From 0dfcfd4814468e949fc34b87f8021271e99f04f0 Mon Sep 17 00:00:00 2001
From: Richard Frith-MacDonald <rfm@gnu.org>
Date: Tue, 23 May 2006 19:29:52 +0000
Subject: [PATCH] Minor substring optimisation

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@22975 72102866-910b-0410-8b05-ffd578937521
---
 ChangeLog         |  2 ++
 Source/GSString.m | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 169ce133a..f2348630b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,8 @@
 	it needed more data even though it had actually completed.
 	* Source/NSException.m: Don't add stacktrace information if we are
 	not building with debug on.
+	* Source/GSString.m: Minor optimisation ... return @"" for all
+	substrings with a zero length range.
 
 2006-05-22  Richard Frith-Macdonald <rfm@gnu.org>
 
diff --git a/Source/GSString.m b/Source/GSString.m
index f5f22b33b..145d771bd 100644
--- a/Source/GSString.m
+++ b/Source/GSString.m
@@ -2455,6 +2455,10 @@ substring_c(GSStr self, NSRange aRange)
     @defs(GSCSubString)
   } *o;
 
+  if (aRange.length == 0)
+    {
+      return @"";
+    }
   o = (typeof(o))NSAllocateObject(GSCSubStringClass,
     0, NSDefaultMallocZone());
   o->_contents.c = self->_contents.c + aRange.location;
@@ -2473,6 +2477,10 @@ substring_u(GSStr self, NSRange aRange)
     @defs(GSUnicodeSubString)
   } *o;
 
+  if (aRange.length == 0)
+    {
+      return @"";
+    }
   o = (typeof(o))NSAllocateObject(GSUnicodeSubStringClass,
     0, NSDefaultMallocZone());
   o->_contents.u = self->_contents.u + aRange.location;
@@ -4127,6 +4135,10 @@ agree, create a new GSUnicodeInlineString otherwise.
 {
   GS_RANGE_CHECK(aRange, _count);
 
+  if (aRange.length == 0)
+    {
+      return @"";
+    }
   if (_flags.wide == 1)
     {
       struct {
@@ -4164,6 +4176,10 @@ agree, create a new GSUnicodeInlineString otherwise.
 {
   GS_RANGE_CHECK(aRange, _count);
 
+  if (aRange.length == 0)
+    {
+      return @"";
+    }
   if (_flags.wide == 1)
     {
       struct {