Initial commit: cframework. Longbow and Libparc

Change-Id: I90378dbd30da6033b20fb1f829b3b822cf366c59
Signed-off-by: Luca Muscariello <lumuscar+fdio@cisco.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/libparc/examples/How To Extend a PARCObject/HowToExtendAPARCObject.c b/libparc/examples/How To Extend a PARCObject/HowToExtendAPARCObject.c
new file mode 100644
index 00000000..e98018d7
--- /dev/null
+++ b/libparc/examples/How To Extend a PARCObject/HowToExtendAPARCObject.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+
+/**
+ *
+ * This example shows a simple extention of an existing PARC Object implementation
+ * (PARCString) to replace the default implementation of the Compare() function with another.
+ *
+ * The demonstration shows how to reverse the sort order of a PARCSortedList
+ * containing a list of PARCString instances without changing PARCSortedList nor PARCString.
+ *
+ */
+#include <stdio.h>
+
+#include <parc/algol/parc_SortedList.h>
+#include <parc/algol/parc_String.h>
+
+/*
+ * This is the default behaviour of the PARCSortedList implementation.
+ */
+void
+forwardOrder(void)
+{
+    PARCSortedList *sortedList = parcSortedList_Create();
+
+    PARCString *aaa = parcString_Create("aaa");
+    PARCString *aab = parcString_Create("aab");
+    PARCString *aac = parcString_Create("aac");
+
+    parcSortedList_Add(sortedList, aaa);
+    parcSortedList_Add(sortedList, aab);
+    parcSortedList_Add(sortedList, aac);
+
+    parcSortedList_Display(sortedList, 0);
+    parcString_Release(&aaa);
+    parcString_Release(&aab);
+    parcString_Release(&aac);
+}
+
+/*
+ * This function will be substituted for the default Compare implementation in the PARCString object.
+ */
+int
+parcString_ReverseCompare(const PARCString *string, const PARCString *other)
+{
+    return parcString_Compare(string, other) * -1;
+}
+
+parcObject_Extends(PARCReverseString, PARCString,
+                   .compare = (PARCObjectCompare *) parcString_ReverseCompare);
+
+
+PARCString *
+parcMyString_Create(const char *string)
+{
+    PARCString *result = parcString_Create(string);
+
+    // By setting the descriptor to our special descriptor here, we effectively
+    // substitute the default compare function with our parcString_ReverseCompare
+    parcObject_SetDescriptor(result, &parcObject_DescriptorName(PARCReverseString));
+
+    return result;
+}
+
+void
+reverseOrder(void)
+{
+    PARCSortedList *sortedList = parcSortedList_Create();
+
+    PARCString *aaa = parcMyString_Create("aaa");
+    PARCString *aab = parcMyString_Create("aab");
+    PARCString *aac = parcMyString_Create("aac");
+
+    parcSortedList_Add(sortedList, aaa);
+    parcSortedList_Add(sortedList, aab);
+    parcSortedList_Add(sortedList, aac);
+
+    parcSortedList_Display(sortedList, 0);
+    parcString_Release(&aaa);
+    parcString_Release(&aab);
+    parcString_Release(&aac);
+}
+
+int
+main(int argc, const char *argv[argc])
+{
+    forwardOrder();
+    reverseOrder();
+    return 0;
+}