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131 lines
2.8 KiB
C
131 lines
2.8 KiB
C
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/*-------------------------------------------------------------------------
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*
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* test_parser.c
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* Simple example of a text search parser
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*
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* Copyright (c) 2007, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/contrib/test_parser/test_parser.c,v 1.1 2007/10/15 21:36:50 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "fmgr.h"
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PG_MODULE_MAGIC;
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/*
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* types
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*/
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/* self-defined type */
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typedef struct {
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char * buffer; /* text to parse */
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int len; /* length of the text in buffer */
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int pos; /* position of the parser */
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} ParserState;
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/* copy-paste from wparser.h of tsearch2 */
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typedef struct {
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int lexid;
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char *alias;
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char *descr;
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} LexDescr;
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/*
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* prototypes
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*/
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PG_FUNCTION_INFO_V1(testprs_start);
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Datum testprs_start(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(testprs_getlexeme);
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Datum testprs_getlexeme(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(testprs_end);
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Datum testprs_end(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(testprs_lextype);
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Datum testprs_lextype(PG_FUNCTION_ARGS);
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/*
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* functions
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*/
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Datum testprs_start(PG_FUNCTION_ARGS)
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{
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ParserState *pst = (ParserState *) palloc0(sizeof(ParserState));
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pst->buffer = (char *) PG_GETARG_POINTER(0);
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pst->len = PG_GETARG_INT32(1);
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pst->pos = 0;
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PG_RETURN_POINTER(pst);
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}
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Datum testprs_getlexeme(PG_FUNCTION_ARGS)
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{
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ParserState *pst = (ParserState *) PG_GETARG_POINTER(0);
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char **t = (char **) PG_GETARG_POINTER(1);
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int *tlen = (int *) PG_GETARG_POINTER(2);
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int type;
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*tlen = pst->pos;
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*t = pst->buffer + pst->pos;
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if ((pst->buffer)[pst->pos] == ' ')
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{
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/* blank type */
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type = 12;
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/* go to the next non-white-space character */
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while ((pst->buffer)[pst->pos] == ' ' &&
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pst->pos < pst->len)
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(pst->pos)++;
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} else {
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/* word type */
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type = 3;
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/* go to the next white-space character */
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while ((pst->buffer)[pst->pos] != ' ' &&
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pst->pos < pst->len)
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(pst->pos)++;
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}
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*tlen = pst->pos - *tlen;
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/* we are finished if (*tlen == 0) */
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if (*tlen == 0)
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type=0;
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PG_RETURN_INT32(type);
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}
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Datum testprs_end(PG_FUNCTION_ARGS)
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{
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ParserState *pst = (ParserState *) PG_GETARG_POINTER(0);
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pfree(pst);
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PG_RETURN_VOID();
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}
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Datum testprs_lextype(PG_FUNCTION_ARGS)
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{
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/*
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* Remarks:
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* - we have to return the blanks for headline reason
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* - we use the same lexids like Teodor in the default
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* word parser; in this way we can reuse the headline
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* function of the default word parser.
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*/
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LexDescr *descr = (LexDescr *) palloc(sizeof(LexDescr) * (2+1));
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/* there are only two types in this parser */
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descr[0].lexid = 3;
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descr[0].alias = pstrdup("word");
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descr[0].descr = pstrdup("Word");
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descr[1].lexid = 12;
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descr[1].alias = pstrdup("blank");
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descr[1].descr = pstrdup("Space symbols");
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descr[2].lexid = 0;
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PG_RETURN_POINTER(descr);
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}
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