Index: src/backend/utils/adt/Makefile
===================================================================
RCS file: /home/sushant/devel/pgsql-cvs/pgsql/src/backend/utils/adt/Makefile,v
retrieving revision 1.69
diff -u -r1.69 Makefile
--- src/backend/utils/adt/Makefile	19 Feb 2008 10:30:08 -0000	1.69
+++ src/backend/utils/adt/Makefile	31 May 2008 19:57:34 -0000
@@ -29,7 +29,7 @@
 	tsginidx.o tsgistidx.o tsquery.o tsquery_cleanup.o tsquery_gist.o \
 	tsquery_op.o tsquery_rewrite.o tsquery_util.o tsrank.o \
 	tsvector.o tsvector_op.o tsvector_parser.o \
-	txid.o uuid.o xml.o
+	txid.o uuid.o xml.o phrase_search.o
 
 like.o: like.c like_match.c
 
Index: src/backend/utils/adt/phrase_search.c
===================================================================
RCS file: src/backend/utils/adt/phrase_search.c
diff -N src/backend/utils/adt/phrase_search.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/backend/utils/adt/phrase_search.c	31 May 2008 19:56:59 -0000
@@ -0,0 +1,167 @@
+#include "postgres.h"
+
+#include "tsearch/ts_type.h"
+#include "tsearch/ts_utils.h"
+
+#include "fmgr.h"
+
+#ifdef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+
+PG_FUNCTION_INFO_V1(is_phrase_present);
+Datum is_phrase_present(PG_FUNCTION_ARGS);
+
+typedef struct {
+	WordEntryPosVector 	*posVector;
+	int4                	posInPhrase;
+	int4 			curpos;	
+} PhraseInfo;
+
+static int
+WordCompareVectorEntry(char *eval, WordEntry *ptr, ParsedWord *prsdword)
+{
+	if (ptr->len == prsdword->len)
+		return strncmp(
+					   eval + ptr->pos,
+					   prsdword->word,
+					   prsdword->len);
+
+	return (ptr->len > prsdword->len) ? 1 : -1;
+}
+
+/*
+ * Returns a pointer to a WordEntry from tsvector t corresponding to prsdword. 
+ * Returns NULL if not found.
+ */
+static WordEntry *
+find_wordentry_prsdword(TSVector t, ParsedWord *prsdword)
+{
+	WordEntry  *StopLow = ARRPTR(t);
+	WordEntry  *StopHigh = (WordEntry *) STRPTR(t);
+	WordEntry  *StopMiddle;
+	int			difference;
+
+	/* Loop invariant: StopLow <= item < StopHigh */
+
+	while (StopLow < StopHigh)
+	{
+		StopMiddle = StopLow + (StopHigh - StopLow) / 2;
+		difference = WordCompareVectorEntry(STRPTR(t), StopMiddle, prsdword);
+		if (difference == 0)
+			return StopMiddle;
+		else if (difference < 0)
+			StopLow = StopMiddle + 1;
+		else
+			StopHigh = StopMiddle;
+	}
+
+	return NULL;
+}
+
+
+static int4 
+check_and_advance(int4 i, PhraseInfo *phraseInfo)
+{
+ 	WordEntryPosVector *posvector1, *posvector2;
+	int4 diff;
+
+	posvector1 = phraseInfo[i].posVector;
+        posvector2 = phraseInfo[i+1].posVector;
+	
+	diff = phraseInfo[i+1].posInPhrase - phraseInfo[i].posInPhrase;
+	while (posvector2->pos[phraseInfo[i+1].curpos] - posvector1->pos[phraseInfo[i].curpos] < diff)
+		if (phraseInfo[i+1].curpos >= posvector2->npos - 1)
+			return 2;
+		else
+			phraseInfo[i+1].curpos += 1;
+
+	if (posvector2->pos[phraseInfo[i+1].curpos] - posvector1->pos[phraseInfo[i].curpos] == diff)
+		return 1;
+	else
+		return 0;
+}
+
+int4
+initialize_phraseinfo(ParsedText *prs, TSVector t, PhraseInfo *phraseInfo)
+{
+	WordEntry *entry;
+	int4 i;
+
+	for (i = 0; i < prs->curwords; i++)
+	{
+		phraseInfo[i].posInPhrase = prs->words[i].pos.pos;
+		entry = find_wordentry_prsdword(t, &(prs->words[i]));
+		if (entry == NULL)
+			return 0;
+		else
+			phraseInfo[i].posVector = _POSVECPTR(t, entry);
+	}			
+	return 1;
+}
+Datum
+is_phrase_present(PG_FUNCTION_ARGS)
+{
+	ParsedText	prs;
+	int4		numwords, i, retval, found = 0;
+	PhraseInfo      *phraseInfo;
+	text    	*phrase	= PG_GETARG_TEXT_P(0);
+	TSVector 	t	= PG_GETARG_TSVECTOR(1);
+        Oid        	cfgId   = getTSCurrentConfig(true);
+
+	prs.lenwords = (VARSIZE(phrase) - VARHDRSZ) / 6;            /* just estimation of                                                                                                                * word's number */
+	if (prs.lenwords == 0)
+		prs.lenwords = 2;
+	prs.curwords = 0;
+	prs.pos = 0;
+	prs.words = (ParsedWord *) palloc0(sizeof(ParsedWord) * prs.lenwords);
+
+	parsetext(cfgId, &prs, VARDATA(phrase), VARSIZE(phrase) - VARHDRSZ);
+
+	// allocate & initialize 
+	numwords 	= prs.curwords;
+	phraseInfo	= palloc0(numwords * sizeof(PhraseInfo));
+
+	
+	if (numwords > 0 && initialize_phraseinfo(&prs, t, phraseInfo))
+	{
+		// if there is only one word and we are able to initialize 
+		// the phraseInfo then it is a success
+		if (numwords == 1)
+			found = 1;
+		while (!found)
+		{
+			retval = check_and_advance(0, phraseInfo); 
+			if (retval == 2)
+				break;
+			else if (retval == 1)
+			{
+				for (i = 1; i < numwords - 1; i++)
+				{
+					retval = check_and_advance(i, phraseInfo);
+					if (retval == 2 || retval == 0)	
+						break;
+				}
+				if (i >= numwords - 1)
+					// found a phrase
+					found = 1;
+				else if (retval == 2)
+					// no chance of finding a phrase
+					break;
+			}
+			// now move the pos of 0th phrase 
+			if (phraseInfo[0].curpos >= phraseInfo[0].posVector->npos- 1)
+				// no chance of finding a phrase
+				break; 
+			else
+				phraseInfo[0].curpos += 1;
+		}
+	}
+	pfree(phraseInfo);
+	pfree(prs.words);
+	// prepare to leave
+	PG_FREE_IF_COPY(phrase, 0);
+	PG_FREE_IF_COPY(t, 1);
+	// return 
+	PG_RETURN_INT32(found);
+}