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Annotation of embedaddon/sqlite3/ext/fts1/fts1_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 _FTS1_HASH_H_
                     18: #define _FTS1_HASH_H_
                     19: 
                     20: /* Forward declarations of structures. */
                     21: typedef struct fts1Hash fts1Hash;
                     22: typedef struct fts1HashElem fts1HashElem;
                     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 fts1Hash {
                     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:   fts1HashElem *first;    /* The first element of the array */
                     37:   void *(*xMalloc)(int);  /* malloc() function to use */
                     38:   void (*xFree)(void *);  /* free() function to use */
                     39:   int htsize;             /* Number of buckets in the hash table */
                     40:   struct _fts1ht {        /* the hash table */
                     41:     int count;               /* Number of entries with this hash */
                     42:     fts1HashElem *chain;     /* Pointer to first entry with this hash */
                     43:   } *ht;
                     44: };
                     45: 
                     46: /* Each element in the hash table is an instance of the following 
                     47: ** structure.  All elements are stored on a single doubly-linked list.
                     48: **
                     49: ** Again, this structure is intended to be opaque, but it can't really
                     50: ** be opaque because it is used by macros.
                     51: */
                     52: struct fts1HashElem {
                     53:   fts1HashElem *next, *prev; /* Next and previous elements in the table */
                     54:   void *data;                /* Data associated with this element */
                     55:   void *pKey; int nKey;      /* Key associated with this element */
                     56: };
                     57: 
                     58: /*
                     59: ** There are 2 different modes of operation for a hash table:
                     60: **
                     61: **   FTS1_HASH_STRING        pKey points to a string that is nKey bytes long
                     62: **                           (including the null-terminator, if any).  Case
                     63: **                           is respected in comparisons.
                     64: **
                     65: **   FTS1_HASH_BINARY        pKey points to binary data nKey bytes long. 
                     66: **                           memcmp() is used to compare keys.
                     67: **
                     68: ** A copy of the key is made if the copyKey parameter to fts1HashInit is 1.  
                     69: */
                     70: #define FTS1_HASH_STRING    1
                     71: #define FTS1_HASH_BINARY    2
                     72: 
                     73: /*
                     74: ** Access routines.  To delete, insert a NULL pointer.
                     75: */
                     76: void sqlite3Fts1HashInit(fts1Hash*, int keytype, int copyKey);
                     77: void *sqlite3Fts1HashInsert(fts1Hash*, const void *pKey, int nKey, void *pData);
                     78: void *sqlite3Fts1HashFind(const fts1Hash*, const void *pKey, int nKey);
                     79: void sqlite3Fts1HashClear(fts1Hash*);
                     80: 
                     81: /*
                     82: ** Shorthand for the functions above
                     83: */
                     84: #define fts1HashInit   sqlite3Fts1HashInit
                     85: #define fts1HashInsert sqlite3Fts1HashInsert
                     86: #define fts1HashFind   sqlite3Fts1HashFind
                     87: #define fts1HashClear  sqlite3Fts1HashClear
                     88: 
                     89: /*
                     90: ** Macros for looping over all elements of a hash table.  The idiom is
                     91: ** like this:
                     92: **
                     93: **   fts1Hash h;
                     94: **   fts1HashElem *p;
                     95: **   ...
                     96: **   for(p=fts1HashFirst(&h); p; p=fts1HashNext(p)){
                     97: **     SomeStructure *pData = fts1HashData(p);
                     98: **     // do something with pData
                     99: **   }
                    100: */
                    101: #define fts1HashFirst(H)  ((H)->first)
                    102: #define fts1HashNext(E)   ((E)->next)
                    103: #define fts1HashData(E)   ((E)->data)
                    104: #define fts1HashKey(E)    ((E)->pKey)
                    105: #define fts1HashKeysize(E) ((E)->nKey)
                    106: 
                    107: /*
                    108: ** Number of entries in a hash table
                    109: */
                    110: #define fts1HashCount(H)  ((H)->count)
                    111: 
                    112: #endif /* _FTS1_HASH_H_ */