common: Add new function strlist_rev.

* common/strlist.c (strlist_rev): New function.
* common/t-strlist.c: New file.
* common/Makefile.am (common_sources): Add strlist.c and strlist.h.
(module_tests): Add t-strlist.
(t_strlist_LDADD): New variable.

--
Signed-off-by: Neal H. Walfield <neal@g10code.com>

common/Makefile.am

@@ -85,7 +85,8 @@ common_sources = \
 	ssh-utils.c ssh-utils.h \
 	agent-opt.c \
 	helpfile.c \
-	mkdir_p.c mkdir_p.h
+	mkdir_p.c mkdir_p.h \
+	strlist.c strlist.h
 
 if HAVE_W32_SYSTEM
 common_sources += w32-reg.c w32-afunix.c w32-afunix.h
@@ -150,7 +151,7 @@ endif
 module_tests = t-stringhelp t-timestuff \
                t-convert t-percent t-gettime t-sysutils t-sexputil \
 	       t-session-env t-openpgp-oid t-ssh-utils \
-	       t-mapstrings t-zb32 t-mbox-util t-iobuf
+	       t-mapstrings t-zb32 t-mbox-util t-iobuf t-strlist
 if !HAVE_W32CE_SYSTEM
 module_tests += t-exechelp
 endif
@@ -198,6 +199,7 @@ t_zb32_LDADD = $(t_common_ldadd)
 
 t_mbox_util_LDADD = $(t_common_ldadd)
 t_iobuf_LDADD = $(t_common_ldadd)
+t_strlist_LDADD = $(t_common_ldadd)
 
 # System specific test
 if HAVE_W32_SYSTEM

common/strlist.c

@@ -231,3 +231,22 @@ strlist_length (strlist_t list)
 
   return i;
 }
+
+/* Reverse the list *LIST in place.  */
+strlist_t
+strlist_rev (strlist_t *list)
+{
+  strlist_t l = *list;
+  strlist_t lrev = NULL;
+
+  while (l)
+    {
+      strlist_t tail = l->next;
+      l->next = lrev;
+      lrev = l;
+      l = tail;
+    }
+
+  *list = lrev;
+  return lrev;
+}

common/strlist.h

@@ -58,6 +58,7 @@ char * strlist_pop (strlist_t *list);
 strlist_t strlist_find (strlist_t haystack, const char *needle);
 int strlist_length (strlist_t list);
 
+strlist_t strlist_rev (strlist_t *haystack);
 
 #define FREE_STRLIST(a) do { free_strlist((a)); (a) = NULL ; } while(0)
 

common/t-strlist.c

@@ -0,0 +1,82 @@
+/* t-strlist.c - Regression tests for strist.c
+ * Copyright (C) 2015  g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify it
+ * under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - the GNU General Public License as published by the Free
+ *     Software Foundation; either version 2 of the License, or (at
+ *     your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * GnuPG 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 copies of the GNU General Public License
+ * and the GNU Lesser General Public License along with this program;
+ * if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <string.h>
+
+#include "strlist.h"
+
+#include "t-support.h"
+
+static void
+test_strlist_rev (void)
+{
+  strlist_t s = NULL;
+
+  /* Reversing an empty list should yield the empty list.  */
+  if (! (strlist_rev (&s) == NULL))
+    fail (1);
+
+  add_to_strlist (&s, "1");
+  add_to_strlist (&s, "2");
+  add_to_strlist (&s, "3");
+
+  if (strcmp (s->d, "3") != 0)
+    fail (2);
+  if (strcmp (s->next->d, "2") != 0)
+    fail (2);
+  if (strcmp (s->next->next->d, "1") != 0)
+    fail (2);
+  if (s->next->next->next)
+    fail (2);
+
+  strlist_rev (&s);
+
+  if (strcmp (s->d, "1") != 0)
+    fail (2);
+  if (strcmp (s->next->d, "2") != 0)
+    fail (2);
+  if (strcmp (s->next->next->d, "3") != 0)
+    fail (2);
+  if (s->next->next->next)
+    fail (2);
+}
+
+
+int
+main (int argc, char **argv)
+{
+  (void)argc;
+  (void)argv;
+
+  test_strlist_rev ();
+
+  return 0;
+}