renamed contracts::lib -> contracts::utils

contracts/erc1155/compiler.json

@@ -22,10 +22,10 @@
         "src/mixins/MNonFungibleToken.sol",
         "src/ERC1155Mintable.sol",
         "src/MixinNonFungibleToken.sol",
-        "src/lib/SafeMath.sol",
-        "src/lib/Address.sol",
         "src/interfaces/IERC1155Mintable.sol",
         "src/interfaces/IERC1155Receiver.sol",
-        "src/interfaces/IERC1155.sol"
+        "src/interfaces/IERC1155.sol",
+        "src/utils/SafeMath.sol",
+        "src/utils/Address.sol"
     ]
 }

contracts/erc1155/contracts/src/ERC1155.sol

@@ -18,8 +18,8 @@
 
 pragma solidity ^0.5.3;
 
-import "./lib/SafeMath.sol";
-import "./lib/Address.sol";
+import "./utils/SafeMath.sol";
+import "./utils/Address.sol";
 import "./interfaces/IERC1155.sol";
 import "./interfaces/IERC1155Receiver.sol";
 import "./MixinNonFungibleToken.sol";

contracts/erc1155/contracts/src/ERC1155Mintable.sol

@@ -1,6 +1,6 @@
 pragma solidity ^0.5.3;
 
-import "./lib/SafeMath.sol";
+import "./utils/SafeMath.sol";
 import "./ERC1155.sol";
 import "./interfaces/IERC1155Mintable.sol";
 

contracts/erc1155/contracts/src/utils/Address.sol

@@ -0,0 +1,29 @@
+pragma solidity ^0.5.3;
+
+
+/**
+ * Utility library of inline functions on addresses
+ */
+library Address {
+
+    /**
+     * Returns whether the target address is a contract
+     * @dev This function will return false if invoked during the constructor of a contract,
+     * as the code is not actually created until after the constructor finishes.
+     * @param account address of the account to check
+     * @return whether the target address is a contract
+     */
+    function isContract(address account) internal view returns (bool) {
+        uint256 size;
+        // XXX Currently there is no better way to check if there is a contract in an address
+        // than to check the size of the code at that address.
+        // See https://ethereum.stackexchange.com/a/14016/36603
+        // for more details about how this works.
+        // TODO Check this again before the Serenity release, because all addresses will be
+        // contracts then.
+        // solium-disable-next-line security/no-inline-assembly
+        assembly { size := extcodesize(account) }
+        return size > 0;
+    }
+
+}

contracts/erc1155/contracts/src/utils/SafeMath.sol

@@ -0,0 +1,87 @@
+pragma solidity ^0.5.3;
+
+
+contract SafeMath {
+
+    function safeMul(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        if (a == 0) {
+            return 0;
+        }
+        uint256 c = a * b;
+        require(
+            c / a == b,
+            "UINT256_OVERFLOW"
+        );
+        return c;
+    }
+
+    function safeDiv(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        uint256 c = a / b;
+        return c;
+    }
+
+    function safeSub(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        require(
+            b <= a,
+            "UINT256_UNDERFLOW"
+        );
+        return a - b;
+    }
+
+    function safeAdd(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        uint256 c = a + b;
+        require(
+            c >= a,
+            "UINT256_OVERFLOW"
+        );
+        return c;
+    }
+
+    function max64(uint64 a, uint64 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a >= b ? a : b;
+    }
+
+    function min64(uint64 a, uint64 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a < b ? a : b;
+    }
+
+    function max256(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a >= b ? a : b;
+    }
+
+    function min256(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a < b ? a : b;
+    }
+}