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-rw-r--r--OLD/csci5271/hw2/ex2-animals.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/OLD/csci5271/hw2/ex2-animals.c b/OLD/csci5271/hw2/ex2-animals.c
new file mode 100644
index 0000000..983d2b5
--- /dev/null
+++ b/OLD/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);
+ }
+ }
+}