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74 changes: 49 additions & 25 deletions
74
bitcoinkit/src/main/kotlin/io/horizontalsystems/bitcoinkit/managers/UnspentOutputSelector.kt
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,56 +1,80 @@ | ||
| package io.horizontalsystems.bitcoinkit.managers | ||
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| import io.horizontalsystems.bitcoinkit.models.TransactionOutput | ||
| import io.horizontalsystems.bitcoinkit.scripts.ScriptType | ||
| import io.horizontalsystems.bitcoinkit.scripts.ScriptType.P2PKH | ||
| import io.horizontalsystems.bitcoinkit.transactions.TransactionSizeCalculator | ||
|
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| class UnspentOutputSelector(private val txSizeCalculator: TransactionSizeCalculator) { | ||
| class UnspentOutputSelector(private val calculator: TransactionSizeCalculator) { | ||
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| class EmptyUnspentOutputs : Exception() | ||
| class InsufficientUnspentOutputs : Exception() | ||
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| fun select(value: Int, feeRate: Int, outputScriptType: Int, senderPay: Boolean, unspentOutputs: List<TransactionOutput>): SelectedUnspentOutputInfo { | ||
| fun select(value: Int, feeRate: Int, outputType: Int = P2PKH, changeType: Int = P2PKH, senderPay: Boolean, outputs: List<TransactionOutput>): SelectedUnspentOutputInfo { | ||
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| if (unspentOutputs.isEmpty()) { | ||
| if (outputs.isEmpty()) { | ||
| throw EmptyUnspentOutputs() | ||
| } | ||
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| val selected = mutableListOf<TransactionOutput>() | ||
| var calculatedFee = (txSizeCalculator.emptyTxSize + txSizeCalculator.outputSize(outputScriptType)) * feeRate | ||
| val dust = txSizeCalculator.inputSize(ScriptType.P2PKH) * feeRate | ||
| val dust = (calculator.inputSize(changeType) + calculator.outputSize(changeType)) * feeRate | ||
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| // try to find 1 unspent output with exactly matching value | ||
| unspentOutputs.firstOrNull { | ||
| val totalFee = if (senderPay) calculatedFee + txSizeCalculator.inputSize(it.scriptType) * feeRate else 0 | ||
| (value + totalFee <= it.value) && (value + totalFee + dust > it.value) //value + input fee + dust | ||
| }?.let { output -> | ||
| selected.add(output) | ||
| calculatedFee += txSizeCalculator.inputSize(output.scriptType) * feeRate | ||
| // try to find 1 unspent output with exactly matching value | ||
| for (output in outputs) { | ||
| val fee = calculator.transactionSize(listOf(output.scriptType), listOf(outputType)) * feeRate | ||
| val totalFee = if (senderPay) fee else 0 | ||
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| return SelectedUnspentOutputInfo(outputs = selected, totalValue = output.value, fee = calculatedFee) | ||
| if (value + totalFee <= output.value && value + totalFee + dust > output.value) { | ||
| return SelectedUnspentOutputInfo( | ||
| outputs = listOf(output), | ||
| totalValue = output.value, | ||
| fee = if (senderPay) output.value.toInt() - value else fee, | ||
| addChangeOutput = false) | ||
| } | ||
| } | ||
|
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| // select outputs with least value until we get needed value | ||
| val sortedOutputs = unspentOutputs.sortedBy { it.value } | ||
| // select outputs with least value until we get needed value | ||
| val sortedOutputs = outputs.sortedBy { it.value } | ||
| val selectedOutputs = mutableListOf<TransactionOutput>() | ||
| val selectedOutputTypes = mutableListOf<Int>() | ||
| var totalValue = 0L | ||
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| var fee = 0 | ||
| var lastCalculatedFee = 0 | ||
| for (output in sortedOutputs) { | ||
| if (totalValue >= value + (if (senderPay) calculatedFee else 0)) { | ||
| lastCalculatedFee = calculator.transactionSize(inputs = selectedOutputTypes, outputs = listOf(outputType)) * feeRate | ||
| if (senderPay) { | ||
| fee = lastCalculatedFee | ||
| } | ||
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| if (totalValue >= value + fee) { | ||
| break | ||
| } | ||
| selected.add(output) | ||
| calculatedFee += txSizeCalculator.inputSize(output.scriptType) * feeRate | ||
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| selectedOutputs.add(output) | ||
| selectedOutputTypes.add(output.scriptType) | ||
| totalValue += output.value | ||
| } | ||
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| // if all outputs are selected and total value less than needed throw error | ||
| if (totalValue < value + (if (senderPay) calculatedFee else 0)) { | ||
| if (totalValue < value + fee) { | ||
| throw InsufficientUnspentOutputs() | ||
| } | ||
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| return SelectedUnspentOutputInfo(outputs = selected, totalValue = totalValue, fee = calculatedFee) | ||
| } | ||
| // if total selected outputs value more than value and fee for transaction with change output + change input -> add fee for change output and mark as need change address | ||
| var addChangeOutput = false | ||
| if (totalValue > value + lastCalculatedFee + (if (senderPay) dust else 0)) { | ||
| lastCalculatedFee = calculator.transactionSize(inputs = selectedOutputTypes, outputs = listOf(outputType, changeType)) * feeRate | ||
| addChangeOutput = true | ||
| } else if (senderPay) { | ||
| lastCalculatedFee = totalValue.toInt() - value | ||
| } | ||
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| return SelectedUnspentOutputInfo(selectedOutputs, totalValue, lastCalculatedFee, addChangeOutput) | ||
| } | ||
| } | ||
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| data class SelectedUnspentOutputInfo(val outputs: List<TransactionOutput>, val totalValue: Long, val fee: Int) | ||
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| data class SelectedUnspentOutputInfo( | ||
| val outputs: List<TransactionOutput>, | ||
| val totalValue: Long, | ||
| val fee: Int, | ||
| val addChangeOutput: Boolean | ||
| ) |
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97 changes: 63 additions & 34 deletions
97
...src/main/kotlin/io/horizontalsystems/bitcoinkit/transactions/TransactionSizeCalculator.kt
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,53 +1,82 @@ | ||
| package io.horizontalsystems.bitcoinkit.transactions | ||
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| import io.horizontalsystems.bitcoinkit.scripts.ScriptType | ||
| import io.horizontalsystems.bitcoinkit.scripts.ScriptType.P2PK | ||
| import io.horizontalsystems.bitcoinkit.scripts.ScriptType.P2PKH | ||
| import io.horizontalsystems.bitcoinkit.scripts.ScriptType.P2WPKHSH | ||
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| class TransactionSizeCalculator { | ||
| private val signatureLength = 72 + 1 // signature length + pushByte | ||
| private val pubKeyLength = 33 + 1 // pubKey length + pushByte | ||
| private val p2wpkhShLength = 22 + 1 // 0014<20-byte-script-hash> + pushByte | ||
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| companion object { | ||
| private const val VERSION_SIZE = 4 | ||
| private const val OUTPUT_COUNT_SIZE = 1 | ||
| private const val INPUT_COUNT_SIZE = 1 | ||
| private const val LOCK_TIME_SIZE = 4 | ||
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| private const val OUTPUT_HEX_SIZE = 32 | ||
| private const val OUTPUT_INDEX_SIZE = 4 | ||
| private const val SEQUENCE_SIZE = 4 | ||
| private const val SCRIPT_SIZE = 1 | ||
| private const val VALUE_SIZE = 8 | ||
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| private const val SIGNATURE_SIZE = 73 | ||
| private const val PUB_KEY_SIZE = 33 | ||
| private const val PUB_KEY_HASH_SIZE = 20 | ||
| private const val SCRIPT_HASH_ADDRESS_SIZE = 20 | ||
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| private const val OP_PUSHDATA_SIZE = 1 | ||
| private const val OP_CHECKSIG_SIZE = 1 | ||
| private const val OP_DUP_SIZE = 1 | ||
| private const val OP_HASH160_SIZE = 1 | ||
| private const val OP_EQUALVERIFY_SIZE = 1 | ||
| private val legacyTx = 16 + 4 + 4 + 16 // 40 Version + number of inputs + number of outputs + locktime | ||
| private val legacyWitnessData = 1 // 1 Only 0x00 for legacy input | ||
| private val witnessTx = legacyTx + 1 + 1 // 42 segwit marker + segwit flag | ||
| private val witnessData = 1 + signatureLength + pubKeyLength // 108 Number of stack items for input + Size of stack item 0 + Stack item 0, signature + Size of stack item 1 + Stack item 1, pubkey | ||
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| fun outputSize(scripType: Int): Int { | ||
| return 8 + 1 + getLockingScriptSize(scripType) | ||
| } | ||
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| val emptyTxSize = VERSION_SIZE + OUTPUT_COUNT_SIZE + INPUT_COUNT_SIZE + LOCK_TIME_SIZE | ||
| fun inputSize(scriptType: Int): Int { | ||
| val sigLength = when (scriptType) { | ||
| P2PKH -> signatureLength + pubKeyLength | ||
| P2PK -> signatureLength | ||
| P2WPKHSH -> p2wpkhShLength | ||
| else -> 0 | ||
| } | ||
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| fun outputSize(scripType: Int) = VALUE_SIZE + SCRIPT_SIZE + getLockingScriptSize(scripType) | ||
| return 32 + 4 + 1 + sigLength + 4 // PreviousOutputHex + OutputIndex + sigLength + sigScript + sequence | ||
| } | ||
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| fun inputSize(scriptType: Int): Int { | ||
| return OUTPUT_HEX_SIZE + OUTPUT_INDEX_SIZE + SCRIPT_SIZE + getUnlockingScriptSize(scriptType) + SEQUENCE_SIZE | ||
| fun transactionSize(inputs: List<Int>, outputs: List<Int>): Int { | ||
| var segwit = false | ||
| var inputWeight = 0 | ||
|
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| for (input in inputs) { | ||
| if (isWitness(input)) { | ||
| segwit = true | ||
| break | ||
| } | ||
| } | ||
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| inputs.forEach { input -> | ||
| inputWeight += inputSize(input) * 4 // to vbytes | ||
| if (isWitness(input)) { | ||
| inputWeight += witnessSize(input) | ||
| } | ||
| } | ||
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| val outputWeight = outputs.fold(0) { memo, next -> memo + outputSize(next) } * 4 // to vbytes | ||
| val txWeight = if (segwit) witnessTx else legacyTx | ||
|
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| return toBytes(txWeight + inputWeight + outputWeight) | ||
| } | ||
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| private fun getUnlockingScriptSize(scriptType: Int) = OP_PUSHDATA_SIZE + SIGNATURE_SIZE + when (scriptType) { | ||
| ScriptType.P2PK -> 0 | ||
| ScriptType.P2PKH -> OP_PUSHDATA_SIZE + PUB_KEY_SIZE | ||
| ScriptType.P2SH -> OP_PUSHDATA_SIZE + SCRIPT_HASH_ADDRESS_SIZE | ||
| else -> 0 | ||
| private fun witnessSize(type: Int): Int { // in vbytes | ||
| if (isWitness(type)) { | ||
| return witnessData | ||
| } | ||
|
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| return legacyWitnessData | ||
| } | ||
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| private fun toBytes(fee: Int): Int { | ||
| return (fee / 4) + if (fee % 4 == 0) 0 else 1 | ||
| } | ||
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| private fun getLockingScriptSize(scriptType: Int) = when (scriptType) { | ||
| ScriptType.P2PK -> OP_PUSHDATA_SIZE + PUB_KEY_SIZE + OP_CHECKSIG_SIZE | ||
| ScriptType.P2PKH -> OP_DUP_SIZE + OP_HASH160_SIZE + OP_PUSHDATA_SIZE + PUB_KEY_HASH_SIZE + OP_EQUALVERIFY_SIZE + OP_CHECKSIG_SIZE | ||
| ScriptType.P2SH -> 23 //todo need to change after adding p2sh addresses | ||
| ScriptType.P2PK -> 35 | ||
| ScriptType.P2PKH -> 25 | ||
| ScriptType.P2SH -> 23 | ||
| ScriptType.P2WPKH -> 22 | ||
| ScriptType.P2WSH -> 34 | ||
| ScriptType.P2WPKHSH -> 23 | ||
| else -> 0 | ||
| } | ||
|
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| private fun isWitness(type: Int): Boolean { | ||
| return type in arrayOf(ScriptType.P2WPKH, ScriptType.P2WSH, ScriptType.P2WPKHSH) | ||
| } | ||
| } |
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