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Annotation of embedaddon/sqlite3/ext/fts2/fts2_hash.h, revision 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_ */