Initial Commit

OU4/src/dlist/dlist_mwe2i.c

@@ -0,0 +1,136 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <dlist.h>
+
+/*
+ * Minimum working example for dlist.c that shows how the internal
+ * structure of a list can be visualized. In this version, the list
+ * "owns" the payload memory, i.e., the list takes over the
+ * responsibility to deallocate the payload memory when the
+ * corresponding elements are removed. See list_mwe1i.c for a version
+ * where the list does not take over the responsibility.
+ *
+ * Authors: Niclas Borlin (niclas@cs.umu.se)
+ *
+ * Version information:
+ *   v1.0 2024-03-14: First public version.
+ *   v1.1 2024-03-15: Moved printout of dot instructions to separate function.
+ */
+
+#define VERSION "v1.1"
+#define VERSION_DATE "2024-03-15"
+
+// Make a dynamic copy of the input string.
+char *copy_string(char *str)
+{
+    char *copy = calloc(strlen(str) + 1, sizeof(char));
+    strcpy(copy, str);
+    return copy;
+}
+
+// Return the memory occupied by the string
+void kill_string(void *v)
+{
+    char *p = v; // Convert to a char ptr, useful in a debugger
+    free(p);
+}
+
+// String print function.
+void print_string(const void *value)
+{
+    const char *s=value;
+    printf("\"%s\"", s);
+}
+
+void print_string_internal(const void *value)
+{
+    const char *s=value;
+    // We must double-escape the double quotes since the output will
+    // be parsed a second time by graphviz.
+    printf("\\\"%s\\\"", s);
+}
+
+// Print cut lines before and after a call list_print_internal.
+void print_internal_with_cut_lines(const dlist *l, const char *desc)
+{
+    // Internal counter that will be remembered between calls.
+
+    // Used to generate sequentially numbered -- CUT HERE -- marker lines
+    // to enable automatic parsing of the output.
+    static int cut = 1;
+
+    // Print starting marker line.
+    printf("\n--- START CUT HERE %d ---\n", cut);
+
+    // Call the internal print function to get the actual dot code.
+    dlist_print_internal(l, print_string_internal, desc, 0);
+
+    // Print ending marker line
+    printf("--- END CUT HERE %d ---\n\n", cut);
+
+    // Increment the cut number. Will be remembered next time the
+    // function is called since cut is a static variable.
+    cut++;
+}
+
+// Print a message with intructions how to use the dot output. prog is
+// the name of the executable.
+void print_dot_usage(char *prog)
+{
+    printf("\nGenerate dot code to visualize internal structure with GraphViz. ");
+    printf("Use\n\n%s ", prog);
+    printf("| sed -n '/START CUT HERE X/,/END CUT HERE X/{//!p}' | dot -Tsvg > /tmp/dot.svg\n\n");
+    printf("to generate an svg file of cut X (replace X by the requested cut number).\n");
+    printf("The generated file can then be visualized with\n\n");
+    printf("firefox /tmp/dot.svg\n\n");
+    printf("Use -Tpng to generate a .png file instead. "
+           "See graphviz.org and %s for documentation.\n", __FILE__);
+
+    printf("\n--- Start of normal output ---\n\n");
+}
+
+// Test program.
+int main(int argc, char *argv[])
+{
+    printf("%s, %s %s: Create list of strings without memfreehandler.\n",
+           __FILE__, VERSION, VERSION_DATE);
+    printf("Code base version %s (%s).\n\n", CODE_BASE_VERSION, CODE_BASE_RELEASE_DATE);
+
+    print_dot_usage(argv[0]);
+
+    // Names to insert in the list.
+    char *names[] = {"Alfons", "Bengt", "Cia", "David", "Florian", "Gunnar"};
+
+    // Create the list
+    dlist *l = dlist_empty(kill_string);
+
+    printf("Empty list from the outside:\n");
+    dlist_print(l, print_string);
+    print_internal_with_cut_lines(l, "Empty list showing the internal structure");
+
+    dlist_pos p = dlist_first(l);
+    for (int i = 0; i < sizeof(names) / sizeof(names[0]); i++) {
+        // Insert dynamic copies of strings at last position.
+        p = dlist_insert(l, copy_string(names[i]), p);
+        p = dlist_next(l, p);
+    }
+    // Print the list.
+    printf("DList from the outside after inserting 6 strings:\n");
+    dlist_print(l, print_string);
+    const char *long_desc = __FILE__
+        ": Internal structure of the DList after inserting 6 strings.\n"
+        "Red lines are used for the list payload.\n\n"
+        "The solid red lines indicate that the payload memory is\n"
+        "OWNED -- not borrowed -- by the list, i.e., the payload\n"
+        "memory WILL be deallocated by the list.\n\n"
+        "See dlist_mwe1i for a list example\nthat borrows the payload memory.";
+    print_internal_with_cut_lines(l, long_desc);
+
+    // Destroy the list.
+    dlist_kill(l);
+
+    printf("\nNormal exit.\n\n");
+    return 0;
+}