/* misc_tools.h
 *
 * Miscellaneous functions and data structures for doing random things.
 *
 *  Copyright (C) 2013 Tox project All Rights Reserved.
 *
 *  This file is part of Tox.
 *
 *  Tox is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Tox is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Tox.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef MISC_TOOLS_H
#define MISC_TOOLS_H

#include <stdlib.h>
#include <stdint.h>
#include <string.h> /* for memcpy() */



/************************Linked List***********************
 * http://wiki.tox.im/index.php/Internal_functions_and_data_structures#Linked_List
 * TODO: Update wiki.
 **********************************************************/

/* 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* 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;

/*  return new tox_list_t. */
static inline void tox_list_new(tox_list *lst)
{
    lst->prev = lst->next = lst;
}

/* Inserts a new tox_lst after lst and returns it. */
static inline void tox_list_add(tox_list *lst, tox_list *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 *lst)
{
    lst->prev->next = lst->next;
    lst->next->prev = lst->prev;
}

/****************************Array***************************
 * Array which manages its own memory allocation.
 * It stores copy of data (not pointers).
 * TODO: Add wiki info usage.
 ************************************************************/

typedef struct tox_array {
    uint8_t *data; /* last elem is data[len-1] */
    uint32_t len;
    size_t elem_size; /* in bytes */
} tox_array;

static inline void tox_array_init(tox_array *arr, size_t elem_size)
{
    arr->len = 0;
    arr->elem_size = elem_size;
    arr->data = NULL;
}

static inline void tox_array_delete(tox_array *arr)
{
    free(arr->data);
    arr->len = arr->elem_size = 0;
}

static inline uint8_t tox_array_push_ptr(tox_array *arr, uint8_t *item)
{
    uint8_t *temp = realloc(arr->data, arr->elem_size * (arr->len + 1));

    if (temp == NULL)
        return 0;

    arr->data = temp;

    if (item != NULL)
        memcpy(arr->data + arr->elem_size * arr->len, item, arr->elem_size);

    arr->len++;

    return 1;
}
#define tox_array_push(arr, item) tox_array_push_ptr(arr, (uint8_t*)(&(item)))

/* Deletes num items from array.
 * Not same as pop in stacks, because to access elements you use data.
 */
static inline void tox_array_pop(tox_array *arr, uint32_t num)
{
    if (num == 0)
        return;

    if (num > arr->len)
        return;

    if (arr->len == num) {
        free(arr->data);
        arr->data = NULL;
        arr->len = 0;
        return;
    }

    uint8_t *temp = realloc(arr->data, arr->elem_size * (arr->len - num));

    if (temp == NULL)
        return;

    arr->len -= num;
    arr->data = temp;
}

/* TODO: return ptr and do not take type */
#define tox_array_get(arr, i, type) (((type*)(arr)->data)[i])


#define tox_array_for_each(arr, type, tmp_name) \
    type *tmp_name = &tox_array_get(arr, 0, type); uint32_t tmp_name ## _i = 0; \
    for (; tmp_name ## _i < (arr)->len; tmp_name = &tox_array_get(arr, ++ tmp_name ## _i, type))

/****************************Algorithms***************************
 * Macro/generic definitions for useful algorithms
 *****************************************************************/

/* Creates a new quick_sort implementation for arrays of the specified type.
 * For a type T (eg: int, char), creates a function named T_quick_sort.
 *
 * Quick Sort: Complexity O(nlogn)
 * arr   - the array to sort
 * n     - the sort index (should be called with n = length(arr))
 * cmpfn - a function that compares two values of type type.
 *         Must return -1, 0, 1 for a < b, a == b, and a > b respectively.
 */
/* Must be called in the header file. */
#define declare_quick_sort(type) \
void type##_quick_sort(type *arr, int n, int (*cmpfn)(type, type));

/* Must be called in the C file. */
#define make_quick_sort(type) \
void type##_quick_sort(type *arr, int n, int (*cmpfn)(type, type)) \
{ \
    if ((n) < 2) \
        return; \
    type _p_ = (arr)[(n) / 2]; \
    type *_l_ = (arr); \
    type *_r_ = (arr) + n - 1; \
    while (_l_ <= _r_) { \
        if (cmpfn(*_l_, _p_) == -1) { \
            ++_l_; \
            continue; \
        } \
        if (cmpfn(*_r_, _p_) == 1) { \
            --_r_; \
            continue; \
        } \
        type _t_ = *_l_; \
        *_l_++ = *_r_; \
        *_r_-- = _t_; \
    } \
    type##_quick_sort((arr), _r_ - (arr) + 1, cmpfn); \
    type##_quick_sort(_l_, (arr) + n - _l_, cmpfn); \
}

#endif // MISC_TOOLS_H