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Annotation of embedaddon/sqlite3/ext/fts3/fts3_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 _FTS3_HASH_H_
                     18: #define _FTS3_HASH_H_
                     19: 
                     20: /* Forward declarations of structures. */
                     21: typedef struct Fts3Hash Fts3Hash;
                     22: typedef struct Fts3HashElem Fts3HashElem;
                     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 Fts3Hash {
                     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:   Fts3HashElem *first;    /* The first element of the array */
                     37:   int htsize;             /* Number of buckets in the hash table */
                     38:   struct _fts3ht {        /* the hash table */
                     39:     int count;               /* Number of entries with this hash */
                     40:     Fts3HashElem *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 Fts3HashElem {
                     51:   Fts3HashElem *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: **   FTS3_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: **   FTS3_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 fts3HashInit is 1.  
                     67: */
                     68: #define FTS3_HASH_STRING    1
                     69: #define FTS3_HASH_BINARY    2
                     70: 
                     71: /*
                     72: ** Access routines.  To delete, insert a NULL pointer.
                     73: */
                     74: void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey);
                     75: void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData);
                     76: void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey);
                     77: void sqlite3Fts3HashClear(Fts3Hash*);
                     78: Fts3HashElem *sqlite3Fts3HashFindElem(const Fts3Hash *, const void *, int);
                     79: 
                     80: /*
                     81: ** Shorthand for the functions above
                     82: */
                     83: #define fts3HashInit     sqlite3Fts3HashInit
                     84: #define fts3HashInsert   sqlite3Fts3HashInsert
                     85: #define fts3HashFind     sqlite3Fts3HashFind
                     86: #define fts3HashClear    sqlite3Fts3HashClear
                     87: #define fts3HashFindElem sqlite3Fts3HashFindElem
                     88: 
                     89: /*
                     90: ** Macros for looping over all elements of a hash table.  The idiom is
                     91: ** like this:
                     92: **
                     93: **   Fts3Hash h;
                     94: **   Fts3HashElem *p;
                     95: **   ...
                     96: **   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
                     97: **     SomeStructure *pData = fts3HashData(p);
                     98: **     // do something with pData
                     99: **   }
                    100: */
                    101: #define fts3HashFirst(H)  ((H)->first)
                    102: #define fts3HashNext(E)   ((E)->next)
                    103: #define fts3HashData(E)   ((E)->data)
                    104: #define fts3HashKey(E)    ((E)->pKey)
                    105: #define fts3HashKeysize(E) ((E)->nKey)
                    106: 
                    107: /*
                    108: ** Number of entries in a hash table
                    109: */
                    110: #define fts3HashCount(H)  ((H)->count)
                    111: 
                    112: #endif /* _FTS3_HASH_H_ */