1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/PoolAllocator.h	Tue Jul 24 23:53:34 2012 -0700
     1.3 @@ -0,0 +1,136 @@
     1.4 +/*
     1.5 + * Copyright (C) 2012 David Anderson
     1.6 + *
     1.7 + * This file is part of JITCraft.
     1.8 + *
     1.9 + * JITCraft is free software: you can redistribute it and/or modify it under
    1.10 + * the terms of the GNU General Public License as published by the Free
    1.11 + * Software Foundation, either version 3 of the License, or (at your option)
    1.12 + * any later version.
    1.13 + * 
    1.14 + * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY
    1.15 + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    1.16 + * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
    1.17 + *
    1.18 + * You should have received a copy of the GNU General Public License along with
    1.19 + * JITCraft. If not, see http://www.gnu.org/licenses/.
    1.20 + */
    1.21 +#ifndef _include_jitcraft_pool_allocator_h_
    1.22 +#define _include_jitcraft_pool_allocator_h_
    1.23 +
    1.24 +#include <new>
    1.25 +#include <stddef.h>
    1.26 +#include <limits.h>
    1.27 +#include "Utility.h"
    1.28 +#include "Vector.h"
    1.29 +
    1.30 +namespace ke {
    1.31 +
    1.32 +// Allocates memory in chunks that are not freed until the entire allocator
    1.33 +// is freed. This is intended for use with large, temporary data structures.
    1.34 +class PoolAllocator
    1.35 +{
    1.36 +    friend class PoolAllocationScope;
    1.37 +
    1.38 +    struct Pool {
    1.39 +        char *base;
    1.40 +        char *ptr;
    1.41 +        char *end;
    1.42 +        Pool *prev;
    1.43 +
    1.44 +        size_t size() const {
    1.45 +            return size_t(end - base);
    1.46 +        }
    1.47 +    };
    1.48 +
    1.49 +    static const size_t kDefaultPoolSize = 8 * 1024;
    1.50 +    static const size_t kMaxReserveSize = 64 * 1024;
    1.51 +
    1.52 +  private:
    1.53 +    Pool *reserved_;
    1.54 +    Pool *last_;
    1.55 +
    1.56 +  private:
    1.57 +    void unwind(char *pos);
    1.58 +    void *slowAllocate(size_t actualBytes);
    1.59 +
    1.60 +  public:
    1.61 +    PoolAllocator();
    1.62 +    ~PoolAllocator();
    1.63 +
    1.64 +    void *allocate(size_t bytes) {
    1.65 +        // Guarantee malloc alignment.
    1.66 +        size_t actualBytes = Align(bytes, kMallocAlignment);
    1.67 +        if (!last_ || (size_t(last_->end - last_->ptr) < actualBytes))
    1.68 +            return slowAllocate(actualBytes);
    1.69 +        char *ptr = last_->ptr;
    1.70 +        last_->ptr += actualBytes;
    1.71 +        return ptr;
    1.72 +    }
    1.73 +
    1.74 +    char *enter();
    1.75 +    void leave(char *position);
    1.76 +};
    1.77 +
    1.78 +class PoolScope
    1.79 +{
    1.80 +    PoolAllocator &pool_;
    1.81 +    char *position_;
    1.82 +
    1.83 +  public:
    1.84 +    PoolScope(PoolAllocator &allocator)
    1.85 +      : pool_(allocator),
    1.86 +        position_(allocator.enter())
    1.87 +    {
    1.88 +    }
    1.89 +    ~PoolScope()
    1.90 +    {
    1.91 +        pool_.leave(position_);
    1.92 +    }
    1.93 +};
    1.94 +
    1.95 +class PoolObject
    1.96 +{
    1.97 +  public:
    1.98 +    void *operator new(size_t size, PoolAllocator &pool) {
    1.99 +        return pool.allocate(size);
   1.100 +    }
   1.101 +    void *operator new [](size_t size, PoolAllocator &pool) {
   1.102 +        return pool.allocate(size);
   1.103 +    }
   1.104 +    
   1.105 +    // Using delete on pool-allocated objects is illegal.
   1.106 +    void operator delete(void *ptr, PoolAllocator &pool) {
   1.107 +        assert(false);
   1.108 +    }
   1.109 +    void operator delete [](void *ptr, PoolAllocator &pool) {
   1.110 +        assert(false);
   1.111 +    }
   1.112 +};
   1.113 +
   1.114 +class PoolAllocationPolicy
   1.115 +{
   1.116 +  protected:
   1.117 +    void reportAllocationOverflow();
   1.118 +    void reportOutOfMemory();
   1.119 +
   1.120 +  public:
   1.121 +    void *malloc(size_t bytes);
   1.122 +    void free(void *ptr);
   1.123 +};
   1.124 +
   1.125 +template <typename T>
   1.126 +class PoolList
   1.127 +  : public Vector<T, PoolAllocationPolicy>,
   1.128 +    public PoolObject
   1.129 +{
   1.130 +  public:
   1.131 +    PoolList()
   1.132 +      : Vector(PoolAllocationPolicy())
   1.133 +    {
   1.134 +    }
   1.135 +};
   1.136 +
   1.137 +}
   1.138 +
   1.139 +#endif // _include_jitcraft_pool_allocator_h_