v0.0.5 - Critical fix to the slice() method (#14)

* Adding test to account for #13

* Fix for #13

Multiples of 32 bytes can now be safely sliced

* More tests for #13

* Bump version to v0.0.5

Author: GNSPS

contracts/BytesLib.sol

@@ -232,11 +232,17 @@ library BytesLib {
                 // the actual length of the slice.
                 let lengthmod := and(_length, 31)
 
-                let mc := add(tempBytes, lengthmod)
+                // The multiplication in the next line is necessary
+                // because when slicing multiples of 32 bytes (lengthmod == 0)
+                // the following copy loop was copying the origin's length
+                // and then ending prematurely not copying everything it should.
+                let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
                 let end := add(mc, _length)
 
                 for {
-                    let cc := add(add(_bytes, lengthmod), _start)
+                    // The multiplication in the next line has the same exact purpose
+                    // as the one above.
+                    let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
                 } lt(mc, end) {
                     mc := add(mc, 0x20)
                     cc := add(cc, 0x20)

ethpm.json

@@ -1,6 +1,6 @@
 {
   "package_name": "bytes",
-  "version": "0.0.4",
+  "version": "0.0.5",
   "description": "Solidity bytes tightly packed arrays utility library.",
   "authors": [
     "Gonçalo Sá <[email protected]>"

package.json

@@ -1,6 +1,6 @@
 {
   "name": "solidity-bytes-utils",
-  "version": "0.0.4",
+  "version": "0.0.5",
   "description": "Solidity bytes tightly packed arrays utility library.",
   "main": "truffle.js",
   "repository": {

test/TestBytesLib2.sol

@@ -54,30 +54,38 @@ contract TestBytesLib2 {
     */
 
     function testSlice() public {
-        bytes memory memBytes33 = hex"f00d0000000000000000000000000000000000000000000000000000000000feed";
+        bytes memory memBytes = hex"f00d0000000000000000000000000000000000000000000000000000000000feedf00d00000000000000000000000000000000000000000000000000000000feed";
 
         bytes memory testBytes;
         bytes memory resultBytes;
 
         testBytes = hex"f00d";
-        resultBytes = memBytes33.slice(0,2);
+        resultBytes = memBytes.slice(0,2);
         AssertBytes.equal(resultBytes, testBytes, "Normal slicing array failed.");
 
         testBytes = hex"";
-        resultBytes = memBytes33.slice(1,0);
+        resultBytes = memBytes.slice(1,0);
         AssertBytes.equal(resultBytes, testBytes, "Slicing with zero-length failed.");
 
         testBytes = hex"";
-        resultBytes = memBytes33.slice(0,0);
+        resultBytes = memBytes.slice(0,0);
         AssertBytes.equal(resultBytes, testBytes, "Slicing with zero-length on index 0 failed.");
 
         testBytes = hex"feed";
-        resultBytes = memBytes33.slice(31,2);
+        resultBytes = memBytes.slice(31,2);
         AssertBytes.equal(resultBytes, testBytes, "Slicing across the 32-byte slot boundary failed.");
 
         testBytes = hex"f00d0000000000000000000000000000000000000000000000000000000000feed";
-        resultBytes = memBytes33.slice(0,33);
+        resultBytes = memBytes.slice(0,33);
         AssertBytes.equal(resultBytes, testBytes, "Full length slice failed.");
+        
+        testBytes = hex"f00d0000000000000000000000000000000000000000000000000000000000fe";
+        resultBytes = memBytes.slice(0,32);
+        AssertBytes.equal(resultBytes, testBytes, "Multiple of 32 bytes slice failed.");
+        
+        testBytes = hex"f00d0000000000000000000000000000000000000000000000000000000000feedf00d00000000000000000000000000000000000000000000000000000000fe";
+        resultBytes = memBytes.slice(0,64);
+        AssertBytes.equal(resultBytes, testBytes, "Multiple (*2) of 32 bytes slice failed.");
 
         // Now we're going to test for slicing actions that throw present in the functions below
         // with a ThrowProxy contract