OLD | NEW |
| (Empty) |
1 /* | |
2 ** 2001 September 22 | |
3 ** | |
4 ** The author disclaims copyright to this source code. In place of | |
5 ** a legal notice, here is a blessing: | |
6 ** | |
7 ** May you do good and not evil. | |
8 ** May you find forgiveness for yourself and forgive others. | |
9 ** May you share freely, never taking more than you give. | |
10 ** | |
11 ************************************************************************* | |
12 ** This is the header file for the generic hash-table implementation | |
13 ** used in SQLite. We've modified it slightly to serve as a standalone | |
14 ** hash table implementation for the full-text indexing module. | |
15 ** | |
16 */ | |
17 #ifndef _FTS3_HASH_H_ | |
18 #define _FTS3_HASH_H_ | |
19 | |
20 /* Forward declarations of structures. */ | |
21 typedef struct Fts3Hash Fts3Hash; | |
22 typedef struct Fts3HashElem Fts3HashElem; | |
23 | |
24 /* A complete hash table is an instance of the following structure. | |
25 ** The internals of this structure are intended to be opaque -- client | |
26 ** code should not attempt to access or modify the fields of this structure | |
27 ** directly. Change this structure only by using the routines below. | |
28 ** However, many of the "procedures" and "functions" for modifying and | |
29 ** accessing this structure are really macros, so we can't really make | |
30 ** this structure opaque. | |
31 */ | |
32 struct Fts3Hash { | |
33 char keyClass; /* HASH_INT, _POINTER, _STRING, _BINARY */ | |
34 char copyKey; /* True if copy of key made on insert */ | |
35 int count; /* Number of entries in this table */ | |
36 Fts3HashElem *first; /* The first element of the array */ | |
37 int htsize; /* Number of buckets in the hash table */ | |
38 struct _fts3ht { /* the hash table */ | |
39 int count; /* Number of entries with this hash */ | |
40 Fts3HashElem *chain; /* Pointer to first entry with this hash */ | |
41 } *ht; | |
42 }; | |
43 | |
44 /* Each element in the hash table is an instance of the following | |
45 ** structure. All elements are stored on a single doubly-linked list. | |
46 ** | |
47 ** Again, this structure is intended to be opaque, but it can't really | |
48 ** be opaque because it is used by macros. | |
49 */ | |
50 struct Fts3HashElem { | |
51 Fts3HashElem *next, *prev; /* Next and previous elements in the table */ | |
52 void *data; /* Data associated with this element */ | |
53 void *pKey; int nKey; /* Key associated with this element */ | |
54 }; | |
55 | |
56 /* | |
57 ** There are 2 different modes of operation for a hash table: | |
58 ** | |
59 ** FTS3_HASH_STRING pKey points to a string that is nKey bytes long | |
60 ** (including the null-terminator, if any). Case | |
61 ** is respected in comparisons. | |
62 ** | |
63 ** FTS3_HASH_BINARY pKey points to binary data nKey bytes long. | |
64 ** memcmp() is used to compare keys. | |
65 ** | |
66 ** A copy of the key is made if the copyKey parameter to fts3HashInit is 1. | |
67 */ | |
68 #define FTS3_HASH_STRING 1 | |
69 #define FTS3_HASH_BINARY 2 | |
70 | |
71 /* | |
72 ** Access routines. To delete, insert a NULL pointer. | |
73 */ | |
74 void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey); | |
75 void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData); | |
76 void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey); | |
77 void sqlite3Fts3HashClear(Fts3Hash*); | |
78 Fts3HashElem *sqlite3Fts3HashFindElem(const Fts3Hash *, const void *, int); | |
79 | |
80 /* | |
81 ** Shorthand for the functions above | |
82 */ | |
83 #define fts3HashInit sqlite3Fts3HashInit | |
84 #define fts3HashInsert sqlite3Fts3HashInsert | |
85 #define fts3HashFind sqlite3Fts3HashFind | |
86 #define fts3HashClear sqlite3Fts3HashClear | |
87 #define fts3HashFindElem sqlite3Fts3HashFindElem | |
88 | |
89 /* | |
90 ** Macros for looping over all elements of a hash table. The idiom is | |
91 ** like this: | |
92 ** | |
93 ** Fts3Hash h; | |
94 ** Fts3HashElem *p; | |
95 ** ... | |
96 ** for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){ | |
97 ** SomeStructure *pData = fts3HashData(p); | |
98 ** // do something with pData | |
99 ** } | |
100 */ | |
101 #define fts3HashFirst(H) ((H)->first) | |
102 #define fts3HashNext(E) ((E)->next) | |
103 #define fts3HashData(E) ((E)->data) | |
104 #define fts3HashKey(E) ((E)->pKey) | |
105 #define fts3HashKeysize(E) ((E)->nKey) | |
106 | |
107 /* | |
108 ** Number of entries in a hash table | |
109 */ | |
110 #define fts3HashCount(H) ((H)->count) | |
111 | |
112 #endif /* _FTS3_HASH_H_ */ | |
OLD | NEW |