Fix bug in RlpString.asBigInteger

Author: folex

crypto/src/main/java/org/web3j/crypto/TransactionDecoder.java

@@ -13,11 +13,11 @@ public static RawTransaction decode(String hexTransaction) {
         byte[] transaction = Numeric.hexStringToByteArray(hexTransaction);
         RlpList rlpList = RlpDecoder.decode(transaction);
         RlpList values = (RlpList) rlpList.getValues().get(0);
-        BigInteger nonce = ((RlpString) values.getValues().get(0)).asBigInteger();
-        BigInteger gasPrice = ((RlpString) values.getValues().get(1)).asBigInteger();
-        BigInteger gasLimit = ((RlpString) values.getValues().get(2)).asBigInteger();
+        BigInteger nonce = ((RlpString) values.getValues().get(0)).asPositiveBigInteger();
+        BigInteger gasPrice = ((RlpString) values.getValues().get(1)).asPositiveBigInteger();
+        BigInteger gasLimit = ((RlpString) values.getValues().get(2)).asPositiveBigInteger();
         String to = ((RlpString) values.getValues().get(3)).asString();
-        BigInteger value = ((RlpString) values.getValues().get(4)).asBigInteger();
+        BigInteger value = ((RlpString) values.getValues().get(4)).asPositiveBigInteger();
         String data = ((RlpString) values.getValues().get(5)).asString();
         if (values.getValues().size() > 6) {
             byte v = ((RlpString) values.getValues().get(6)).getBytes()[0];

rlp/src/main/java/org/web3j/rlp/RlpString.java

@@ -21,11 +21,11 @@ public byte[] getBytes() {
         return value;
     }
 
-    public BigInteger asBigInteger() {
+    public BigInteger asPositiveBigInteger() {
         if (value.length == 0) {
             return BigInteger.ZERO;
         }
-        return new BigInteger(value);
+        return new BigInteger(1, value);
     }
 
     public String asString() {

rlp/src/test/java/org/web3j/rlp/RlpDecoderTest.java

@@ -21,6 +21,12 @@ public class RlpDecoderTest {
     @Test
     public void testRLPDecode() {
 
+        // big positive number should stay positive after encoding-decoding
+        // https://github.com/web3j/web3j/issues/562
+        long value = 3000000000L;
+        assertThat(RlpString.create(BigInteger.valueOf(value)).asPositiveBigInteger().longValue(),
+                equalTo(value));
+
         // empty array of binary
         assertTrue(RlpDecoder.decode(new byte[]{}).getValues().isEmpty());
 
@@ -187,6 +193,5 @@ public void testRLPDecode() {
         assertThat(((RlpList)
                    ((RlpList) rlpList.getValues().get(0)).getValues().get(1)).getValues().size(),
                 equalTo(9));
-
     }
 }