asherkin@263: /*
asherkin@263:  * Copyright (C) 2012 David Anderson
asherkin@263:  *
asherkin@263:  * This file is part of JITCraft.
asherkin@263:  *
asherkin@263:  * JITCraft is free software: you can redistribute it and/or modify it under
asherkin@263:  * the terms of the GNU General Public License as published by the Free
asherkin@263:  * Software Foundation, either version 3 of the License, or (at your option)
asherkin@263:  * any later version.
asherkin@263:  * 
asherkin@263:  * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY
asherkin@263:  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
asherkin@263:  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
asherkin@263:  *
asherkin@263:  * You should have received a copy of the GNU General Public License along with
asherkin@263:  * JITCraft. If not, see http://www.gnu.org/licenses/.
asherkin@263:  */
asherkin@263: #ifndef _include_jitcraft_pool_allocator_h_
asherkin@263: #define _include_jitcraft_pool_allocator_h_
asherkin@263: 
asherkin@263: #include <new>
asherkin@263: #include <stddef.h>
asherkin@263: #include <limits.h>
asherkin@263: #include "Utility.h"
asherkin@263: #include "Vector.h"
asherkin@263: 
asherkin@263: namespace ke {
asherkin@263: 
asherkin@263: // Allocates memory in chunks that are not freed until the entire allocator
asherkin@263: // is freed. This is intended for use with large, temporary data structures.
asherkin@263: class PoolAllocator
asherkin@263: {
asherkin@263:     friend class PoolAllocationScope;
asherkin@263: 
asherkin@263:     struct Pool {
asherkin@263:         char *base;
asherkin@263:         char *ptr;
asherkin@263:         char *end;
asherkin@263:         Pool *prev;
asherkin@263: 
asherkin@263:         size_t size() const {
asherkin@263:             return size_t(end - base);
asherkin@263:         }
asherkin@263:     };
asherkin@263: 
asherkin@263:     static const size_t kDefaultPoolSize = 8 * 1024;
asherkin@263:     static const size_t kMaxReserveSize = 64 * 1024;
asherkin@263: 
asherkin@263:   private:
asherkin@263:     Pool *reserved_;
asherkin@263:     Pool *last_;
asherkin@263: 
asherkin@263:   private:
asherkin@263:     void unwind(char *pos);
asherkin@263:     void *slowAllocate(size_t actualBytes);
asherkin@263: 
asherkin@263:   public:
asherkin@263:     PoolAllocator();
asherkin@263:     ~PoolAllocator();
asherkin@263: 
asherkin@263:     void *rawAllocate(size_t bytes) {
asherkin@263:         // Guarantee malloc alignment.
asherkin@263:         size_t actualBytes = Align(bytes, kMallocAlignment);
asherkin@263:         if (!last_ || (size_t(last_->end - last_->ptr) < actualBytes))
asherkin@263:             return slowAllocate(actualBytes);
asherkin@263:         char *ptr = last_->ptr;
asherkin@263:         last_->ptr += actualBytes;
asherkin@263:         return ptr;
asherkin@263:     }
asherkin@263: 
asherkin@263:     template <typename T>
asherkin@263:     T *alloc(size_t count = 1) {
asherkin@263:         void *ptr = rawAllocate(count * sizeof(T));
asherkin@263:         if (!ptr)
asherkin@263:             return NULL;
asherkin@263: 
asherkin@263:         return reinterpret_cast<T *>(ptr);
asherkin@263:     }
asherkin@263: 
asherkin@263:     char *enter();
asherkin@263:     void leave(char *position);
asherkin@263: };
asherkin@263: 
asherkin@263: class PoolScope
asherkin@263: {
asherkin@263:     PoolAllocator &pool_;
asherkin@263:     char *position_;
asherkin@263: 
asherkin@263:   public:
asherkin@263:     PoolScope(PoolAllocator &allocator)
asherkin@263:       : pool_(allocator),
asherkin@263:         position_(allocator.enter())
asherkin@263:     {
asherkin@263:     }
asherkin@263:     ~PoolScope()
asherkin@263:     {
asherkin@263:         pool_.leave(position_);
asherkin@263:     }
asherkin@263: };
asherkin@263: 
asherkin@263: class PoolObject
asherkin@263: {
asherkin@263:   public:
asherkin@263:     void *operator new(size_t size, PoolAllocator &pool) {
asherkin@263:         return pool.rawAllocate(size);
asherkin@263:     }
asherkin@263:     void *operator new [](size_t size, PoolAllocator &pool) {
asherkin@263:         return pool.rawAllocate(size);
asherkin@263:     }
asherkin@263:     
asherkin@263:     // Using delete on pool-allocated objects is illegal.
asherkin@263:     void operator delete(void *ptr, PoolAllocator &pool) {
asherkin@263:         assert(false);
asherkin@263:     }
asherkin@263:     void operator delete [](void *ptr, PoolAllocator &pool) {
asherkin@263:         assert(false);
asherkin@263:     }
asherkin@263: };
asherkin@263: 
asherkin@263: class PoolAllocationPolicy
asherkin@263: {
asherkin@263:   protected:
asherkin@263:     void reportAllocationOverflow();
asherkin@263:     void reportOutOfMemory();
asherkin@263: 
asherkin@263:   public:
asherkin@263:     void *malloc(size_t bytes);
asherkin@263:     void free(void *ptr);
asherkin@263: };
asherkin@263: 
asherkin@263: template <typename T>
asherkin@263: class PoolList
asherkin@263:   : public Vector<T, PoolAllocationPolicy>,
asherkin@263:     public PoolObject
asherkin@263: {
asherkin@263:   public:
asherkin@263:     PoolList()
asherkin@263:       : Vector<T, PoolAllocationPolicy>(PoolAllocationPolicy())
asherkin@263:     {
asherkin@263:     }
asherkin@263: };
asherkin@263: 
asherkin@263: }
asherkin@263: 
asherkin@263: #endif // _include_jitcraft_pool_allocator_h_