1 /*
2  * This file is part of ltrace.
3  * Copyright (C) 2012, 2013 Petr Machata, Red Hat Inc.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation; either version 2 of the
8  * License, or (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18  * 02110-1301 USA
19  */
20 
21 #ifndef _DICT_H_
22 #define _DICT_H_
23 
24 #include <stddef.h>
25 #include <assert.h>
26 #include "vect.h"
27 
28 struct dict {
29 	/* The invariant is that KEYS, VALUES and STATUS are of the
30 	 * same size.  */
31 	struct vect keys;
32 	struct vect values;
33 	struct vect status;
34 	size_t size;
35 
36 	size_t (*hash1)(const void *);
37 	int (*eq)(const void *, const void *);
38 	size_t (*hash2)(size_t);
39 };
40 
41 /* Initialize a dictionary DICT.  The dictionary will hold keys of the
42  * size KEY_SIZE and values of the size VALUE_SIZE.  HASH1 and HASH2
43  * are, respectively, primary and secondary hashing functions.  The
44  * latter may be NULL, in which case a default internal hash is used.
45  * EQ is a callback for comparing two keys.  */
46 void dict_init(struct dict *dict,
47 	       size_t key_size, size_t value_size,
48 	       size_t (*hash1)(const void *),
49 	       int (*eq)(const void *, const void *),
50 	       size_t (*hash2)(size_t));
51 
52 /* Wrapper around dict_init.  Initializes a dictionary DITCP which
53  * will hold keys of type KEY_TYPE and values of type VALUE_TYPE.
54  * Other arguments as above.  */
55 #define DICT_INIT(DICTP, KEY_TYPE, VALUE_TYPE, HASH1, EQ, HASH2)	\
56 	({								\
57 		/* Check that callbacks are typed properly.  */		\
58 		size_t (*_hash1_callback)(const KEY_TYPE *) = HASH1;	\
59 		int (*_eq_callback)(const KEY_TYPE *, const KEY_TYPE *) = EQ; \
60 		dict_init(DICTP, sizeof(KEY_TYPE), sizeof(VALUE_TYPE),	\
61 			  (size_t (*)(const void *))_hash1_callback,	\
62 			  (int (*)(const void *, const void *))_eq_callback, \
63 			  HASH2);					\
64 	})
65 
66 /* Clone SOURCE to TARGET.  For cloning slots, CLONE_KEY and
67  * CLONE_VALUE are called.  These callbacks return 0 on success or a
68  * negative value on failure.  If any of the callbacks is NULL, the
69  * default action is simple memmove.  Returns 0 on success.  If the
70  * cloning fails for any reason, already-cloned keys and values are
71  * destroyed again by DTOR_KEY and DTOR_VALUE callbacks (if non-NULL),
72  * and the function returns a negative value.  DATA is passed to all
73  * callbacks verbatim.  */
74 int dict_clone(struct dict *target, const struct dict *source,
75 	       int (*clone_key)(void *tgt, const void *src, void *data),
76 	       void (*dtor_key)(void *tgt, void *data),
77 	       int (*clone_value)(void *tgt, const void *src, void *data),
78 	       void (*dtor_value)(void *tgt, void *data),
79 	       void *data);
80 
81 /* Clone SRC_DICTP, which holds KEY_TYPE-VALUE_TYPE pairs, into
82  * TGT_DICTP.  Other arguments and return codes as above.  */
83 #define DICT_CLONE(TGT_DICTP, SRC_DICTP, KEY_TYPE, VALUE_TYPE,		\
84 		   CLONE_KEY, DTOR_KEY, CLONE_VALUE, DTOR_VALUE, DATA)	\
85 	/* xxx GCC-ism necessary to get in the safety latches.  */	\
86 	({								\
87 		const struct dict *_source_d = (SRC_DICTP);		\
88 		assert(_source_d->keys.elt_size == sizeof(KEY_TYPE));	\
89 		assert(_source_d->values.elt_size == sizeof(VALUE_TYPE)); \
90 		/* Check that callbacks are typed properly.  */		\
91 		void (*_key_dtor_cb)(KEY_TYPE *, void *) = DTOR_KEY;	\
92 		int (*_key_clone_cb)(KEY_TYPE *, const KEY_TYPE *,	\
93 				     void *) = CLONE_KEY;		\
94 		void (*_value_dtor_cb)(VALUE_TYPE *, void *) = DTOR_VALUE; \
95 		int (*_value_clone_cb)(VALUE_TYPE *, const VALUE_TYPE *, \
96 				       void *) = CLONE_VALUE;		\
97 		dict_clone((TGT_DICTP), _source_d,			\
98 			   (int (*)(void *, const void *,		\
99 				    void *))_key_clone_cb,		\
100 			   (void (*)(void *, void *))_key_dtor_cb,	\
101 			   (int (*)(void *, const void *,		\
102 				    void *))_value_clone_cb,		\
103 			   (void (*)(void *, void *))_value_dtor_cb,	\
104 			   (DATA));					\
105 	})
106 
107 /* Return number of key-value pairs stored in DICT.  */
108 size_t dict_size(const struct dict *dict);
109 
110 /* Emptiness predicate.  */
111 int dict_empty(const struct dict *dict);
112 
113 /* Insert into DICT a pair of KEY and VALUE.  Returns 0 if insertion
114  * was successful, a negative value on error, or a positive value if
115  * this key is already present in the table.  */
116 int dict_insert(struct dict *dict, void *key, void *value);
117 
118 /* Insert into DICT a pair of KEY and VALUE.  See dict_insert for
119  * details.  In addition, make a check whether DICTP holds elements of
120  * the right size.  */
121 #define DICT_INSERT(DICTP, KEYP, VALUEP)				\
122 	(assert((DICTP)->keys.elt_size == sizeof(*(KEYP))),		\
123 	 assert((DICTP)->values.elt_size == sizeof(*(VALUEP))),		\
124 	 dict_insert((DICTP), (KEYP), (VALUEP)))
125 
126 /* Find in DICT a value corresponding to KEY and return a pointer to
127  * it.  Returns NULL if the key was not found.  */
128 void *dict_find(struct dict *dict, const void *key);
129 
130 /* Look into DICTP for a key *KEYP.  Return a boolean indicating
131  * whether the key was found.  */
132 #define DICT_HAS_KEY(DICTP, KEYP)				\
133 	(assert((DICTP)->keys.elt_size == sizeof(*(KEYP))),	\
134 	 dict_find((DICTP), (KEYP)) != NULL)
135 
136 /* Find in DICTP a value of type VALUE_TYPE corresponding to KEYP and
137  * return a pointer (VALUE_TYPE *) to it.  Returns NULL if the key was
138  * not found.  */
139 #define DICT_FIND_REF(DICTP, KEYP, VALUE_TYPE)			\
140 	(assert((DICTP)->keys.elt_size == sizeof(*(KEYP))),	\
141 	 (VALUE_TYPE *)dict_find((DICTP), (KEYP)))
142 
143 /* Find in DICTP a value of type VALUE_TYPE corresponding to KEYP and
144  * copy it to the memory pointed-to by VAR.  Returns 0 on success, or
145  * a negative value if the key was not found.  */
146 #define DICT_FIND_VAL(DICTP, KEYP, VAR)					\
147 	({								\
148 		assert((DICTP)->keys.elt_size == sizeof(*(KEYP)));	\
149 		assert((DICTP)->values.elt_size == sizeof((VAR)));	\
150 		void *_ptr = dict_find((DICTP), (KEYP));		\
151 		if (_ptr != NULL)					\
152 			memcpy((VAR), _ptr, (DICTP)->values.elt_size);	\
153 		_ptr != NULL ? 0 : -1;					\
154 	})
155 
156 /* Erase from DICT the entry corresponding to KEY.  Returns a negative
157  * value if the key was not found, or 0 on success.  DTOR_KEY and
158  * DTOR_VALUE, if non-NULL, are called to destroy the erased
159  * value.  */
160 int dict_erase(struct dict *dict, const void *key,
161 	       void (*dtor_key)(void *tgt, void *data),
162 	       void (*dtor_value)(void *tgt, void *data),
163 	       void *data);
164 
165 /* Erase from DICTP a value of type VALUE_TYPE corresponding to
166  * KEYP.  */
167 #define DICT_ERASE(DICTP, KEYP, VALUE_TYPE, DTOR_KEY, DTOR_VALUE, DATA) \
168 	({								\
169 		struct dict *_d = (DICTP);				\
170 		assert(_d->keys.elt_size == sizeof(*KEYP));		\
171 		assert(_d->values.elt_size == sizeof(VALUE_TYPE));	\
172 		/* Check that callbacks are typed properly.  */		\
173 		void (*_value_dtor_cb)(VALUE_TYPE *, void *) = DTOR_VALUE; \
174 		dict_erase(_d, (KEYP), (DTOR_KEY),			\
175 			   (void (*)(void *, void *))_value_dtor_cb,	\
176 			   (DATA));					\
177 	})
178 
179 /* Destroy DICT.  If KEY_DTOR is non-NULL, then it's called on each
180  * key stored in DICT.  Similarly for VALUE_DTOR.  DATA is passed to
181  * DTOR's verbatim.  The memory pointed-to by DICT is not freed.  */
182 void dict_destroy(struct dict *dict,
183 		  void (*dtor_key)(void *tgt, void *data),
184 		  void (*dtor_value)(void *tgt, void *data),
185 		  void *data);
186 
187 /* Destroy DICTP, which holds keys of type KEY_TYPE and values of type
188  * VALUE_TYPE, using DTOR.  */
189 #define DICT_DESTROY(DICTP, KEY_TYPE, VALUE_TYPE, DTOR_KEY, DTOR_VALUE, DATA) \
190 	do {								\
191 		struct dict *_d = (DICTP);				\
192 		assert(_d->keys.elt_size == sizeof(KEY_TYPE));		\
193 		assert(_d->values.elt_size == sizeof(VALUE_TYPE));	\
194 		/* Check that callbacks are typed properly.  */		\
195 		void (*_key_dtor_cb)(KEY_TYPE *, void *) = DTOR_KEY;	\
196 		void (*_value_dtor_cb)(VALUE_TYPE *, void *) = DTOR_VALUE; \
197 		dict_destroy(_d, (void (*)(void *, void *))_key_dtor_cb, \
198 			     (void (*)(void *, void *))_value_dtor_cb,	\
199 			     (DATA));					\
200 	} while (0)
201 
202 /* Iterate through DICT.  See callback.h for notes on iteration
203  * interfaces.  Callback arguments are key, value, DATA.  Note that
204  * the iteration over DICT is more expensive than in other containers:
205  * while CB is only called for items present in the table, and is
206  * therefore O(number of elements), the iterator needs to go through
207  * all the table, which is proportional to O(size of table).
208  * START_AFTER and the returned iterator are key where the iteration
209  * stopped.  */
210 void *dict_each(struct dict *dict, void *start_after,
211 		enum callback_status (*cb)(void *, void *, void *), void *data);
212 
213 #define DICT_EACH(DICTP, KEY_TYPE, VALUE_TYPE, START_AFTER, CB, DATA)	\
214 	/* xxx GCC-ism necessary to get in the safety latches.  */	\
215 	({								\
216 		assert((DICTP)->keys.elt_size == sizeof(KEY_TYPE));	\
217 		assert((DICTP)->values.elt_size == sizeof(VALUE_TYPE));	\
218 		/* Check that CB is typed properly.  */			\
219 		enum callback_status (*_cb)(KEY_TYPE *, VALUE_TYPE *,	\
220 					    void *) = CB;		\
221 		KEY_TYPE *_start_after = (START_AFTER);			\
222 		(KEY_TYPE *)dict_each((DICTP), _start_after,		\
223 				      (enum callback_status		\
224 				       (*)(void *, void *, void *))_cb,	\
225 				      (DATA));				\
226 	})
227 
228 /* A callback for hashing integers.  */
229 size_t dict_hash_int(const int *key);
230 
231 /* An equality predicate callback for integers.  */
232 int dict_eq_int(const int *key1, const int *key2);
233 
234 /* A callback for hashing NULL-terminated strings.  */
235 size_t dict_hash_string(const char **key);
236 
237 /* An equality predicate callback for strings.  */
238 int dict_eq_string(const char **key1, const char **key2);
239 
240 /* A dtor which calls 'free' on keys in a table.  */
241 void dict_dtor_string(const char **key, void *data);
242 
243 /* A cloner that calls 'strdup' on keys in a table.  */
244 int dict_clone_string(const char **tgt, const char **src, void *data);
245 
246 #endif /* _DICT_H_ */
247