Annotation of embedaddon/sqlite3/ext/fts2/fts2_hash.h, revision 1.1.1.1
1.1 misho 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 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.
15: **
16: */
17: #ifndef _FTS2_HASH_H_
18: #define _FTS2_HASH_H_
19:
20: /* Forward declarations of structures. */
21: typedef struct fts2Hash fts2Hash;
22: typedef struct fts2HashElem fts2HashElem;
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 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;
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 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 */
54: };
55:
56: /*
57: ** There are 2 different modes of operation for a hash table:
58: **
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.
62: **
63: ** FTS2_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 fts2HashInit is 1.
67: */
68: #define FTS2_HASH_STRING 1
69: #define FTS2_HASH_BINARY 2
70:
71: /*
72: ** Access routines. To delete, insert a NULL pointer.
73: */
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*);
78:
79: /*
80: ** Shorthand for the functions above
81: */
82: #define fts2HashInit sqlite3Fts2HashInit
83: #define fts2HashInsert sqlite3Fts2HashInsert
84: #define fts2HashFind sqlite3Fts2HashFind
85: #define fts2HashClear sqlite3Fts2HashClear
86:
87: /*
88: ** Macros for looping over all elements of a hash table. The idiom is
89: ** like this:
90: **
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: ** }
98: */
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)
104:
105: /*
106: ** Number of entries in a hash table
107: */
108: #define fts2HashCount(H) ((H)->count)
109:
110: #endif /* _FTS2_HASH_H_ */
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