feat(ContractFunctionParameters): adds addBytes4 and addBytes4Array

sdk/src/main/java/com/hedera/hashgraph/sdk/ContractFunctionParameters.java

@@ -21,6 +21,7 @@
 
 import com.google.errorprone.annotations.Var;
 import com.google.protobuf.ByteString;
+
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -29,6 +30,7 @@
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 import javax.annotation.Nullable;
+
 import org.bouncycastle.util.encoders.DecoderException;
 import org.bouncycastle.util.encoders.Hex;
 
@@ -86,6 +88,14 @@ private static ByteString encodeBytes(byte[] bytes) {
  .concat(rightPad32(ByteString.copyFrom(bytes)));
  }
 
+ private static ByteString encodeBytes4(byte[] bytes) {
+ if (bytes.length > 4) {
+ throw new IllegalArgumentException("bytes4 encoding forbids byte array length greater than 4");
+ }
+ return rightPad32(ByteString.copyFrom(bytes));
+ }
+
+
  private static ByteString encodeBytes32(byte[] bytes) {
  if (bytes.length > 32) {
  throw new IllegalArgumentException("byte32 encoding forbids byte array length greater than 32");
@@ -187,7 +197,7 @@ static ByteString leftPad32(ByteString input, boolean negative) {
  return rem == 32
  ? input
  : (negative ? negativePadding : padding).substring(0, rem)
-  .concat(input);
+ .concat(input);
  }
 
  static ByteString leftPad32(byte[] input, boolean negative) {
@@ -275,6 +285,35 @@ public ContractFunctionParameters addBytesArray(byte[][] param) {
  return this;
  }
 
+ /**
+ * Add a parameter of type {@code bytes4}, a 4-byte fixed-length byte-string.
+ *
+ * @param param The 4-byte array to be added
+ * @return {@code this}
+ * @throws IllegalArgumentException if the length of the byte array is not 4.
+ */
+ public ContractFunctionParameters addBytes4(byte[] param) {
+ args.add(new Argument("bytes4", encodeBytes4(param), false));
+
+ return this;
+ }
+
+ /**
+ * Add a parameter of type {@code bytes4[]}, an array of 4-byte fixed-length byte-strings.
+ *
+ * @param param The array of 4-byte arrays to be added
+ * @return {@code this}
+ * @throws IllegalArgumentException if the length of any byte array is not 4.
+ */
+ public ContractFunctionParameters addBytes4Array(byte[][] param) {
+ Stream<ByteString> byteArrays = Arrays.stream(param)
+ .map(ContractFunctionParameters::encodeBytes4);
+
+ args.add(new Argument("bytes4[]", encodeArray(byteArrays), true));
+
+ return this;
+ }
+
  /**
  * Add a parameter of type {@code bytes32}, a 32-byte byte-string.
  * <p>

sdk/src/test/java/com/hedera/hashgraph/sdk/ContractFunctionParametersTest.java

@@ -254,6 +254,44 @@ void functionsError() {
  });
  }
 
+ @Test
+ @DisplayName("encodes bytes4 correctly")
+ void bytes4Encoding() {
+ var params = new ContractFunctionParameters()
+ .addBytes4(new byte[]{1, 2, 3, 4});
+ assertThat(
+ "580526ee" +
+ "0102030400000000000000000000000000000000000000000000000000000000"
+ ).isEqualTo(Hex.toHexString(params.toBytes("foo").toByteArray()));
+ }
+
+ @Test
+ @DisplayName("fails to encode bytes4 if length too long")
+ void bytes4EncodingError() {
+ assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> {
+ new ContractFunctionParameters().addBytes4(new byte[]{1, 2, 3, 4, 5});
+ });
+ }
+
+ @Test
+ @DisplayName("encodes UTF-8 string as bytes4 correctly")
+ void bytes4UTF8Encoding() {
+ var params = new ContractFunctionParameters()
+ .addBytes4("ABCD".getBytes(StandardCharsets.UTF_8));
+ assertThat(
+ "580526ee" +
+ "4142434400000000000000000000000000000000000000000000000000000000"
+ ).isEqualTo(Hex.toHexString(params.toBytes("foo").toByteArray()));
+ }
+
+ @Test
+ @DisplayName("fails to encode UTF-8 string as bytes4 if length is bigger than 4 bytes")
+ void bytes4UTF8EncodingError() {
+ assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> {
+ new ContractFunctionParameters().addBytes4("ABCDE".getBytes(StandardCharsets.UTF_8));
+ });
+ }
+
  @Test
  @DisplayName("encodes bytes32 correctly")
  void bytes() {
@@ -410,6 +448,24 @@ void arrayTypesEncoding() {
  ).isEqualTo(Hex.toHexString(params.toBytes("foo").toByteArray()));
  }
 
+ @Test
+ @DisplayName("bytes4[] encodes correctly")
+ void fixedBytes4ArrayEncoding() {
+ ContractFunctionParameters params = new ContractFunctionParameters()
+ .addBytes4Array(new byte[][]{
+ {1, 2, 3, 4},
+ {5, 6, 7, 8},
+ {9, 10, 11, 12}
+ });
+ assertThat(
+ "0000000000000000000000000000000000000000000000000000000000000020" + // offset of array
+ "0000000000000000000000000000000000000000000000000000000000000003" + // length of array
+ "0102030400000000000000000000000000000000000000000000000000000000" + // first bytes4
+ "0506070800000000000000000000000000000000000000000000000000000000" + // second bytes4
+ "090a0b0c00000000000000000000000000000000000000000000000000000000" // third bytes4
+ ).isEqualTo(Hex.toHexString(params.toBytes(null).toByteArray()));
+ }
+
  @Test
  @DisplayName("bytes32[] encodes correctly")
  void fixedBytesArrayEncoding() {
@@ -544,10 +600,10 @@ void uInt256EncodesCorrectly(long val, String hexString, int bitWidth) {
  @Test
  void intSizesEncodeCorrectly() throws Exception {
  List<String> snapshotStrings = new ArrayList<>();
- for (int n = 8; n <= 256; n+= 8) {
+ for (int n = 8; n <= 256; n += 8) {
  var bitWidth = n;
 
- var argType = ((Supplier<Class<?>>)() -> {
+ var argType = ((Supplier<Class<?>>) () -> {
  if (bitWidth == 8) {
  return byte.class;
  } else if (bitWidth <= 32) {
@@ -559,7 +615,7 @@ void intSizesEncodeCorrectly() throws Exception {
  }
  }).get();
 
- var argVal = ((Supplier<Object>)() -> {
+ var argVal = ((Supplier<Object>) () -> {
  if (bitWidth == 8) {
  return (byte) (1 << (bitWidth - 1));
  } else if (bitWidth <= 32) {