memory time

include/blt/std/memory.h

@@ -11,6 +11,7 @@
 #include <iterator>
 #include <cstring>
 #include "queue.h"
+#include "utility.h"
 #include <blt/std/assert.h>
 #include <blt/std/logging.h>
 #include <cstdint>
@@ -519,7 +520,7 @@ namespace blt
         private:
             struct pointer_view
             {
-                const_pointer p;
+                pointer p;
                 size_t n;
             };
             
@@ -531,13 +532,65 @@ namespace blt
                 std::vector<pointer_view> unallocated_blocks;
             };
             
-            void allocate_block()
+            inline void allocate_block()
             {
                 BLT_INFO("Allocating a new block of size %d", BLOCK_SIZE);
-                block_storage blk;
+                auto* blk = new block_storage();
-                blk.data = static_cast<pointer>(malloc(sizeof(T) * BLOCK_SIZE));
+                blk->data = static_cast<pointer>(malloc(sizeof(T) * BLOCK_SIZE));
                 blocks.push_back(blk);
             }
+            
+            inline pointer find_available_block(size_t n)
+            {
+                for (auto* blk : blocks)
+                {
+                    size_t index = -1ull;
+                    size_t leftover = 0;
+                    for (auto kv : blt::enumerate(blk->unallocated_blocks))
+                    {
+                        if (kv.second.n >= n)
+                        {
+                            index = kv.first;
+                            leftover = kv.second.n - n;
+                            break;
+                        }
+                    }
+                    if (index != -1ull)
+                    {
+                        pointer_view ptr = blk->unallocated_blocks[index];
+                        std::iter_swap(blk->unallocated_blocks.begin() + index, blk->unallocated_blocks.end() - 1);
+                        blk->unallocated_blocks.pop_back();
+//                        BLT_INFO("Found block! %d, Unallocated leftover %d", index, leftover);
+                        if (leftover > 0)
+                            blk->unallocated_blocks.push_back({ptr.p + n, leftover});
+                        return ptr.p;
+                    }
+                }
+                return nullptr;
+            }
+            
+            inline std::pair<pointer, size_t> getBlock(size_t n)
+            {
+                auto* blk = find_available_block(n);
+                if (blk != nullptr)
+                    return {blk, 0};
+                
+                if (blocks.back()->used + n > BLOCK_SIZE)
+                    allocate_block();
+                
+                auto ptr = std::pair<pointer, size_t>{blocks.back()->data, blocks.back()->used};
+                blocks.back()->used += n;
+                return ptr;
+            }
+            
+            inline void allocate_in_block(pointer begin, size_t n)
+            {
+                if constexpr (std::is_default_constructible_v<T> && !std::is_trivially_default_constructible_v<T>)
+                {
+                    for (size_t i = 0; i < n; i++)
+                        new(&begin[i]) T();
+                }
+            }
         
         public:
             area_allocator()
@@ -548,26 +601,14 @@ namespace blt
             [[nodiscard]] pointer allocate(size_t n)
             {
                 if (n > BLOCK_SIZE)
-                {
-                    // handle cases where they want to allocate one large huge block
-                    // in this case we do not care about it since the allocator is meant for small object allocations
                     throw std::runtime_error("Requested allocation is too large!");
-                }
-                // TODO: something better
-                if (blocks.back().used + n > BLOCK_SIZE)
-                {
-                    BLT_TRACE("Moving to a new block");
-                    allocate_block();
-                }
-                auto& current_block = blocks.back();
                 
-                auto* ptr = &blocks.back().data[current_block.used];
+                auto block_info = getBlock(n);
-                if constexpr (std::is_default_constructible_v<T> && !std::is_trivially_default_constructible_v<T>)
+                
-                {
+                auto* ptr = &block_info.first[block_info.second];
-                    for (size_t i = 0; i < n; i++)
+                // call constructors on the objects if they require it
-                        new(&ptr[i]) T();
+                allocate_in_block(ptr, n);
-                }
+                
-                current_block.used += n;
                 return ptr;
             }
             
@@ -575,11 +616,11 @@ namespace blt
             {
                 for (size_t i = 0; i < n; i++)
                     p[i].~T();
-                for (auto& blk : blocks)
+                for (auto*& blk : blocks)
                 {
-                    if (p >= blk.data && p <= (blk.data + BLOCK_SIZE))
+                    if (p >= blk->data && p <= (blk->data + BLOCK_SIZE))
                     {
-                        blk.unallocated_blocks.push_back({p, n});
+                        blk->unallocated_blocks.push_back({p, n});
                         break;
                     }
                 }
@@ -587,30 +628,15 @@ namespace blt
             
             ~area_allocator()
             {
-                for (auto& blk : blocks)
+                for (auto*& blk : blocks)
                 {
-//                    for (size_t i = 0; i < blk.used; i++)
+                    free(blk->data);
-//                    {
+                    delete blk;
-//                        bool alreadyDeallocated = false;
-//                        for (const auto& dealoc : blk.unallocated_blocks)
-//                        {
-//                            auto pos = (blk.data + i);
-//                            if (pos >= dealoc.p && pos <= (dealoc.p + dealoc.n))
-//                            {
-//                                alreadyDeallocated = true;
-//                                break;
-//                            }
-//                        }
-//                        if (!alreadyDeallocated)
-//                            blk.data[i].~T();
-//                    }
-                    // it is UB to not deallocate allocated memory. Get fucked.
-                    free(blk.data);
                 }
             }
         
         private:
-            std::vector<block_storage> blocks;
+            std::vector<block_storage*> blocks;
     };
     
 }

tests/src/memory_test.cpp

@@ -22,6 +22,8 @@
 #include <blt/std/random.h>
 #include <type_traits>
 #include "blt/std/utility.h"
+#include <unordered_set>
+#include <blt/compatibility.h>
 
 template<typename T>
 blt::scoped_buffer<T> create_scoped_buffer(size_t size)
@@ -136,67 +138,133 @@ void blt::test::memory::static_vector_test()
     BLT_DEBUG_STREAM << '\n';
 }
 
-struct fucked_type1
-{
-    private:
-        int T = 0;
-    public:
-        fucked_type1() = default;
-};
-
 struct fucked_type2
 {
     public:
+        static constexpr size_t initial_value = 50;
         int T = 0;
     public:
         fucked_type2()
         {
-            T = 50;
+            T = initial_value;
-            BLT_DEBUG("I HAVE BEEN CONSTRUCTED");
+            //BLT_DEBUG("I HAVE BEEN CONSTRUCTED");
+        }
+        
+        void set(int t)
+        {
+            T = t;
         }
         
         ~fucked_type2()
         {
-            BLT_DEBUG("I HAVE BEEN DESTRUCTED!");
+            //BLT_DEBUG("I HAVE BEEN DESTRUCTED!");
         }
 };
 
+#define ALLOC(alloc, amount) alloc.allocate(amount), amount
+
+/**
+ * run tests to make sure that we can actually allocate blocks of memory.
+ * we are using a custom type to ensure that the state is known and the example is complex enough
+ * if this work then it should work for any generic type
+ */
+template<size_t allocator_size = 20>
+void test_allocations_1()
+{
+    std::vector<std::pair<fucked_type2*, size_t>> types;
+    blt::area_allocator<fucked_type2, allocator_size> int_test{};
+    
+    types.emplace_back(ALLOC(int_test, static_cast<size_t>(allocator_size * 0.75)));
+    for (size_t i = 0; i < static_cast<size_t>(allocator_size * 0.30); i++)
+    {
+        types.emplace_back(ALLOC(int_test, 1));
+        auto v = std::pair{ALLOC(int_test, 1)};
+        v.first->set(120);
+        int_test.deallocate(v.first, 1);
+        types.emplace_back(ALLOC(int_test, 1));
+        types.emplace_back(ALLOC(int_test, 1));
+        types.emplace_back(ALLOC(int_test, 1));
+    }
+    
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
+    
+    bool passed = true;
+    
+    std::unordered_set<fucked_type2*> used_pointers;
+    
+    for (const auto& pair : types)
+    {
+        for (size_t i = 0; i < pair.second; i++)
+        {
+            // every value should be the initial value assigned in the constructor
+            // if this isn't the case there was an error.
+            if (pair.first[i].T != fucked_type2::initial_value)
+            {
+                BLT_WARN("We have an allocated value that isn't initial at index %d (allocated in a block of size %d at pointer %p)", i, pair.second,
+                         pair.first);
+                passed = false;
+                break;
+            }
+            // every allocation here should be unique.
+            // if we have a pointer in our list which is not unique,
+            // we know we have an error
+            if (BLT_CONTAINS(used_pointers, &pair.first[i]))
+            {
+                BLT_WARN(
+                        "We have found another pointer which was allocated as a unique block but isn't (in block %d with size %d; pointer in question: %p)",
+                        i, pair.second, pair.first);
+                passed = false;
+                break;
+            }
+            used_pointers.insert(&pair.first[i]);
+        }
+        int_test.deallocate(pair.first, pair.second);
+    }
+    if (passed)
+        BLT_INFO("Test (1) with size %d passed!", allocator_size);
+    else
+        BLT_ERROR("Test (1) with size %d failed!", allocator_size);
+}
+
 void blt::test::memory::test()
 {
+    test_allocations_1();
+    test_allocations_1<50>();
+    test_allocations_1<4096>();
+    
+    std::vector<std::pair<fucked_type2*, size_t>> types;
     area_allocator<fucked_type2, 20> int_test{};
     //auto arr = int_test.allocate(10);
-    auto arr2 = int_test.allocate(15);
+    types.emplace_back(ALLOC(int_test, 15));
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
-    blt::black_box(int_test.allocate(1));
+    auto v = std::pair{ALLOC(int_test, 1)};
-    blt::black_box(int_test.allocate(1));
+    v.first->set(120);
-    blt::black_box(int_test.allocate(1));
+    int_test.deallocate(v.first, 1);
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
+    types.emplace_back(ALLOC(int_test, 1));
     
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
-    blt::black_box(int_test.allocate(1));
+    types.emplace_back(ALLOC(int_test, 1));
     //blt::black_box(arr4);
     BLT_INFO("CUM");
-//    arr3 = int_test.allocate(2);
-//    blt::black_box(arr3);
-//    arr3 = int_test.allocate(5);
-//    blt::black_box(arr3);
-//    arr3 = int_test.allocate(10);
-//    blt::black_box(arr3);
-    //auto arr3 = int_test.allocate(20);
     
-    //std::memset(arr, 0, 10);
+    for (const auto& pair : types)
-    //std::memset(arr2, 0, 15);
-    //std::memset(arr3, 0, 20);
-    
-    for (int i = 0; i < 15; i++)
     {
-        BLT_TRACE_STREAM << arr2[i].T << ' ';
+        BLT_TRACE("Pointer: %p", pair.first);
+        for (size_t i = 0; i < pair.second; i++)
+        {
+            BLT_TRACE_STREAM << pair.first[i].T << ' ';
+        }
+        BLT_TRACE_STREAM << '\n';
+        int_test.deallocate(pair.first, pair.second);
+        BLT_INFO("-----------------");
     }
-    BLT_TRACE_STREAM << "\n";
-    
-    int_test.deallocate(arr2, 15);
-    BLT_INFO("-----------------");
 }