Use defer in ByteReader's functions

This allows to express backwards logic explicitly as well as eliminate temporary variables in uintX() functions.

Author: tsolomko

Sources/ByteReader.swift

@@ -41,8 +41,8 @@ public class ByteReader {
      */
     public func byte() -> UInt8 {
         precondition(self.offset < self.data.endIndex)
-        self.offset += 1
-        return self.data[self.offset - 1]
+        defer { self.offset += 1 }
+        return self.data[self.offset]
     }
 
     /**
@@ -56,9 +56,8 @@ public class ByteReader {
         guard count > 0
             else { return [] }
         precondition(self.offset + count <= self.data.endIndex)
-        let result = self.data[self.offset..<self.offset + count].toArray(type: UInt8.self, count: count)
-        self.offset += count
-        return result
+        defer { self.offset += count }
+        return self.data[self.offset..<self.offset + count].toArray(type: UInt8.self, count: count)
     }
 
     /**
@@ -68,9 +67,8 @@ public class ByteReader {
      */
     public func uint64() -> UInt64 {
         precondition(self.offset + 8 <= self.data.endIndex)
-        let result = self.data[self.offset..<self.offset + 8].to(type: UInt64.self)
-        self.offset += 8
-        return result
+        defer { self.offset += 8 }
+        return self.data[self.offset..<self.offset + 8].to(type: UInt64.self)
     }
 
     /**
@@ -80,9 +78,8 @@ public class ByteReader {
      */
     public func uint32() -> UInt32 {
         precondition(self.offset + 4 <= self.data.endIndex)
-        let result = self.data[self.offset..<self.offset + 4].to(type: UInt32.self)
-        self.offset += 4
-        return result
+        defer { self.offset += 4 }
+        return self.data[self.offset..<self.offset + 4].to(type: UInt32.self)
     }
 
     /**
@@ -92,9 +89,8 @@ public class ByteReader {
      */
     public func uint16() -> UInt16 {
         precondition(self.offset + 2 <= self.data.endIndex)
-        let result = self.data[self.offset..<self.offset + 2].to(type: UInt16.self)
-        self.offset += 2
-        return result
+        defer { self.offset += 2 }
+        return self.data[self.offset..<self.offset + 2].to(type: UInt16.self)
     }
 
 }