ts_public.h

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/*-------------------------------------------------------------------------
 *
 * ts_public.h
 *    Public interface to various tsearch modules, such as
 *    parsers and dictionaries.
 *
 * Copyright (c) 1998-2013, PostgreSQL Global Development Group
 *
 * src/include/tsearch/ts_public.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef _PG_TS_PUBLIC_H_
#define _PG_TS_PUBLIC_H_

#include "tsearch/ts_type.h"

/*
 * Parser's framework
 */

/*
 * returning type for prslextype method of parser
 */
typedef struct
{
    int         lexid;
    char       *alias;
    char       *descr;
} LexDescr;

/*
 * Interface to headline generator
 */
typedef struct
{
    uint32      selected:1,
                in:1,
                replace:1,
                repeated:1,
                skip:1,
                unused:3,
                type:8,
                len:16;
    char       *word;
    QueryOperand *item;
} HeadlineWordEntry;

typedef struct
{
    HeadlineWordEntry *words;
    int32       lenwords;
    int32       curwords;
    char       *startsel;
    char       *stopsel;
    char       *fragdelim;
    int16       startsellen;
    int16       stopsellen;
    int16       fragdelimlen;
} HeadlineParsedText;

/*
 * Common useful things for tsearch subsystem
 */
extern char *get_tsearch_config_filename(const char *basename,
                            const char *extension);

/*
 * Often useful stopword list management
 */
typedef struct
{
    int         len;
    char      **stop;
} StopList;

extern void readstoplist(const char *fname, StopList *s,
             char *(*wordop) (const char *));
extern bool searchstoplist(StopList *s, char *key);

/*
 * Interface with dictionaries
 */

/* return struct for any lexize function */
typedef struct
{
    /*----------
     * Number of current variant of split word.  For example the Norwegian
     * word 'fotballklubber' has two variants to split: ( fotball, klubb )
     * and ( fot, ball, klubb ). So, dictionary should return:
     *
     * nvariant    lexeme
     *     1       fotball
     *     1       klubb
     *     2       fot
     *     2       ball
     *     2       klubb
     *
     * In general, a TSLexeme will be considered to belong to the same split
     * variant as the previous one if they have the same nvariant value.
     * The exact values don't matter, only changes from one lexeme to next.
     *----------
     */
    uint16      nvariant;

    uint16      flags;          /* See flag bits below */

    char       *lexeme;         /* C string */
} TSLexeme;

/* Flag bits that can appear in TSLexeme.flags */
#define TSL_ADDPOS      0x01
#define TSL_PREFIX      0x02
#define TSL_FILTER      0x04

/*
 * Struct for supporting complex dictionaries like thesaurus.
 * 4th argument for dictlexize method is a pointer to this
 */
typedef struct
{
    bool        isend;          /* in: marks for lexize_info about text end is
                                 * reached */
    bool        getnext;        /* out: dict wants next lexeme */
    void       *private_state;  /* internal dict state between calls with
                                 * getnext == true */
} DictSubState;

#endif   /* _PG_TS_PUBLIC_H_ */