From 5068d34c08f951a7ea6257d305a1627b09a95817 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sat, 4 May 2024 19:44:55 +0200
Subject: Adding upstream version 0.11.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/base/opt_util.hh | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 src/base/opt_util.hh

(limited to 'src/base/opt_util.hh')

diff --git a/src/base/opt_util.hh b/src/base/opt_util.hh
new file mode 100644
index 0000000..aea038e
--- /dev/null
+++ b/src/base/opt_util.hh
@@ -0,0 +1,105 @@
+/**
+ * Copyright (c) 2019, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef lnav_opt_util_hh
+#define lnav_opt_util_hh
+
+#include <stdlib.h>
+
+#include "optional.hpp"
+
+namespace detail {
+
+template<class T>
+typename std::enable_if<std::is_void<T>::value, T>::type
+void_or_nullopt()
+{
+    return;
+}
+
+template<class T>
+typename std::enable_if<not std::is_void<T>::value, T>::type
+void_or_nullopt()
+{
+    return nonstd::nullopt;
+}
+
+template<class T>
+struct is_optional : std::false_type {
+};
+
+template<class T>
+struct is_optional<nonstd::optional<T>> : std::true_type {
+};
+}  // namespace detail
+
+template<class T,
+         class F,
+         std::enable_if_t<detail::is_optional<std::decay_t<T>>::value, int> = 0>
+auto
+operator|(T&& t, F f)
+    -> decltype(detail::void_or_nullopt<decltype(f(std::forward<T>(t).
+                                                   operator*()))>())
+{
+    using return_type = decltype(f(std::forward<T>(t).operator*()));
+    if (t)
+        return f(std::forward<T>(t).operator*());
+    else
+        return detail::void_or_nullopt<return_type>();
+}
+
+template<class T>
+optional_constexpr nonstd::optional<typename std::decay<T>::type>
+make_optional_from_nullable(T&& v)
+{
+    if (v != nullptr) {
+        return nonstd::optional<typename std::decay<T>::type>(
+            std::forward<T>(v));
+    }
+    return nonstd::nullopt;
+}
+
+template<template<typename, typename...> class C, typename T>
+nonstd::optional<T>
+cget(const C<T>& container, size_t index)
+{
+    if (index < container.size()) {
+        return container[index];
+    }
+
+    return nonstd::nullopt;
+}
+
+inline nonstd::optional<const char*>
+getenv_opt(const char* name)
+{
+    return make_optional_from_nullable(getenv(name));
+}
+
+#endif
-- 
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