Added a linked list implementation.

testing/misc_tools.c

@@ -25,7 +25,11 @@
 
 #include <string.h>
 #include <stdlib.h>
-#include <stdio.h> /* for sscanf */
+#include <stdio.h>
+
+#ifdef DEBUG
+#include <assert.h>
+#endif // DEBUG
 
 /* TODO: rewrite */
 unsigned char * hex_string_to_bin(char hex_string[])
@@ -39,3 +43,9 @@ unsigned char * hex_string_to_bin(char hex_string[])
 
     return val;
 }
+
+
+
+
+
+

testing/misc_tools.h

@@ -25,5 +25,114 @@
 #define MISC_TOOLS_H
 
 unsigned char * hex_string_to_bin(char hex_string[]);
- 
+
+
+
+
+
+/************************Linked List***********************
+ * This is a simple linked list implementation, very similar
+ * to Linux kernel's /include/linux/list.h (which we can't 
+ * use because Tox is GPLv3 and Linux is GPLv2.)
+ *
+ * TODO: Make the lists easier to use with some sweat pre-
+ * processor syntactic sugar.
+ **********************************************************/
+
+/* Example usage
+
+This sample program makes a new struct which contains a
+character and a tox_list_t. It then prompts a user for
+input until he enters q or e. It then adds each character
+to the list, and uses a special for loop to print them.
+It then removes all the 'z' characters, and prints the list
+again.
+
+//Notice that the data to be put in the list *contains* tox_list_t;
+//usually, this is the other way around!
+typedef struct tox_string {
+   char c;
+   tox_list_t tox_lst; //Notice that tox_lst is *NOT* a pointer.
+} tox_string_t;
+
+int main()
+{
+   tox_list_t head;
+   tox_list_new(&head); //initialize head
+   
+   //input a new character, until user enters q or e
+   char c = '\0';
+   while (c != 'q' && c != 'e') {
+      scanf("%c", &c);
+      tox_string_t* tmp = malloc(sizeof(tox_string_t));
+      tmp->c = c;
+      tox_list_add(&head, &tmp->tox_lst); //add it to the list
+   }
+   
+TOX_LIST_FOR_EACH() takes a struct tox_list and a name for a temporary pointer to use in the loop.
+   
+TOX_LIST_GET_VALUE() uses magic to return an instance of a structure that contains tox_list_t.
+You have to give it a temporary tox_string_t, name of tox_list_t member inside our structure (tox_lst),
+and the type of structure to return.
+   
+   TOX_LIST_FOR_EACH(head, tmp)
+      printf("%c", TOX_LIST_GET_VALUE(*tmp, tox_lst, tox_string_t).c);
+   
+   TOX_LIST_FOR_EACH(head, tmp) {
+      if (TOX_LIST_GET_VALUE(*tmp, tox_lst, tox_string_t).c == 'z') {
+         //If you delete tmp, you have to quit the loop, or it will go on infinitly.
+         //This will be fixed later on.
+         tox_list_remove(tmp);
+         break;
+      }
+   }
+   
+   printf("\n");
+   TOX_LIST_FOR_EACH(head, tmp)
+      printf("%c", TOX_LIST_GET_VALUE(*tmp, tox_lst, tox_string_t).c);
+   
+   
+   return 0;
+}
+*/
+
+#define MEMBER_OFFSET(var_name_in_parent, parent_type) \
+   (&(((parent_type*)0)->var_name_in_parent))
+
+#define GET_PARENT(var, var_name_in_parent, parent_type) \
+   (*((parent_type*)((uint64_t)(&(var)) - (uint64_t)(MEMBER_OFFSET(var_name_in_parent, parent_type)))))
+
+#define TOX_LIST_FOR_EACH(lst, tmp_name) \
+   for (tox_list_t* tmp_name = lst.next; tmp_name != &lst; tmp_name = tmp_name->next)
+
+#define TOX_LIST_GET_VALUE(tmp_name, name_in_parent, parent_type) GET_PARENT(tmp_name, name_in_parent, parent_type)
+
+typedef struct tox_list {
+   struct tox_list *prev, *next;
+} tox_list_t;
+
+/* Returns a new tox_list_t. */
+static inline void tox_list_new(tox_list_t* lst) {
+   lst->prev = lst->next = lst;
+}
+      
+/* Inserts a new tox_lst after lst and returns it. */
+static inline void tox_list_add(tox_list_t* lst, tox_list_t* new_lst) {
+   tox_list_new(new_lst);
+
+   new_lst->next = lst->next;
+   new_lst->next->prev = new_lst;
+
+   lst->next = new_lst;
+   new_lst->prev = lst;
+}
+
+static inline void tox_list_remove(tox_list_t* lst) {
+#ifdef DEBUG /* TODO: check how debugging is done in Tox. */
+   assert(lst->next != lst && lst->prev != lst);
+#endif
+   lst->prev->next = lst->next;
+   lst->next->prev = lst->prev;
+}
+
 #endif // MISC_TOOLS_H