1 files changed, 133 insertions, 0 deletions
diff --git a/hicn-light/src/content_store/listLRU.c b/hicn-light/src/content_store/listLRU.c
new file mode 100755
index 000000000..42b491d7c
--- /dev/null
+++ b/hicn-light/src/content_store/listLRU.c
@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2017-2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <src/config.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/queue.h>
+
+#include <parc/algol/parc_Memory.h>
+#include <parc/assert/parc_Assert.h>
+#include <src/content_store/listLRU.h>
+
+struct list_lru_entry {
+  void *userData;
+
+  // always set to the list
+  ListLru *parentList;
+
+  // indicates if the Entry is currently in the list
+  bool inList;
+
+  TAILQ_ENTRY(list_lru_entry) list;
+};
+
+// this defines the TAILQ structure so we can access the tail pointer
+TAILQ_HEAD(lru_s, list_lru_entry);
+
+struct list_lru {
+  struct lru_s head;
+  size_t itemsInList;
+};
+
+void listLRU_EntryDestroy(ListLruEntry **entryPtr) {
+  parcAssertNotNull(entryPtr,
+                    "Parameter entryPtr must be non-null double pointer");
+
+  ListLruEntry *entry = *entryPtr;
+  if (entry->inList) {
+    TAILQ_REMOVE(&entry->parentList->head, entry, list);
+    parcAssertTrue(
+        entry->parentList->itemsInList > 0,
+        "Invalid state, removed entry from list, but itemsInList is 0");
+    entry->parentList->itemsInList--;
+  }
+
+  parcMemory_Deallocate((void **)&entry);
+  *entryPtr = NULL;
+}
+
+void listLRU_EntryMoveToHead(ListLruEntry *entry) {
+  parcAssertNotNull(entry, "Parameter entry must be non-null");
+
+  TAILQ_REMOVE(&entry->parentList->head, entry, list);
+  TAILQ_INSERT_HEAD(&entry->parentList->head, entry, list);
+}
+
+void *listLRU_EntryGetData(ListLruEntry *entry) { return entry->userData; }
+
+ListLru *listLRU_Create() {
+  ListLru *list = parcMemory_AllocateAndClear(sizeof(ListLru));
+  parcAssertNotNull(list, "parcMemory_AllocateAndClear(%zu) returned NULL",
+                    sizeof(ListLru));
+  list->itemsInList = 0;
+  TAILQ_INIT(&list->head);
+  return list;
+}
+
+void listLRU_Destroy(ListLru **lruPtr) {
+  parcAssertNotNull(lruPtr, "Parameter lruPtr must be non-null double pointer");
+
+  ListLru *lru = *lruPtr;
+
+  ListLruEntry *entry = TAILQ_FIRST(&lru->head);
+  while (entry != NULL) {
+    ListLruEntry *next = TAILQ_NEXT(entry, list);
+    listLRU_EntryDestroy(&entry);
+    entry = next;
+  }
+
+  parcMemory_Deallocate((void **)&lru);
+  *lruPtr = NULL;
+}
+
+ListLruEntry *listLRU_NewHeadEntry(ListLru *lru, void *data) {
+  parcAssertNotNull(lru, "Parameter lru must be non-null");
+  parcAssertNotNull(data, "Parameter data must be non-null");
+
+  ListLruEntry *entry = parcMemory_AllocateAndClear(sizeof(ListLruEntry));
+  parcAssertNotNull(entry, "parcMemory_AllocateAndClear(%zu) returned NULL",
+                    sizeof(ListLruEntry));
+  entry->userData = data;
+  entry->parentList = lru;
+  entry->inList = true;
+
+  TAILQ_INSERT_HEAD(&lru->head, entry, list);
+  lru->itemsInList++;
+
+  return entry;
+}
+
+ListLruEntry *listLRU_PopTail(ListLru *lru) {
+  parcAssertNotNull(lru, "Parameter lru must be non-null");
+
+  ListLruEntry *entry = TAILQ_LAST(&lru->head, lru_s);
+
+  if (entry) {
+    parcAssertTrue(
+        lru->itemsInList > 0,
+        "Invalid state, removed entry from list, but itemsInList is 0");
+    lru->itemsInList--;
+    TAILQ_REMOVE(&lru->head, entry, list);
+    entry->inList = false;
+  }
+
+  return entry;
+}
+
+size_t listLRU_Length(const ListLru *lru) {
+  parcAssertNotNull(lru, "Parameter lru must be non-null");
+  return lru->itemsInList;
+}