Fix code indentation. No logic changes.
[sqlite.git] / ext / fts2 / fts2_hash.h
blob02936f18bbaa76eecddf7064074cfc288a410f5d
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.
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.
17 #ifndef _FTS2_HASH_H_
18 #define _FTS2_HASH_H_
20 /* Forward declarations of structures. */
21 typedef struct fts2Hash fts2Hash;
22 typedef struct fts2HashElem fts2HashElem;
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.
32 struct fts2Hash {
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 fts2HashElem *first; /* The first element of the array */
37 int htsize; /* Number of buckets in the hash table */
38 struct _fts2ht { /* the hash table */
39 int count; /* Number of entries with this hash */
40 fts2HashElem *chain; /* Pointer to first entry with this hash */
41 } *ht;
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.
47 ** Again, this structure is intended to be opaque, but it can't really
48 ** be opaque because it is used by macros.
50 struct fts2HashElem {
51 fts2HashElem *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 */
57 ** There are 2 different modes of operation for a hash table:
59 ** FTS2_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.
63 ** FTS2_HASH_BINARY pKey points to binary data nKey bytes long.
64 ** memcmp() is used to compare keys.
66 ** A copy of the key is made if the copyKey parameter to fts2HashInit is 1.
68 #define FTS2_HASH_STRING 1
69 #define FTS2_HASH_BINARY 2
72 ** Access routines. To delete, insert a NULL pointer.
74 void sqlite3Fts2HashInit(fts2Hash*, int keytype, int copyKey);
75 void *sqlite3Fts2HashInsert(fts2Hash*, const void *pKey, int nKey, void *pData);
76 void *sqlite3Fts2HashFind(const fts2Hash*, const void *pKey, int nKey);
77 void sqlite3Fts2HashClear(fts2Hash*);
80 ** Shorthand for the functions above
82 #define fts2HashInit sqlite3Fts2HashInit
83 #define fts2HashInsert sqlite3Fts2HashInsert
84 #define fts2HashFind sqlite3Fts2HashFind
85 #define fts2HashClear sqlite3Fts2HashClear
88 ** Macros for looping over all elements of a hash table. The idiom is
89 ** like this:
91 ** fts2Hash h;
92 ** fts2HashElem *p;
93 ** ...
94 ** for(p=fts2HashFirst(&h); p; p=fts2HashNext(p)){
95 ** SomeStructure *pData = fts2HashData(p);
96 ** // do something with pData
97 ** }
99 #define fts2HashFirst(H) ((H)->first)
100 #define fts2HashNext(E) ((E)->next)
101 #define fts2HashData(E) ((E)->data)
102 #define fts2HashKey(E) ((E)->pKey)
103 #define fts2HashKeysize(E) ((E)->nKey)
106 ** Number of entries in a hash table
108 #define fts2HashCount(H) ((H)->count)
110 #endif /* _FTS2_HASH_H_ */