Initial Commit

OU4/src/list/list_mwe1i.c

@@ -0,0 +1,131 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <list.h>
+
+/*
+ * Minimum working example for list.c that shows how the internal
+ * structure of a list can be visualized. In this version, the list
+ * "borrows" the payload memory, i.e., the user of the list is
+ * responsible for deallocating the payload memory. See list_mwe2i.c
+ * for a version where the list takes 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"
+
+// Integers are stored via int pointers stored as void pointers.
+// Convert the given pointer and print the dereferenced value.
+void print_int(const void *data)
+{
+    const int *v = data;
+    printf("%d", *v);
+}
+
+// Create a dynamic copy of the integer i.
+int *int_create(int i)
+{
+    // Allocate memory for an integer and set the value
+    int *v = malloc(sizeof(*v));
+    *v = i;
+    return v;
+}
+
+// Return the memory used by the integer.
+void int_kill(void *v)
+{
+    int *p = v; // Convert to a readable pointer - useful in a debugger
+    free(p);
+}
+
+// Print cut lines before and after a call list_print_internal.
+void print_internal_with_cut_lines(const list *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.
+    list_print_internal(l, print_int, 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");
+}
+
+int main(int argc, char *argv[])
+{
+    printf("%s, %s %s: Create integer list without kill_function.\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]);
+
+    // Create the list.
+    list *l = list_empty(NULL);
+
+    printf("Empty list from the outside:\n");
+    list_print(l, print_int);
+    print_internal_with_cut_lines(l, "Empty list showing the internal structure");
+
+    // Insert the value 5 first in the list.
+    list_insert(l, int_create(5), list_first(l));
+    // Insert the value 8 last in the list.
+    list_insert(l, int_create(8), list_end(l));
+    // Insert the value 2 at the second position in the list.
+    list_insert(l, int_create(2), list_next(l, list_first(l)));
+
+    printf("List from the outside after inserting 3 values:\n");
+    list_print(l, print_int);
+    const char *long_desc = __FILE__
+        ": Internal structure of the List after inserting 3 values.\n"
+        "Red lines are used for the list payload.\n\n"
+        "The dashed red lines indicate that the payload memory is\n"
+        "BORROWED by the list, i.e., the payload\n"
+        "memory will NOT be deallocated by the list.\n\n"
+        "See list_mwe2i for a list example\nthat owns the payload memory.";
+    print_internal_with_cut_lines(l, long_desc);
+
+    // Empty the list.
+    while (!list_is_empty(l)) {
+        list_pos p=list_first(l);
+        int *v=list_inspect(l,p);
+        int_kill(v);
+        list_remove(l,p);
+    }
+    // Done, kill the list.
+    list_kill(l);
+
+    printf("\nNormal exit.\n\n");
+    return 0;
+}