libcpp/include/symtab.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001, 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify it
   5 under the terms of the GNU General Public License as published by the
   6 Free Software Foundation; either version 2, or (at your option) any
   7 later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  17
  18 #ifndef LIBCPP_SYMTAB_H
  19 #define LIBCPP_SYMTAB_H
  20
  21 #include "obstack.h"
  22 #ifndef GTY
  23 #define GTY(x) /* nothing */
  24 #endif
  25
  26 /* This is what each hash table entry points to.  It may be embedded
  27    deeply within another object.  */
  28 typedef struct ht_identifier ht_identifier;
  29 struct ht_identifier GTY(())
  30 {
  31   const unsigned char *str;
  32   unsigned int len;
  33   unsigned int hash_value;
  34 };
  35
  36 #define HT_LEN(NODE) ((NODE)->len)
  37 #define HT_STR(NODE) ((NODE)->str)
  38
  39 typedef struct ht hash_table;
  40 typedef struct ht_identifier *hashnode;
  41
  42 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
  43
  44 /* An identifier hash table for cpplib and the front ends.  */
  45 struct ht
  46 {
  47   /* Identifiers are allocated from here.  */
  48   struct obstack stack;
  49
  50   hashnode *entries;
  51   /* Call back, allocate a node.  */
  52   hashnode (*alloc_node) (hash_table *);
  53   /* Call back, allocate something that hangs off a node like a cpp_macro.
  54      NULL means use the usual allocator.  */
  55   void * (*alloc_subobject) (size_t);
  56
  57   unsigned int nslots;          /* Total slots in the entries array.  */
  58   unsigned int nelements;       /* Number of live elements.  */
  59
  60   /* Link to reader, if any.  For the benefit of cpplib.  */
  61   struct cpp_reader *pfile;
  62
  63   /* Table usage statistics.  */
  64   unsigned int searches;
  65   unsigned int collisions;
  66
  67   /* Should 'entries' be freed when it is no longer needed?  */
  68   bool entries_owned;
  69 };
  70
  71 /* Initialize the hashtable with 2 ^ order entries.  */
  72 extern hash_table *ht_create (unsigned int order);
  73
  74 /* Frees all memory associated with a hash table.  */
  75 extern void ht_destroy (hash_table *);
  76
  77 extern hashnode ht_lookup (hash_table *, const unsigned char *,
  78                            size_t, enum ht_lookup_option);
  79 extern hashnode ht_lookup_with_hash (hash_table *, const unsigned char *,
  80                                      size_t, unsigned int,
  81                                      enum ht_lookup_option);
  82 #define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
  83 #define HT_HASHFINISH(r, len) ((r) + (len))
  84
  85 /* For all nodes in TABLE, make a callback.  The callback takes
  86    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  87    if the callback returns zero.  */
  88 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  89 extern void ht_forall (hash_table *, ht_cb, const void *);
  90
  91 /* For all nodes in TABLE, call the callback.  If the callback returns
  92    a nonzero value, the node is removed from the table.  */
  93 extern void ht_purge (hash_table *, ht_cb, const void *);
  94
  95 /* Restore the hash table.  */
  96 extern void ht_load (hash_table *ht, hashnode *entries,
  97                      unsigned int nslots, unsigned int nelements, bool own);
  98
  99 /* Dump allocation statistics to stderr.  */
 100 extern void ht_dump_statistics (hash_table *);
 101
 102 #endif /* LIBCPP_SYMTAB_H */