Move bits(count:) function to classes from extension to allow preconditions

Author: tsolomko

Sources/BitReader.swift

@@ -44,23 +44,3 @@ public protocol BitReader: class {
     func uint16() -> UInt16
 
 }
-
-extension BitReader {
-
-    /**
-     - Warning: Doesn't check if there is any data left.
-     */
-    public func bits(count: Int) -> [UInt8] {
-        guard count > 0
-            else { return [] }
-
-        var array = [UInt8]()
-        array.reserveCapacity(count)
-        for _ in 0..<count {
-            array.append(self.bit())
-        }
-
-        return array
-    }
-
-}

Sources/ByteReader.swift

@@ -48,8 +48,8 @@ public class ByteReader {
     /**
      Reads `count` bytes and returns them as an array of `UInt8`, advancing by `count` positions.
 
-     - Precondition: There MUST be enough data left.
      - Precondition: Parameter `count` MUST not be less than 0.
+     - Precondition: There MUST be enough data left.
      */
     public func bytes(count: Int) -> [UInt8] {
         precondition(count >= 0)

Sources/LsbBitReader.swift

@@ -57,10 +57,31 @@ public final class LsbBitReader: ByteReader, BitReader {
     }
 
     /**
-     Reads `count` bits and returns them as a `Int` number, advancing by `count` BIT positions.
+     Reads `count` bits and returns them as an array of `UInt8`, advancing by `count` BIT positions.
 
+     - Precondition: Parameter `count` MUST not be less than 0.
      - Precondition: There MUST be enough data left.
+     */
+    public func bits(count: Int) -> [UInt8] {
+        precondition(count >= 0)
+        guard count > 0
+            else { return [] }
+        precondition(bitsLeft >= count)
+
+        var array = [UInt8]()
+        array.reserveCapacity(count)
+        for _ in 0..<count {
+            array.append(self.bit())
+        }
+
+        return array
+    }
+
+    /**
+     Reads `count` bits and returns them as a `Int` number, advancing by `count` BIT positions.
+
      - Precondition: Parameter `fromBits` MUST not be less than 0.
+     - Precondition: There MUST be enough data left.
      */
     public func int(fromBits count: Int) -> Int {
         precondition(count >= 0)

Sources/MsbBitReader.swift

@@ -57,7 +57,28 @@ public final class MsbBitReader: ByteReader, BitReader {
     }
 
     /**
-     Reads `count` bits and returns them as a `Int` number, advancing by `count` BIT positions.
+     Reads `count` bits and returns them as an array of `UInt8`, advancing by `count` BIT positions.
+
+     - Precondition: Parameter `count` MUST not be less than 0.
+     - Precondition: There MUST be enough data left.
+     */
+    public func bits(count: Int) -> [UInt8] {
+        precondition(count >= 0)
+        guard count > 0
+            else { return [] }
+        precondition(bitsLeft >= count)
+
+        var array = [UInt8]()
+        array.reserveCapacity(count)
+        for _ in 0..<count {
+            array.append(self.bit())
+        }
+
+        return array
+    }
+
+    /**
+     Reads `fromBits` bits and returns them as a `Int` number, advancing by `count` BIT positions.
 
      - Precondition: Parameter `fromBits` MUST not be less than 0.
      - Precondition: There MUST be enough data left.