libcpp/include/symtab.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001, 2003, 2004 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #ifndef LIBCPP_SYMTAB_H
  19 #define LIBCPP_SYMTAB_H
  20
  21 #include "obstack.h"
  22 #define GTY(x) /* nothing */
  23
  24 /* This is what each hash table entry points to.  It may be embedded
  25    deeply within another object.  */
  26 typedef struct ht_identifier ht_identifier;
  27 struct ht_identifier GTY(())
  28 {
  29   const unsigned char *str;
  30   unsigned int len;
  31   unsigned int hash_value;
  32 };
  33
  34 #define HT_LEN(NODE) ((NODE)->len)
  35 #define HT_STR(NODE) ((NODE)->str)
  36
  37 typedef struct ht hash_table;
  38 typedef struct ht_identifier *hashnode;
  39
  40 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC, HT_ALLOCED};
  41
  42 /* An identifier hash table for cpplib and the front ends.  */
  43 struct ht
  44 {
  45   /* Identifiers are allocated from here.  */
  46   struct obstack stack;
  47
  48   hashnode *entries;
  49   /* Call back, allocate a node.  */
  50   hashnode (*alloc_node) (hash_table *);
  51   /* Call back, allocate something that hangs off a node like a cpp_macro.
  52      NULL means use the usual allocator.  */
  53   void * (*alloc_subobject) (size_t);
  54
  55   unsigned int nslots;          /* Total slots in the entries array.  */
  56   unsigned int nelements;       /* Number of live elements.  */
  57
  58   /* Link to reader, if any.  For the benefit of cpplib.  */
  59   struct cpp_reader *pfile;
  60
  61   /* Table usage statistics.  */
  62   unsigned int searches;
  63   unsigned int collisions;
  64
  65   /* Should 'entries' be freed when it is no longer needed?  */
  66   bool entries_owned;
  67 };
  68
  69 /* Initialize the hashtable with 2 ^ order entries.  */
  70 extern hash_table *ht_create (unsigned int order);
  71
  72 /* Frees all memory associated with a hash table.  */
  73 extern void ht_destroy (hash_table *);
  74
  75 extern hashnode ht_lookup (hash_table *, const unsigned char *,
  76                            size_t, enum ht_lookup_option);
  77 extern hashnode ht_lookup_with_hash (hash_table *, const unsigned char *,
  78                                      size_t, unsigned int,
  79                                      enum ht_lookup_option);
  80 #define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
  81 #define HT_HASHFINISH(r, len) ((r) + (len))
  82
  83 /* For all nodes in TABLE, make a callback.  The callback takes
  84    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  85    if the callback returns zero.  */
  86 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  87 extern void ht_forall (hash_table *, ht_cb, const void *);
  88
  89 /* Restore the hash table.  */
  90 extern void ht_load (hash_table *ht, hashnode *entries,
  91                      unsigned int nslots, unsigned int nelements, bool own);
  92
  93 /* Dump allocation statistics to stderr.  */
  94 extern void ht_dump_statistics (hash_table *);
  95
  96 #endif /* LIBCPP_SYMTAB_H */