sl@0: /*
sl@0: ** 2001 September 22
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: ** This is the header file for the generic hash-table implemenation
sl@0: ** used in SQLite.  We've modified it slightly to serve as a standalone
sl@0: ** hash table implementation for the full-text indexing module.
sl@0: **
sl@0: */
sl@0: #ifndef _FTS3_HASH_H_
sl@0: #define _FTS3_HASH_H_
sl@0: 
sl@0: /* Forward declarations of structures. */
sl@0: typedef struct fts3Hash fts3Hash;
sl@0: typedef struct fts3HashElem fts3HashElem;
sl@0: 
sl@0: /* A complete hash table is an instance of the following structure.
sl@0: ** The internals of this structure are intended to be opaque -- client
sl@0: ** code should not attempt to access or modify the fields of this structure
sl@0: ** directly.  Change this structure only by using the routines below.
sl@0: ** However, many of the "procedures" and "functions" for modifying and
sl@0: ** accessing this structure are really macros, so we can't really make
sl@0: ** this structure opaque.
sl@0: */
sl@0: struct fts3Hash {
sl@0:   char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
sl@0:   char copyKey;           /* True if copy of key made on insert */
sl@0:   int count;              /* Number of entries in this table */
sl@0:   fts3HashElem *first;    /* The first element of the array */
sl@0:   int htsize;             /* Number of buckets in the hash table */
sl@0:   struct _fts3ht {        /* the hash table */
sl@0:     int count;               /* Number of entries with this hash */
sl@0:     fts3HashElem *chain;     /* Pointer to first entry with this hash */
sl@0:   } *ht;
sl@0: };
sl@0: 
sl@0: /* Each element in the hash table is an instance of the following 
sl@0: ** structure.  All elements are stored on a single doubly-linked list.
sl@0: **
sl@0: ** Again, this structure is intended to be opaque, but it can't really
sl@0: ** be opaque because it is used by macros.
sl@0: */
sl@0: struct fts3HashElem {
sl@0:   fts3HashElem *next, *prev; /* Next and previous elements in the table */
sl@0:   void *data;                /* Data associated with this element */
sl@0:   void *pKey; int nKey;      /* Key associated with this element */
sl@0: };
sl@0: 
sl@0: /*
sl@0: ** There are 2 different modes of operation for a hash table:
sl@0: **
sl@0: **   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
sl@0: **                           (including the null-terminator, if any).  Case
sl@0: **                           is respected in comparisons.
sl@0: **
sl@0: **   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long. 
sl@0: **                           memcmp() is used to compare keys.
sl@0: **
sl@0: ** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.  
sl@0: */
sl@0: #define FTS3_HASH_STRING    1
sl@0: #define FTS3_HASH_BINARY    2
sl@0: 
sl@0: /*
sl@0: ** Access routines.  To delete, insert a NULL pointer.
sl@0: */
sl@0: void sqlite3Fts3HashInit(fts3Hash*, int keytype, int copyKey);
sl@0: void *sqlite3Fts3HashInsert(fts3Hash*, const void *pKey, int nKey, void *pData);
sl@0: void *sqlite3Fts3HashFind(const fts3Hash*, const void *pKey, int nKey);
sl@0: void sqlite3Fts3HashClear(fts3Hash*);
sl@0: 
sl@0: /*
sl@0: ** Shorthand for the functions above
sl@0: */
sl@0: #define fts3HashInit   sqlite3Fts3HashInit
sl@0: #define fts3HashInsert sqlite3Fts3HashInsert
sl@0: #define fts3HashFind   sqlite3Fts3HashFind
sl@0: #define fts3HashClear  sqlite3Fts3HashClear
sl@0: 
sl@0: /*
sl@0: ** Macros for looping over all elements of a hash table.  The idiom is
sl@0: ** like this:
sl@0: **
sl@0: **   fts3Hash h;
sl@0: **   fts3HashElem *p;
sl@0: **   ...
sl@0: **   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
sl@0: **     SomeStructure *pData = fts3HashData(p);
sl@0: **     // do something with pData
sl@0: **   }
sl@0: */
sl@0: #define fts3HashFirst(H)  ((H)->first)
sl@0: #define fts3HashNext(E)   ((E)->next)
sl@0: #define fts3HashData(E)   ((E)->data)
sl@0: #define fts3HashKey(E)    ((E)->pKey)
sl@0: #define fts3HashKeysize(E) ((E)->nKey)
sl@0: 
sl@0: /*
sl@0: ** Number of entries in a hash table
sl@0: */
sl@0: #define fts3HashCount(H)  ((H)->count)
sl@0: 
sl@0: #endif /* _FTS3_HASH_H_ */