/*
** 2014 May 31
**
** 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.
**
******************************************************************************
**
** Interfaces to extend FTS5. Using the interfaces defined in this file,
** FTS5 may be extended with:
**
** * custom tokenizers, and
** * custom auxiliary functions.
*/
#ifndef _FTS5_H
#define _FTS5_H
#include "sqlite3.h"
/*************************************************************************
** CUSTOM AUXILIARY FUNCTIONS
**
** Virtual table implemenations may overload SQL functions by implementing
** the sqlite3_module.xFindFunction() method.
*/
typedef struct Fts5ExtensionApi Fts5ExtensionApi;
typedef struct Fts5Context Fts5Context;
typedef void (*fts5_extension_function)(
const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
Fts5Context *pFts, /* First arg to pass to pApi functions */
sqlite3_context *pCtx, /* Context for returning result/error */
int nVal, /* Number of values in apVal[] array */
sqlite3_value **apVal /* Array of trailing arguments */
);
/*
**
** xUserData:
** Return a copy of the context pointer the extension function was
** registered with.
**
** xColumnCount:
** Returns the number of columns in the FTS5 table.
**
** xColumnSize:
** Reports the size in tokens of a column value from the current row.
**
** xColumnText:
** Reports the size in tokens of a column value from the current row.
**
** xPhraseCount:
** Returns the number of phrases in the current query expression.
**
** xPhraseSize:
** Returns the number of tokens in phrase iPhrase of the query. Phrases
** are numbered starting from zero.
**
** xRowid:
** Returns the rowid of the current row.
**
** xPoslist:
** Iterate through instances of phrase iPhrase in the current row.
*/
struct Fts5ExtensionApi {
int iVersion; /* Currently always set to 1 */
void *(*xUserData)(Fts5Context*);
int (*xColumnCount)(Fts5Context*);
int (*xColumnAvgSize)(Fts5Context*, int iCol, int *pnToken);
int (*xTokenize)(Fts5Context*,
const char *pText, int nText, /* Text to tokenize */
void *pCtx, /* Context passed to xToken() */
int (*xToken)(void*, const char*, int, int, int, int) /* Callback */
);
int (*xPhraseCount)(Fts5Context*);
int (*xPhraseSize)(Fts5Context*, int iPhrase);
sqlite3_int64 (*xRowid)(Fts5Context*);
int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
int (*xPoslist)(Fts5Context*, int iPhrase, int *pi, int *piCol, int *piOff);
};
/*
** CUSTOM AUXILIARY FUNCTIONS
*************************************************************************/
#endif /* _FTS5_H */