lavu/mem: add av_dynarray_add_nofree function

av_dynarray_add_nofree function have similar functionality
as existing av_dynarray_add, but it doesn't deallocate memory
on fails.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2014-03-xx - xxxxxxx - lavu 52.70.100 - mem.h
+  Add av_dynarray_add_nofree() function.
+
 2014-02-xx - xxxxxxx - lavu 53.08.0 - frame.h
   Add av_frame_remove_side_data() for removing a single side data
   instance from a frame.

libavutil/mem.c

@@ -278,6 +278,19 @@ void *av_memdup(const void *p, size_t size)
     return ptr;
 }
 
+int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
+{
+    void **tab = *(void ***)tab_ptr;
+
+    AV_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
+        tab[*nb_ptr] = elem;
+        *(void ***)tab_ptr = tab;
+    }, {
+        return AVERROR(ENOMEM);
+    });
+    return 0;
+}
+
 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
 {
     void **tab = *(void ***)tab_ptr;

libavutil/mem.h

@@ -276,10 +276,25 @@ void av_freep(void *ptr);
  * @param tab_ptr pointer to the array to grow
  * @param nb_ptr  pointer to the number of elements in the array
  * @param elem    element to add
- * @see av_dynarray2_add()
+ * @see av_dynarray_add_nofree(), av_dynarray2_add()
  */
 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
 
+/**
+ * Add an element to a dynamic array.
+ *
+ * Function has the same functionality as av_dynarray_add(),
+ * but it doesn't free memory on fails. It returns error code
+ * instead and leave current buffer untouched.
+ *
+ * @param tab_ptr pointer to the array to grow
+ * @param nb_ptr  pointer to the number of elements in the array
+ * @param elem    element to add
+ * @return >=0 on success, negative otherwise.
+ * @see av_dynarray_add(), av_dynarray2_add()
+ */
+int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem);
+
 /**
  * Add an element of size elem_size to a dynamic array.
  *
@@ -299,7 +314,7 @@ void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
  *                  the new added element is not filled.
  * @return          pointer to the data of the element to copy in the new allocated space.
  *                  If NULL, the new allocated space is left uninitialized."
- * @see av_dynarray_add()
+ * @see av_dynarray_add(), av_dynarray_add_nofree()
  */
 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
                        const uint8_t *elem_data);

libavutil/version.h

@@ -56,7 +56,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  52
-#define LIBAVUTIL_VERSION_MINOR  69
+#define LIBAVUTIL_VERSION_MINOR  70
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \