Refactored linked list administration in rhc so that it becomes reusable

Signed-off-by: Dennis Potman <dennis.potman@adlinktech.com>

src/ddsrt/CMakeLists.txt

@@ -101,6 +101,10 @@ set(include_path "${CMAKE_CURRENT_SOURCE_DIR}/include")
 set(source_path "${CMAKE_CURRENT_SOURCE_DIR}/src")
 
 list(APPEND headers
+  "${include_path}/dds/ddsrt/avl.h"
+  "${include_path}/dds/ddsrt/fibheap.h"
+  "${include_path}/dds/ddsrt/hopscotch.h"
+  "${include_path}/dds/ddsrt/thread_pool.h"
   "${include_path}/dds/ddsrt/log.h"
   "${include_path}/dds/ddsrt/retcode.h"
   "${include_path}/dds/ddsrt/attributes.h"
@@ -113,7 +117,8 @@ list(APPEND headers
   "${include_path}/dds/ddsrt/strtol.h"
   "${include_path}/dds/ddsrt/types.h"
   "${include_path}/dds/ddsrt/countargs.h"
-  "${include_path}/dds/ddsrt/static_assert.h")
+  "${include_path}/dds/ddsrt/static_assert.h"
+  "${include_path}/dds/ddsrt/circlist.h")
 
 list(APPEND sources
   "${source_path}/bswap.c"
@@ -121,21 +126,14 @@ list(APPEND sources
   "${source_path}/log.c"
   "${source_path}/retcode.c"
   "${source_path}/strtod.c"
-  "${source_path}/strtol.c")
-
-list(APPEND headers
-  "${include_path}/dds/ddsrt/avl.h"
-  "${include_path}/dds/ddsrt/fibheap.h"
-  "${include_path}/dds/ddsrt/hopscotch.h"
-  "${include_path}/dds/ddsrt/thread_pool.h")
-
-list(APPEND sources
+  "${source_path}/strtol.c"
   "${source_path}/avl.c"
   "${source_path}/expand_envvars.c"
   "${source_path}/fibheap.c"
   "${source_path}/hopscotch.c"
   "${source_path}/thread_pool.c"
-  "${source_path}/xmlparser.c")
+  "${source_path}/xmlparser.c"
+  "${source_path}/circlist.c")
 
 # Not every target offers the same set of features. For embedded targets the
 # set of features may even be different between builds. e.g. a FreeRTOS build

src/ddsrt/include/dds/ddsrt/circlist.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright(c) 2006 to 2019 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#ifndef DDSRT_CIRCLIST_H
+#define DDSRT_CIRCLIST_H
+
+/* Circular doubly linked list implementation */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "dds/export.h"
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#define DDSRT_FROM_CIRCLIST(typ_, member_, cle_) ((typ_ *) ((char *) (cle_) - offsetof (typ_, member_)))
+
+struct ddsrt_circlist {
+  struct ddsrt_circlist_elem *latest; /* pointer to latest inserted element */
+};
+
+struct ddsrt_circlist_elem {
+  struct ddsrt_circlist_elem *next;
+  struct ddsrt_circlist_elem *prev;
+};
+
+DDS_EXPORT void ddsrt_circlist_init (struct ddsrt_circlist *list);
+DDS_EXPORT bool ddsrt_circlist_isempty (const struct ddsrt_circlist *list);
+DDS_EXPORT void ddsrt_circlist_append (struct ddsrt_circlist *list, struct ddsrt_circlist_elem *elem);
+DDS_EXPORT void ddsrt_circlist_remove (struct ddsrt_circlist *list, struct ddsrt_circlist_elem *elem);
+DDS_EXPORT struct ddsrt_circlist_elem *ddsrt_circlist_oldest (const struct ddsrt_circlist *list);
+DDS_EXPORT struct ddsrt_circlist_elem *ddsrt_circlist_latest (const struct ddsrt_circlist *list);
+
+#endif /* DDSRT_CIRCLIST_H */

src/ddsrt/src/circlist.c

@@ -0,0 +1,84 @@
+/*
+ * Copyright(c) 2006 to 2019 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#include <assert.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include "dds/ddsrt/circlist.h"
+
+void ddsrt_circlist_init (struct ddsrt_circlist *list)
+{
+  list->latest = NULL;
+}
+
+bool ddsrt_circlist_isempty (const struct ddsrt_circlist *list)
+{
+  return list->latest == NULL;
+}
+
+void ddsrt_circlist_append (struct ddsrt_circlist *list, struct ddsrt_circlist_elem *elem)
+{
+  if (list->latest == NULL)
+    elem->next = elem->prev = elem;
+  else
+  {
+    struct ddsrt_circlist_elem * const hd = list->latest;
+#ifndef NDEBUG
+    {
+      const struct ddsrt_circlist_elem *x = hd;
+      do { assert (x != elem); x = x->next; } while (x != hd);
+    }
+#endif
+    elem->next = hd->next;
+    elem->prev = hd;
+    hd->next = elem;
+    elem->next->prev = elem;
+  }
+  list->latest = elem;
+}
+
+void ddsrt_circlist_remove (struct ddsrt_circlist *list, struct ddsrt_circlist_elem *elem)
+{
+#ifndef NDEBUG
+  {
+    const struct ddsrt_circlist_elem *x = list->latest;
+    assert (x);
+    do { if (x == elem) break; x = x->next; } while (x != list->latest);
+    assert (x == elem);
+  }
+#endif
+  if (elem->next == elem)
+    list->latest = NULL;
+  else
+  {
+    struct ddsrt_circlist_elem * const elem_prev = elem->prev;
+    struct ddsrt_circlist_elem * const elem_next = elem->next;
+    elem_prev->next = elem_next;
+    elem_next->prev = elem_prev;
+    if (list->latest == elem)
+      list->latest = elem_prev;
+  }
+}
+
+struct ddsrt_circlist_elem *ddsrt_circlist_oldest (const struct ddsrt_circlist *list)
+{
+  assert (!ddsrt_circlist_isempty (list));
+  return list->latest->next;
+}
+
+struct ddsrt_circlist_elem *ddsrt_circlist_latest (const struct ddsrt_circlist *list)
+{
+  assert (!ddsrt_circlist_isempty (list));
+  return list->latest;
+}
+
+