From a79ff46c2d847db4ef6cc64d93acea8abd0bde1a Mon Sep 17 00:00:00 2001
From: thebeing <thebeing@72102866-910b-0410-8b05-ffd578937521>
Date: Tue, 1 Sep 2015 11:31:16 +0000
Subject: [PATCH] Fix handling of capture groups not participating in the
 current match.

The Cocoa API specifies to return theses as (NSNotFound,0) ranges, but the
ICU API returns them as (-1,-1) pairs of start/end indices. The necessary
conversion was missing here.


git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@38963 72102866-910b-0410-8b05-ffd578937521
---
 ChangeLog                    |  4 ++++
 Source/NSRegularExpression.m | 14 ++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6065d08b5..751fbfd32 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2015-09-01 Niels Grewe <niels.grewe@halbordnung.de>
+
+	* Source/NSRegularExpression.m: Fix handling of empty capture groups.
+
 2015-08-30  Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSOperation.m: Fix potential deadlock with adding observers.
diff --git a/Source/NSRegularExpression.m b/Source/NSRegularExpression.m
index df0cd12b3..3c4de5183 100644
--- a/Source/NSRegularExpression.m
+++ b/Source/NSRegularExpression.m
@@ -297,8 +297,18 @@ prepareResult(NSRegularExpression *regex,
 
   for (i = 0; i < groups; i++)
     {
-      NSUInteger start = uregex_start(r, i, s);
-      NSUInteger end = uregex_end(r, i, s);
+      NSInteger start = uregex_start(r, i, s);
+      NSInteger end = uregex_end(r, i, s);
+      // The ICU API defines -1 as not found. Convert to
+      // NSNotFound if applicable.
+      if (start == -1)
+        {
+          start = NSNotFound;
+        }
+      if (end == -1)
+        {
+          end = NSNotFound;
+        }
 
       if (end < start)
         {