Merge branch 'new_alloca0_newa0' into 'main'

galloca: Add new API g_alloca0 and g_newa0

Closes #475

See merge request GNOME/glib!2367

docs/reference/glib/glib-sections.txt

@@ -1389,7 +1389,9 @@ g_mem_gc_friendly
 
 <SUBSECTION>
 g_alloca
+g_alloca0
 g_newa
+g_newa0
 
 <SUBSECTION>
 g_memmove

gio/gsocket.c

@@ -4570,8 +4570,7 @@ G_STMT_START { \
       _msg->msg_control = NULL; \
     else \
       { \
-        _msg->msg_control = g_alloca (_msg->msg_controllen); \
-        memset (_msg->msg_control, '\0', _msg->msg_controllen); \
+        _msg->msg_control = g_alloca0 (_msg->msg_controllen); \
       } \
  \
     cmsg = CMSG_FIRSTHDR (_msg); \

glib/galloca.h

@@ -30,6 +30,7 @@
 #endif
 
 #include <glib/gtypes.h>
+#include <string.h>
 
 #if defined(__BIONIC__) && defined (GLIB_HAVE_ALLOCA_H)
 # include <alloca.h>
@@ -94,6 +95,22 @@ G_END_DECLS
  * Returns: space for @size bytes, allocated on the stack
  */
 #define g_alloca(size)		 alloca (size)
+
+/**
+ * g_alloca0:
+ * @size: number of bytes to allocate.
+ *
+ * Wraps g_alloca() and initializes allocated memory to zeroes.
+ * If @size is `0` it returns %NULL.
+ *
+ * Note that the @size argument will be evaluated multiple times.
+ *
+ * Returns: (nullable) (transfer full): space for @size bytes, allocated on the stack
+ *
+ * Since: 2.72
+ */
+#define g_alloca0(size)  ((size) == 0 ? NULL : memset (g_alloca (size), 0, (size)))
+
 /**
  * g_newa:
  * @struct_type: Type of memory chunks to be allocated
@@ -111,4 +128,18 @@ G_END_DECLS
  */
 #define g_newa(struct_type, n_structs)	((struct_type*) g_alloca (sizeof (struct_type) * (gsize) (n_structs)))
 
+/**
+ * g_newa0:
+ * @struct_type: the type of the elements to allocate.
+ * @n_structs: the number of elements to allocate.
+ *
+ * Wraps g_alloca0() in a more typesafe manner.
+ *
+ * Returns: (nullable) (transfer full): Pointer to stack space for @n_structs
+ *   chunks of type @struct_type
+ *
+ * Since: 2.72
+ */
+#define g_newa0(struct_type, n_structs)  ((struct_type*) g_alloca0 (sizeof (struct_type) * (gsize) (n_structs)))
+
 #endif /* __G_ALLOCA_H__ */

glib/ghmac.c

@@ -127,11 +127,9 @@ g_hmac_new (GChecksumType  digest_type,
   hmac->digesti = checksum;
   hmac->digesto = g_checksum_new (digest_type);
 
-  buffer = g_alloca (block_size);
+  buffer = g_alloca0 (block_size);
   pad = g_alloca (block_size);
 
-  memset (buffer, 0, block_size);
-
   /* If the key is too long, hash it */
   if (key_len > block_size)
     {

glib/goption.c

@@ -2113,8 +2113,7 @@ g_option_context_parse (GOptionContext   *context,
                   gboolean has_h_entry = context_has_h_entry (context);
                   arg = (*argv)[i] + 1;
                   arg_length = strlen (arg);
-                  nulled_out = g_newa (gboolean, arg_length);
-                  memset (nulled_out, 0, arg_length * sizeof (gboolean));
+                  nulled_out = g_newa0 (gboolean, arg_length);
                   for (j = 0; j < arg_length; j++)
                     {
                       if (context->help_enabled && (arg[j] == '?' ||

gobject/gobject.c

@@ -2163,8 +2163,7 @@ g_object_new_with_properties (GType          object_type,
           params[count].pspec = pspec;
 
           /* Init GValue */
-          params[count].value = g_newa (GValue, 1);
-          memset (params[count].value, 0, sizeof (GValue));
+          params[count].value = g_newa0 (GValue, 1);
           g_value_init (params[count].value, G_VALUE_TYPE (&values[i]));
 
           g_value_copy (&values[i], params[count].value);

gobject/gsignal.c

@@ -2266,8 +2266,7 @@ g_signal_chain_from_overridden_handler (gpointer instance,
       va_start (var_args, instance);
 
       signal_return_type = node->return_type;
-      instance_and_params = g_alloca (sizeof (GValue) * (n_params + 1));
-      memset (instance_and_params, 0, sizeof (GValue) * (n_params + 1));
+      instance_and_params = g_newa0 (GValue, n_params + 1);
       param_values = instance_and_params + 1;
 
       for (i = 0; i < node->n_params; i++)
@@ -3462,8 +3461,7 @@ g_signal_emit_valist (gpointer instance,
 
   n_params = node->n_params;
   signal_return_type = node->return_type;
-  instance_and_params = g_alloca (sizeof (GValue) * (n_params + 1));
-  memset (instance_and_params, 0, sizeof (GValue) * (n_params + 1));
+  instance_and_params = g_newa0 (GValue, n_params + 1);
   param_values = instance_and_params + 1;
 
   for (i = 0; i < node->n_params; i++)

tests/slice-test.c

@@ -95,8 +95,7 @@ test_memchunk_thread (gpointer data)
     }
 
   /* prepare for memchunk creation */
-  memchunks = g_alloca (sizeof (memchunks[0]) * prime_size);
-  memset (memchunks, 0, sizeof (memchunks[0]) * prime_size);
+  memchunks = g_newa0 (GMemChunk*, prime_size);
 
   ps = g_new (guint8*, number_of_blocks);
   ss = g_new (guint, number_of_blocks);