mem: implement most of StandardAllocator

This was tested using `https://github.com/node-dot-cpp/alloc-test` plus a few other by-hand tests.

It seems to work for the case we care about (sysmodules without thread cache-ing).

External users are advised to build with assertions on and contact SciresM if you find issues.

This is a lot of code to have gotten right in one go, and it was written mostly after midnight while sick, so there are probably un-noticed issues.

libraries/libstratosphere/include/stratosphere/mem/mem_standard_allocator.hpp

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2019-2020 Adubbz, Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere/os.hpp>
+#include <stratosphere/mem/impl/mem_impl_declarations.hpp>
+
+namespace ams::mem {
+
+    class StandardAllocator {
+        NON_COPYABLE(StandardAllocator);
+        NON_MOVEABLE(StandardAllocator);
+        public:
+            using WalkCallback = int (*)(void *ptr, size_t size, void *user_data);
+
+            struct AllocatorHash {
+                size_t allocated_count;
+                size_t allocated_size;
+                size_t hash;
+            };
+        private:
+            bool initialized;
+            bool enable_thread_cache;
+            uintptr_t unused;
+            os::TlsSlot tls_slot;
+            impl::InternalCentralHeapStorage central_heap_storage;
+        public:
+            StandardAllocator();
+            StandardAllocator(void *mem, size_t size);
+            StandardAllocator(void *mem, size_t size, bool enable_cache);
+
+            ~StandardAllocator() {
+                if (this->initialized) {
+                    this->Finalize();
+                }
+            }
+
+            void Initialize(void *mem, size_t size);
+            void Initialize(void *mem, size_t size, bool enable_cache);
+            void Finalize();
+
+            void *Allocate(size_t size);
+            void *Allocate(size_t size, size_t alignment);
+            void Free(void *ptr);
+            void *Reallocate(void *ptr, size_t new_size);
+            size_t Shrink(void *ptr, size_t new_size);
+
+            void ClearThreadCache() const;
+            void CleanUpManagementArea() const;
+
+            size_t GetSizeOf(const void *ptr) const;
+            size_t GetTotalFreeSize() const;
+            size_t GetAllocatableSize() const;
+
+            void WalkAllocatedBlocks(WalkCallback callback, void *user_data) const;
+
+            void Dump() const;
+            AllocatorHash Hash() const;
+    };
+
+}