Merge pull request #615 from FactomProject/FD-740_smart_unmarshal_limits

fixed limit on fblock to handle possible empty coinbase transactions

common/directoryBlock/directoryBlock.go

@@ -282,13 +282,12 @@ func (e *DirectoryBlock) String() string {
 	out.WriteString(fmt.Sprintf("%20s %v\n", "fullhash:", fh.String()))
 
 	out.WriteString(e.GetHeader().String())
-	out.WriteString("entries: \n")
+	out.WriteString("entries:\n")
 	for i, entry := range e.DBEntries {
 		out.WriteString(fmt.Sprintf("%5d %s", i, entry.String()))
 	}
 
 	return (string)(out.DeepCopyBytes())
-
 }
 
 func (b *DirectoryBlock) MarshalBinary() (rval []byte, err error) {

common/factoid/fblock.go

@@ -346,18 +346,17 @@ func (b *FBlock) UnmarshalBinaryData(data []byte) ([]byte, error) {
 		return nil, err
 	}
 
-	// txLimit is the maximum number of transactions (min 78 bytes) that could
-	// fit into the remaining unread portion of the buffer.
+	// txLimit is the maximum number of transactions (min 20 bytes for an empty
+	// coinbase tx) that could fit into the unread portion of the buffer.
 	l := buf.Len()
-	txLimit := uint32(l / 78)
+	txLimit := uint32(l / 20)
 
 	if txCount > txLimit {
-		//return nil, fmt.Errorf(
-		//	"Error: FBlock.Unmarshal: transaction count %d higher than space "+
-		//		"in body %d (uint underflow?)",
-		//	txCount, txLimit,
-		//)
-		fmt.Println("Got here", txCount, txLimit)
+		return nil, fmt.Errorf(
+			"Error: FBlock.Unmarshal: transaction count %d higher than space "+
+				"in body %d (uint underflow?)",
+			txCount, txLimit,
+		)
 	}
 
 	b.Transactions = make([]interfaces.ITransaction, int(txCount), int(txCount))