[glib: 1/8] galloca: Add new API g_alloca0 and g_newa0

[Philip Withnall <pwithnall src gnome org>]

commit b4631c44ad49574b30bdd71ac50ce2c9ddb1262b
Author: Marc-André Lureau <marcandre lureau redhat com>
Date:   Thu Nov 25 13:38:11 2021 +0530

    galloca: Add new API g_alloca0 and g_newa0
    
    Added `g_alloca0()` which wraps `g_alloca()` and initializes
    allocated memory to zeroes.
    
    Added `g_newa0()` which wraps `g_alloca0()` in a typesafe manner.
    
    Refreshed and tweaked by Nishal Kulkarni.

 docs/reference/glib/glib-sections.txt |  2 ++
 glib/galloca.h                        | 31 +++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index 340e29dfa..c563a0bcd 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/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
diff --git a/glib/galloca.h b/glib/galloca.h
index 014a0efcb..86f0d7665 100644
--- a/glib/galloca.h
+++ b/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__ */