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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_ */