libcpp/include/symtab.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001, 2003, 2004, 2007, 2008, 2009
   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 #ifdef __cplusplus
  25 extern "C" {
  26 #endif
  27
  28 #ifndef GTY
  29 #define GTY(x) /* nothing */
  30 #endif
  31
  32 /* This is what each hash table entry points to.  It may be embedded
  33    deeply within another object.  */
  34 typedef struct ht_identifier ht_identifier;
  35 struct GTY(()) ht_identifier {
  36   const unsigned char *str;
  37   unsigned int len;
  38   unsigned int hash_value;
  39 };
  40
  41 #define HT_LEN(NODE) ((NODE)->len)
  42 #define HT_STR(NODE) ((NODE)->str)
  43
  44 typedef struct ht hash_table;
  45 typedef struct ht_identifier *hashnode;
  46
  47 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
  48
  49 /* An identifier hash table for cpplib and the front ends.  */
  50 struct ht
  51 {
  52   /* Identifiers are allocated from here.  */
  53   struct obstack stack;
  54
  55   hashnode *entries;
  56   /* Call back, allocate a node.  */
  57   hashnode (*alloc_node) (hash_table *);
  58   /* Call back, allocate something that hangs off a node like a cpp_macro.
  59      NULL means use the usual allocator.  */
  60   void * (*alloc_subobject) (size_t);
  61
  62   unsigned int nslots;          /* Total slots in the entries array.  */
  63   unsigned int nelements;       /* Number of live elements.  */
  64
  65   /* Link to reader, if any.  For the benefit of cpplib.  */
  66   struct cpp_reader *pfile;
  67
  68   /* Table usage statistics.  */
  69   unsigned int searches;
  70   unsigned int collisions;
  71
  72   /* Should 'entries' be freed when it is no longer needed?  */
  73   bool entries_owned;
  74 };
  75
  76 /* Initialize the hashtable with 2 ^ order entries.  */
  77 extern hash_table *ht_create (unsigned int order);
  78
  79 /* Frees all memory associated with a hash table.  */
  80 extern void ht_destroy (hash_table *);
  81
  82 extern hashnode ht_lookup (hash_table *, const unsigned char *,
  83                            size_t, enum ht_lookup_option);
  84 extern hashnode ht_lookup_with_hash (hash_table *, const unsigned char *,
  85                                      size_t, unsigned int,
  86                                      enum ht_lookup_option);
  87 #define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
  88 #define HT_HASHFINISH(r, len) ((r) + (len))
  89
  90 /* For all nodes in TABLE, make a callback.  The callback takes
  91    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  92    if the callback returns zero.  */
  93 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  94 extern void ht_forall (hash_table *, ht_cb, const void *);
  95
  96 /* For all nodes in TABLE, call the callback.  If the callback returns
  97    a nonzero value, the node is removed from the table.  */
  98 extern void ht_purge (hash_table *, ht_cb, const void *);
  99
 100 /* Restore the hash table.  */
 101 extern void ht_load (hash_table *ht, hashnode *entries,
 102                      unsigned int nslots, unsigned int nelements, bool own);
 103
 104 /* Dump allocation statistics to stderr.  */
 105 extern void ht_dump_statistics (hash_table *);
 106
 107 #ifdef __cplusplus
 108 }
 109 #endif
 110
 111 #endif /* LIBCPP_SYMTAB_H */