Add preconditions for bitsCount in bit writers to be within int bit width

Author: tsolomko

Sources/BitWriter.swift

@@ -52,6 +52,7 @@ extension BitWriter {
     }
 
     public func write(number: Int, bitsCount: Int) {
+        precondition(0...Int.bitWidth ~= bitsCount)
         self.write(unsignedNumber: UInt(bitPattern: number), bitsCount: bitsCount)
     }
 

Sources/LsbBitWriter.swift

@@ -50,7 +50,8 @@ public final class LsbBitWriter: BitWriter {
      thus, crashes when converting to an `Int` if `write(number:bitsCount:)` method is used.
      */
     public func write(unsignedNumber: UInt, bitsCount: Int) {
-        var mask: UInt = 1
+        precondition(0...UInt.bitWidth ~= bitsCount)
+        var mask = 1 as UInt
         for _ in 0..<bitsCount {
             self.write(bit: unsignedNumber & mask > 0 ? 1 : 0)
             mask <<= 1

Sources/MsbBitWriter.swift

@@ -50,7 +50,8 @@ public final class MsbBitWriter: BitWriter {
      thus, crashes when converting to an `Int` if `write(number:bitsCount:)` method is used.
      */
     public func write(unsignedNumber: UInt, bitsCount: Int) {
-        var mask: UInt = 1 << (UInt(truncatingIfNeeded: bitsCount) - 1)
+        precondition(0...UInt.bitWidth ~= bitsCount)
+        var mask = (1 as UInt) << (bitsCount - 1)
         for _ in 0..<bitsCount {
             self.write(bit: unsignedNumber & mask > 0 ? 1 : 0)
             mask >>= 1