iframe-proxy | Sunbelt Computer Software

History

204 lines (150 loc) · 7.1 KB

Raw

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

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

/* An expandable hash tables datatype.

Contributed by Vladimir Makarov (vmakarov@cygnus.com).

This program 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 2 of the License, or

(at your option) any later version.

This program 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 this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */

/* This package implements basic hash table functionality. It is possible

to search for an entry, create an entry and destroy an entry.

Elements in the table are generic pointers.

The size of the table is not fixed; if the occupancy of the table

grows too high the hash table will be expanded.

The abstract data implementation is based on generalized Algorithm D

from Knuth's book "The art of computer programming". Hash table is

expanded by creation of new hash table and transferring elements from

the old table to the new table. */

#ifndef __HASHTAB_H__

#define __HASHTAB_H__

#ifdef __cplusplus

extern "C" {

#endif /* __cplusplus */

#include "ansidecl.h"

/* The type for a hash code. */

typedef unsigned int hashval_t;

/* Callback function pointer types. */

/* Calculate hash of a table entry. */

typedef hashval_t (*htab_hash) (const void *);

/* Compare a table entry with a possible entry. The entry already in

the table always comes first, so the second element can be of a

different type (but in this case htab_find and htab_find_slot

cannot be used; instead the variants that accept a hash value

must be used). */

typedef int (*htab_eq) (const void *, const void *);

/* Cleanup function called whenever a live element is removed from

the hash table. */

typedef void (*htab_del) (void *);

/* Function called by htab_traverse for each live element. The first

arg is the slot of the element (which can be passed to htab_clear_slot

if desired), the second arg is the auxiliary pointer handed to

htab_traverse. Return 1 to continue scan, 0 to stop. */

typedef int (*htab_trav) (void **, void *);

/* Memory-allocation function, with the same functionality as calloc().

Iff it returns NULL, the hash table implementation will pass an error

code back to the user, so if your code doesn't handle errors,

best if you use xcalloc instead. */

typedef void *(*htab_alloc) (size_t, size_t);

/* We also need a free() routine. */

typedef void (*htab_free) (void *);

/* Memory allocation and deallocation; variants which take an extra

argument. */

typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t);

typedef void (*htab_free_with_arg) (void *, void *);

/* This macro defines reserved value for empty table entry. */

#define HTAB_EMPTY_ENTRY ((PTR) 0)

/* This macro defines reserved value for table entry which contained

a deleted element. */

#define HTAB_DELETED_ENTRY ((PTR) 1)

/* Hash tables are of the following type. The structure

(implementation) of this type is not needed for using the hash

tables. All work with hash table should be executed only through

functions mentioned below. The size of this structure is subject to

change. */

struct htab {

/* Pointer to hash function. */

htab_hash hash_f;

/* Pointer to comparison function. */

htab_eq eq_f;

/* Pointer to cleanup function. */

htab_del del_f;

/* Table itself. */

void **entries;

/* Current size (in entries) of the hash table. */

size_t size;

/* Current number of elements including also deleted elements. */

size_t n_elements;

/* Current number of deleted elements in the table. */

size_t n_deleted;

/* The following member is used for debugging. Its value is number

of all calls of `htab_find_slot' for the hash table. */

unsigned int searches;

/* The following member is used for debugging. Its value is number

of collisions fixed for time of work with the hash table. */

unsigned int collisions;

/* Pointers to allocate/free functions. */

htab_alloc alloc_f;

htab_free free_f;

/* Alternate allocate/free functions, which take an extra argument. */

void *alloc_arg;

htab_alloc_with_arg alloc_with_arg_f;

htab_free_with_arg free_with_arg_f;

/* Current size (in entries) of the hash table, as an index into the

table of primes. */

unsigned int size_prime_index;

};

typedef struct htab *htab_t;

/* An enum saying whether we insert into the hash table or not. */

enum insert_option {NO_INSERT, INSERT};

/* The prototypes of the package functions. */

extern htab_t htab_create_alloc (size_t, htab_hash,

htab_eq, htab_del,

htab_alloc, htab_free);

extern htab_t htab_create_alloc_ex (size_t, htab_hash,

htab_eq, htab_del,

void *, htab_alloc_with_arg,

htab_free_with_arg);

extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del,

htab_alloc, htab_alloc, htab_free);

/* Backward-compatibility functions. */

extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del);

extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del);

extern void htab_set_functions_ex (htab_t, htab_hash,

htab_eq, htab_del,

void *, htab_alloc_with_arg,

htab_free_with_arg);

extern void htab_delete (htab_t);

extern void htab_empty (htab_t);

extern void * htab_find (htab_t, const void *);

extern void ** htab_find_slot (htab_t, const void *, enum insert_option);

extern void * htab_find_with_hash (htab_t, const void *, hashval_t);

extern void ** htab_find_slot_with_hash (htab_t, const void *,

hashval_t, enum insert_option);

extern void htab_clear_slot (htab_t, void **);

extern void htab_remove_elt (htab_t, void *);

extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t);

extern void htab_traverse (htab_t, htab_trav, void *);

extern void htab_traverse_noresize (htab_t, htab_trav, void *);

extern size_t htab_size (htab_t);

extern size_t htab_elements (htab_t);

extern double htab_collisions (htab_t);

/* A hash function for pointers. */

extern htab_hash htab_hash_pointer;

/* An equality function for pointers. */

extern htab_eq htab_eq_pointer;

/* A hash function for null-terminated strings. */

extern hashval_t htab_hash_string (const void *);

/* An iterative hash function for arbitrary data. */

extern hashval_t iterative_hash (const void *, size_t, hashval_t);

/* Shorthand for hashing something with an intrinsic size. */

#define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)

#ifdef __cplusplus

}

#endif /* __cplusplus */

#endif /* __HASHTAB_H */

Sunbelt Computer Software

PL/B Language Development and Support

Navigation Menu

Uh oh!

Sunbelt Computer Software

PL/B Language Development and Support

Uh oh!

FilesExpand file tree

hashtab.h

Latest commit

History

hashtab.h

File metadata and controls