libcpp/include/symtab.h

   1 /* Hash tables.
   2    Copyright (C) 2000-2018 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 3, 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; see the file COPYING3.  If not see
  16 <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef LIBCPP_SYMTAB_H
  19 #define LIBCPP_SYMTAB_H
  20
  21 #include "obstack.h"
  22
  23 #ifndef GTY
  24 #define GTY(x) /* nothing */
  25 #endif
  26
  27 /* This is what each hash table entry points to.  It may be embedded
  28    deeply within another object.  */
  29 typedef struct ht_identifier ht_identifier;
  30 typedef struct ht_identifier *ht_identifier_ptr;
  31 struct GTY(()) ht_identifier {
  32   const unsigned char *str;
  33   unsigned int len;
  34   unsigned int hash_value;
  35 };
  36
  37 #define HT_LEN(NODE) ((NODE)->len)
  38 #define HT_STR(NODE) ((NODE)->str)
  39
  40 typedef struct ht cpp_hash_table;
  41 typedef struct ht_identifier *hashnode;
  42
  43 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
  44
  45 /* An identifier hash table for cpplib and the front ends.  */
  46 struct ht
  47 {
  48   /* Identifiers are allocated from here.  */
  49   struct obstack stack;
  50
  51   hashnode *entries;
  52   /* Call back, allocate a node.  */
  53   hashnode (*alloc_node) (cpp_hash_table *);
  54   /* Call back, allocate something that hangs off a node like a cpp_macro.
  55      NULL means use the usual allocator.  */
  56   void * (*alloc_subobject) (size_t);
  57
  58   unsigned int nslots;          /* Total slots in the entries array.  */
  59   unsigned int nelements;       /* Number of live elements.  */
  60
  61   /* Link to reader, if any.  For the benefit of cpplib.  */
  62   struct cpp_reader *pfile;
  63
  64   /* Table usage statistics.  */
  65   unsigned int searches;
  66   unsigned int collisions;
  67
  68   /* Should 'entries' be freed when it is no longer needed?  */
  69   bool entries_owned;
  70 };
  71
  72 /* Initialize the hashtable with 2 ^ order entries.  */
  73 extern cpp_hash_table *ht_create (unsigned int order);
  74
  75 /* Frees all memory associated with a hash table.  */
  76 extern void ht_destroy (cpp_hash_table *);
  77
  78 extern hashnode ht_lookup (cpp_hash_table *, const unsigned char *,
  79                            size_t, enum ht_lookup_option);
  80 extern hashnode ht_lookup_with_hash (cpp_hash_table *, const unsigned char *,
  81                                      size_t, unsigned int,
  82                                      enum ht_lookup_option);
  83 #define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
  84 #define HT_HASHFINISH(r, len) ((r) + (len))
  85
  86 /* For all nodes in TABLE, make a callback.  The callback takes
  87    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  88    if the callback returns zero.  */
  89 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  90 extern void ht_forall (cpp_hash_table *, ht_cb, const void *);
  91
  92 /* For all nodes in TABLE, call the callback.  If the callback returns
  93    a nonzero value, the node is removed from the table.  */
  94 extern void ht_purge (cpp_hash_table *, ht_cb, const void *);
  95
  96 /* Restore the hash table.  */
  97 extern void ht_load (cpp_hash_table *ht, hashnode *entries,
  98                      unsigned int nslots, unsigned int nelements, bool own);
  99
 100 /* Dump allocation statistics to stderr.  */
 101 extern void ht_dump_statistics (cpp_hash_table *);
 102
 103 #endif /* LIBCPP_SYMTAB_H */