core: make "callback_cmp" optional in call to function arraylist_new()

If no callback is given, a default callback is used, which just compares
pointers.

doc/en/weechat_plugin_api.en.adoc

@@ -3875,7 +3875,8 @@ Arguments:
 * _sorted_: 1 to sort the array list, 0 for no sort
 * _allow_duplicates_: 1 to allow duplicate entries, 0 to prevent a same entry
   to be added again
-* _callback_cmp_: callback used to compare two items, arguments and return value:
+* _callback_cmp_: callback used to compare two items (optional), arguments and
+  return value:
 ** _void *data_: pointer
 ** _struct t_arraylist *arraylist_: array list pointer
 ** _void *pointer1_: pointer to first item

doc/fr/weechat_plugin_api.fr.adoc

@@ -3937,8 +3937,8 @@ Paramètres :
 * _sorted_ : 1 pour trier la liste avec tableau, 0 pour ne pas trier
 * _allow_duplicates_ : 1 pour autoriser les entrées dupliquées, 0 pour empêcher
   une même entrée d'être ajoutée à nouveau
-* _callback_cmp_ : fonction appelée pour comparer deux éléments, paramètres et
-  valeur de retour :
+* _callback_cmp_ : fonction appelée pour comparer deux éléments (optionnelle),
+  paramètres et valeur de retour :
 ** _void *data_ : pointeur
 ** _struct t_arraylist *arraylist_ : pointeur vers la liste avec tableau
 ** _void *pointer1_ : pointeur vers le premier élément

doc/it/weechat_plugin_api.it.adoc

@@ -4006,7 +4006,8 @@ Argomenti:
 * _sorted_: 1 to sort the array list, 0 for no sort
 * _allow_duplicates_: 1 to allow duplicate entries, 0 to prevent a same entry
   to be added again
-* _callback_cmp_: callback used to compare two items, arguments and return value:
+* _callback_cmp_: callback used to compare two items (optional), arguments and
+  return value:
 ** _void *data_: pointer
 ** _struct t_arraylist *arraylist_: array list pointer
 ** _void *pointer1_: pointer to first item

doc/ja/weechat_plugin_api.ja.adoc

@@ -3882,7 +3882,9 @@ struct t_arraylist *weechat_arraylist_new (int initial_size,
 * _sorted_: 1 の場合には配列リストをソートし、0 の場合にはソートしません
 * _allow_duplicates_: 1 の場合にはエントリの重複を許可し、0
   の場合にはエントリが重複して追加されることを防ぎます
-* _callback_cmp_: 2 つの要素を比較する際に使われるコールバック、引数と戻り値は以下:
+// TRANSLATION MISSING
+* _callback_cmp_: callback used to compare two items (optional), arguments and
+  return value:
 ** _void *data_: ポインタ
 ** _struct t_arraylist *arraylist_: 配列リストポインタ
 ** _void *pointer1_: 1 番目の要素へのポインタ

src/core/wee-arraylist.c

@@ -32,6 +32,31 @@
 #include "wee-string.h"
 
 
+/*
+ * Compares two arraylist entries (default comparator).
+ * It just compares pointers.
+ *
+ * Returns:
+ *   -1: pointer1 < pointer2
+ *    0: pointer1 == pointer2
+ *    1: pointer1 > pointer2
+ */
+
+int
+arraylist_cmp_default_cb (void *data, struct t_arraylist *arraylist,
+                          void *pointer1, void *pointer2)
+{
+    /* make C compiler happy */
+    (void) data;
+    (void) arraylist;
+
+    if (pointer1 < pointer2)
+        return -1;
+    if (pointer1 > pointer2)
+        return 1;
+    return 0;
+}
+
 /*
  * Creates a new arraylist.
  *
@@ -48,7 +73,7 @@ arraylist_new (int initial_size,
     struct t_arraylist *new_arraylist;
 
     /* check arguments */
-    if ((initial_size < 0) || !callback_cmp)
+    if (initial_size < 0)
         return NULL;
 
     new_arraylist = malloc (sizeof (*new_arraylist));
@@ -76,8 +101,10 @@ arraylist_new (int initial_size,
     }
     new_arraylist->sorted = sorted;
     new_arraylist->allow_duplicates = allow_duplicates;
-    new_arraylist->callback_cmp = callback_cmp;
-    new_arraylist->callback_cmp_data = callback_cmp_data;
+    new_arraylist->callback_cmp = (callback_cmp) ?
+        callback_cmp : &arraylist_cmp_default_cb;
+    new_arraylist->callback_cmp_data = (callback_cmp) ?
+        callback_cmp_data : NULL;
     new_arraylist->callback_free = callback_free;
     new_arraylist->callback_free_data = callback_free_data;
 

tests/unit/core/test-arraylist.cpp

@@ -489,8 +489,6 @@ TEST(Arraylist, New)
                    arraylist_new (-1, 0, 0, NULL, NULL, NULL, NULL));
     POINTERS_EQUAL(NULL,
                    arraylist_new (-1, 0, 0, &test_cmp_cb, NULL, NULL, NULL));
-    POINTERS_EQUAL(NULL,
-                   arraylist_new (0, 0, 0, NULL, NULL, NULL, NULL));
 
     /* tests on arraylists */
     for (initial_size = 0; initial_size < 2; initial_size++)