aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.9/gcc/pointer-set.h
blob: a426534ac441b7da2581438aeb88a324dc165308 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/* Set operations on pointers
   Copyright (C) 2004-2014 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#ifndef POINTER_SET_H
#define POINTER_SET_H


/* A pointer set is represented as a simple open-addressing hash
   table.  Simplifications: The hash code is based on the value of the
   pointer, not what it points to.  The number of buckets is always a
   power of 2.  Null pointers are a reserved value.  Deletion is not
   supported (yet).  There is no mechanism for user control of hash
   function, equality comparison, initial size, or resizing policy.  */

struct pointer_set_t
{
  size_t log_slots;
  size_t n_slots;		/* n_slots = 2^log_slots */
  size_t n_elements;
  const void **slots;
};

struct pointer_set_t *pointer_set_create (void);
void pointer_set_destroy (struct pointer_set_t *pset);
int pointer_set_contains (const struct pointer_set_t *pset, const void *p);
int pointer_set_insert (struct pointer_set_t *pset, const void *p);
void pointer_set_traverse (const struct pointer_set_t *,
			   bool (*) (const void *, void *),
			   void *);
bool pointer_set_lookup (const pointer_set_t *, const void *, size_t *);

/* A pointer map is represented the same way as a pointer_set, so
   the hash code is based on the address of the key, rather than
   its contents.  Null keys are a reserved value.  Deletion is not
   supported (yet).  There is no mechanism for user control of hash
   function, equality comparison, initial size, or resizing policy.  */

template <typename T>
class pointer_map : protected pointer_set_t
{
  T *values;

public:
  pointer_map ();
  ~pointer_map ();
  T *contains (const void *p);
  T *insert (const void *p, bool *existed_p = NULL);
  void traverse (bool (*fn) (const void *, T *, void *), void *data);
};

/* Allocate an empty pointer map.  */
template <typename T>
pointer_map<T>::pointer_map (void)
{
  n_elements = 0;
  log_slots = 8;
  n_slots = (size_t) 1 << log_slots;

  slots = XCNEWVEC (const void *, n_slots);
  values = XNEWVEC (T, n_slots);
}

/* Reclaims all memory associated with PMAP.  */
template <typename T>
pointer_map<T>::~pointer_map (void)
{
  XDELETEVEC (slots);
  XDELETEVEC (values);
}

/* Returns a pointer to the value to which P maps, if PMAP contains P.  P
   must be nonnull.  Return NULL if PMAP does not contain P.

   Collisions are resolved by linear probing.  */
template <typename T>
T *
pointer_map<T>::contains (const void *p)
{
  size_t n;
  if (!pointer_set_lookup (this, p, &n))
    return NULL;
  return &values[n];
}

/* Inserts P into PMAP if it wasn't already there.  Returns a pointer
   to the value.  P must be nonnull.  */
template <typename T>
T *
pointer_map<T>::insert (const void *p, bool *existed_p)
{
  size_t n;

  /* For simplicity, expand the map even if P is already there.  This can be
     superfluous but can happen at most once.  */
  /* ???  Fugly that we have to inline that here.  */
  if (n_elements > n_slots / 4)
    {
      size_t old_n_slots = n_slots;
      const void **old_keys = slots;
      T *old_values = values;
      log_slots = log_slots + 1;
      n_slots = n_slots * 2;
      slots = XCNEWVEC (const void *, n_slots);
      values = XNEWVEC (T, n_slots);
      for (size_t i = 0; i < old_n_slots; ++i)
	if (old_keys[i])
	  {
	    const void *key = old_keys[i];
	    pointer_set_lookup (this, key, &n);
	    slots[n] = key;
	    values[n] = old_values[i];
	  }
      XDELETEVEC (old_keys);
      XDELETEVEC (old_values);
    }

  if (!pointer_set_lookup (this, p, &n))
    {
      ++n_elements;
      slots[n] = p;
      if (existed_p)
	*existed_p = false;
    }
  else if (existed_p)
    *existed_p = true;

  return &values[n];
}

/* Pass each pointer in PMAP to the function in FN, together with the pointer
   to the value and the fixed parameter DATA.  If FN returns false, the
   iteration stops.  */

template <class T>
void
pointer_map<T>::traverse (bool (*fn) (const void *, T *, void *), void *data)
{
  for (size_t i = 0; i < n_slots; ++i)
    if (slots[i] && !fn (slots[i], &values[i], data))
      break;
}


struct pointer_map_t;
pointer_map_t *pointer_map_create (void);
void pointer_map_destroy (pointer_map_t *pmap);

void **pointer_map_contains (const pointer_map_t *pmap, const void *p);
void **pointer_map_insert (pointer_map_t *pmap, const void *p);
void pointer_map_traverse (const pointer_map_t *,
			   bool (*) (const void *, void **, void *), void *);


#endif  /* POINTER_SET_H  */