1 files changed, 131 insertions, 0 deletions
diff --git a/csci5271/hw2/ex2-animals.c b/csci5271/hw2/ex2-animals.c
new file mode 100644
index 0000000..983d2b5
--- /dev/null
+++ b/csci5271/hw2/ex2-animals.c
@@ -0,0 +1,131 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef void (*toes_func)(void);
+
+void even_toes(void) {
+    printf("with even-toed hoofs");
+}
+
+void odd_toes(void) {
+    printf("with odd-toed hoofs");
+}
+
+/* Assume this function has the address 0x4012ce */
+void shellcode(void) {
+    printf("Uh-oh, this looks like some sort of attack\n");
+    exit(42);
+}
+
+struct herbivore {
+    struct herbivore *next;
+    toes_func func;
+};
+
+struct herbivore *herbivore_list = 0;
+
+struct carnivore {
+    struct carnivore *next;
+    long num_teeth;
+};
+
+struct carnivore *carnivore_list = 0;
+
+#define NUM_ANIMALS 256
+
+/* Initialized to all null pointers */
+void *animals_by_num[NUM_ANIMALS];
+
+void new_herbivore(long x) {
+    int loc = x & (NUM_ANIMALS - 1);
+    struct herbivore *hp = malloc(sizeof(struct herbivore));
+    printf("Allocating herbivore at %p\n", hp);
+    if (!hp)
+	exit(1);
+    if (x & 1)
+	hp->func = odd_toes;
+    else
+	hp->func = even_toes;
+    hp->next = herbivore_list;
+    herbivore_list = hp;
+    animals_by_num[loc] = hp;
+}
+
+void new_carnivore(long x) {
+    int loc = x & (NUM_ANIMALS - 1);
+    struct carnivore *cp = malloc(sizeof(struct carnivore));
+    printf("Allocating carnivore at %p\n", cp);
+    if (!cp)
+	exit(1);
+    cp->num_teeth = x;
+    cp->next = carnivore_list;
+    carnivore_list = cp;
+    animals_by_num[loc] = cp;
+}
+
+void release_animal(long x) {
+    int loc = x & (NUM_ANIMALS - 1);
+    if (!animals_by_num[loc]) {
+	fprintf(stderr, "Attempt to release non-existant animal\n");
+	exit(1);
+    }
+    free(animals_by_num[loc]);
+    animals_by_num[loc] = 0;
+}
+
+void list_animals(void) {
+    struct herbivore *hp;
+    struct carnivore *cp;
+    for (hp = herbivore_list; hp; hp = hp->next) {
+	printf("A herbivore ");
+	(hp->func)();
+	printf("\n");
+    }
+
+    for (cp = carnivore_list; cp; cp = cp->next) {
+	printf("A carnivore with %ld teeth\n", cp->num_teeth);
+    }
+}
+
+void syntax_error(void) {
+    fprintf(stderr, "Unrecognized syntax\n");
+    exit(1);
+}
+
+int main(int argc, char **argv) {
+    for (;;) {
+	int c = getchar();
+	long x;
+	while (isspace(c))
+	    c = getchar();
+	if (c == EOF)
+	    return 0;
+	switch (c) {
+	case 'h':
+	    if (scanf(" %li", &x) != 1)
+		syntax_error();
+	    new_herbivore(x);
+	    break;
+	case 'c':
+	    if (scanf(" %li", &x) != 1)
+		syntax_error();
+	    new_carnivore(x);
+	    break;
+	case 'r':
+	    if (scanf(" %li", &x) != 1)
+		syntax_error();
+	    release_animal(x);
+	    break;
+	case 'l':
+	    list_animals();
+	    break;
+	case 'q':
+	    return 0;
+	    break;
+	default:
+	    fprintf(stderr, "Unrecognized command %c\n", c);
+	    exit(1);
+	}
+    }
+}