Merge pull request #7 from ipfs/feat/faster-b58

switch to a faster b58 library

package.json

@@ -7,15 +7,15 @@
   "gxDependencies": [
     {
       "author": "multiformats",
-      "hash": "QmYeKnKpubCMRiq3PGZcTREErthbb5Q9cXsCoSkD9bjEBd",
+      "hash": "QmZyZDi491cCNTLfAhwcaDii2Kg4pwKRkhqQzURGDvY6ua",
       "name": "go-multihash",
-      "version": "1.0.6"
+      "version": "1.0.7"
     },
     {
-      "author": "whyrusleeping",
-      "hash": "QmT8rehPR3F6bmwL6zjUN8XpiDBFFpMP2myPdC6ApsWfJf",
-      "name": "go-base58",
-      "version": "0.0.0"
+      "author": "mr-tron",
+      "hash": "QmWFAMPqsEyUX7gDUsRVmMWz59FxSpJ1b2v6bJ1yYzo7jY",
+      "name": "go-base58-fast",
+      "version": "0.1.1"
     }
   ],
   "gxVersion": "0.9.1",

util.go

@@ -12,7 +12,7 @@ import (
 	"strings"
 	"time"
 
-	b58 "github.com/jbenet/go-base58"
+	b58 "github.com/mr-tron/base58/base58"
 	mh "github.com/multiformats/go-multihash"
 )
 
@@ -140,15 +140,12 @@ func Hash(data []byte) mh.Multihash {
 
 // IsValidHash checks whether a given hash is valid (b58 decodable, len > 0)
 func IsValidHash(s string) bool {
-	out := b58.Decode(s)
-	if out == nil || len(out) == 0 {
-		return false
-	}
-	_, err := mh.Cast(out)
+	out, err := b58.Decode(s)
 	if err != nil {
 		return false
 	}
-	return true
+	_, err = mh.Cast(out)
+	return err == nil
 }
 
 // XOR takes two byte slices, XORs them together, returns the resulting slice.