first commit for openGauss server

contrib/test_parser/test_parser.cpp

@@ -0,0 +1,127 @@
+/*-------------------------------------------------------------------------
+ *
+ * test_parser.c
+ *	  Simple example of a text search parser
+ *
+ * Copyright (c) 2007-2012, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/test_parser/test_parser.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+#include "knl/knl_variable.h"
+
+#include "fmgr.h"
+
+PG_MODULE_MAGIC;
+
+/*
+ * types
+ */
+
+/* self-defined type */
+typedef struct {
+    char* buffer; /* text to parse */
+    int len;      /* length of the text in buffer */
+    int pos;      /* position of the parser */
+} ParserState;
+
+/* copy-paste from wparser.h of tsearch2 */
+typedef struct {
+    int lexid;
+    char* alias;
+    char* descr;
+} LexDescr;
+
+/*
+ * prototypes
+ */
+PG_FUNCTION_INFO_V1(testprs_start);
+extern "C" Datum testprs_start(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(testprs_getlexeme);
+extern "C" Datum testprs_getlexeme(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(testprs_end);
+extern "C" Datum testprs_end(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(testprs_lextype);
+extern "C" Datum testprs_lextype(PG_FUNCTION_ARGS);
+
+/*
+ * functions
+ */
+Datum testprs_start(PG_FUNCTION_ARGS)
+{
+    ParserState* pst = (ParserState*)palloc0(sizeof(ParserState));
+
+    pst->buffer = (char*)PG_GETARG_POINTER(0);
+    pst->len = PG_GETARG_INT32(1);
+    pst->pos = 0;
+
+    PG_RETURN_POINTER(pst);
+}
+
+Datum testprs_getlexeme(PG_FUNCTION_ARGS)
+{
+    ParserState* pst = (ParserState*)PG_GETARG_POINTER(0);
+    char** t = (char**)PG_GETARG_POINTER(1);
+    int* tlen = (int*)PG_GETARG_POINTER(2);
+    int startpos = pst->pos;
+    int type;
+
+    *t = pst->buffer + pst->pos;
+
+    if (pst->pos < pst->len && (pst->buffer)[pst->pos] == ' ') {
+        /* blank type */
+        type = 12;
+        /* go to the next non-space character */
+        while (pst->pos < pst->len && (pst->buffer)[pst->pos] == ' ')
+            (pst->pos)++;
+    } else {
+        /* word type */
+        type = 3;
+        /* go to the next space character */
+        while (pst->pos < pst->len && (pst->buffer)[pst->pos] != ' ')
+            (pst->pos)++;
+    }
+
+    *tlen = pst->pos - startpos;
+
+    /* we are finished if (*tlen == 0) */
+    if (*tlen == 0)
+        type = 0;
+
+    PG_RETURN_INT32(type);
+}
+
+Datum testprs_end(PG_FUNCTION_ARGS)
+{
+    ParserState* pst = (ParserState*)PG_GETARG_POINTER(0);
+
+    pfree(pst);
+    PG_RETURN_VOID();
+}
+
+Datum testprs_lextype(PG_FUNCTION_ARGS)
+{
+    /*
+     * Remarks: - we have to return the blanks for headline reason - we use
+     * the same lexids like Teodor in the default word parser; in this way we
+     * can reuse the headline function of the default word parser.
+     */
+    LexDescr* descr = (LexDescr*)palloc(sizeof(LexDescr) * (2 + 1));
+
+    /* there are only two types in this parser */
+    descr[0].lexid = 3;
+    descr[0].alias = pstrdup("word");
+    descr[0].descr = pstrdup("Word");
+    descr[1].lexid = 12;
+    descr[1].alias = pstrdup("blank");
+    descr[1].descr = pstrdup("Space symbols");
+    descr[2].lexid = 0;
+
+    PG_RETURN_POINTER(descr);
+}