Bitcoin Transaction: Java parsing library

KS implementation details

License: MIT

This page hosts a formal specification of Bitcoin Transaction using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Java generated by Kaitai Struct depends on the Java runtime library. You have to install it before you can parse data.

The Java runtime library is published in the Maven Central Repository. Refer to the artifact page for instructions how to add it into your project with the build tool that you use.

Code

Parse a local file and get structure in memory:

BitcoinTransaction data = BitcoinTransaction.fromFile("path/to/local/file.Bitcoin Transaction");

Or parse structure from a byte array:

byte[] someArray = new byte[] { ... };
BitcoinTransaction data = new BitcoinTransaction(new ByteBufferKaitaiStream(someArray));

After that, one can get various attributes from the structure by invoking getter methods like:

data.version() // => Version number.

Java source code to parse Bitcoin Transaction

BitcoinTransaction.java

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

import io.kaitai.struct.ByteBufferKaitaiStream;
import io.kaitai.struct.KaitaiStruct;
import io.kaitai.struct.KaitaiStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Map;
import java.util.HashMap;


/**
 * @see <a href="https://bitcoin.org/en/developer-guide#transactions
 * https://en.bitcoin.it/wiki/Transaction
 * ">Source</a>
 */
public class BitcoinTransaction extends KaitaiStruct {
    public static BitcoinTransaction fromFile(String fileName) throws IOException {
        return new BitcoinTransaction(new ByteBufferKaitaiStream(fileName));
    }

    public BitcoinTransaction(KaitaiStream _io) {
        this(_io, null, null);
    }

    public BitcoinTransaction(KaitaiStream _io, KaitaiStruct _parent) {
        this(_io, _parent, null);
    }

    public BitcoinTransaction(KaitaiStream _io, KaitaiStruct _parent, BitcoinTransaction _root) {
        super(_io);
        this._parent = _parent;
        this._root = _root == null ? this : _root;
        _read();
    }
    private void _read() {
        this.version = this._io.readU4le();
        this.numVins = this._io.readU1();
        vins = new ArrayList<Vin>(((Number) (numVins())).intValue());
        for (int i = 0; i < numVins(); i++) {
            this.vins.add(new Vin(this._io, this, _root));
        }
        this.numVouts = this._io.readU1();
        vouts = new ArrayList<Vout>(((Number) (numVouts())).intValue());
        for (int i = 0; i < numVouts(); i++) {
            this.vouts.add(new Vout(this._io, this, _root));
        }
        this.locktime = this._io.readU4le();
    }
    public static class Vin extends KaitaiStruct {
        public static Vin fromFile(String fileName) throws IOException {
            return new Vin(new ByteBufferKaitaiStream(fileName));
        }

        public Vin(KaitaiStream _io) {
            this(_io, null, null);
        }

        public Vin(KaitaiStream _io, BitcoinTransaction _parent) {
            this(_io, _parent, null);
        }

        public Vin(KaitaiStream _io, BitcoinTransaction _parent, BitcoinTransaction _root) {
            super(_io);
            this._parent = _parent;
            this._root = _root;
            _read();
        }
        private void _read() {
            this.txid = this._io.readBytes(32);
            this.outputId = this._io.readU4le();
            this.lenScript = this._io.readU1();
            this._raw_scriptSig = this._io.readBytes(lenScript());
            KaitaiStream _io__raw_scriptSig = new ByteBufferKaitaiStream(_raw_scriptSig);
            this.scriptSig = new ScriptSignature(_io__raw_scriptSig, this, _root);
            this.endOfVin = this._io.readBytes(4);
            if (!(Arrays.equals(endOfVin(), new byte[] { -1, -1, -1, -1 }))) {
                throw new KaitaiStream.ValidationNotEqualError(new byte[] { -1, -1, -1, -1 }, endOfVin(), _io(), "/types/vin/seq/4");
            }
        }
        public static class ScriptSignature extends KaitaiStruct {
            public static ScriptSignature fromFile(String fileName) throws IOException {
                return new ScriptSignature(new ByteBufferKaitaiStream(fileName));
            }

            public enum SighashType {
                SIGHASH_ALL(1),
                SIGHASH_NONE(2),
                SIGHASH_SINGLE(3),
                SIGHASH_ANYONECANPAY(80);

                private final long id;
                SighashType(long id) { this.id = id; }
                public long id() { return id; }
                private static final Map<Long, SighashType> byId = new HashMap<Long, SighashType>(4);
                static {
                    for (SighashType e : SighashType.values())
                        byId.put(e.id(), e);
                }
                public static SighashType byId(long id) { return byId.get(id); }
            }

            public ScriptSignature(KaitaiStream _io) {
                this(_io, null, null);
            }

            public ScriptSignature(KaitaiStream _io, BitcoinTransaction.Vin _parent) {
                this(_io, _parent, null);
            }

            public ScriptSignature(KaitaiStream _io, BitcoinTransaction.Vin _parent, BitcoinTransaction _root) {
                super(_io);
                this._parent = _parent;
                this._root = _root;
                _read();
            }
            private void _read() {
                this.lenSigStack = this._io.readU1();
                this.derSig = new DerSignature(this._io, this, _root);
                this.sigType = SighashType.byId(this._io.readU1());
                this.lenPubkeyStack = this._io.readU1();
                this.pubkey = new PublicKey(this._io, this, _root);
            }
            public static class DerSignature extends KaitaiStruct {
                public static DerSignature fromFile(String fileName) throws IOException {
                    return new DerSignature(new ByteBufferKaitaiStream(fileName));
                }

                public DerSignature(KaitaiStream _io) {
                    this(_io, null, null);
                }

                public DerSignature(KaitaiStream _io, BitcoinTransaction.Vin.ScriptSignature _parent) {
                    this(_io, _parent, null);
                }

                public DerSignature(KaitaiStream _io, BitcoinTransaction.Vin.ScriptSignature _parent, BitcoinTransaction _root) {
                    super(_io);
                    this._parent = _parent;
                    this._root = _root;
                    _read();
                }
                private void _read() {
                    this.sequence = this._io.readBytes(1);
                    if (!(Arrays.equals(sequence(), new byte[] { 48 }))) {
                        throw new KaitaiStream.ValidationNotEqualError(new byte[] { 48 }, sequence(), _io(), "/types/vin/types/script_signature/types/der_signature/seq/0");
                    }
                    this.lenSig = this._io.readU1();
                    this.sep1 = this._io.readBytes(1);
                    if (!(Arrays.equals(sep1(), new byte[] { 2 }))) {
                        throw new KaitaiStream.ValidationNotEqualError(new byte[] { 2 }, sep1(), _io(), "/types/vin/types/script_signature/types/der_signature/seq/2");
                    }
                    this.lenSigR = this._io.readU1();
                    this.sigR = this._io.readBytes(lenSigR());
                    this.sep2 = this._io.readBytes(1);
                    if (!(Arrays.equals(sep2(), new byte[] { 2 }))) {
                        throw new KaitaiStream.ValidationNotEqualError(new byte[] { 2 }, sep2(), _io(), "/types/vin/types/script_signature/types/der_signature/seq/5");
                    }
                    this.lenSigS = this._io.readU1();
                    this.sigS = this._io.readBytes(lenSigS());
                }
                private byte[] sequence;
                private int lenSig;
                private byte[] sep1;
                private int lenSigR;
                private byte[] sigR;
                private byte[] sep2;
                private int lenSigS;
                private byte[] sigS;
                private BitcoinTransaction _root;
                private BitcoinTransaction.Vin.ScriptSignature _parent;
                public byte[] sequence() { return sequence; }
                public int lenSig() { return lenSig; }
                public byte[] sep1() { return sep1; }

                /**
                 * 'r' value's length.
                 */
                public int lenSigR() { return lenSigR; }

                /**
                 * 'r' value of the ECDSA signature.
                 * @see <a href="https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm">Source</a>
                 */
                public byte[] sigR() { return sigR; }
                public byte[] sep2() { return sep2; }

                /**
                 * 's' value's length.
                 */
                public int lenSigS() { return lenSigS; }

                /**
                 * 's' value of the ECDSA signature.
                 * @see <a href="https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm">Source</a>
                 */
                public byte[] sigS() { return sigS; }
                public BitcoinTransaction _root() { return _root; }
                public BitcoinTransaction.Vin.ScriptSignature _parent() { return _parent; }
            }
            public static class PublicKey extends KaitaiStruct {
                public static PublicKey fromFile(String fileName) throws IOException {
                    return new PublicKey(new ByteBufferKaitaiStream(fileName));
                }

                public PublicKey(KaitaiStream _io) {
                    this(_io, null, null);
                }

                public PublicKey(KaitaiStream _io, BitcoinTransaction.Vin.ScriptSignature _parent) {
                    this(_io, _parent, null);
                }

                public PublicKey(KaitaiStream _io, BitcoinTransaction.Vin.ScriptSignature _parent, BitcoinTransaction _root) {
                    super(_io);
                    this._parent = _parent;
                    this._root = _root;
                    _read();
                }
                private void _read() {
                    this.type = this._io.readU1();
                    this.x = this._io.readBytes(32);
                    this.y = this._io.readBytes(32);
                }
                private int type;
                private byte[] x;
                private byte[] y;
                private BitcoinTransaction _root;
                private BitcoinTransaction.Vin.ScriptSignature _parent;
                public int type() { return type; }

                /**
                 * 'x' coordinate of the public key on the elliptic curve.
                 */
                public byte[] x() { return x; }

                /**
                 * 'y' coordinate of the public key on the elliptic curve.
                 */
                public byte[] y() { return y; }
                public BitcoinTransaction _root() { return _root; }
                public BitcoinTransaction.Vin.ScriptSignature _parent() { return _parent; }
            }
            private int lenSigStack;
            private DerSignature derSig;
            private SighashType sigType;
            private int lenPubkeyStack;
            private PublicKey pubkey;
            private BitcoinTransaction _root;
            private BitcoinTransaction.Vin _parent;
            public int lenSigStack() { return lenSigStack; }

            /**
             * DER-encoded ECDSA signature.
             * @see <a href="https://en.wikipedia.org/wiki/X.690#DER_encoding
             * https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
             * ">Source</a>
             */
            public DerSignature derSig() { return derSig; }

            /**
             * Type of signature.
             */
            public SighashType sigType() { return sigType; }
            public int lenPubkeyStack() { return lenPubkeyStack; }

            /**
             * Public key (bitcoin address of the recipient).
             */
            public PublicKey pubkey() { return pubkey; }
            public BitcoinTransaction _root() { return _root; }
            public BitcoinTransaction.Vin _parent() { return _parent; }
        }
        private byte[] txid;
        private long outputId;
        private int lenScript;
        private ScriptSignature scriptSig;
        private byte[] endOfVin;
        private BitcoinTransaction _root;
        private BitcoinTransaction _parent;
        private byte[] _raw_scriptSig;

        /**
         * Previous transaction hash.
         */
        public byte[] txid() { return txid; }

        /**
         * ID indexing an ouput of the transaction refered by txid.
         * This output will be used as an input in the present transaction.
         */
        public long outputId() { return outputId; }

        /**
         * ScriptSig's length.
         */
        public int lenScript() { return lenScript; }

        /**
         * ScriptSig.
         * @see <a href="https://en.bitcoin.it/wiki/Transaction#Input
         * https://en.bitcoin.it/wiki/Script
         * ">Source</a>
         */
        public ScriptSignature scriptSig() { return scriptSig; }

        /**
         * Magic number indicating the end of the current input.
         */
        public byte[] endOfVin() { return endOfVin; }
        public BitcoinTransaction _root() { return _root; }
        public BitcoinTransaction _parent() { return _parent; }
        public byte[] _raw_scriptSig() { return _raw_scriptSig; }
    }
    public static class Vout extends KaitaiStruct {
        public static Vout fromFile(String fileName) throws IOException {
            return new Vout(new ByteBufferKaitaiStream(fileName));
        }

        public Vout(KaitaiStream _io) {
            this(_io, null, null);
        }

        public Vout(KaitaiStream _io, BitcoinTransaction _parent) {
            this(_io, _parent, null);
        }

        public Vout(KaitaiStream _io, BitcoinTransaction _parent, BitcoinTransaction _root) {
            super(_io);
            this._parent = _parent;
            this._root = _root;
            _read();
        }
        private void _read() {
            this.amount = this._io.readU8le();
            this.lenScript = this._io.readU1();
            this.scriptPubKey = this._io.readBytes(lenScript());
        }
        private long amount;
        private int lenScript;
        private byte[] scriptPubKey;
        private BitcoinTransaction _root;
        private BitcoinTransaction _parent;

        /**
         * Number of Satoshis to be transfered.
         */
        public long amount() { return amount; }

        /**
         * ScriptPubKey's length.
         */
        public int lenScript() { return lenScript; }

        /**
         * ScriptPubKey.
         * @see <a href="https://en.bitcoin.it/wiki/Transaction#Output
         * https://en.bitcoin.it/wiki/Script
         * ">Source</a>
         */
        public byte[] scriptPubKey() { return scriptPubKey; }
        public BitcoinTransaction _root() { return _root; }
        public BitcoinTransaction _parent() { return _parent; }
    }
    private long version;
    private int numVins;
    private ArrayList<Vin> vins;
    private int numVouts;
    private ArrayList<Vout> vouts;
    private long locktime;
    private BitcoinTransaction _root;
    private KaitaiStruct _parent;

    /**
     * Version number.
     */
    public long version() { return version; }

    /**
     * Number of input transactions.
     */
    public int numVins() { return numVins; }

    /**
     * Input transactions.
     * An input refers to an output from a previous transaction.
     */
    public ArrayList<Vin> vins() { return vins; }

    /**
     * Number of output transactions.
     */
    public int numVouts() { return numVouts; }

    /**
     * Output transactions.
     */
    public ArrayList<Vout> vouts() { return vouts; }
    public long locktime() { return locktime; }
    public BitcoinTransaction _root() { return _root; }
    public KaitaiStruct _parent() { return _parent; }
}