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/* Hash tables.

   Copyright (C) 2000, 2001, 2003, 2004, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by the

Free Software Foundation; either version 3, or (at your option) any

later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

#ifndef LIBCPP_SYMTAB_H

#define LIBCPP_SYMTAB_H

#include "obstack.h"

#ifndef GTY

#define GTY(x) /* nothing */

#endif

/* This is what each hash table entry points to.  It may be embedded

   deeply within another object.  */

typedef struct ht_identifier ht_identifier;

typedef struct ht_identifier *ht_identifier_ptr;

struct GTY(()) ht_identifier {

  const unsigned char *str;

  unsigned int len;

  unsigned int hash_value;

};

#define HT_LEN(NODE) ((NODE)->len)

#define HT_STR(NODE) ((NODE)->str)

typedef struct ht cpp_hash_table;

typedef struct ht_identifier *hashnode;

enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};

/* An identifier hash table for cpplib and the front ends.  */

struct ht

{

  /* Identifiers are allocated from here.  */

  struct obstack stack;

  hashnode *entries;

  /* Call back, allocate a node.  */

  hashnode (*alloc_node) (cpp_hash_table *);

  /* Call back, allocate something that hangs off a node like a cpp_macro.

     NULL means use the usual allocator.  */

  void * (*alloc_subobject) (size_t);

  unsigned int nslots;          /* Total slots in the entries array.  */

  unsigned int nelements;       /* Number of live elements.  */

  /* Link to reader, if any.  For the benefit of cpplib.  */

  struct cpp_reader *pfile;

  /* Table usage statistics.  */

  unsigned int searches;

  unsigned int collisions;

  /* Should 'entries' be freed when it is no longer needed?  */

  bool entries_owned;

};

/* Initialize the hashtable with 2 ^ order entries.  */

extern cpp_hash_table *ht_create (unsigned int order);

/* Frees all memory associated with a hash table.  */

extern void ht_destroy (cpp_hash_table *);

extern hashnode ht_lookup (cpp_hash_table *, const unsigned char *,

                           size_t, enum ht_lookup_option);

extern hashnode ht_lookup_with_hash (cpp_hash_table *, const unsigned char *,

                                     size_t, unsigned int,

                                     enum ht_lookup_option);

#define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));

#define HT_HASHFINISH(r, len) ((r) + (len))

/* For all nodes in TABLE, make a callback.  The callback takes

   TABLE->PFILE, the node, and a PTR, and the callback sequence stops

   if the callback returns zero.  */

typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);

extern void ht_forall (cpp_hash_table *, ht_cb, const void *);

/* For all nodes in TABLE, call the callback.  If the callback returns

   a nonzero value, the node is removed from the table.  */

extern void ht_purge (cpp_hash_table *, ht_cb, const void *);

/* Restore the hash table.  */

extern void ht_load (cpp_hash_table *ht, hashnode *entries,

                     unsigned int nslots, unsigned int nelements, bool own);

/* Dump allocation statistics to stderr.  */

extern void ht_dump_statistics (cpp_hash_table *);

#endif /* LIBCPP_SYMTAB_H */