From bd307bd52ec402af4a265387467fc4a7f0c5a70c Mon Sep 17 00:00:00 2001
From: q66 <daniel@octaforge.org>
Date: Tue, 14 Feb 2017 18:32:51 +0100
Subject: [PATCH] standard iter() for any std container type without
 ranged_traits

---
 examples/range_pipe.cc |  4 ++--
 ostd/array.hh          | 31 --------------------------
 ostd/filesystem.hh     |  1 -
 ostd/range.hh          | 49 +++++++++++++++++++++++++++++++++++-------
 ostd/unordered_map.hh  | 20 -----------------
 ostd/vector.hh         | 14 ------------
 6 files changed, 43 insertions(+), 76 deletions(-)
 delete mode 100644 ostd/array.hh

diff --git a/examples/range_pipe.cc b/examples/range_pipe.cc
index 34b4481..31a11eb 100644
--- a/examples/range_pipe.cc
+++ b/examples/range_pipe.cc
@@ -1,6 +1,6 @@
-#include <time.h>
+#include <array>
+#include <ctime>
 
-#include <ostd/array.hh>
 #include <ostd/range.hh>
 #include <ostd/io.hh>
 #include <ostd/algorithm.hh>
diff --git a/ostd/array.hh b/ostd/array.hh
deleted file mode 100644
index f50a17f..0000000
--- a/ostd/array.hh
+++ /dev/null
@@ -1,31 +0,0 @@
-/* OctaSTD extensions for std::array.
- *
- * This file is part of OctaSTD. See COPYING.md for futher information.
- */
-
-#ifndef OSTD_ARRAY_HH
-#define OSTD_ARRAY_HH
-
-#include <array>
-
-#include "ostd/range.hh"
-
-namespace ostd {
-
-template<typename T, size_t N>
-struct ranged_traits<std::array<T, N>> {
-    static IteratorRange<T *> iter(std::array<T, N> &v) {
-        return IteratorRange<T *>{v.data(), v.data() + N};
-    }
-};
-
-template<typename T, size_t N>
-struct ranged_traits<std::array<T, N> const> {
-    static IteratorRange<T const *> iter(std::array<T, N> const &v) {
-        return IteratorRange<T const *>{v.data(), v.data() + N};
-    }
-};
-
-} /* namespace ostd */
-
-#endif
diff --git a/ostd/filesystem.hh b/ostd/filesystem.hh
index 97863fe..9c2274a 100644
--- a/ostd/filesystem.hh
+++ b/ostd/filesystem.hh
@@ -23,7 +23,6 @@
 #include "ostd/range.hh"
 #include "ostd/vector.hh"
 #include "ostd/string.hh"
-#include "ostd/array.hh"
 #include "ostd/algorithm.hh"
 
 namespace ostd {
diff --git a/ostd/range.hh b/ostd/range.hh
index 9a1c423..8af04c9 100644
--- a/ostd/range.hh
+++ b/ostd/range.hh
@@ -815,9 +815,6 @@ inline auto zip(R1 &&r1, R &&...rr) {
     };
 }
 
-template<typename C, typename = void>
-struct ranged_traits;
-
 namespace detail {
     template<typename C>
     static std::true_type test_direct_iter(decltype(std::declval<C>().iter()) *);
@@ -827,14 +824,20 @@ namespace detail {
 
     template<typename C>
     constexpr bool direct_iter_test = decltype(test_direct_iter<C>(0))::value;
+
+    template<typename C, typename = void>
+    struct ranged_traits_core {};
+
+    template<typename C>
+    struct ranged_traits_core<C, std::enable_if_t<detail::direct_iter_test<C>>> {
+        static auto iter(C &r) -> decltype(r.iter()) {
+            return r.iter();
+        }
+    };
 }
 
 template<typename C>
-struct ranged_traits<C, std::enable_if_t<detail::direct_iter_test<C>>> {
-    static auto iter(C &r) -> decltype(r.iter()) {
-        return r.iter();
-    }
-};
+struct ranged_traits: detail::ranged_traits_core<C> {};
 
 template<typename T>
 inline auto iter(T &r) -> decltype(ranged_traits<T>::iter(r)) {
@@ -1842,6 +1845,36 @@ inline IteratorRange<T *> iter(T *a, size_t b) {
     return IteratorRange<T *>(a, a + b);
 }
 
+/* iter on standard containers */
+
+namespace detail {
+    template<typename C>
+    static std::true_type test_std_iter(
+        decltype(std::begin(std::declval<C>())) *,
+        decltype(std::end(std::declval<C>())) *
+    );
+
+    template<typename>
+    static std::false_type test_std_iter(...);
+
+    template<typename C>
+    constexpr bool std_iter_test = decltype(test_std_iter<C>(0, 0))::value;
+
+    template<typename C>
+    struct ranged_traits_core<C, std::enable_if_t<
+        detail::std_iter_test<C> && !detail::direct_iter_test<C>
+    >> {
+        using range_type = std::conditional_t<
+            std::is_const_v<C>,
+            IteratorRange<typename C::const_iterator>,
+            IteratorRange<typename C::iterator>
+        >;
+        static range_type iter(C &r) {
+            return range_type{r.begin(), r.end()};
+        }
+    };
+}
+
 } /* namespace ostd */
 
 #endif
diff --git a/ostd/unordered_map.hh b/ostd/unordered_map.hh
index 0531dc5..edbe046 100644
--- a/ostd/unordered_map.hh
+++ b/ostd/unordered_map.hh
@@ -13,26 +13,6 @@
 
 namespace ostd {
 
-template<typename K, typename T, typename H, typename E, typename A>
-struct ranged_traits<std::unordered_map<K, T, H, E, A>> {
-    using Range = IteratorRange<
-        typename std::unordered_map<K, T, H, E, A>::iterator
-    >;
-    static Range iter(std::unordered_map<K, T, H, E, A> &v) {
-        return Range{v.begin(), v.end()};
-    }
-};
-
-template<typename K, typename T, typename H, typename E, typename A>
-struct ranged_traits<std::unordered_map<K, T, H, E, A> const> {
-    using Range = IteratorRange<
-        typename std::unordered_map<K, T, H, E, A>::const_iterator
-    >;
-    static Range iter(std::unordered_map<K, T, H, E, A> const &v) {
-        return Range{v.cbegin(), v.cend()};
-    }
-};
-
 namespace detail {
     template<typename T>
     std::integral_constant<
diff --git a/ostd/vector.hh b/ostd/vector.hh
index 72857cb..f393ca1 100644
--- a/ostd/vector.hh
+++ b/ostd/vector.hh
@@ -14,20 +14,6 @@
 
 namespace ostd {
 
-template<typename T, typename A>
-struct ranged_traits<std::vector<T, A>> {
-    static IteratorRange<T *> iter(std::vector<T, A> &v) {
-        return IteratorRange<T *>{v.data(), v.data() + v.size()};
-    }
-};
-
-template<typename T, typename A>
-struct ranged_traits<std::vector<T, A> const> {
-    static IteratorRange<T const *> iter(std::vector<T, A> const &v) {
-        return IteratorRange<T const *>{v.data(), v.data() + v.size()};
-    }
-};
-
 template<typename T, typename A = std::allocator<T>, typename R>
 inline std::vector<T, A> make_vector(R range, A const &alloc = A{}) {
     std::vector<T, A> ret{alloc};