renderdoc/renderdoc/common/wrapped_pool.h

/******************************************************************************
 * The MIT License (MIT)
 * 
 * Copyright (c) 2014 Crytek
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * THE SOFTWARE.
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#pragma once

#include <stdint.h>

#include "common.h"
#include "threading.h"

#if !defined(_RELEASE)
#define INCLUDE_TYPE_NAMES
#endif

#ifdef INCLUDE_TYPE_NAMES
template<class T> class GetTypeName { public: static const char *Name(); };
#endif

template<class C> class FriendMaker { public: typedef C Type; };

// allocate each class in its own pool so we can identify the type by the pointer
template<typename WrapType, int PoolCount = 8192, int MaxPoolByteSize = 1024*1024, bool DebugClear = true>
class WrappingPool
{
	public:
		void *Allocate()
		{
			SCOPED_LOCK(m_Lock);

			// try and allocate from immediate pool
			void *ret = m_ImmediatePool.Allocate();
			if(ret != NULL) return ret;

			// fall back to additional pools, if there are any
			for(size_t i=0; i < m_AdditionalPools.size(); i++)
			{
				ret = m_AdditionalPools[i]->Allocate();
				if(ret != NULL)
					return ret;
			}

			// warn when we need to allocate an additional pool
#ifdef INCLUDE_TYPE_NAMES
			RDCWARN("Ran out of free slots in %s pool!", GetTypeName<WrapType>::Name());
#else
			RDCWARN("Ran out of free slots in pool 0x%p!", &m_ImmediatePool.items[0]);
#endif
			
			// allocate a new additional pool and use that to allocate from
			m_AdditionalPools.push_back(new ItemPool());
			
#ifdef INCLUDE_TYPE_NAMES
			RDCDEBUG("WrappingPool[%d]<%s>: %p -> %p", (uint32_t)m_AdditionalPools.size() - 1, GetTypeName<WrapType>::Name(),
													&m_AdditionalPools.back()->items[0], &m_AdditionalPools.back()->items[AllocCount-1]);
#endif

			return m_AdditionalPools.back()->Allocate();
		}

		bool IsAlloc(const void *p)
		{
			// we can check the immediate pool without locking
			if(m_ImmediatePool.IsAlloc(p))
				return true;

			// if we have additional pools, lock and check them.
			// TODO: Check for additional pools in a lock-free manner,
			// to prevent the cost of locking if there are no more pools.
			{
				SCOPED_LOCK(m_Lock);

				for(size_t i=0; i < m_AdditionalPools.size(); i++)
					if(m_AdditionalPools[i]->IsAlloc(p))
						return true;
			}

			return false;
		}

		void Deallocate(void *p)
		{
			SCOPED_LOCK(m_Lock);

			// try immediate pool
			if(m_ImmediatePool.IsAlloc(p))
			{
				m_ImmediatePool.Deallocate(p);
				return;
			}
			else if(!m_AdditionalPools.empty())
			{
				// fall back and try additional pools
				for(size_t i=0; i < m_AdditionalPools.size(); i++)
				{
					if(m_AdditionalPools[i]->IsAlloc(p))
					{
						m_AdditionalPools[i]->Deallocate(p);
						return;
					}
				}
			}
			
			// this is an error - deleting an object that we don't recognise
#ifdef INCLUDE_TYPE_NAMES
			RDCERR("Resource being deleted through wrong pool - 0x%p not a member of %s", p, GetTypeName<WrapType>::Name());
#else
			RDCERR("Resource being deleted through wrong pool - 0x%p not a member of 0x%p", p, &m_ImmediatePool.items[0]));
#endif
		}

		static const size_t AllocCount = PoolCount;
		static const size_t AllocMaxByteSize = MaxPoolByteSize;
		static const size_t AllocByteSize;

	private:
		WrappingPool()
		{
#ifdef INCLUDE_TYPE_NAMES
			// hack - print in kB because float printing relies on statics that might not be initialised
			// yet in loading order. Ugly :(
			RDCDEBUG("WrappingPool<%s> %d in %dkB: %p -> %p", GetTypeName<WrapType>::Name(), PoolCount, (PoolCount*AllocByteSize)/1024, &m_ImmediatePool.items[0], &m_ImmediatePool.items[AllocCount-1]);
#endif
		}
		~WrappingPool()
		{
			for(size_t i=0; i < m_AdditionalPools.size(); i++)
				delete m_AdditionalPools[i];

			m_AdditionalPools.clear();
		}

		Threading::CriticalSection m_Lock;

		struct ItemPool
		{
			ItemPool()
			{
				lastAllocIdx = 0;
				RDCEraseEl(allocated);

				items = (WrapType *)(new uint8_t[AllocCount*AllocByteSize]);
			}
			~ItemPool()
			{
				delete[] (uint8_t *)items;
			}

			void *Allocate()
			{
				int lastAlloc = lastAllocIdx;

				if(allocated[lastAlloc])
				{
					int end = lastAlloc;

					do 
					{
						lastAlloc = (lastAlloc+1) % PoolCount;
					} while (allocated[lastAlloc] && lastAlloc != end);

					if(allocated[lastAlloc])
					{
						return NULL;
					}
				}

				void *ret = (void *)&items[lastAlloc];
				allocated[lastAlloc] = true;

#if !defined(RELEASE)
				memset(ret, 0xb0, AllocByteSize);
#endif

				lastAllocIdx = lastAlloc;

				return ret;
			}

			void Deallocate(void *p)
			{
				RDCASSERT(IsAlloc(p));

#if !defined(RELEASE)
				if(!IsAlloc(p))
				{
					RDCERR("Resource being deleted through wrong pool - 0x%p not a memory of 0x%p", p, &items[0]);
					return;
				}
#endif

				size_t idx = (WrapType *)p-&items[0];

				allocated[idx] = false;

#if !defined(RELEASE)
				if(DebugClear)
					memset(p, 0xfe, AllocByteSize);
#endif
			}

			bool IsAlloc(const void *p) const
			{
				return p >= &items[0] && p < &items[PoolCount];
			}

			WrapType *items;

			// could possibly make this uint32s and check via bitmasks, but
			// we'll see if it shows up in profiling
			bool allocated[PoolCount];

			// store the last allocations index. Good place to start from and we
			// go through the pool in a ring. Good performance when the pool is empty
			// or contiguously allocated, poorer performance when the pool gets filled up.
			// It also has the bonus of handling repeated new/free well by reallocating the
			// same element.
			int lastAllocIdx;
		};
		
		ItemPool m_ImmediatePool;
		std::vector<ItemPool *> m_AdditionalPools;

		friend typename FriendMaker<WrapType>::Type;
};

#define ALLOCATE_WITH_WRAPPED_POOL(...) \
	typedef WrappingPool<__VA_ARGS__> PoolType; \
	static PoolType m_Pool; \
  void* operator new(size_t sz) { return m_Pool.Allocate(); } \
	void operator delete(void* p) { m_Pool.Deallocate(p); } \
	static bool IsAlloc(void *p) { return m_Pool.IsAlloc(p); }

#ifdef INCLUDE_TYPE_NAMES
#define DECL_TYPENAME(a) template<> const char *GetTypeName< a >::Name() { return #a; }
#else
#define DECL_TYPENAME(a)
#endif

#define WRAPPED_POOL_INST(a) \
	a::PoolType a::m_Pool; \
	template<> const size_t a::PoolType::AllocByteSize = sizeof(a); \
	RDCCOMPILE_ASSERT(a::PoolType::AllocCount*a::PoolType::AllocByteSize <= a::PoolType::AllocMaxByteSize, "Pool is bigger than max pool size cap"); \
	RDCCOMPILE_ASSERT(a::PoolType::AllocCount > 2, "Pool isn't greater than 2 in size. Bad parameters?"); \
	DECL_TYPENAME(a);