File: hash.h

package info (click to toggle)
mcl 1%3A14-137-1
  • links: PTS, VCS
  • area: main
  • in suites: jessie, jessie-kfreebsd, stretch
  • size: 10,704 kB
  • ctags: 5,125
  • sloc: ansic: 53,217; sh: 4,448; perl: 3,967; makefile: 422
file content (395 lines) | stat: -rw-r--r-- 10,871 bytes parent folder | download | duplicates (9)
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
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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
/*   (C) Copyright 2001, 2002, 2003, 2004, 2005 Stijn van Dongen
 *   (C) Copyright 2006, 2007, 2008, 2009  Stijn van Dongen
 *
 * This file is part of tingea.  You can redistribute and/or modify tingea
 * under the terms of the GNU General Public License; either version 3 of the
 * License or (at your option) any later version.  You should have received a
 * copy of the GPL along with tingea, in the file COPYING.
*/

#ifndef tingea_hash_h
#define tingea_hash_h

#include <stdio.h>

/* TODO:
 * -  make sort routines for keys and values by key or value criteria.
 * -  make interface for storing integers, preferably without objectifying them.
 * -  shrink hashes dynamically.
 *
*/


/*  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * *
 **            Implementation notes (a few).
 *
 *
 *    This hash interface is very powerful. It gives you more than enough
 *    rope to hang yourself and then some. It can be used as is, or wrappers
 *    can be made around it that restrict a caller's ability to err.
 *
 *    The danger lies in the fact that this interface only does retrieval
 *    and storage of pointers (both for keys and values), and does not clone
 *    anything. Anything happening with the objects pointed to during the
 *    lifetime of the hash is the responsibility of the caller.
 *
 *    What the interface cannot do currently is hash integers by value (rather
 *    than by reference). This functionality will probably be added someday.

 * Features:
 *    o  Searching, inserting, and deletion are all done by
 *       mcxHashSearch. It returns a pointer to mcxKV. In all modes, the
 *       caller can use the returned mcxKV* structure to obtain
 *       the 'val' and 'key' members.
 *
 *    o  Hashes grow automatically once the average load per bucket
 *       exceeds a settable threshold and if the hash was not declared
 *       constant.
 *
 *    o  Caller supplies both the hash function and the compare function.
 *       This interface provides several hash functions operating on a
 *       (void* base, int len) combo, where base is cast to char by the
 *       hash function. These functions can be used in creating custom hash
 *       functions for your custom objects.
 *
 *    o  You can (of course) have multiple hashes. This is not really
 *       a feature - however, since the idiotic <hsearch.h> does not offer
 *       this I thought I'd mention it.
 *
 *    o  Witness mcxHashWalkInit, mcxHashWalkStep.
 * 
 *    o  There is mcxHashMerge.
 *
 *    o  mcxHashKeys, mcxHashKVs.
 *
 *    Enjoy.

 * Notes
 *    There is a utility hashfile.c (distributed in a separate package)
 *    that can be used to stress-test this module. It allows customization
 *    of several aspects, including the hash function that should be used.
*/

#include "types.h"
#include "list.h"


/* The hash struct is hidden. Use mcxHashGetSettings if you need
 * to peek into the interior. Or read hash.c
*/

typedef struct mcxHash mcxHash;


typedef struct
{  void*       key
;  void*       val
;
}  mcxKV       ;


mcxHash* mcxHashNew
(  dim         n_buckets
,  u32         (*hash)  (const void *a)
,  int         (*cmp)   (const void *a, const void *b)
)  ;


#define MCX_HASH_OPT_DEFAULTS    0
#define MCX_HASH_OPT_CONSTANT    1
#define MCX_HASH_OPT_UNUSED      2


void mcxHashSetOpts
(  mcxHash*    hash
,  double      load
,  int         option      /* negative values will be ignored (feature) */
)  ;

dim mcxHashMemSize
(  mcxHash*    hash
)  ;


typedef struct mcxHashSettings
{  dim         n_buckets
;  dim         n_entries
;  float       load
;  mcxbits     options
;  
}  mcxHashSettings   ;


void mcxHashGetSettings
(  mcxHash*          hash
,  mcxHashSettings*  settings
)  ;


/*  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * *
 **            mcxHashSearch
 *
 *    action               returns
 *
 *    MCX_DATUM_DELETE   ->    deleted mcxKV* or NULL if not present
 *    MCX_DATUM_INSERT   ->    new or present mcxKV*
 *    MCX_DATUM_FIND     ->    mcxKV* if present NULL otherwise.
 * 
 * usage:
 *
 *    Values have to be inserted by the caller into the returned KV struct.
 *    Make sure that keys point to objects that are constant
 *    (with respect to the cmp function) during the lifetime of the hash.
 *    YOU have to ensure the integrity of both keys and values.
 *    This enables you to do whatever suits you, such as appending to
 *    values.
 *
 *    When inserting, check whether kv->key != key (where kv is returned value)
 *    if this is the case, an identically comparing key is already present.
 *    You may want to destroy one of the two keys and decide what to do
 *    with the value.
 *
 *    When deleting, the key-value pair is removed from the hash *AND RETURNED
 *    TO CALLER* - you have to decide yourself what to do with it.  You have to
 *    fetch the val and key members of the returned mcxKV object immediately:
 *    Subsequent inserts in the hash may reuse it.  If the key was not present,
 *    a value of NULL is returned.
 *
 *    When finding, life is simple. NULL if absent, matching kv otherwise.
 *
 * note:
 *
 *    memory management of keys and values is totally up to caller.
 *    If usage is clean, you can use mcxHashFree for disposal of hash.
*/

#define mcxHashSearch(key, hash, ACTION)  mcxHashSearchx(key, hash, ACTION, NULL)

mcxKV*   mcxHashSearchx
(  void*       key
,  mcxHash*    hash
,  mcxmode     ACTION
,  int*        delta
)  ;



/*  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * *
 **            mcxHashMerge
 *
 *    this one COPIES OBJECT POINTERS and DOES NOT CLONE.
 *    so after the merge, hash1 and hash2 keys and values should not be freed.
 *    In case there are equivalent keys in hash1 and hash2, this may
 *    cause trouble when the caller wants to do cleaning afterwards.
 *    This interface is still under development.
 *
 *    hashd may be equal to hash1 or hash2, and it may also be NULL.
*/

mcxHash* mcxHashMerge
(  mcxHash*    hash1
,  mcxHash*    hash2
,  mcxHash*    hashd
,  void*       merge(void* val1, void* val2)
)  ;


/*  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * *
 **            mcxHashFree
 *
 *    This only works if all keys are of the same type and/or all values
 *    are of the same type, and if your objects were created as expected by
 *    the free routines (presumably malloced heap memory) - be careful with
 *    constant objects like constant strings.
 *
 *    freekey and freeval may not free their argument. This is because
 *    tingea does not allow routines that leave arguments in an
 *    inconsistent state, and free routines in tingea generally accept
 *    an argument of the form <type>** pptr.
 *    In the case of mcxHashFree this means that the interface may
 *    feel slighly more cumbersome.
 *    A way out would have been to make the callbacks of signature
 *
 *          void freemem(void** mempp)
 * 
 *    The caller could access *mempp, cast it to the expected type,
 *    and later set *mempp to NULL. However, this would require
 *    new free routines for lots of types. With the current interface
 *    existing <type>Release routines can be used:
 *
 *    The type of free routine expected by mcxHashFree is generally
 *    called <type>Release or <type>Release_v, e.g. mcxTingRelease.
 *    Release routines release all memory of a composite object except the
 *    memory which holds the outer struct.
 *
 *    If one of key or val is *not* a composite type or is a composite type
 *    that does not contain malloced memory, use mcxHashFreeScalar.
 *
 *    Both freekey and freeval may be NULL. When NULL, the corresponding
 *    KV member is not loooked at. This is useful e.g. when hashing objects
 *    owned by someone else.
*/


void mcxHashFree
(  mcxHash**   hashpp
,  void        freekey(void* keypp)    /* (yourtype1** keypp)     */
,  void        freeval(void* valpp)    /* (yourtype2** valpp)     */
)  ;

void mcxHashFreeScalar
(  void* scalar
)  ;



/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *    It copies the pointers stored in the hash
*/

void** mcxHashKeys
(  mcxHash*    hash
,  dim*        n_entries
,  int       (*cmp)(const void*, const void*)         /* works on keys */
,  mcxbits     opts        /* unused yet */
)  ;
                           /* Future options: SORT, SORT_DESC */


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *    It copies the pointers stored in the hash
*/

void** mcxHashKVs
(  mcxHash*    hash
,  dim*        n_entries
,  int       (*cmp)(const void*, const void*)
,  mcxbits     opts        /* unused yet */
)  ;



/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *    Prints some information to stdout.
*/

void mcxHashStats
(  FILE*       fp
,  mcxHash*    hash
)  ;


typedef struct mcxHashWalk mcxHashWalk;


mcxHashWalk* mcxHashWalkInit
(  mcxHash  *hash
)  ;


mcxKV* mcxHashWalkStep
(  mcxHashWalk* walk
,  dim          *i_bucket
)  ;


void mcxHashWalkFree
(  mcxHashWalk  **walkpp
)  ;


void mcxHashApply
(  mcxHash* hash
,  void    (*cb)(const void* key, void* val, void* data)
,  void*    data
)  ;

                        /* UNIX ELF hash */
                        /* POOR! */
u32 mcxELFhash
(  const void *key
,  u32 len
)  ;

                        /* created by Bob Jenkins     */
u32 mcxBJhash
(  const void* key
,  u32         len
)  ;

                        /* One at a time hash, Bob Jenkins/Colin Plumb */
u32 mcxOAThash
(  const void *key
,  u32        len
)  ;

                        /* created by Daniel Phillips */
u32 mcxDPhash
(  const void* key
,  u32         len
)  ;

                        /* "Berkely Database" hash (from Ozan Yigit's page) */
                        /* POOR! */
u32 mcxBDBhash
(  const void *key
,  u32        len
)  ;

                        /* Dan Bernstein hash (from Ozan Yigit's page) */
u32 mcxDJBhash
(  const void *key
,  u32        len
)  ;

                        /* created by Chris Torek */
u32 mcxCThash
(  const void* key
,  u32         len
)  ;

                        /* "GNU Emacs" hash (from m4) */
                        /* not among the best */
u32 mcxGEhash
(  const void* key
,  u32         len
)  ;


                        /* Fowler Noll Vo hash */
u32   mcxFNVhash
(  const void *buf
,  u32 len
)  ;

                        /* All experimental with weak points. */
u32   mcxSvDhash
(  const void        *key
,  u32               len
)  ;
u32   mcxSvD2hash
(  const void        *key
,  u32               len
)  ;
u32   mcxSvD1hash
(  const void        *key
,  u32               len
)  ;

                        /* uses mcxDPhash             */
u32 mcxStrHash
(  const void* s
)  ;

int mcxStrCmp
(  const void* a
,  const void* b
)  ;


#endif