4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
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.
11 *************************************************************************
12 ** This is the header file for the generic hash-table implemenation
13 ** used in SQLite. We've modified it slightly to serve as a standalone
14 ** hash table implementation for the full-text indexing module.
20 /* Forward declarations of structures. */
21 typedef struct fts1Hash fts1Hash;
22 typedef struct fts1HashElem fts1HashElem;
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.
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 fts1HashElem *first; /* The first element of the array */
37 void *(*xMalloc)(int); /* malloc() function to use */
38 void (*xFree)(void *); /* free() function to use */
39 int htsize; /* Number of buckets in the hash table */
40 struct _fts1ht { /* the hash table */
41 int count; /* Number of entries with this hash */
42 fts1HashElem *chain; /* Pointer to first entry with this hash */
46 /* Each element in the hash table is an instance of the following
47 ** structure. All elements are stored on a single doubly-linked list.
49 ** Again, this structure is intended to be opaque, but it can't really
50 ** be opaque because it is used by macros.
53 fts1HashElem *next, *prev; /* Next and previous elements in the table */
54 void *data; /* Data associated with this element */
55 void *pKey; int nKey; /* Key associated with this element */
59 ** There are 2 different modes of operation for a hash table:
61 ** FTS1_HASH_STRING pKey points to a string that is nKey bytes long
62 ** (including the null-terminator, if any). Case
63 ** is respected in comparisons.
65 ** FTS1_HASH_BINARY pKey points to binary data nKey bytes long.
66 ** memcmp() is used to compare keys.
68 ** A copy of the key is made if the copyKey parameter to fts1HashInit is 1.
70 #define FTS1_HASH_STRING 1
71 #define FTS1_HASH_BINARY 2
74 ** Access routines. To delete, insert a NULL pointer.
76 void sqlite3Fts1HashInit(fts1Hash*, int keytype, int copyKey);
77 void *sqlite3Fts1HashInsert(fts1Hash*, const void *pKey, int nKey, void *pData);
78 void *sqlite3Fts1HashFind(const fts1Hash*, const void *pKey, int nKey);
79 void sqlite3Fts1HashClear(fts1Hash*);
82 ** Shorthand for the functions above
84 #define fts1HashInit sqlite3Fts1HashInit
85 #define fts1HashInsert sqlite3Fts1HashInsert
86 #define fts1HashFind sqlite3Fts1HashFind
87 #define fts1HashClear sqlite3Fts1HashClear
90 ** Macros for looping over all elements of a hash table. The idiom is
96 ** for(p=fts1HashFirst(&h); p; p=fts1HashNext(p)){
97 ** SomeStructure *pData = fts1HashData(p);
98 ** // do something with pData
101 #define fts1HashFirst(H) ((H)->first)
102 #define fts1HashNext(E) ((E)->next)
103 #define fts1HashData(E) ((E)->data)
104 #define fts1HashKey(E) ((E)->pKey)
105 #define fts1HashKeysize(E) ((E)->nKey)
108 ** Number of entries in a hash table
110 #define fts1HashCount(H) ((H)->count)
112 #endif /* _FTS1_HASH_H_ */