Merge pull request #312 from remedcu/master

Changes to RNG Folder

Author: clesaege

contracts/standard/rng/BlockhashRNG.sol

@@ -1,15 +1,22 @@
+ /**
+ *  @authors: [@clesaege]
+ *  @reviewers: [@remedcu]
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.4.15;
+
+import "./RNG.sol";
+
 /**
  *  @title Random Number Generator usign blockhash
  *  @author Clément Lesaege - <clement@lesaege.com>
  *
  *  This contract implements the RNG standard and gives parties incentives to save the blockhash to avoid it to become unreachable after 256 blocks.
  *
- */
-pragma solidity ^0.4.15;
-
-import "./RNG.sol";
-
-/** Simple Random Number Generator returning the blockhash.
+ *  Simple Random Number Generator returning the blockhash.
  *  Allows saving the random number for use in the future.
  *  It allows the contract to still access the blockhash even after 256 blocks.
  *  The first party to call the save function gets the reward.
@@ -19,8 +26,6 @@ contract BlockHashRNG is RNG {
     mapping (uint => uint) public randomNumber; // randomNumber[block] is the random number for this block, 0 otherwise.
     mapping (uint => uint) public reward; // reward[block] is the amount to be paid to the party w.
 
-
-
     /** @dev Contribute to the reward of a random number.
      *  @param _block Block the random number is linked to.
      */
@@ -47,8 +52,6 @@ contract BlockHashRNG is RNG {
     function saveRN(uint _block) public {
         if (blockhash(_block) != 0x0)
             randomNumber[_block] = uint(blockhash(_block));
-        else
-            randomNumber[_block] = getFallbackRN(_block);
 
         if (randomNumber[_block] != 0) { // If the number is set.
             uint rewardToSend = reward[_block];
@@ -57,10 +60,4 @@ contract BlockHashRNG is RNG {
         }
     }
 
-    /** @dev Fallback strategy. This class has no fallback. Subclass provides fallback strategy by overriding this method.
-     *  @param _block Block the random number is linked to.
-     */
-    function getFallbackRN(uint _block) internal view returns (uint) {
-        return 0x0; 
-    }
 }

contracts/standard/rng/BlockhashRNGFallback.sol

@@ -1,31 +1,48 @@
+ /**
+ *  @authors: [@clesaege]
+ *  @reviewers: [@remedcu]
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: [ https://etherscan.io/address/0x1738b62e403090666687243e758b1c29edffc90e ]
+ */
+
+pragma solidity ^0.4.15;
+
+import "./BlockhashRNG.sol";
+
 /**
  *  @title Random Number Generator using blockhash with fallback.
  *  @author Clément Lesaege - <clement@lesaege.com>
- *  
+ *
  *  This contract implements the RNG standard and gives parties incentives to save the blockhash to avoid it to become unreachable after 256 blocks.
  *  In case no one called it within the 256 blocks, it returns the previous blockhash.
  *  This contract must be used when returning 0 is a worse failure mode than returning another blockhash.
  *  Note that if someone calls it within the timeframe, this contracts acts exactly as BlockHashRNG.
- */
-pragma solidity ^0.4.15;
- 
-import "./BlockhashRNG.sol";
-
-/** Random Number Generator returning the blockhash with a backup behaviour.
- *  Allows saving the random number for use in the future. 
+ *
+ *  Random Number Generator returning the blockhash with a backup behaviour.
+ *  Allows saving the random number for use in the future.
  *  It allows the contract to still access the blockhash even after 256 blocks.
  *  The first party to call the save function gets the reward.
- *  If no one calls the contract within 256 blocks, the contract fallback in returning the blockhash of a block in range.
+ *  If no one calls the contract within 256 blocks, the contract fallback in returning the blockhash of the previous block.
  */
 contract BlockHashRNGFallback is BlockHashRNG {
-    
-    /** @dev Fallback by returning a blockhash in range.
+
+    /** @dev Save the random number for this blockhash and give the reward to the caller.
      *  @param _block Block the random number is linked to.
      */
-    function getFallbackRN(uint _block) internal view returns (uint) {
-        if (_block >= block.number) {
-            return 0x0;
+    function saveRN(uint _block) public {
+        if (_block<block.number && randomNumber[_block]==0) {// If the random number is not already set and can be.
+            if (blockhash(_block) != 0x0) // Normal case.
+                randomNumber[_block] = uint(blockhash(_block));
+            else // The contract was not called in time. Fallback to returning previous blockhash.
+                randomNumber[_block] = uint(blockhash(block.number-1));
+        }
+
+        if (randomNumber[_block] != 0) { // If the random number is set.
+            uint rewardToSend = reward[_block];
+            reward[_block] = 0;
+            msg.sender.send(rewardToSend); // Note that the use of send is on purpose as we don't want to block in case the msg.sender has a fallback issue.
         }
-        return uint(blockhash((block.number - 1) - (block.number - 1 - _block)%256));
     }
+
 }

contracts/standard/rng/RNG.sol

@@ -1,11 +1,18 @@
+ /**
+ *  @authors: [@clesaege]
+ *  @reviewers: [@remedcu]
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.4.15;
+
 /**
 *  @title Random Number Generator Standard
 *  @author Clément Lesaege - <clement@lesaege.com>
-*
+*  @dev This is an abstract contract
 */
-
-pragma solidity ^0.4.15;
-
 contract RNG{
 
     /** @dev Contribute to the reward of a random number.