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140 lines
2.8 KiB
C
140 lines
2.8 KiB
C
/*-------------------------------------------------------------------------
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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) 2007-2014, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/test_parser/test_parser.c
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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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{
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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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{
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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
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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
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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 startpos = pst->pos;
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int type;
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*t = pst->buffer + pst->pos;
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if (pst->pos < pst->len &&
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(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-space character */
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while (pst->pos < pst->len &&
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(pst->buffer)[pst->pos] == ' ')
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(pst->pos)++;
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}
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else
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{
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/* word type */
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type = 3;
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/* go to the next space character */
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while (pst->pos < pst->len &&
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(pst->buffer)[pst->pos] != ' ')
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(pst->pos)++;
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}
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*tlen = pst->pos - startpos;
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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
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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
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testprs_lextype(PG_FUNCTION_ARGS)
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{
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/*
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* Remarks: - we have to return the blanks for headline reason - we use
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* the same lexids like Teodor in the default word parser; in this way we
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* can reuse the headline 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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