New file scratch_buffer_dupfree.c

* lib/malloc/scratch_buffer_dupfree.c: New file, from Gnulib
(originally from glibc 2.33 code).
This is needed on macOS and some other platforms;
I forgot to commit it in the most recent Gnulib update.

diff --git a/lib/malloc/scratch_buffer_dupfree.c b/lib/malloc/scratch_buffer_dupfree.c
new file mode 100644 (file)
index 0000000..775bff5
--- /dev/null
+++ b/lib/malloc/scratch_buffer_dupfree.c
@@ -0,0 +1,41 @@
+/* Variable-sized buffer with on-stack default allocation.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C 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 of the License, or (at your option) any later version.
+
+   The GNU C 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 the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
+#include <scratch_buffer.h>
+#include <string.h>
+
+void *
+__libc_scratch_buffer_dupfree (struct scratch_buffer *buffer, size_t size)
+{
+  void *data = buffer->data;
+  if (data == buffer->__space.__c)
+    {
+      void *copy = malloc (size);
+      return copy != NULL ? memcpy (copy, data, size) : NULL;
+    }
+  else
+    {
+      void *copy = realloc (data, size);
+      return copy != NULL ? copy : data;
+    }
+}
+libc_hidden_def (__libc_scratch_buffer_dupfree)