Prepare ntcore for merge into allwpilib.

ntcore/src/main/native/cpp/Handle.h

@@ -0,0 +1,65 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016-2018. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef NTCORE_HANDLE_H_
+#define NTCORE_HANDLE_H_
+
+#include "ntcore_c.h"
+
+namespace nt {
+
+// Handle data layout:
+// Bits 30-28: Type
+// Bits 27-20: Instance index
+// Bits 19-0:  Handle index (0/unused for instance handles)
+
+class Handle {
+ public:
+  enum Type {
+    kConnectionListener = 1,
+    kConnectionListenerPoller,
+    kEntry,
+    kEntryListener,
+    kEntryListenerPoller,
+    kInstance,
+    kLogger,
+    kLoggerPoller,
+    kRpcCall,
+    kRpcCallPoller
+  };
+  enum { kIndexMax = 0xfffff };
+
+  explicit Handle(NT_Handle handle) : m_handle(handle) {}
+  operator NT_Handle() const { return m_handle; }
+
+  NT_Handle handle() const { return m_handle; }
+
+  Handle(int inst, int index, Type type) {
+    if (inst < 0 || index < 0) {
+      m_handle = 0;
+      return;
+    }
+    m_handle = ((static_cast<int>(type) & 0xf) << 27) | ((inst & 0x7f) << 20) |
+               (index & 0xfffff);
+  }
+
+  int GetIndex() const { return static_cast<int>(m_handle) & 0xfffff; }
+  Type GetType() const {
+    return static_cast<Type>((static_cast<int>(m_handle) >> 27) & 0xf);
+  }
+  int GetInst() const { return (static_cast<int>(m_handle) >> 20) & 0x7f; }
+  bool IsType(Type type) const { return type == GetType(); }
+  int GetTypedIndex(Type type) const { return IsType(type) ? GetIndex() : -1; }
+  int GetTypedInst(Type type) const { return IsType(type) ? GetInst() : -1; }
+
+ private:
+  NT_Handle m_handle;
+};
+
+}  // namespace nt
+
+#endif  // NTCORE_HANDLE_H_