Change size from ioctl to extract window buffer format and size to co…

…nstants

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Changed
 * Change the ioctl system call support check to use the output method
+* Change size from ioctl to extract window buffer format and size to constants
 
 ### Fixed
 * Fix ioctl call test to stub terminal size encoding for big-endian systems

lib/tty/screen.rb

@@ -188,20 +188,35 @@ def size_from_io_console(verbose: false)
       TIOCGWINSZ_PPC = 0x40087468 # macos, freedbsd, netbsd, openbsd
       TIOCGWINSZ_SOL = 0x5468 # solaris
 
+      # The ioctl window buffer format
+      #
+      # @return [String]
+      #
+      # @api private
+      TIOCGWINSZ_FORMAT = "SSSS"
+      private_constant :TIOCGWINSZ_FORMAT
+
+      # The ioctl window buffer format size
+      #
+      # @return [Integer]
+      #
+      # @api private
+      TIOCGWINSZ_FORMAT_SIZE = TIOCGWINSZ_FORMAT.size
+      private_constant :TIOCGWINSZ_FORMAT_SIZE
+
       # Read terminal size from Unix ioctl
       #
       # @return [nil, Array[Integer, Integer]]
       #
       # @api private
       def size_from_ioctl
-        format = "SSSS"
-        buffer = ([0] * format.size).pack(format)
+        buffer = ([0] * TIOCGWINSZ_FORMAT_SIZE).pack(TIOCGWINSZ_FORMAT)
 
         if ioctl?(TIOCGWINSZ, buffer) ||
            ioctl?(TIOCGWINSZ_PPC, buffer) ||
            ioctl?(TIOCGWINSZ_SOL, buffer)
 
-          rows, cols, = buffer.unpack(format)[0..1]
+          rows, cols, = buffer.unpack(TIOCGWINSZ_FORMAT)[0..1]
           return [rows, cols] if nonzero_column?(cols)
         end
       end