Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System/sys/system/IO/compression/CompressionTracing.cs

@@ -0,0 +1,58 @@
+namespace System.IO.Compression
+{
+    using System.Diagnostics;
+
+    internal enum CompressionTracingSwitchLevel {
+        Off = 0,
+        Informational = 1,
+        Verbose = 2
+    }
+
+    // No tracing on Silverlight nor Windows Phone 7.
+    internal class CompressionTracingSwitch
+#if !FEATURE_NETCORE
+        : Switch
+#endif // !FEATURE_NETCORE
+    {
+        internal readonly static CompressionTracingSwitch tracingSwitch =
+            new CompressionTracingSwitch("CompressionSwitch", "Compression Library Tracing Switch");
+
+        internal CompressionTracingSwitch(string displayName, string description)
+#if !FEATURE_NETCORE
+            : base(displayName, description)
+#endif // !FEATURE_NETCORE
+        {
+        }
+
+        public static bool Verbose {
+            get {
+#if FEATURE_NETCORE
+                return false;
+#else
+                return tracingSwitch.SwitchSetting >= (int)CompressionTracingSwitchLevel.Verbose;
+#endif
+            }
+        }
+
+        public static bool Informational {
+            get {
+#if FEATURE_NETCORE
+                return false;
+#else
+                return tracingSwitch.SwitchSetting >= (int)CompressionTracingSwitchLevel.Informational;
+#endif
+            }
+        }
+
+#if ENABLE_TRACING
+        public void SetSwitchSetting(CompressionTracingSwitchLevel level) {
+            if (level < CompressionTracingSwitchLevel.Off || level > CompressionTracingSwitchLevel.Verbose) {
+                throw new ArgumentOutOfRangeException("level");
+            }
+            this.SwitchSetting = (int)level;
+        }
+#endif
+
+    }    
+}
+