Added a linked list implementation.

This commit is contained in:
Konstantin Kowalski 2013-08-06 13:52:05 -04:00 committed by Nick ODell
parent 29773d97fc
commit 60f333328c
2 changed files with 121 additions and 2 deletions

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@ -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;
}

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@ -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