enum node_type;

/* different kinds of things that can appear in the value field
   of a hash node.  Actually, this may be useless now. */
union hashval {
    int             ival;
    char           *cpval;
    DEFINITION     *defn;
};

struct hashnode {
    struct hashnode *next;      /* double links for easy deletion */
    struct hashnode *prev;
    struct hashnode **bucket_hdr;       /* also, a back pointer to this node's hash
                                         * chain is kept, in case the node is the head
                                         * of the chain and gets deleted. */
    enum node_type  type;       /* type of special token */
    int             length;     /* length of token, for quick comparison */
    char           *name;       /* the actual name */
    union hashval   value;      /* pointer to expansion, or whatever */
};

typedef struct hashnode HASHNODE;

/* Some definitions for the hash table.  The hash function MUST be
   computed as shown in hashf () below.  That is because the rescan
   loop computes the hash value `on the fly' for most tokens,
   in order to avoid the overhead of a lot of procedure calls to
   the hashf () function.  Hashf () only exists for the sake of
   politeness, for use when speed isn't so important. */

#define HASHSIZE 1403
#define HASHSTEP(old, c) ((old << 2) + c)
#define MAKE_POS(v) (v & 0x7fffffff)    /* make number positive */

extern int      hashf(const char *name, int len, int hashsize);
extern HASHNODE *cpp_lookup(const char *name, int len, int hash);
extern void     delete_macro(HASHNODE * hp);
extern HASHNODE *install(const char *name, int len, enum node_type type,
                         int ivalue, char *value, int hash);
extern void     cpp_hash_cleanup(cpp_reader * pfile);