Fix subpath and subltree. Allow to return '' value.

subpath(ltree,0,0) returns ''.

diff --git a/contrib/ltree/expected/ltree.out b/contrib/ltree/expected/ltree.out
index d856f0dbabc2b06cc12da2328a0e37c050887418..a87738bf35d49ae9524097b633491f157a23ad6c 100644 (file)
--- a/contrib/ltree/expected/ltree.out
+++ b/contrib/ltree/expected/ltree.out
@@ -74,15 +74,15 @@ SELECT subpath('Top.Child1.Child2',0,-1);
 (1 row)
 
 SELECT subpath('Top.Child1.Child2',0,0);
-      subpath      
--------------------
- Top.Child1.Child2
+ subpath 
+---------
+ 
 (1 row)
 
 SELECT subpath('Top.Child1.Child2',1,0);
-    subpath    
----------------
- Child1.Child2
+ subpath 
+---------
+ 
 (1 row)
 
 SELECT subpath('Top.Child1.Child2',0);

diff --git a/contrib/ltree/ltree_op.c b/contrib/ltree/ltree_op.c
index 28fcfb7f7e3bfe4c053311ba54da113fd4e48924..44721bf6d0ed88a834a23dbc5bdccc02304c1e27 100644 (file)
--- a/contrib/ltree/ltree_op.c
+++ b/contrib/ltree/ltree_op.c
@@ -196,12 +196,13 @@ inner_subltree(ltree * t, int4 startpos, int4 endpos)
        ltree      *res;
        int                     i;
 
-       if (startpos < 0 || endpos < 0 || startpos >= t->numlevel || startpos >= endpos)
+       if (startpos < 0 || endpos < 0 || startpos >= t->numlevel || startpos > endpos)
                elog(ERROR, "Wrong positions");
 
        if (endpos > t->numlevel)
                endpos = t->numlevel;
 
+       start = end = (char *) ptr;
        for (i = 0; i < endpos; i++)
        {
                if (i == startpos)
@@ -258,7 +259,7 @@ subpath(PG_FUNCTION_ARGS)
        if (len < 0)
                end = t->numlevel + len;
        else if (len == 0)
-               end = 0xffff;
+               end = (fcinfo->nargs == 3) ? start : 0xffff;
 
        res = inner_subltree(t, start, end);