lwsac_use_zero

include/libwebsockets/lws-lwsac.h

@@ -99,6 +99,27 @@ lws_list_ptr_insert(lws_list_ptr *phead, lws_list_ptr *add,
 LWS_VISIBLE LWS_EXTERN void *
 lwsac_use(struct lwsac **head, size_t ensure, size_t chunk_size);
 
+/**
+ * lwsac_use_zero - allocate / use some memory from a lwsac and zero it
+ *
+ * \param head: pointer to the lwsac list object
+ * \param ensure: the number of bytes we want to use
+ * \param chunk_size: 0, or the size of the chunk to (over)allocate if
+ *			what we want won't fit in the current tail chunk.  If
+ *			0, the default value of 4000 is used. If ensure is
+ *			larger, it is used instead.
+ *
+ * This also serves to init the lwsac if *head is NULL.  Basically it does
+ * whatever is necessary to return you a pointer to ensure bytes of memory
+ * reserved for the caller.
+ *
+ * \p ensure bytes at the return address are zeroed if the allocation succeeded.
+ *
+ * Returns NULL if OOM.
+ */
+LWS_VISIBLE LWS_EXTERN void *
+lwsac_use_zero(struct lwsac **head, size_t ensure, size_t chunk_size);
+
 /**
  * lwsac_use - allocate / use some memory from a lwsac
  *

lib/misc/lwsac/lwsac.c

@@ -131,6 +131,17 @@ lwsac_use(struct lwsac **head, size_t ensure, size_t chunk_size)
 	return (char *)(*head)->curr + ofs;
 }
 
+void *
+lwsac_use_zero(struct lwsac **head, size_t ensure, size_t chunk_size)
+{
+	void *p = lwsac_use(head, ensure, chunk_size);
+
+	if (p)
+		memset(p, 0, ensure);
+
+	return p;
+}
+
 void *
 lwsac_use_zeroed(struct lwsac **head, size_t ensure, size_t chunk_size)
 {