[svn:parrot] r48533 - in branches/substr_eq_at: src/string t/op

[chromatic at svn.parrot.org]

Author: chromatic
Date: Mon Aug 16 19:28:18 2010
New Revision: 48533
URL: https://trac.parrot.org/parrot/changeset/48533

Log:
[str] Sanitized Parrot_str_compare_offset.

These new boundary checks help its safety, but they might not be sufficient.
Additional tests welcome.

Modified:
   branches/substr_eq_at/src/string/api.c
   branches/substr_eq_at/t/op/substr_cmp.t

Modified: branches/substr_eq_at/src/string/api.c
==============================================================================
--- branches/substr_eq_at/src/string/api.c	Mon Aug 16 19:14:05 2010	(r48532)
+++ branches/substr_eq_at/src/string/api.c	Mon Aug 16 19:28:18 2010	(r48533)
@@ -1350,6 +1350,12 @@
 {
     ASSERT_ARGS(Parrot_str_compare_offset)
 
+    if (offset > a->strlen)
+        return -1;
+
+    if (offset + length > a->strlen)
+        length = offset - a->strlen;
+
     if (a->encoding == b->encoding)
         return memcmp(a->strstart + offset, b->strstart, length);
 

Modified: branches/substr_eq_at/t/op/substr_cmp.t
==============================================================================
--- branches/substr_eq_at/t/op/substr_cmp.t	Mon Aug 16 19:14:05 2010	(r48532)
+++ branches/substr_eq_at/t/op/substr_cmp.t	Mon Aug 16 19:28:18 2010	(r48533)
@@ -19,7 +19,7 @@
 .sub main :main
     .include 'test_more.pir'
 
-    plan(14)
+    plan(16)
 
     test_cmp_str_at_i_s_sc_ic_ic()
 .end
@@ -67,6 +67,15 @@
 
     $I0 = cmp_str_at $S0, 'xy', 3, 3
     is( $I0, -1, "2nd argument is short" )
+
+    $I0 = cmp_str_at $S0, '', 0, 0
+    is( $I0, 0, "2nd argument is empty" )
+
+    $I0 = cmp_str_at $S0, 'my def = Integer', 0, 16
+    is( $I0, -1, "2nd argument is longer" )
+
+    $I0 = cmp_str_at $S0, 'my def = Integer', 15, 1
+    is( $I0, -1, "offset out of bounds of first string" )
 .end
 
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