source: thirdparty/SZ/sz/src/dictionary.c @ 2c47b73

Revision 2c47b73, 11.9 KB checked in by Hal Finkel <hfinkel@…>, 6 years ago (diff)

more work on adding SZ (latest version)

  • Property mode set to 100644
RevLine 
[2c47b73]1/*-------------------------------------------------------------------------*/
2/**
3   @file    dictionary.c
4   @author  N. Devillard
5   @brief   Implements a dictionary for string variables.
6
7   This module implements a simple dictionary object, i.e. a list
8   of string/string associations. This object is useful to store e.g.
9   informations retrieved from a configuration file (ini files).
10*/
11/*--------------------------------------------------------------------------*/
12
13/*---------------------------------------------------------------------------
14                                Includes
15 ---------------------------------------------------------------------------*/
16#include "dictionary.h"
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <string.h>
21#include <unistd.h>
22
23/** Maximum value size for integers and doubles. */
24#define MAXVALSZ    1024
25
26/** Minimal allocated number of entries in a dictionary */
27#define DICTMINSZ   128
28
29/** Invalid key token */
30#define DICT_INVALID_KEY    ((char*)-1)
31
32/*---------------------------------------------------------------------------
33                            Private functions
34 ---------------------------------------------------------------------------*/
35
36/* Doubles the allocated size associated to a pointer */
37/* 'size' is the current allocated size. */
38static void * mem_double(void * ptr, int size)
39{
40    void * newptr ;
41 
42    newptr = calloc(2*size, 1);
43    if (newptr==NULL) {
44        return NULL ;
45    }
46    memcpy(newptr, ptr, size);
47    free(ptr);
48    return newptr ;
49}
50
51/*-------------------------------------------------------------------------*/
52/**
53  @brief    Duplicate a string
54  @param    s String to duplicate
55  @return   Pointer to a newly allocated string, to be freed with free()
56
57  This is a replacement for strdup(). This implementation is provided
58  for systems that do not have it.
59 */
60/*--------------------------------------------------------------------------*/
61static char * xstrdup(const char * s)
62{
63    char * t ;
64    if (!s)
65        return NULL ;
66    t = (char*)malloc(strlen(s)+1) ;
67    if (t) {
68        strcpy(t,s);
69    }
70    return t ;
71}
72
73/*---------------------------------------------------------------------------
74                            Function codes
75 ---------------------------------------------------------------------------*/
76/*-------------------------------------------------------------------------*/
77/**
78  @brief    Compute the hash key for a string.
79  @param    key     Character string to use for key.
80  @return   1 unsigned int on at least 32 bits.
81
82  This hash function has been taken from an Article in Dr Dobbs Journal.
83  This is normally a collision-free function, distributing keys evenly.
84  The key is stored anyway in the struct so that collision can be avoided
85  by comparing the key itself in last resort.
86 */
87/*--------------------------------------------------------------------------*/
88unsigned dictionary_hash(const char * key)
89{
90    int         len ;
91    unsigned    hash ;
92    int         i ;
93
94    len = strlen(key);
95    for (hash=0, i=0 ; i<len ; i++) {
96        hash += (unsigned)key[i] ;
97        hash += (hash<<10);
98        hash ^= (hash>>6) ;
99    }
100    hash += (hash <<3);
101    hash ^= (hash >>11);
102    hash += (hash <<15);
103    return hash ;
104}
105
106/*-------------------------------------------------------------------------*/
107/**
108  @brief    Create a new dictionary object.
109  @param    size    Optional initial size of the dictionary.
110  @return   1 newly allocated dictionary objet.
111
112  This function allocates a new dictionary object of given size and returns
113  it. If you do not know in advance (roughly) the number of entries in the
114  dictionary, give size=0.
115 */
116/*--------------------------------------------------------------------------*/
117dictionary * dictionary_new(int size)
118{
119    dictionary  *   d ;
120
121    /* If no size was specified, allocate space for DICTMINSZ */
122    if (size<DICTMINSZ) size=DICTMINSZ ;
123
124    if (!(d = (dictionary *)calloc(1, sizeof(dictionary)))) {
125        return NULL;
126    }
127    d->size = size ;
128    d->val  = (char **)calloc(size, sizeof(char*));
129    d->key  = (char **)calloc(size, sizeof(char*));
130    d->hash = (unsigned int *)calloc(size, sizeof(unsigned));
131    return d ;
132}
133
134/*-------------------------------------------------------------------------*/
135/**
136  @brief    Delete a dictionary object
137  @param    d   dictionary object to deallocate.
138  @return   void
139
140  Deallocate a dictionary object and all memory associated to it.
141 */
142/*--------------------------------------------------------------------------*/
143void dictionary_del(dictionary * d)
144{
145    int     i ;
146
147    if (d==NULL) return ;
148    for (i=0 ; i<d->size ; i++) {
149        if (d->key[i]!=NULL)
150            free(d->key[i]);
151        if (d->val[i]!=NULL)
152            free(d->val[i]);
153    }
154    free(d->val);
155    free(d->key);
156    free(d->hash);
157    free(d);
158    return ;
159}
160
161/*-------------------------------------------------------------------------*/
162/**
163  @brief    Get a value from a dictionary.
164  @param    d       dictionary object to search.
165  @param    key     Key to look for in the dictionary.
166  @param    def     Default value to return if key not found.
167  @return   1 pointer to internally allocated character string.
168
169  This function locates a key in a dictionary and returns a pointer to its
170  value, or the passed 'def' pointer if no such key can be found in
171  dictionary. The returned character pointer points to data internal to the
172  dictionary object, you should not try to free it or modify it.
173 */
174/*--------------------------------------------------------------------------*/
175char * dictionary_get(dictionary * d, const char * key, char * def)
176{
177    unsigned    hash ;
178    int         i ;
179
180    hash = dictionary_hash(key);
181    for (i=0 ; i<d->size ; i++) {
182        if (d->key[i]==NULL)
183            continue ;
184        /* Compare hash */
185        if (hash==d->hash[i]) {
186            /* Compare string, to avoid hash collisions */
187            if (!strcmp(key, d->key[i])) {
188                return d->val[i] ;
189            }
190        }
191    }
192    return def ;
193}
194
195/*-------------------------------------------------------------------------*/
196/**
197  @brief    Set a value in a dictionary.
198  @param    d       dictionary object to modify.
199  @param    key     Key to modify or add.
200  @param    val     Value to add.
201  @return   int     0 if Ok, anything else otherwise
202
203  If the given key is found in the dictionary, the associated value is
204  replaced by the provided one. If the key cannot be found in the
205  dictionary, it is added to it.
206
207  It is Ok to provide a NULL value for val, but NULL values for the dictionary
208  or the key are considered as errors: the function will return immediately
209  in such a case.
210
211  Notice that if you dictionary_set a variable to NULL, a call to
212  dictionary_get will return a NULL value: the variable will be found, and
213  its value (NULL) is returned. In other words, setting the variable
214  content to NULL is equivalent to deleting the variable from the
215  dictionary. It is not possible (in this implementation) to have a key in
216  the dictionary without value.
217
218  This function returns non-zero in case of failure.
219 */
220/*--------------------------------------------------------------------------*/
221int dictionary_set(dictionary * d, const char * key, const char * val)
222{
223    int         i ;
224    unsigned    hash ;
225
226    if (d==NULL || key==NULL) return -1 ;
227   
228    /* Compute hash for this key */
229    hash = dictionary_hash(key) ;
230    /* Find if value is already in dictionary */
231    if (d->n>0) {
232        for (i=0 ; i<d->size ; i++) {
233            if (d->key[i]==NULL)
234                continue ;
235            if (hash==d->hash[i]) { /* Same hash value */
236                if (!strcmp(key, d->key[i])) {   /* Same key */
237                    /* Found a value: modify and return */
238                    if (d->val[i]!=NULL)
239                        free(d->val[i]);
240                    d->val[i] = val ? xstrdup(val) : NULL ;
241                    /* Value has been modified: return */
242                    return 0 ;
243                }
244            }
245        }
246    }
247    /* Add a new value */
248    /* See if dictionary needs to grow */
249    if (d->n==d->size) {
250
251        /* Reached maximum size: reallocate dictionary */
252        d->val  = (char **)mem_double(d->val,  d->size * sizeof(char*)) ;
253        d->key  = (char **)mem_double(d->key,  d->size * sizeof(char*)) ;
254        d->hash = (unsigned int *)mem_double(d->hash, d->size * sizeof(unsigned)) ;
255        if ((d->val==NULL) || (d->key==NULL) || (d->hash==NULL)) {
256            /* Cannot grow dictionary */
257            return -1 ;
258        }
259        /* Double size */
260        d->size *= 2 ;
261    }
262
263    /* Insert key in the first empty slot. Start at d->n and wrap at
264       d->size. Because d->n < d->size this will necessarily
265       terminate. */
266    for (i=d->n ; d->key[i] ; ) {
267        if(++i == d->size) i = 0;
268    }
269    /* Copy key */
270    d->key[i]  = xstrdup(key);
271    d->val[i]  = val ? xstrdup(val) : NULL ;
272    d->hash[i] = hash;
273    d->n ++ ;
274    return 0 ;
275}
276
277/*-------------------------------------------------------------------------*/
278/**
279  @brief    Delete a key in a dictionary
280  @param    d       dictionary object to modify.
281  @param    key     Key to remove.
282  @return   void
283
284  This function deletes a key in a dictionary. Nothing is done if the
285  key cannot be found.
286 */
287/*--------------------------------------------------------------------------*/
288void dictionary_unset(dictionary * d, const char * key)
289{
290    unsigned    hash ;
291    int         i ;
292
293    if (key == NULL) {
294        return;
295    }
296
297    hash = dictionary_hash(key);
298    for (i=0 ; i<d->size ; i++) {
299        if (d->key[i]==NULL)
300            continue ;
301        /* Compare hash */
302        if (hash==d->hash[i]) {
303            /* Compare string, to avoid hash collisions */
304            if (!strcmp(key, d->key[i])) {
305                /* Found key */
306                break ;
307            }
308        }
309    }
310    if (i>=d->size)
311        /* Key not found */
312        return ;
313
314    free(d->key[i]);
315    d->key[i] = NULL ;
316    if (d->val[i]!=NULL) {
317        free(d->val[i]);
318        d->val[i] = NULL ;
319    }
320    d->hash[i] = 0 ;
321    d->n -- ;
322    return ;
323}
324
325/*-------------------------------------------------------------------------*/
326/**
327  @brief    Dump a dictionary to an opened file pointer.
328  @param    d   Dictionary to dump
329  @param    f   Opened file pointer.
330  @return   void
331
332  Dumps a dictionary onto an opened file pointer. Key pairs are printed out
333  as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as
334  output file pointers.
335 */
336/*--------------------------------------------------------------------------*/
337void dictionary_dump(dictionary * d, FILE * out)
338{
339    int     i ;
340
341    if (d==NULL || out==NULL) return ;
342    if (d->n<1) {
343        fprintf(out, "empty dictionary\n");
344        return ;
345    }
346    for (i=0 ; i<d->size ; i++) {
347        if (d->key[i]) {
348            fprintf(out, "%20s\t[%s]\n",
349                    d->key[i],
350                    d->val[i] ? d->val[i] : "UNDEF");
351        }
352    }
353    return ;
354}
355
356
357/* Test code */
358#ifdef TESTDIC
359#define NVALS 20000
360int main(int argc, char *argv[])
361{
362    dictionary  *   d ;
363    char    *   val ;
364    int         i ;
365    char        cval[90] ;
366
367    /* Allocate dictionary */
368    printf("allocating...\n");
369    d = dictionary_new(0);
370   
371    /* Set values in dictionary */
372    printf("setting %d values...\n", NVALS);
373    for (i=0 ; i<NVALS ; i++) {
374        sprintf(cval, "%04d", i);
375        dictionary_set(d, cval, "salut");
376    }
377    printf("getting %d values...\n", NVALS);
378    for (i=0 ; i<NVALS ; i++) {
379        sprintf(cval, "%04d", i);
380        val = dictionary_get(d, cval, DICT_INVALID_KEY);
381        if (val==DICT_INVALID_KEY) {
382            printf("cannot get value for key [%s]\n", cval);
383        }
384    }
385    printf("unsetting %d values...\n", NVALS);
386    for (i=0 ; i<NVALS ; i++) {
387        sprintf(cval, "%04d", i);
388        dictionary_unset(d, cval);
389    }
390    if (d->n != 0) {
391        printf("error deleting values\n");
392    }
393    printf("deallocating...\n");
394    dictionary_del(d);
395    return 0 ;
396}
397#endif
398/* vim: set ts=4 et sw=4 tw=75 */
Note: See TracBrowser for help on using the repository browser.