libcpp/include/symtab.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001, 2003, 2004, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or modify it
   6 under the terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 3, or (at your option) any
   8 later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; see the file COPYING3.  If not see
  17 <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef LIBCPP_SYMTAB_H
  20 #define LIBCPP_SYMTAB_H
  21
  22 #include "obstack.h"
  23
  24 #ifndef GTY
  25 #define GTY(x) /* nothing */
  26 #endif
  27
  28 /* This is what each hash table entry points to.  It may be embedded
  29    deeply within another object.  */
  30 typedef struct ht_identifier ht_identifier;
  31 typedef struct ht_identifier *ht_identifier_ptr;
  32 struct GTY(()) ht_identifier {
  33   const unsigned char *str;
  34   unsigned int len;
  35   unsigned int hash_value;
  36 };
  37
  38 #define HT_LEN(NODE) ((NODE)->len)
  39 #define HT_STR(NODE) ((NODE)->str)
  40
  41 typedef struct ht cpp_hash_table;
  42 typedef struct ht_identifier *hashnode;
  43
  44 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
  45
  46 /* An identifier hash table for cpplib and the front ends.  */
  47 struct ht
  48 {
  49   /* Identifiers are allocated from here.  */
  50   struct obstack stack;
  51
  52   hashnode *entries;
  53   /* Call back, allocate a node.  */
  54   hashnode (*alloc_node) (cpp_hash_table *);
  55   /* Call back, allocate something that hangs off a node like a cpp_macro.
  56      NULL means use the usual allocator.  */
  57   void * (*alloc_subobject) (size_t);
  58
  59   unsigned int nslots;          /* Total slots in the entries array.  */
  60   unsigned int nelements;       /* Number of live elements.  */
  61
  62   /* Link to reader, if any.  For the benefit of cpplib.  */
  63   struct cpp_reader *pfile;
  64
  65   /* Table usage statistics.  */
  66   unsigned int searches;
  67   unsigned int collisions;
  68
  69   /* Should 'entries' be freed when it is no longer needed?  */
  70   bool entries_owned;
  71 };
  72
  73 /* Initialize the hashtable with 2 ^ order entries.  */
  74 extern cpp_hash_table *ht_create (unsigned int order);
  75
  76 /* Frees all memory associated with a hash table.  */
  77 extern void ht_destroy (cpp_hash_table *);
  78
  79 extern hashnode ht_lookup (cpp_hash_table *, const unsigned char *,
  80                            size_t, enum ht_lookup_option);
  81 extern hashnode ht_lookup_with_hash (cpp_hash_table *, const unsigned char *,
  82                                      size_t, unsigned int,
  83                                      enum ht_lookup_option);
  84 #define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
  85 #define HT_HASHFINISH(r, len) ((r) + (len))
  86
  87 /* For all nodes in TABLE, make a callback.  The callback takes
  88    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  89    if the callback returns zero.  */
  90 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  91 extern void ht_forall (cpp_hash_table *, ht_cb, const void *);
  92
  93 /* For all nodes in TABLE, call the callback.  If the callback returns
  94    a nonzero value, the node is removed from the table.  */
  95 extern void ht_purge (cpp_hash_table *, ht_cb, const void *);
  96
  97 /* Restore the hash table.  */
  98 extern void ht_load (cpp_hash_table *ht, hashnode *entries,
  99                      unsigned int nslots, unsigned int nelements, bool own);
 100
 101 /* Dump allocation statistics to stderr.  */
 102 extern void ht_dump_statistics (cpp_hash_table *);
 103
 104 #endif /* LIBCPP_SYMTAB_H */