Contract ABI and Recursive Length Prefix made easy for the JVM. Everything heavily optimized for maximum throughput (ABI function call encoding up to 500x faster than a popular competitor. One function init plus one encode up to 50x faster ("sam(bytes,bool,uint256[])"
, openjdk 12.0.1)).
ABI spec: https://solidity.readthedocs.io/en/latest/abi-spec.html
RLP spec: https://github.com/ethereum/wiki/wiki/RLP
SHA-256 (headlong-1.5.0.jar): c3ead2c7a6c93ad53a19ca6ca7e8779c39715fdc9e95ebc903f0a277bb7e417c
Function f = new Function("baz(uint32,bool)"); // canonicalizes and parses any signature automatically
Function f2 = Function.fromJson("{\"type\":\"function\",\"name\":\"foo\",\"inputs\":[{\"name\":\"complex_nums\",\"type\":\"tuple[]\",\"components\":[{\"name\":\"real\",\"type\":\"decimal\"},{\"name\":\"imaginary\",\"type\":\"decimal\"}]}]}");
Tuple args = new Tuple(69L, true);
// Two equivalent styles:
ByteBuffer one = f.encodeCall(args);
ByteBuffer two = f.encodeCallWithArgs(69L, true);
System.out.println(Function.formatCall(one.array())); // a multi-line hex representation
System.out.println(f.decodeCall((ByteBuffer) two.flip()).equals(args));
Function getUfixedAndString = new Function("gogo((fixed[],int8)[1][][5])", "(ufixed,string)");
Tuple decoded = getUfixedAndString.decodeReturn(
FastHex.decode(
"0000000000000000000000000000000000000000000000000000000000000045"
+ "0000000000000000000000000000000000000000000000000000000000000020"
+ "0000000000000000000000000000000000000000000000000000000000000004"
+ "7730307400000000000000000000000000000000000000000000000000000000"
)
);
System.out.println(decoded.equals(new Tuple(new BigDecimal(BigInteger.valueOf(69L), 18), "w00t")));
// for an example class Student
public Student(byte[] rlp) throws DecodeException {
RLPIterator iter = RLP_STRICT.sequenceIterator(rlp);
this.name = iter.next().asString(UTF_8);
this.gpa = iter.next().asFloat();
this.publicKey = iter.next().asBytes();
this.balance = new BigDecimal(iter.next().asBigInt(), iter.next().asInt());
}
@Override
public Object[] toObjectArray() {
return new Object[] {
Strings.decode(name, UTF_8),
FloatingPoint.toBytes(gpa),
publicKey,
balance.unscaledValue().toByteArray(),
Integers.toBytes(balance.scale())
};
}
@Override
public byte[] toRLP() {
return RLPEncoder.encodeSequentially(toObjectArray());
}
Also includes a fast hex codec and an optimized Keccak implementation.
Now available in Maven Central Repository.
Or build locally:
Clone the project and install to your local maven repository using gradle publishToMavenLocal
or mvn install
. Then you can use one of these:
implementation 'com.esaulpaugh:headlong:2.0.0-SNAPSHOT'
<dependency>
<groupId>com.esaulpaugh</groupId>
<artifactId>headlong</artifactId>
<version>2.0.0-SNAPSHOT</version>
</dependency>
Alternatively:
- Run
gradle build
orgradle jar
which output to/build/libs
- Use
mvn package
which outputs to/target
- Execute
ant all build-jar
which outputs to/build/lib
- Add headlong as a project dependency
https://github.com/esaulpaugh/headlong-cli
headlong depends on gson. Test suite should take less than one minute to run. Test packages require junit and spongycastle. Jar size is ~115 KB as of 09/27/19. Java 8+.
See the wiki for more, such as TupleTypes, packed encoding, RLP Lists, and RLP Object Notation: https://github.com/esaulpaugh/headlong/wiki
Licensed under Apache 2.0 terms