Introduce string_printf

This introduces the string_printf function.  Like asprintf, but
returns a std::string.

gdb/ChangeLog:
2016-11-08  Pedro Alves  <palves@redhat.com>

	* Makefile.in (COMMON_OBS): Add utils-selftests.o.
	* common/common-utils.c (string_printf): New function.
	* common/common-utils.h: Include <string>.
	(string_printf): Declare.
	* utils-selftests.c: New file.

1 files changed, 60 insertions, 0 deletions

diff --git a/gdb/utils-selftests.c b/gdb/utils-selftests.c
new file mode 100644
index 0000000000..f424655546
--- /dev/null
+++ b/gdb/utils-selftests.c
@@ -0,0 +1,60 @@
+/* Self tests for general utility routines for GDB, the GNU debugger.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "selftest.h"
+
+#if GDB_SELF_TEST
+
+namespace selftests {
+
+/* common-utils self tests.  Defined here instead of in
+   common/common-utils.c because that file is shared with
+   gdbserver.  */
+
+static void
+common_utils_tests (void)
+{
+  SELF_CHECK (string_printf ("%s", "") == "");
+  SELF_CHECK (string_printf ("%d comes before 2", 1) == "1 comes before 2");
+  SELF_CHECK (string_printf ("hello %s", "world") == "hello world");
+
+#define X10 "0123456789"
+#define X100 X10 X10 X10 X10 X10 X10 X10 X10 X10 X10
+#define X1000 X100 X100 X100 X100 X100 X100 X100 X100 X100 X100
+#define X10000 X1000 X1000 X1000 X1000 X1000 X1000 X1000 X1000 X1000 X1000
+#define X100000 X10000 X10000 X10000 X10000 X10000 X10000 X10000 X10000 X10000 X10000
+  SELF_CHECK (string_printf ("%s", X10) == X10);
+  SELF_CHECK (string_printf ("%s", X100) == X100);
+  SELF_CHECK (string_printf ("%s", X1000) == X1000);
+  SELF_CHECK (string_printf ("%s", X10000) == X10000);
+  SELF_CHECK (string_printf ("%s", X100000) == X100000);
+}
+
+} /* namespace selftests */
+
+#endif
+
+void
+_initialize_utils_selftests (void)
+{
+#if GDB_SELF_TEST
+  register_self_test (selftests::common_utils_tests);
+#endif
+}