improve string find algorithm

Message ID 20170106212329.GK2966@redhat.com
State New
Headers show

Commit Message

Jonathan Wakely Jan. 6, 2017, 9:23 p.m.
On 06/01/17 20:32 +0000, Jonathan Wakely wrote:
>On 06/01/17 13:35 +0000, Jonathan Wakely wrote:

>>I'm surprised we don't have any tests for this case, but apparently we

>>don't, as your patch passes all our tests.

>

>My bad, we do have tests that FAIL with this patch, but only after a

>'make clean' (otherwise the explicit instantiation definitions in the

>library don't get rebuilt after applying the patch, so the tests use

>the old code).

>

>FAIL: 21_strings/basic_string/operations/find/char/1.cc execution test

>FAIL: 21_strings/basic_string/operations/find/wchar_t/1.cc execution test

>

>These fail on assert(s.find(s, 1) == std::string::npos) which gives

>the wrong answer as explained in my previous mail.

>

>The infinite loop caused by this patch isn't caught by any existing

>tests, so I'll add a check for that.


Committed to trunk.

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commit b81b226d9eb336f205e5ac91fb8ab4bbbfaf2cb8
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jan 6 21:20:57 2017 +0000

    Add more tests for std::basic_string::find
    
    	* testsuite/21_strings/basic_string/operations/find/char/6.cc: New.
    	* testsuite/21_strings/basic_string/operations/find/wchar_t/6.cc: New.

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/char/6.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/char/6.cc
new file mode 100644
index 0000000..6925fbb
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/char/6.cc
@@ -0,0 +1,41 @@ 
+// 2017-01-06  Jonathan Wakely  <jwakely@redhat.com>
+
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++11 21.4.7.2 [string::find] basic_string find
+
+#include <string>
+#include <testsuite_hooks.h>
+
+// https://gcc.gnu.org/ml/libstdc++/2017-01/msg00021.html
+void test01()
+{
+  typedef std::string string_type;
+  string_type::size_type npos = string_type::npos;
+
+  string_type use = "aaa";
+  string_type::size_type pos1 = use.find("ab");
+
+  VERIFY( pos1 == npos );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/wchar_t/6.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/wchar_t/6.cc
new file mode 100644
index 0000000..eb3463d
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/find/wchar_t/6.cc
@@ -0,0 +1,41 @@ 
+// 2017-01-06  Jonathan Wakely  <jwakely@redhat.com>
+
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++11 21.4.7.2 [string::find] basic_string find
+
+#include <string>
+#include <testsuite_hooks.h>
+
+// https://gcc.gnu.org/ml/libstdc++/2017-01/msg00021.html
+void test01()
+{
+  typedef std::wstring string_type;
+  string_type::size_type npos = string_type::npos;
+
+  string_type use = L"aaa";
+  string_type::size_type pos1 = use.find(L"ab");
+
+  VERIFY( pos1 == npos );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}