From 8c75f8ad843d19857ae6d5333186374d977a0f6c Mon Sep 17 00:00:00 2001
From: mutouyun <mark.lonr@tom.com>
Date: Sat, 29 Dec 2018 18:31:01 +0800
Subject: [PATCH] pool_alloc (TBD)

---
 README.md                  |   2 +-
 src/channel.inc            |   2 +-
 src/ipc.cpp                |  33 ++++++++--
 src/memory/alloc.hpp       | 128 ++++++++++++++++++++++++-------------
 src/memory/resource.hpp    |  58 +++++++++--------
 src/memory/wrapper.hpp     |  55 ++++++++++++++--
 src/platform/shm_linux.cpp |   2 +-
 src/platform/shm_win.cpp   |   2 +-
 8 files changed, 201 insertions(+), 81 deletions(-)

diff --git a/README.md b/README.md
index c798800..18e1705 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ A high-performance inter-process communication using shared memory on Linux/Wind
  
 ## Performance
 
- | | Environment |
+ | Environment | Value |
  | ------ | ------ |
  | Device | Lenovo ThinkPad T450 |
  | CPU | Intel(R) Core(TM) i5-4300U @ 2.5 GHz |
diff --git a/src/channel.inc b/src/channel.inc
index 8f58e92..439e2e0 100644
--- a/src/channel.inc
+++ b/src/channel.inc
@@ -4,8 +4,8 @@
 #include <string>
 #include <array>
 #include <limits>
-#include <shared_mutex>
 #include <mutex>
+#include <shared_mutex>
 #include <thread>
 #include <memory>
 #include <utility>
diff --git a/src/ipc.cpp b/src/ipc.cpp
index 399cb19..64188b2 100644
--- a/src/ipc.cpp
+++ b/src/ipc.cpp
@@ -46,6 +46,29 @@ constexpr queue_t* queue_of(handle_t h) {
     return static_cast<queue_t*>(h);
 }
 
+using cache_t = mem::vector<byte_t>;
+
+template <std::size_t N>
+cache_t make_cache(byte_t const (& data)[N]) {
+    return {
+        static_cast<buff_t::value_type const *>(data),
+        static_cast<buff_t::value_type const *>(data) + N
+    };
+}
+
+template <typename T>
+using remove_cv_ref_t = std::remove_cv_t<std::remove_reference_t<T>>;
+
+template <typename Cache>
+constexpr auto to_buff(Cache&& cac) -> Requires<std::is_same<remove_cv_ref_t<Cache>, buff_t>::value, buff_t> {
+    return cac;
+}
+
+template <typename Cache>
+auto to_buff(Cache&& cac) -> Requires<!std::is_same<remove_cv_ref_t<Cache>, buff_t>::value, buff_t> {
+    return make_buff(cac.data(), cac.size());
+}
+
 inline auto& recv_cache() {
     /*
         <Remarks> thread_local may have some bugs.
@@ -56,12 +79,12 @@ inline auto& recv_cache() {
              https://developercommunity.visualstudio.com/content/problem/124121/thread-local-variables-fail-to-be-initialized-when.html
              https://software.intel.com/en-us/forums/intel-c-compiler/topic/684827
     */
-    static tls::pointer<memory::unordered_map<msg_id_t, buff_t>> rc;
+    static tls::pointer<mem::unordered_map<msg_id_t, cache_t>> rc;
     return *rc.create();
 }
 
 inline auto& queues_cache() {
-    static tls::pointer<std::vector<queue_t*>> qc;
+    static tls::pointer<mem::vector<queue_t*>> qc;
     return *qc.create();
 }
 
@@ -168,7 +191,7 @@ buff_t multi_recv(F&& upd) {
                 return make_buff(msg.data_, remain);
             }
             // cache the first message fragment
-            else rc.emplace(msg.id_, make_buff(msg.data_));
+            else rc.emplace(msg.id_, make_cache(msg.data_));
         }
         // has cached before this message
         else {
@@ -177,9 +200,9 @@ buff_t multi_recv(F&& upd) {
             if (msg.remain_ <= 0) {
                 cache.insert(cache.end(), msg.data_, msg.data_ + remain);
                 // finish this message, erase it from cache
-                auto buf = std::move(cache);
+                auto cac = std::move(cache);
                 rc.erase(cache_it);
-                return buf;
+                return to_buff(std::move(cac));
             }
             // there are remain datas after this message
             cache.insert(cache.end(), msg.data_, msg.data_ + data_length);
diff --git a/src/memory/alloc.hpp b/src/memory/alloc.hpp
index fc6a845..9b125ce 100644
--- a/src/memory/alloc.hpp
+++ b/src/memory/alloc.hpp
@@ -2,19 +2,22 @@
 
 #include <limits>
 #include <algorithm>
+#include <utility>
 #include <cstdlib>
 
 #include "def.h"
 
 namespace ipc {
-namespace memory {
+namespace mem {
 
-struct static_alloc {
+class static_alloc {
+public:
     static constexpr std::size_t remain() {
         return (std::numeric_limits<std::size_t>::max)();
     }
 
     static constexpr void clear() {}
+    static constexpr void swap(static_alloc&) {}
 
     static void* alloc(std::size_t size) {
         return size ? std::malloc(size) : nullptr;
@@ -33,19 +36,40 @@ struct static_alloc {
 /// Scope allocation -- The destructor will release all allocated blocks.
 ////////////////////////////////////////////////////////////////
 
+namespace detail {
+
+class scope_alloc_base {
+protected:
+    struct block_t {
+        block_t* next_;
+    };
+    block_t* list_ = nullptr;
+
+public:
+    std::size_t remain() const {
+        std::size_t c = 0;
+        auto curr = list_;
+        while (curr != nullptr) {
+            ++c;
+            curr = curr->next_;
+        }
+        return c;
+    }
+
+    void free(void* /*p*/) {}
+    void free(void* /*p*/, std::size_t) {}
+};
+
+} // namespace detail
+
 template <typename AllocP = static_alloc>
-class scope_alloc {
+class scope_alloc : public detail::scope_alloc_base {
 public:
     using alloc_policy = AllocP;
 
 private:
     alloc_policy alloc_;
 
-    struct block_t {
-        block_t* next_;
-    };
-    block_t* list_ = nullptr;
-
 public:
     scope_alloc() = default;
 
@@ -60,16 +84,6 @@ public:
         std::swap(this->list_ , rhs.list_);
     }
 
-    std::size_t remain() const {
-        std::size_t c = 0;
-        auto curr = list_;
-        while (curr != nullptr) {
-            ++c;
-            curr = curr->next_;
-        }
-        return c;
-    }
-
     void clear() {
         while (list_ != nullptr) {
             auto curr = list_;
@@ -85,16 +99,59 @@ public:
         curr->next_ = list_;
         return ((list_ = curr) + 1);
     }
-
-    void free(void* /*p*/) {}
 };
 
 ////////////////////////////////////////////////////////////////
 /// Fixed-size blocks allocation
 ////////////////////////////////////////////////////////////////
 
+namespace detail {
+
+class fixed_pool_base {
+protected:
+    std::size_t init_expand_;
+    std::size_t iter_;
+    void*       cursor_;
+
+    void init(std::size_t init_expand) {
+        iter_ = init_expand_ = init_expand;
+        cursor_ = nullptr;
+    }
+
+    static void** node_p(void* node) {
+        return reinterpret_cast<void**>(node);
+    }
+
+    static auto& next(void* node) {
+        return *node_p(node);
+    }
+
+public:
+    std::size_t remain() const {
+        std::size_t c = 0;
+        void* curr = cursor_;
+        while (curr != nullptr) {
+            ++c;
+            curr = next(curr);
+        }
+        return c;
+    }
+
+    void free(void* p) {
+        if (p == nullptr) return;
+        next(p) = cursor_;
+        cursor_ = p;
+    }
+
+    void free(void* p, std::size_t) {
+        free(p);
+    }
+};
+
+} // namespace detail
+
 template <std::size_t BlockSize, typename AllocP = scope_alloc<>>
-class fixed_pool {
+class fixed_pool : public detail::fixed_pool_base {
 public:
     using alloc_policy = AllocP;
 
@@ -104,22 +161,15 @@ public:
 
 private:
     alloc_policy alloc_;
-    std::size_t init_expand_, iter_;
-    void*  cursor_;
 
     void expand() {
-        void** p = reinterpret_cast<void**>(cursor_ = alloc_.alloc(block_size * iter_));
+        auto p = node_p(cursor_ = alloc_.alloc(block_size * iter_));
         for (std::size_t i = 0; i < iter_ - 1; ++i)
-            p = reinterpret_cast<void**>((*p) = reinterpret_cast<byte_t*>(p) + block_size);
+            p = node_p((*p) = reinterpret_cast<byte_t*>(p) + block_size);
         (*p) = nullptr;
         iter_ *= 2;
     }
 
-    void init(std::size_t init_expand) {
-        iter_ = init_expand_ = init_expand;
-        cursor_ = nullptr;
-    }
-
 public:
     explicit fixed_pool(std::size_t init_expand = 1) {
         init(init_expand);
@@ -139,13 +189,7 @@ public:
     }
 
     std::size_t remain() const {
-        std::size_t c = 0;
-        void* curr = cursor_;
-        while (curr != nullptr) {
-            ++c;
-            curr = *reinterpret_cast<void**>(curr); // curr = next
-        }
-        return c * block_size;
+        return detail::fixed_pool_base::remain() * block_size;
     }
 
     void clear() {
@@ -156,16 +200,14 @@ public:
     void* alloc() {
         if (cursor_ == nullptr) expand();
         void* p = cursor_;
-        cursor_ = *reinterpret_cast<void**>(p);
+        cursor_ = next(p);
         return p;
     }
 
-    void free(void* p) {
-        if (p == nullptr) return;
-        *reinterpret_cast<void**>(p) = cursor_;
-        cursor_ = p;
+    void* alloc(std::size_t) {
+        return alloc();
     }
 };
 
-} // namespace memory
+} // namespace mem
 } // namespace ipc
diff --git a/src/memory/resource.hpp b/src/memory/resource.hpp
index 43b29bb..fa87f93 100644
--- a/src/memory/resource.hpp
+++ b/src/memory/resource.hpp
@@ -1,27 +1,31 @@
 #pragma once
 
 #include <type_traits>
-#include <initializer_list>
 #include <limits>
 #include <utility>
 #include <functional>
 #include <unordered_map>
-
-#include "tls_pointer.h"
+#include <vector>
 
 #include "memory/alloc.hpp"
 #include "memory/wrapper.hpp"
 
+#include "tls_pointer.h"
+
 namespace ipc {
-namespace memory {
+namespace mem {
 
 namespace detail {
 
-template <typename Comp, typename F, std::size_t...I>
-void switch_constexpr(std::size_t i, std::index_sequence<I...>, F&& f) {
-    [[maybe_unused]] std::initializer_list<int> expand {
-        (Comp{}(i, I) && (f(std::integral_constant<size_t, I>{}), 0))...
-    };
+template <typename F, typename D>
+constexpr decltype(auto) switch_constexpr(std::size_t /*i*/, std::index_sequence<>, F&& /*f*/, D&& def) {
+    return def();
+}
+
+template <typename F, typename D, std::size_t N, std::size_t...I>
+constexpr decltype(auto) switch_constexpr(std::size_t i, std::index_sequence<N, I...>, F&& f, D&& def) {
+    return (i == N) ? f(std::integral_constant<size_t, N>{}) :
+                      switch_constexpr(i, std::index_sequence<I...>{}, f, def);
 }
 
 } // namespace detail
@@ -35,18 +39,21 @@ private:
     }
 
     template <typename F>
-    static void choose(std::size_t size, F&& f) {
+    static decltype(auto) choose(std::size_t size, F&& f) {
         enum : std::size_t { base_size = sizeof(void*) };
-        detail::switch_constexpr<std::less_equal<std::size_t>>(size, std::index_sequence<
+        size = ((size - 1) & (~(base_size - 1))) + base_size;
+        return detail::switch_constexpr(size, std::index_sequence<
             base_size     , base_size * 2 ,
-            base_size * 4 , base_size * 6 ,
-            base_size * 8 , base_size * 12,
-            base_size * 16, base_size * 20,
-            base_size * 24, base_size * 28,
-            base_size * 32, base_size * 40,
-            base_size * 48, base_size * 56,
-            base_size * 64
-        >{}, [&f](auto index) { f(fixed<decltype(index)::value>()); });
+            base_size * 3 , base_size * 4 ,
+            base_size * 5 , base_size * 6 ,
+            base_size * 7 , base_size * 8 ,
+            base_size * 9 , base_size * 10,
+            base_size * 11, base_size * 12,
+            base_size * 13, base_size * 14,
+            base_size * 15, base_size * 16
+        >{}, [&f](auto index) {
+            return f(fixed<decltype(index)::value>());
+        }, [&f] { return f(static_alloc{}); });
     }
 
 public:
@@ -63,23 +70,24 @@ public:
     static constexpr void clear() {}
 
     static void* alloc(std::size_t size) {
-        void* p;
-        choose(size, [&p](auto& fp) { p = fp.alloc(); });
-        return p;
+        return choose(size, [size](auto&& fp) { return fp.alloc(size); });
     }
 
     static void free(void* p, std::size_t size) {
-        choose(size, [p](auto& fp) { fp.free(p); });
+        choose(size, [p](auto&& fp) { fp.free(p); });
     }
 };
 
 template <typename T>
 using allocator = allocator_wrapper<T, pool_alloc>;
 
-template<typename Key, typename T>
+template <typename Key, typename T>
 using unordered_map = std::unordered_map<
     Key, T//, std::hash<Key>, std::equal_to<Key>, allocator<std::pair<const Key, T>>
 >;
 
-} // namespace memory
+template <typename T>
+using vector = std::vector<T/*, allocator<T>*/>;
+
+} // namespace mem
 } // namespace ipc
diff --git a/src/memory/wrapper.hpp b/src/memory/wrapper.hpp
index f8a07c5..69fb531 100644
--- a/src/memory/wrapper.hpp
+++ b/src/memory/wrapper.hpp
@@ -1,14 +1,61 @@
 #pragma once
 
-#include <utility>
 #include <limits>
 #include <new>
+#include <mutex>
+#include <shared_mutex>
+#include <vector>
+#include <utility>
+
+#include "rw_lock.h"
+#include "tls_pointer.h"
 
 namespace ipc {
-namespace memory {
+namespace mem {
 
 ////////////////////////////////////////////////////////////////
-/// The allocator wrapper class
+/// Thread-safe allocation wrapper
+////////////////////////////////////////////////////////////////
+
+template <typename AllocP>
+class synchronized_pool {
+public:
+    using alloc_policy = AllocP;
+
+private:
+    rw_lock lc_;
+    std::vector<alloc_policy*> allocs_;
+
+    struct alloc_t {
+        synchronized_pool* t_;
+        alloc_policy* alc_;
+
+        alloc_t(synchronized_pool* t)
+            : t_ { t }
+        {}
+
+        ~alloc_t() {
+
+        }
+    };
+
+public:
+    static constexpr std::size_t remain() {
+        return (std::numeric_limits<std::size_t>::max)();
+    }
+
+    static void* alloc() {
+        static tls::pointer<alloc_policy> alc;
+        return nullptr;
+    }
+
+    static void* alloc(std::size_t) {
+        return alloc();
+    }
+};
+
+////////////////////////////////////////////////////////////////
+/// The allocator wrapper class for STL
 ////////////////////////////////////////////////////////////////
 
 template <typename T, typename AllocP>
@@ -106,5 +153,5 @@ constexpr bool operator!=(const allocator_wrapper<T, AllocP>&, const allocator_w
     return false;
 }
 
-} // namespace memory
+} // namespace mem
 } // namespace ipc
diff --git a/src/platform/shm_linux.cpp b/src/platform/shm_linux.cpp
index 13d47e5..e5d94ac 100644
--- a/src/platform/shm_linux.cpp
+++ b/src/platform/shm_linux.cpp
@@ -25,7 +25,7 @@ constexpr void* mem_of(void* mem) {
 }
 
 inline auto& m2h() {
-    static ipc::tls::pointer<ipc::memory::unordered_map<void*, std::string>> cache;
+    static ipc::tls::pointer<ipc::mem::unordered_map<void*, std::string>> cache;
     return *cache.create();
 }
 
diff --git a/src/platform/shm_win.cpp b/src/platform/shm_win.cpp
index 130102f..2b4f612 100644
--- a/src/platform/shm_win.cpp
+++ b/src/platform/shm_win.cpp
@@ -28,7 +28,7 @@ constexpr auto to_tchar(std::string && str) -> IsSame<T, std::wstring> {
 }
 
 inline auto& m2h() {
-    static ipc::tls::pointer<ipc::memory::unordered_map<void*, HANDLE>> cache;
+    static ipc::tls::pointer<ipc::mem::unordered_map<void*, HANDLE>> cache;
     return *cache.create();
 }