gcc/hashtable.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001 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 GCC_HASHTABLE_H
  19 #define GCC_HASHTABLE_H
  20
  21 #include "obstack.h"
  22
  23 /* This is what each hash table entry points to.  It may be embedded
  24    deeply within another object.  */
  25 typedef struct ht_identifier ht_identifier;
  26 struct ht_identifier
  27 {
  28   unsigned int len;
  29   const unsigned char *str;
  30 };
  31
  32 #define HT_LEN(NODE) ((NODE)->len)
  33 #define HT_STR(NODE) ((NODE)->str)
  34
  35 /* We want code outside cpplib, such as the compiler front-ends, to be
  36    able to include this header, and to be able to link with
  37    cpphashtbl.o without pulling in any other parts of cpplib.  */
  38
  39 struct cpp_reader;
  40 typedef struct ht hash_table;
  41 typedef struct ht_identifier *hashnode;
  42
  43 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC, HT_ALLOCED};
  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.  */
  53   hashnode (*alloc_node) PARAMS ((hash_table *));
  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
  66 extern void gcc_obstack_init PARAMS ((struct obstack *));
  67 /* Initialise the hashtable with 2 ^ order entries.  */
  68 extern hash_table *ht_create PARAMS ((unsigned int order));
  69 extern hashnode ht_lookup PARAMS ((hash_table *, const unsigned char *,
  70                                    unsigned int, enum ht_lookup_option));
  71
  72 /* For all nodes in TABLE, make a callback.  The callback takes
  73    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  74    if the callback returns zero.  */
  75 typedef int (*ht_cb) PARAMS ((struct cpp_reader *, hashnode, const void *));
  76 extern void ht_forall PARAMS ((hash_table *, ht_cb, const void *));
  77
  78 /* Dump allocation statistics to stderr.  */
  79 extern void ht_dump_statistics PARAMS ((hash_table *));
  80
  81 /* Approximate positive square root of a host double.  This is for
  82    statistical reports, not code generation.  */
  83 extern double approx_sqrt PARAMS ((double));
  84
  85 #endif /* GCC_HASHTABLE_H */