bighashmap_arena.hh

// -*- c-basic-offset: 4; related-file-name: "../../lib/bighashmap_arena.cc" -*-
#ifndef CLICK_BIGHASHMAP_ARENA_HH
#define CLICK_BIGHASHMAP_ARENA_HH
CLICK_DECLS
 
class HashMap_Arena { public:
 
    HashMap_Arena(uint32_t element_size);
 
    void use()                  { _refcount++; }
    void unuse();
 
    bool detached() const       { return _detached; }
    void detach()               { _detached = true; }
 
    void *alloc();
    void free(void *);
 
  private:
 
    struct Link {
        Link *next;
    };
    Link *_free;
 
    enum { NELEMENTS = 127 };   // not a power of 2 so we don't fall into a
                                // too-large bucket
    char *_cur_buffer;
    int _buffer_pos;
 
    uint32_t _element_size;
 
    char **_buffers;
    int _nbuffers;
    int _buffers_cap;
 
    uint32_t _refcount;
    bool _detached;
 
    HashMap_Arena(const HashMap_Arena &);
    ~HashMap_Arena();
    HashMap_Arena &operator=(const HashMap_Arena &);
 
    void *hard_alloc();
 
    friend struct Link;         // shut up, compiler
 
};
 
class HashMap_ArenaFactory { public:
 
    HashMap_ArenaFactory();
    virtual ~HashMap_ArenaFactory();
 
    static void static_initialize();
    static void static_cleanup();
 
    static HashMap_Arena *get_arena(uint32_t, HashMap_ArenaFactory * =0);
    virtual HashMap_Arena *get_arena_func(uint32_t);
 
  private:
 
    HashMap_Arena **_arenas[2];
    int _narenas[2];
 
    static HashMap_ArenaFactory *the_factory;
 
};
 
inline void
HashMap_Arena::unuse()
{
    _refcount--;
    if (_refcount <= 0)
        delete this;
}
 
inline void *
HashMap_Arena::alloc()
{
    if (_free) {
        void *ret = _free;
        _free = _free->next;
        return ret;
    } else if (_buffer_pos > 0) {
        _buffer_pos -= _element_size;
        return _cur_buffer + _buffer_pos;
    } else
        return hard_alloc();
}
 
inline void
HashMap_Arena::free(void *v)
{
    Link *link = reinterpret_cast<Link *>(v);
    link->next = _free;
    _free = link;
}
 
CLICK_ENDDECLS
#endif