zip iterators work. now have .take

.idea/misc.xml

@@ -1,4 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="CMakePythonSetting">
+    <option name="pythonIntegrationState" value="YES" />
+  </component>
   <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$" />
 </project>

.vscode/launch.json

@@ -0,0 +1,32 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "(gdb) Launch",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${workspaceFolder}/cmake-build-debug/BLT_TESTS",
+            "args": [],
+            "stopAtEntry": false,
+            "cwd": "${fileDirname}",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                },
+                {
+                    "description": "Set Disassembly Flavor to Intel",
+                    "text": "-gdb-set disassembly-flavor intel",
+                    "ignoreFailures": true
+                }
+            ]
+        }
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,75 @@
+{
+    "files.associations": {
+        "iostream": "cpp",
+        "cctype": "cpp",
+        "clocale": "cpp",
+        "cmath": "cpp",
+        "cstdarg": "cpp",
+        "cstddef": "cpp",
+        "cstdio": "cpp",
+        "cstdlib": "cpp",
+        "cstring": "cpp",
+        "ctime": "cpp",
+        "cwchar": "cpp",
+        "cwctype": "cpp",
+        "any": "cpp",
+        "array": "cpp",
+        "atomic": "cpp",
+        "strstream": "cpp",
+        "bit": "cpp",
+        "*.tcc": "cpp",
+        "bitset": "cpp",
+        "chrono": "cpp",
+        "cinttypes": "cpp",
+        "compare": "cpp",
+        "complex": "cpp",
+        "concepts": "cpp",
+        "condition_variable": "cpp",
+        "cstdint": "cpp",
+        "deque": "cpp",
+        "list": "cpp",
+        "map": "cpp",
+        "set": "cpp",
+        "string": "cpp",
+        "unordered_map": "cpp",
+        "unordered_set": "cpp",
+        "vector": "cpp",
+        "exception": "cpp",
+        "algorithm": "cpp",
+        "functional": "cpp",
+        "iterator": "cpp",
+        "memory": "cpp",
+        "memory_resource": "cpp",
+        "numeric": "cpp",
+        "optional": "cpp",
+        "random": "cpp",
+        "ratio": "cpp",
+        "string_view": "cpp",
+        "system_error": "cpp",
+        "tuple": "cpp",
+        "type_traits": "cpp",
+        "utility": "cpp",
+        "fstream": "cpp",
+        "initializer_list": "cpp",
+        "iomanip": "cpp",
+        "iosfwd": "cpp",
+        "istream": "cpp",
+        "limits": "cpp",
+        "mutex": "cpp",
+        "new": "cpp",
+        "numbers": "cpp",
+        "ostream": "cpp",
+        "scoped_allocator": "cpp",
+        "semaphore": "cpp",
+        "shared_mutex": "cpp",
+        "sstream": "cpp",
+        "stdexcept": "cpp",
+        "stop_token": "cpp",
+        "streambuf": "cpp",
+        "thread": "cpp",
+        "cfenv": "cpp",
+        "typeindex": "cpp",
+        "typeinfo": "cpp",
+        "variant": "cpp"
+    }
+}

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
-set(BLT_VERSION 1.0.3)
+set(BLT_VERSION 1.0.4)
 
 set(BLT_TARGET BLT)
 

include/blt/iterator/zip.h

@@ -20,28 +20,23 @@
 #define BLT_ITERATOR_ZIP
 
 #include <blt/iterator/iter_common.h>
+#include <blt/meta/meta.h>
+#include <blt/meta/iterator.h>
 #include <tuple>
 
 namespace blt
 {
-    
     namespace iterator
     {
         template<typename Tag, typename... Iter>
         class zip_wrapper;
         
-        template<typename Tag, typename... Iter>
-        class zip_iterator_storage;
-        
-        template<typename Tag, typename... Iter>
-        class zip_iterator_storage_rev;
-        
         template<typename... Iter>
-        class zip_wrapper<std::forward_iterator_tag, Iter...>
+        class zip_wrapper<std::input_iterator_tag, Iter...>
         {
             public:
-                using iterator_category = std::forward_iterator_tag;
+                using iterator_category = std::input_iterator_tag;
-                using value_type = std::tuple<blt::meta::deref_return_t<Iter>...>;
+                using value_type = std::tuple<meta::deref_return_t<Iter>...>;
                 using difference_type = blt::ptrdiff_t;
                 using pointer = value_type;
                 using reference = value_type;
@@ -49,9 +44,9 @@ namespace blt
                 explicit zip_wrapper(Iter... iter): iter(std::make_tuple(iter...))
                 {}
                 
-                std::tuple<blt::meta::deref_return_t<Iter>...> operator*() const
+                std::tuple<meta::deref_return_t<Iter>...> operator*() const
                 {
-                    return std::apply([](auto& ... i) { return std::make_tuple(*i...); }, iter);
+                    return std::apply([](auto& ... i) { return std::tuple<meta::deref_return_t<Iter>...>{*i...}; }, iter);
                 }
                 
                 friend bool operator==(const zip_wrapper& a, const zip_wrapper& b)
@@ -87,17 +82,30 @@ namespace blt
         };
         
         template<typename... Iter>
-        class zip_wrapper<std::bidirectional_iterator_tag, Iter...> : public zip_wrapper<std::forward_iterator_tag, Iter...>
+        class zip_wrapper<std::forward_iterator_tag, Iter...> : public zip_wrapper<std::input_iterator_tag, Iter...>
         {
             public:
-                using zip_wrapper<std::forward_iterator_tag, Iter...>::zip_wrapper;
+                using iterator_category = std::forward_iterator_tag;
-                
+                using value_type = std::tuple<meta::deref_return_t<Iter>...>;
-                using iterator_category = std::bidirectional_iterator_tag;
-                using value_type = std::tuple<blt::meta::deref_return_t<Iter>...>;
                 using difference_type = blt::ptrdiff_t;
                 using pointer = value_type;
                 using reference = value_type;
                 
+                using zip_wrapper<std::input_iterator_tag, Iter...>::zip_wrapper;
+        };
+        
+        template<typename... Iter>
+        class zip_wrapper<std::bidirectional_iterator_tag, Iter...> : public zip_wrapper<std::forward_iterator_tag, Iter...>
+        {
+            public:
+                using iterator_category = std::bidirectional_iterator_tag;
+                using value_type = std::tuple<meta::deref_return_t<Iter>...>;
+                using difference_type = blt::ptrdiff_t;
+                using pointer = value_type;
+                using reference = value_type;
+            public:
+                using zip_wrapper<std::forward_iterator_tag, Iter...>::zip_wrapper;
+                
                 zip_wrapper& operator--()
                 {
                     std::apply([](auto& ... i) { ((--i), ...); }, this->iter);
@@ -115,25 +123,25 @@ namespace blt
         template<typename... Iter>
         class zip_wrapper<std::random_access_iterator_tag, Iter...> : public zip_wrapper<std::bidirectional_iterator_tag, Iter...>
         {
+            public:
+                using iterator_category = std::random_access_iterator_tag;
+                using value_type = std::tuple<meta::deref_return_t<Iter>...>;
+                using difference_type = blt::ptrdiff_t;
+                using pointer = value_type;
+                using reference = value_type;
             private:
                 template<typename T, T... n>
                 static blt::ptrdiff_t sub(const zip_wrapper& a, const zip_wrapper& b,
                                           std::integer_sequence<T, n...>)
                 {
-                    auto min = std::min(std::get<n>(a.iter) - std::get<n>(b.iter)...);
+                    blt::ptrdiff_t min = std::numeric_limits<blt::ptrdiff_t>::max();
+                    ((min = std::min(min, std::get<n>(a.iter) - std::get<n>(b.iter))), ...);
                     return min;
                 }
+            
             public:
                 using zip_wrapper<std::bidirectional_iterator_tag, Iter...>::zip_wrapper;
                 
-                using iterator_category = std::random_access_iterator_tag;
-                using value_type = std::tuple<blt::meta::deref_return_t<Iter>...>;
-                using difference_type = blt::ptrdiff_t;
-                using pointer = value_type;
-                using reference = value_type;
-                
-                using zip_bidirectional_iterator<Iter...>::zip_bidirectional_iterator;
-                
                 zip_wrapper& operator+=(blt::ptrdiff_t n)
                 {
                     std::apply([n](auto& ... i) { ((i += n), ...); }, this->iter);
@@ -148,22 +156,22 @@ namespace blt
                 
                 friend zip_wrapper operator+(const zip_wrapper& a, blt::ptrdiff_t n)
                 {
-                    return std::apply([n](auto& ... i) { return zip_random_access_iterator{(i + n)...}; }, a.iter);
+                    return std::apply([n](auto& ... i) { return zip_wrapper{(i + n)...}; }, a.iter);
                 }
                 
                 friend zip_wrapper operator+(blt::ptrdiff_t n, const zip_wrapper& a)
                 {
-                    return std::apply([n](auto& ... i) { return zip_random_access_iterator{(i + n)...}; }, a.iter);
+                    return std::apply([n](auto& ... i) { return zip_wrapper{(i + n)...}; }, a.iter);
                 }
                 
                 friend zip_wrapper operator-(const zip_wrapper& a, blt::ptrdiff_t n)
                 {
-                    return std::apply([n](auto& ... i) { return zip_random_access_iterator{(i - n)...}; }, a.iter);
+                    return std::apply([n](auto& ... i) { return zip_wrapper{(i - n)...}; }, a.iter);
                 }
                 
                 friend zip_wrapper operator-(blt::ptrdiff_t n, const zip_wrapper& a)
                 {
-                    return std::apply([n](auto& ... i) { return zip_random_access_iterator{(i - n)...}; }, a.iter);
+                    return std::apply([n](auto& ... i) { return zip_wrapper{(i - n)...}; }, a.iter);
                 }
                 
                 friend blt::ptrdiff_t operator-(const zip_wrapper& a, const zip_wrapper& b)
@@ -197,43 +205,199 @@ namespace blt
                 }
         };
         
-        template<typename... Iter>
+        template<typename Iter>
-        class zip_iterator_storage<std::forward_iterator_tag, Iter...>
+        auto get_base(Iter iter)
         {
-        
+            if constexpr (meta::is_reverse_iterator_v<Iter>)
-        };
-        
-        template<typename... Iter>
-        class zip_iterator_storage<std::bidirectional_iterator_tag, Iter...>
             {
-        
+                return std::move(iter).base();
-        };
+            } else
-        
-        template<typename... Iter>
-        class zip_iterator_storage<std::random_access_iterator_tag, Iter...>
             {
+                return std::move(iter);
+            }
+        }
         
-        };
+        template<typename Derived>
-        
+        class take_impl
-        template<typename... Iter>
-        class zip_iterator_storage_rev<std::forward_iterator_tag, Iter...>
         {
-        
+            private:
-        };
+                template<bool check>
-        
+                auto take_base(blt::size_t n)
-        template<typename... Iter>
-        class zip_iterator_storage_rev<std::bidirectional_iterator_tag, Iter...>
                 {
+                    static_assert(!std::is_same_v<typename Derived::iterator_category, std::input_iterator_tag>,
+                                  "Cannot .take() on an input iterator!");
+                    auto* d = static_cast<Derived*>(this);
+                    auto begin = d->begin();
+                    auto end = d->end();
                     
-        };
+                    // take variant for forward and bidirectional iterators
-        
+                    if constexpr (std::is_same_v<typename Derived::iterator_category, std::forward_iterator_tag> ||
-        template<typename... Iter>
+                                  std::is_same_v<typename Derived::iterator_category, std::bidirectional_iterator_tag>)
-        class zip_iterator_storage_rev<std::random_access_iterator_tag, Iter...>
                     {
+                        // with these guys we have to loop forward to move the iterators. an unfortunate inefficiency
+                        auto new_end = begin;
+                        for (blt::size_t i = 0; i < n; i++)
+                        {
+                            if constexpr (check)
+                            {
+                                if (new_end == end)
+                                    break;
+                            }
+                            ++new_end;
+                        }
+                        return Derived{get_base(std::move(begin)), get_base(std::move(new_end))};
+                    } else if constexpr (std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>)
+                    {
+                        // random access iterators can have math directly applied to them.
+                        if constexpr (check)
+                        {
+                            return Derived{get_base(begin),
+                                           get_base(begin + std::min(n, static_cast<blt::size_t>(std::distance(begin, end))))};
+                        } else
+                        {
+                            return Derived{get_base(begin), get_base(begin + n)};
+                        }
+                    }
+                }
             
+            public:
+                auto take(blt::size_t n)
+                { return take_base<false>(n); }
+                
+                auto take_or(blt::size_t n)
+                { return take_base<true>(n); }
         };
     }
     
+    template<typename Iter>
+    struct iterator_pair
+    {
+        using type = Iter;
+        
+        iterator_pair(Iter begin, Iter end): begin(std::move(begin)), end(std::move(end))
+        {}
+        
+        Iter begin;
+        Iter end;
+    };
+    
+    template<typename... Iter>
+    class zip_iterator_storage;
+    
+    template<typename... Iter>
+    class zip_iterator_storage_rev;
+    
+    template<typename... Iter>
+    class zip_iterator_storage : public iterator::take_impl<zip_iterator_storage<Iter...>>
+    {
+        public:
+            using iterator_category = meta::lowest_iterator_category_t<Iter...>;
+        public:
+            zip_iterator_storage(iterator_pair<Iter>... iterator_pairs):
+                    m_begins(std::move(iterator_pairs.begin)...), m_ends(std::move(iterator_pairs.end)...)
+            {}
+            
+            zip_iterator_storage(iterator::zip_wrapper<iterator_category, Iter...> begins, iterator::zip_wrapper<iterator_category, Iter...> ends):
+                    m_begins(std::move(begins)), m_ends(std::move(ends))
+            {}
+            
+            auto rev()
+            {
+                static_assert((std::is_same_v<iterator_category, std::bidirectional_iterator_tag> ||
+                               std::is_same_v<iterator_category, std::random_access_iterator_tag>),
+                              ".rev() must be used with bidirectional (or better) iterators!");
+                return zip_iterator_storage_rev{m_ends, m_begins};
+            }
+            
+            auto skip(blt::size_t n)
+            {
+                if constexpr (std::is_same_v<iterator_category, std::input_iterator_tag>)
+                {
+                
+                }
+            }
+            
+            auto begin() const
+            {
+                return m_begins;
+            }
+            
+            auto end() const
+            {
+                return m_ends;
+            }
+        
+        private:
+            iterator::zip_wrapper<iterator_category, Iter...> m_begins;
+            iterator::zip_wrapper<iterator_category, Iter...> m_ends;
+    };
+    
+    template<typename... Iter>
+    class zip_iterator_storage_rev : public iterator::take_impl<zip_iterator_storage_rev<Iter...>>
+    {
+        public:
+            using iterator_category = meta::lowest_iterator_category_t<Iter...>;
+        public:
+            zip_iterator_storage_rev(iterator_pair<Iter>... iterator_pairs): m_begins(iterator_pairs.begin...), m_ends(iterator_pairs.end...)
+            {
+                static_assert((std::is_same_v<iterator_category, std::bidirectional_iterator_tag> ||
+                               std::is_same_v<iterator_category, std::random_access_iterator_tag>),
+                              "reverse iteration is only supported on bidirectional or better iterators!");
+            }
+            
+            zip_iterator_storage_rev(iterator::zip_wrapper<iterator_category, Iter...> begins,
+                                     iterator::zip_wrapper<iterator_category, Iter...> ends): m_begins(std::move(begins)), m_ends(std::move(ends))
+            {
+                static_assert((std::is_same_v<iterator_category, std::bidirectional_iterator_tag> ||
+                               std::is_same_v<iterator_category, std::random_access_iterator_tag>),
+                              "reverse iteration is only supported on bidirectional or better iterators!");
+            }
+            
+            auto rev()
+            {
+                return zip_iterator_storage{m_ends.base(), m_begins.base()};
+            }
+            
+            auto begin() const
+            {
+                return m_begins;
+            }
+            
+            auto end() const
+            {
+                return m_ends;
+            }
+        
+        private:
+            std::reverse_iterator<iterator::zip_wrapper<iterator_category, Iter...>> m_begins;
+            std::reverse_iterator<iterator::zip_wrapper<iterator_category, Iter...>> m_ends;
+    };
+    
+    /*
+     * CTAD for the zip containers
+     */
+    
+    template<typename... Iter>
+    zip_iterator_storage(iterator_pair<Iter>...) -> zip_iterator_storage<Iter...>;
+    
+    template<typename... Iter>
+    zip_iterator_storage(std::initializer_list<Iter>...) -> zip_iterator_storage<Iter...>;
+    
+    template<typename... Iter>
+    zip_iterator_storage_rev(iterator_pair<Iter>...) -> zip_iterator_storage_rev<Iter...>;
+    
+    template<typename... Iter>
+    zip_iterator_storage_rev(std::initializer_list<Iter>...) -> zip_iterator_storage_rev<Iter...>;
+    
+    /*
+     * Helper functions for creating zip containers
+     */
+    
+    template<typename... Container>
+    auto zip(Container& ... container)
+    {
+        return blt::zip_iterator_storage{iterator_pair{container.begin(), container.end()}...};
+    }
 }
 
 #endif //BLT_ITERATOR_ZIP

include/blt/meta/iterator.h

@@ -114,6 +114,18 @@ namespace blt::meta
     
     template<typename... Iter>
     using lowest_iterator_category_t = typename lowest_iterator_category<Iter...>::type;
+    
+    template<typename Iter>
+    struct is_reverse_iterator : std::false_type
+    {
+    };
+    
+    template<typename Iter>
+    struct is_reverse_iterator<std::reverse_iterator<Iter>> : std::true_type
+    {};
+    
+    template<typename Iter>
+    inline constexpr bool is_reverse_iterator_v = is_reverse_iterator<Iter>::value;
 }
 
 #endif //BLT_META_ITERATOR_H

libraries/parallel-hashmap

@@ -1 +1 @@
-Subproject commit 7ef2e733416953b222851f9a360d7fc72d068ee5
+Subproject commit 93201da2ba5a6aba0a6e57ada64973555629b3e3

tests/iterator_tests.cpp

@@ -24,13 +24,17 @@
 #include <blt/iterator/iterator.h>
 #include <blt/format/boxing.h>
 #include <array>
+#include <forward_list>
 
-constexpr auto increasing_reverse_pairs = [](blt::size_t i, blt::size_t index, blt::size_t size) { return i == 0 ? index : (size - 1) - index; };
+constexpr auto increasing_reverse_pairs =
-constexpr auto increasing_pairs = [](blt::size_t, blt::size_t index, blt::size_t) { return index; };
+        [](blt::size_t i, blt::size_t index, blt::size_t size) { return i == 0 ? index : (size - 1) - index; };
-constexpr auto decreasing_pairs = [](blt::size_t, blt::size_t index, blt::size_t size) { return size - index; };
+constexpr auto increasing_pairs =
+        [](blt::size_t, blt::size_t index, blt::size_t) { return index; };
+constexpr auto decreasing_pairs =
+        [](blt::size_t, blt::size_t index, blt::size_t size) { return size - index; };
 
 template<blt::size_t n, typename Func>
-std::array<blt::vec2, n> make_array(Func&& func)
+std::array<blt::vec2, n> make_array(Func func)
 {
     std::array<blt::vec2, n> array;
     for (auto&& [index, value] : blt::enumerate(array))
@@ -38,11 +42,22 @@ std::array<blt::vec2, n> make_array(Func&& func)
     return array;
 }
 
+template<blt::size_t n, typename Func>
+std::forward_list<blt::vec2> make_list(Func func)
+{
+    std::forward_list<blt::vec2> array;
+    for (auto index : blt::range(0ul, n))
+        array.push_front(blt::vec2(func(0, index, n), func(1, index, n)));
+    return array;
+}
+
 constexpr blt::size_t array_size = 10;
 auto array_1 = make_array<array_size>(increasing_reverse_pairs);
 auto array_2 = make_array<array_size>(increasing_pairs);
 auto array_3 = make_array<array_size>(decreasing_pairs);
 
+auto list_1 = make_list<array_size>(increasing_reverse_pairs);
+
 void test_enumerate()
 {
     blt::log_box_t box(std::cout, "Enumerate Tests", 25);
@@ -111,6 +126,30 @@ void test_pairs()
 void test_zip()
 {
     blt::log_box_t box(std::cout, "Zip Tests", 25);
+    for (auto [a1, a2, a3] : blt::zip(array_1, array_2, array_3))
+    {
+        BLT_TRACE_STREAM << a1 << " : " << a2 << " : " << a3 << "\n";
+    }
+    BLT_TRACE("================================");
+    for (auto [a1, a2, a3] : blt::zip(array_1, array_2, array_3).take(3))
+    {
+        BLT_TRACE_STREAM << a1 << " : " << a2 << " : " << a3 << "\n";
+    }
+    BLT_TRACE("================================");
+    for (auto [a1, a2, a3] : blt::zip(array_1, array_2, array_3).take(3).rev())
+    {
+        BLT_TRACE_STREAM << a1 << " : " << a2 << " : " << a3 << "\n";
+    }
+    BLT_TRACE("================================");
+    for (auto [a1, a2, a3] : blt::zip(array_1, array_2, array_3).take_or(13))
+    {
+        BLT_TRACE_STREAM << a1 << " : " << a2 << " : " << a3 << "\n";
+    }
+    BLT_TRACE("================================");
+    for (auto [a1, a2, a3] : blt::zip(array_1, array_2, array_3).rev().take(3))
+    {
+        BLT_TRACE_STREAM << a1 << " : " << a2 << " : " << a3 << "\n";
+    }
 }
 
 int main()