fts3_hash.h.svn-base
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- /*
- ** 2001 September 22
- **
- ** The author disclaims copyright to this source code. In place of
- ** a legal notice, here is a blessing:
- **
- ** May you do good and not evil.
- ** May you find forgiveness for yourself and forgive others.
- ** May you share freely, never taking more than you give.
- **
- *************************************************************************
- ** This is the header file for the generic hash-table implemenation
- ** used in SQLite. We've modified it slightly to serve as a standalone
- ** hash table implementation for the full-text indexing module.
- **
- */
- #ifndef _FTS3_HASH_H_
- #define _FTS3_HASH_H_
- /* Forward declarations of structures. */
- typedef struct fts3Hash fts3Hash;
- typedef struct fts3HashElem fts3HashElem;
- /* A complete hash table is an instance of the following structure.
- ** The internals of this structure are intended to be opaque -- client
- ** code should not attempt to access or modify the fields of this structure
- ** directly. Change this structure only by using the routines below.
- ** However, many of the "procedures" and "functions" for modifying and
- ** accessing this structure are really macros, so we can't really make
- ** this structure opaque.
- */
- struct fts3Hash {
- char keyClass; /* HASH_INT, _POINTER, _STRING, _BINARY */
- char copyKey; /* True if copy of key made on insert */
- int count; /* Number of entries in this table */
- fts3HashElem *first; /* The first element of the array */
- int htsize; /* Number of buckets in the hash table */
- struct _fts3ht { /* the hash table */
- int count; /* Number of entries with this hash */
- fts3HashElem *chain; /* Pointer to first entry with this hash */
- } *ht;
- };
- /* Each element in the hash table is an instance of the following
- ** structure. All elements are stored on a single doubly-linked list.
- **
- ** Again, this structure is intended to be opaque, but it can't really
- ** be opaque because it is used by macros.
- */
- struct fts3HashElem {
- fts3HashElem *next, *prev; /* Next and previous elements in the table */
- void *data; /* Data associated with this element */
- void *pKey; int nKey; /* Key associated with this element */
- };
- /*
- ** There are 2 different modes of operation for a hash table:
- **
- ** FTS3_HASH_STRING pKey points to a string that is nKey bytes long
- ** (including the null-terminator, if any). Case
- ** is respected in comparisons.
- **
- ** FTS3_HASH_BINARY pKey points to binary data nKey bytes long.
- ** memcmp() is used to compare keys.
- **
- ** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.
- */
- #define FTS3_HASH_STRING 1
- #define FTS3_HASH_BINARY 2
- /*
- ** Access routines. To delete, insert a NULL pointer.
- */
- void sqlite3Fts3HashInit(fts3Hash*, int keytype, int copyKey);
- void *sqlite3Fts3HashInsert(fts3Hash*, const void *pKey, int nKey, void *pData);
- void *sqlite3Fts3HashFind(const fts3Hash*, const void *pKey, int nKey);
- void sqlite3Fts3HashClear(fts3Hash*);
- /*
- ** Shorthand for the functions above
- */
- #define fts3HashInit sqlite3Fts3HashInit
- #define fts3HashInsert sqlite3Fts3HashInsert
- #define fts3HashFind sqlite3Fts3HashFind
- #define fts3HashClear sqlite3Fts3HashClear
- /*
- ** Macros for looping over all elements of a hash table. The idiom is
- ** like this:
- **
- ** fts3Hash h;
- ** fts3HashElem *p;
- ** ...
- ** for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
- ** SomeStructure *pData = fts3HashData(p);
- ** // do something with pData
- ** }
- */
- #define fts3HashFirst(H) ((H)->first)
- #define fts3HashNext(E) ((E)->next)
- #define fts3HashData(E) ((E)->data)
- #define fts3HashKey(E) ((E)->pKey)
- #define fts3HashKeysize(E) ((E)->nKey)
- /*
- ** Number of entries in a hash table
- */
- #define fts3HashCount(H) ((H)->count)
- #endif /* _FTS3_HASH_H_ */