support 0x80 as a false boolean encoding (#6)

* support 0x80 as a false boolean encoding

* fix travis

* add back in ganache into travis

* bump truffle/ganache versions

* commit to a single truffle config file

* specify ganache port in travis

* show ganache output

* use node verison 12 and supress output

* fix travis.yml

.travis.yml

@@ -1,14 +1,13 @@
 language: node_js
 
-node_js: "node"
+node_js:
+  - 12
 
 before_script:
-  - npm install -g truffle@5.0.1 ganache-cli@6.1.8
+  - npm install -g truffle@5.1.41 ganache-cli@6.10.1
   - npm install
 
 script: 
-  - ganache-cli > /dev/null &
+  - ganache-cli -p 8545 > /dev/null &
   - sleep 5
-  - rm -rf build
-  - truffle migrate
-  - truffle test
+  - npm run test

contracts/RLPReader.sol

@@ -135,7 +135,7 @@ library RLPReader {
         return result;
     }
 
-    // any non-zero byte is considered true
+    // any non-zero byte except "0x80" is considered true
     function toBoolean(RLPItem memory item) internal pure returns (bool) {
         require(item.len == 1);
         uint result;
@@ -144,7 +144,15 @@ library RLPReader {
             result := byte(0, mload(memPtr))
         }
 
-        return result == 0 ? false : true;
+        // SEE Github Issue #5.
+        // Summary: Most commonly used RLP libraries (i.e Geth) will encode
+        // "0" as "0x80" instead of as "0". We handle this edge case explicitly
+        // here.
+        if (result == 0 || result == STRING_SHORT_START) {
+            return false;
+        } else {
+            return true;
+        }
     }
 
     function toAddress(RLPItem memory item) internal pure returns (address) {

test/basic-tests.js

@@ -164,7 +164,10 @@ contract("RLPReader", async (accounts) => {
 
         // toBoolean
         result = await helper.toBoolean.call(toHex(rlp.encode(1)));
-        assert(result == true, "Incorrect toBoolean conversion");
+        assert(result == true, "Incorrect toBoolean true conversion");
+
+        result = await helper.toBoolean.call(toHex(rlp.encode(0)));
+        assert(result == false, "Incorrect toBoolean false conversion");
 
         // Mix of data types
         str = [accounts[0], 1, 65537];
@@ -282,7 +285,7 @@ contract("RLPReader", async (accounts) => {
             totalDifficulty: '10690776258913596267754',
         };
         const rlpHeader = toRLPHeader(block);
-        const result = await helper.toBlockHeader.call(rlpHeader, {});
+        const result = await helper.toBlockHeader.call(rlpHeader);
         assert(result.parentHash == block.parentHash, "parentHash not equal");
         assert(result.sha3Uncles == block.sha3Uncles, "sha3Uncles not equal");
         assert(result.stateRoot  == block.stateRoot,  "stateRoot not equal");

truffle-config.js

@@ -1,4 +1,11 @@
 module.exports = {
   // See <http://truffleframework.com/docs/advanced/configuration>
   // to customize your Truffle configuration!
+  networks: {
+      development: {
+          host: 'localhost',
+          port: 8545,
+          network_id: '*'
+      }
+  }
 };