From d3ef2d36ead57e6a0490cebba3cdbc434c729e24 Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Fri, 25 Mar 2016 00:14:56 +0000
Subject: [PATCH] Add a SplitView container view

---
 src/containers.hh | 82 +++++++++++++++++++++++++++++++++++++++++++++--
 src/enum.hh       |  2 +-
 src/file.cc       |  2 +-
 src/normal.cc     |  2 +-
 src/selection.cc  |  2 +-
 5 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/src/containers.hh b/src/containers.hh
index b0fc58e3..675a7fb5 100644
--- a/src/containers.hh
+++ b/src/containers.hh
@@ -49,10 +49,16 @@ struct ReverseFactory
 
 inline ContainerView<ReverseFactory> reverse() { return {}; }
 
+template<typename Container>
+using IteratorOf = decltype(std::begin(std::declval<Container>()));
+
+template<typename Container>
+using ValueOf = typename Container::value_type;
+
 template<typename Container, typename Filter>
 struct FilterView
 {
-    using ContainerIt = decltype(begin(std::declval<Container>()));
+    using ContainerIt = IteratorOf<Container>;
 
     struct Iterator : std::iterator<std::forward_iterator_tag,
                                     typename ContainerIt::value_type>
@@ -119,7 +125,7 @@ using TransformedResult = decltype(std::declval<T>()(*std::declval<I>()));
 template<typename Container, typename Transform>
 struct TransformView
 {
-    using ContainerIt = decltype(begin(std::declval<Container>()));
+    using ContainerIt = IteratorOf<Container>;
 
     struct Iterator : std::iterator<std::forward_iterator_tag,
                                     typename std::remove_reference<TransformedResult<ContainerIt, Transform>>::type>
@@ -170,6 +176,78 @@ struct TransformFactory
 template<typename Transform>
 inline ContainerView<TransformFactory<Transform>> transform(Transform t) { return {{std::move(t)}}; }
 
+template<typename Container, typename Separator = ValueOf<Container>,
+         typename ValueTypeParam = void>
+struct SplitView
+{
+    using ContainerIt = IteratorOf<Container>;
+    using ValueType = typename std::conditional<std::is_same<void, ValueTypeParam>::value,
+                                                std::pair<IteratorOf<Container>, IteratorOf<Container>>,
+                                                ValueTypeParam>::type;
+
+    struct Iterator : std::iterator<std::forward_iterator_tag, ValueType>
+    {
+        Iterator(ContainerIt pos, ContainerIt end, char separator)
+         : pos(pos), sep(pos), end(end), separator(separator)
+        {
+            while (sep != end and *sep != separator)
+                ++sep;
+        }
+
+        Iterator& operator++() { advance(); return *this; }
+        Iterator operator++(int) { auto copy = *this; advance(); return copy; }
+
+        bool operator==(const Iterator& other) const { return pos == other.pos; }
+        bool operator!=(const Iterator& other) const { return pos != other.pos; }
+
+        ValueType operator*() { return {pos, sep}; }
+
+    private:
+        void advance()
+        {
+            if (sep == end)
+            {
+                pos = end;
+                return;
+            }
+
+            pos = sep+1;
+            for (sep = pos; sep != end; ++sep)
+            {
+                if (*sep == separator)
+                    break;
+            }
+        }
+
+        ContainerIt pos;
+        ContainerIt sep;
+        ContainerIt end;
+        Separator separator;
+    };
+
+    Iterator begin() const { return {m_container.begin(), m_container.end(), m_separator}; }
+    Iterator end()   const { return {m_container.end(), m_container.end(), m_separator}; }
+
+    Container m_container;
+    Separator m_separator;
+};
+
+template<typename ValueType, typename Separator>
+struct SplitViewFactory
+{
+    template<typename Container>
+    SplitView<RemoveReference<Container>, Separator, ValueType>
+    operator()(Container&& container) const { return {std::move(container), std::move(separator)}; }
+
+    template<typename Container>
+    SplitView<Container&, Separator, ValueType>
+    operator()(Container& container) const { return {container, std::move(separator)}; }
+
+    Separator separator;
+};
+
+template<typename ValueType = void, typename Separator>
+ContainerView<SplitViewFactory<ValueType, Separator>> split(Separator separator) { return {{std::move(separator)}}; }
 
 template<typename Container1, typename Container2>
 struct ConcatView
diff --git a/src/enum.hh b/src/enum.hh
index 728a56d2..6f4a4bdb 100644
--- a/src/enum.hh
+++ b/src/enum.hh
@@ -54,7 +54,7 @@ EnableIfWithBitOps<Flags> option_from_string(StringView str, Flags& flags)
 {
     constexpr auto desc = enum_desc(Flags{});
     flags = Flags{};
-    for (auto s : split(str, '|'))
+    for (auto s : str | split<StringView>('|'))
     {
         auto it = find_if(desc, [s](const EnumDesc<Flags>& d) { return d.name == s; });
         if (it == desc.end())
diff --git a/src/file.cc b/src/file.cc
index 6cf9a735..a558dc29 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -449,7 +449,7 @@ Vector<String> complete_command(StringView prefix, ByteCount cursor_pos)
     static UnorderedMap<String, CommandCache, MemoryDomain::Commands> command_cache;
 
     Vector<RankedMatch> matches;
-    for (auto dir : split(getenv("PATH"), ':'))
+    for (auto dir : StringView{getenv("PATH")} | split<StringView>(':'))
     {
         auto dirname = ((not dir.empty() and dir.back() == '/') ? dir.substr(0, dir.length()-1) : dir).str();
 
diff --git a/src/normal.cc b/src/normal.cc
index ab08da9b..13ecd9e2 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -1385,7 +1385,7 @@ void restore_selections(Context& context, NormalParams params)
     size_t timestamp = str_to_int({percent + 1, desc.end()});
 
     Vector<Selection> sels;
-    for (auto sel_desc : split({desc.begin(), arobase}, ':'))
+    for (auto sel_desc : StringView{desc.begin(), arobase} | split<StringView>(':'))
         sels.push_back(selection_from_string(sel_desc));
 
     SelectionList sel_list{buffer, std::move(sels), timestamp};
diff --git a/src/selection.cc b/src/selection.cc
index 8d9c7274..a2b2d1f2 100644
--- a/src/selection.cc
+++ b/src/selection.cc
@@ -587,7 +587,7 @@ Selection selection_from_string(StringView desc)
 SelectionList selection_list_from_string(Buffer& buffer, StringView desc)
 {
     Vector<Selection> sels;
-    for (auto sel_desc : split(desc, ':'))
+    for (auto sel_desc : desc | split<StringView>(':'))
         sels.push_back(selection_from_string(sel_desc));
     return {buffer, std::move(sels)};
 }