Fix text_substr bug intrduced in 7.3 development

tatsuo-ishii · tatsuo-ishii · commit c4e0c113b8f7 · 2002-04-15T07:54:37.000Z
using Joe Conway's patches (submitted at pgsql-patches on 2002/04/08)
 + small fix.
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.82 2002/04/03 05:39:32 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.83 2002/04/15 07:54:37 ishii Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -373,7 +373,10 @@ text_substr(PG_FUNCTION_ARGS)
 	if (eml > 1)
 	{
 		sm = 0;
-		sn = (m + n) * eml + 3; /* +3 to avoid mb characters overhanging slice end */
+		if (n > -1)
+			sn = (m + n) * eml + 3; /* +3 to avoid mb characters overhanging slice end */
+		else
+			sn = n;		/* n < 0 is special-cased by heap_tuple_untoast_attr_slice */
 	}
 #endif 
 
@@ -387,7 +390,10 @@ text_substr(PG_FUNCTION_ARGS)
 	PG_RETURN_NULL();   /* notreached: suppress compiler warning */
 #endif
 #ifdef MULTIBYTE
-	len = pg_mbstrlen_with_len (VARDATA (string), sn - 3);
+	if (n > -1)
+		len = pg_mbstrlen_with_len (VARDATA (string), sn - 3);
+	else	/* n < 0 is special-cased; need full string length */
+		len = pg_mbstrlen_with_len (VARDATA (string), VARSIZE(string)-VARHDRSZ);
 
 	if (m > len)
 	{

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.82 2002/04/03 05:39:32 petere Exp $`
	`11`	`+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.83 2002/04/15 07:54:37 ishii Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -373,7 +373,10 @@ text_substr(PG_FUNCTION_ARGS)`
`373`	`373`	`if (eml > 1)`
`374`	`374`	`{`
`375`	`375`	`sm = 0;`
`376`		`- sn = (m + n) * eml + 3; /* +3 to avoid mb characters overhanging slice end */`
	`376`	`+ if (n > -1)`
	`377`	`+ sn = (m + n) * eml + 3; /* +3 to avoid mb characters overhanging slice end */`
	`378`	`+ else`
	`379`	`+ sn = n; /* n < 0 is special-cased by heap_tuple_untoast_attr_slice */`
`377`	`380`	`}`
`378`	`381`	`#endif`
`379`	`382`
`@@ -387,7 +390,10 @@ text_substr(PG_FUNCTION_ARGS)`
`387`	`390`	`PG_RETURN_NULL(); /* notreached: suppress compiler warning */`
`388`	`391`	`#endif`
`389`	`392`	`#ifdef MULTIBYTE`
`390`		`- len = pg_mbstrlen_with_len (VARDATA (string), sn - 3);`
	`393`	`+ if (n > -1)`
	`394`	`+ len = pg_mbstrlen_with_len (VARDATA (string), sn - 3);`
	`395`	`+ else /* n < 0 is special-cased; need full string length */`
	`396`	`+ len = pg_mbstrlen_with_len (VARDATA (string), VARSIZE(string)-VARHDRSZ);`
`391`	`397`
`392`	`398`	`if (m > len)`
`393`	`399`	`{`