
226 20
            "scriptSig" => $scriptSig,
227 20
            "witness" => $witness,
228
        ];
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    }
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    /**
232
     * @param UTXO[] $utxos
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     * @param bool $withWitness
234
     * @return integer
235
     */
236 15
    public static function estimateInputsSize(array $utxos, $withWitness) {
237 15
        $inputSize = 0;
238 15
        $witnessSize = 0;
239 15
        foreach ($utxos as $utxo) {
240 15
            $estimate = SizeEstimation::estimateUtxo($utxo);
241 15
            $inputSize += 32 + 4 + 4;
242 15
            $inputSize += $estimate['scriptSig'];
243 15
            if ($withWitness) {
244 15
                $witnessSize += $estimate['witness'];
245
            }
246
        }
247
248 15
        if ($withWitness && $witnessSize != 0) {
249 8
            $inputSize += $witnessSize;
250 8
            $inputSize += 2; // flag bytes
251
        }
252
253 15
        return $inputSize;
254
    }
255
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    /**
257
     * @param array $outputs
258
     * @return int
259
     */
260 15
    public static function estimateOutputsSize(array $outputs) {
261 15
        $outputSize = 0;
262 15
        foreach ($outputs as $output) {
263 13
            $size = 8;
264
265 13
            $scriptSize = null;
0 ignored issues
show
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.

Loading history...
266 13
            if ($output instanceof TransactionOutputInterface) {
267 6
                $scriptSize = $output->getScript()->getBuffer()->getSize();
268
            } else {
269 11
                if (isset($output['scriptPubKey'])) {
270 11
                    if ($output['scriptPubKey'] instanceof ScriptInterface) {
271 11
                        $scriptSize = $output['scriptPubKey']->getBuffer()->getSize();
272
                    } else {
273 11
                        $scriptSize = strlen($output['scriptPubKey']) / 2;
274
                    }
275
                } else {
276 6
                    $scriptSize = 25;
277
                }
278
            }
279
280 13
            $size += SizeEstimation::getLengthOfVarInt($scriptSize) + $scriptSize;
281 13
            $outputSize += $size;
282
        }
283 15
        return $outputSize;
284
    }
285
286
    /**
287
     * @param UTXO[] $utxos
288
     * @param array $outputs
289
     * @return int
290
     */
291 15
    public static function estimateVsize(array $utxos, array $outputs) {
292 15
        return (int)ceil(self::estimateWeight($utxos, $outputs) / 4);
293
    }
294
295
    /**
296
     * @param UTXO[] $utxos
297
     * @param array $outputs
298
     * @return int
299
     */
300 15
    public static function estimateWeight(array $utxos, array $outputs) {
301 15
        $outputsSize = SizeEstimation::estimateOutputsSize($outputs);
302 15
        $outputsSize += SizeEstimation::getLengthOfVarInt(count($outputs));
303
304
        $baseSize = 4 +
305 15
            SizeEstimation::getLengthOfVarInt(count($utxos)) + SizeEstimation::estimateInputsSize($utxos, false) +
306 15
            $outputsSize + 4;
307
308
        $witnessSize = 4 +
309 15
            SizeEstimation::getLengthOfVarInt(count($utxos)) + SizeEstimation::estimateInputsSize($utxos, true) +
310 15
            $outputsSize + 4;
311
312 15
        return ($baseSize * 3) + $witnessSize;
313
    }
314
}
315