dvander@0: /*
dvander@0:  * Copyright (C) 2012 David Anderson
dvander@0:  *
dvander@0:  * This file is part of JITCraft.
dvander@0:  *
dvander@0:  * JITCraft is free software: you can redistribute it and/or modify it under
dvander@0:  * the terms of the GNU General Public License as published by the Free
dvander@0:  * Software Foundation, either version 3 of the License, or (at your option)
dvander@0:  * any later version.
dvander@0:  * 
dvander@0:  * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY
dvander@0:  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
dvander@0:  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
dvander@0:  *
dvander@0:  * You should have received a copy of the GNU General Public License along with
dvander@0:  * JITCraft. If not, see http://www.gnu.org/licenses/.
dvander@0:  */
dvander@0: #ifndef _include_jitcraft_pool_allocator_h_
dvander@0: #define _include_jitcraft_pool_allocator_h_
dvander@0: 
dvander@0: #include <new>
dvander@0: #include <stddef.h>
dvander@0: #include <limits.h>
dvander@0: #include "Utility.h"
dvander@56: #include "Vector.h"
dvander@0: 
dvander@59: namespace ke {
dvander@0: 
dvander@0: // Allocates memory in chunks that are not freed until the entire allocator
dvander@0: // is freed. This is intended for use with large, temporary data structures.
dvander@0: class PoolAllocator
dvander@0: {
dvander@0:     friend class PoolAllocationScope;
dvander@0: 
dvander@0:     struct Pool {
dvander@0:         char *base;
dvander@0:         char *ptr;
dvander@0:         char *end;
dvander@0:         Pool *prev;
dvander@0: 
dvander@0:         size_t size() const {
dvander@0:             return size_t(end - base);
dvander@0:         }
dvander@0:     };
dvander@0: 
dvander@0:     static const size_t kDefaultPoolSize = 8 * 1024;
dvander@0:     static const size_t kMaxReserveSize = 64 * 1024;
dvander@0: 
dvander@0:   private:
dvander@0:     Pool *reserved_;
dvander@0:     Pool *last_;
dvander@0: 
dvander@0:   private:
dvander@0:     void unwind(char *pos);
dvander@0:     void *slowAllocate(size_t actualBytes);
dvander@0: 
dvander@0:   public:
dvander@0:     PoolAllocator();
dvander@0:     ~PoolAllocator();
dvander@0: 
dvander@195:     void *rawAllocate(size_t bytes) {
dvander@0:         // Guarantee malloc alignment.
dvander@0:         size_t actualBytes = Align(bytes, kMallocAlignment);
dvander@0:         if (!last_ || (size_t(last_->end - last_->ptr) < actualBytes))
dvander@0:             return slowAllocate(actualBytes);
dvander@0:         char *ptr = last_->ptr;
dvander@0:         last_->ptr += actualBytes;
dvander@0:         return ptr;
dvander@0:     }
dvander@0: 
dvander@195:     template <typename T>
dvander@195:     T *alloc(size_t count = 1) {
dvander@195:         void *ptr = rawAllocate(count * sizeof(T));
dvander@195:         if (!ptr)
dvander@195:             return NULL;
dvander@195: 
dvander@195:         return reinterpret_cast<T *>(ptr);
dvander@195:     }
dvander@195: 
dvander@0:     char *enter();
dvander@0:     void leave(char *position);
dvander@0: };
dvander@0: 
dvander@0: class PoolScope
dvander@0: {
dvander@0:     PoolAllocator &pool_;
dvander@0:     char *position_;
dvander@0: 
dvander@0:   public:
dvander@0:     PoolScope(PoolAllocator &allocator)
dvander@0:       : pool_(allocator),
dvander@0:         position_(allocator.enter())
dvander@0:     {
dvander@0:     }
dvander@0:     ~PoolScope()
dvander@0:     {
dvander@0:         pool_.leave(position_);
dvander@0:     }
dvander@0: };
dvander@0: 
dvander@0: class PoolObject
dvander@0: {
dvander@0:   public:
dvander@0:     void *operator new(size_t size, PoolAllocator &pool) {
dvander@195:         return pool.rawAllocate(size);
dvander@0:     }
dvander@0:     void *operator new [](size_t size, PoolAllocator &pool) {
dvander@195:         return pool.rawAllocate(size);
dvander@0:     }
dvander@0:     
dvander@0:     // Using delete on pool-allocated objects is illegal.
dvander@0:     void operator delete(void *ptr, PoolAllocator &pool) {
dvander@0:         assert(false);
dvander@0:     }
dvander@0:     void operator delete [](void *ptr, PoolAllocator &pool) {
dvander@0:         assert(false);
dvander@0:     }
dvander@0: };
dvander@0: 
dvander@55: class PoolAllocationPolicy
dvander@55: {
dvander@55:   protected:
dvander@55:     void reportAllocationOverflow();
dvander@55:     void reportOutOfMemory();
dvander@55: 
dvander@55:   public:
dvander@55:     void *malloc(size_t bytes);
dvander@55:     void free(void *ptr);
dvander@55: };
dvander@55: 
dvander@56: template <typename T>
dvander@56: class PoolList
dvander@56:   : public Vector<T, PoolAllocationPolicy>,
dvander@56:     public PoolObject
dvander@56: {
dvander@56:   public:
dvander@56:     PoolList()
danderson@91:       : Vector<T, PoolAllocationPolicy>(PoolAllocationPolicy())
dvander@56:     {
dvander@56:     }
dvander@56: };
dvander@56: 
dvander@0: }
dvander@0: 
dvander@0: #endif // _include_jitcraft_pool_allocator_h_