From af416f81b14a3bee682e300b165a6efdb9739d54 Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Fri, 23 Nov 2018 16:41:24 +0100
Subject: o Trying to improve compatibility with some feature checks. o Misc
 nits.

---
 include/ble/Bluetooth.h        |  4 ---
 include/ble/att.h              |  6 ++--
 include/ble/compiler-support.h | 62 ++++++++++++++++++++++++++++++++++++++++++
 include/ble/misc.h             |  4 +--
 4 files changed, 68 insertions(+), 8 deletions(-)
 create mode 100644 include/ble/compiler-support.h

(limited to 'include')

diff --git a/include/ble/Bluetooth.h b/include/ble/Bluetooth.h
index 5f7cd17..28e2794 100644
--- a/include/ble/Bluetooth.h
+++ b/include/ble/Bluetooth.h
@@ -1,7 +1,6 @@
 #ifndef BLUETOOTH_H
 #define BLUETOOTH_H
 
-#include <optional>
 #include <iosfwd>
 #include <iostream>
 #include <stdexcept>
@@ -23,9 +22,6 @@ using std::vector;
 using std::map;
 using std::runtime_error;
 
-template<typename T>
-using o = std::optional<T>;
-
 class BluetoothAdapter;
 class BluetoothDevice;
 class BluetoothGatt;
diff --git a/include/ble/att.h b/include/ble/att.h
index 152a779..7b77812 100644
--- a/include/ble/att.h
+++ b/include/ble/att.h
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <variant>
 #include <vector>
 
 #include "ble/ByteBuffer.h"
@@ -9,6 +8,9 @@
 namespace trygvis {
 namespace bluetooth {
 
+using ::trygvis::compiler::variant;
+using ::trygvis::compiler::monostate;
+
 /**
  * BLUETOOTH SPECIFICATION Version 4.0 [Vol 3] - Attribute Protocol (ATT) - 3.4.8 Attribute Opcode Summary
  * Table 3.37
@@ -144,7 +146,7 @@ struct HandleValueIndication {
     ByteBuffer data;
 };
 
-using AttVariant = std::variant<std::monostate,
+using AttVariant = variant<monostate,
     ErrorRes,
     ExchangeMtuReq, ExchangeMtuRes,
     FindInformationRes,
diff --git a/include/ble/compiler-support.h b/include/ble/compiler-support.h
new file mode 100644
index 0000000..1e7e185
--- /dev/null
+++ b/include/ble/compiler-support.h
@@ -0,0 +1,62 @@
+#ifndef COMPILER_SUPPORT_H
+
+#ifdef __has_include
+
+#  if __has_include(<optional>)
+#    include <optional>
+#    define have_optional 1
+#  elif __has_include(<experimental/optional>)
+#    include <experimental/optional>
+#    define have_optional 1
+#    define have_experimental_optional 1
+#  else
+#    define have_optional 0
+#  endif
+
+#  if __has_include(<variant>)
+#    include <variant>
+#    define have_variant 1
+#  elif __has_include(<experimental/variant>)
+#    include <experimental/variant>
+#    define have_variant 1
+#    define have_experimental_variant 1
+#  else
+#    define have_variant 0
+#  endif
+
+#endif
+
+namespace trygvis {
+namespace compiler {
+
+#if have_experimental_optional
+
+template<typename T>
+using o = std::experimental::optional<T>;
+
+#elif have_optional
+
+template<typename T>
+using o = std::optional<T>;
+
+#endif
+
+#if have_experimental_variant
+
+template<typename... T>
+using variant = std::experimental::variant<T>;
+using monostate = std::experimental::monostate;
+
+#elif have_variant
+
+template<typename... T>
+using variant = std::variant<T...>;
+using monostate = std::monostate;
+
+#endif
+
+} // namespace compiler
+} // namespace trygvis
+
+
+#endif
diff --git a/include/ble/misc.h b/include/ble/misc.h
index 563d039..aa0ba2e 100644
--- a/include/ble/misc.h
+++ b/include/ble/misc.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "ble/compiler-support.h"
 #include "ByteBuffer.h"
 
 #include <optional>
@@ -10,8 +11,7 @@
 namespace trygvis {
 namespace bluetooth {
 
-template<typename T>
-using o = std::optional<T>;
+using ::trygvis::compiler::o;
 
 class BluetoothAdapter;
 class BluetoothDevice;
-- 
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