add mallocz

Signed-off-by: Mattias Andrée <maandree@operamail.com>

4 files changed, 58 insertions, 0 deletions

diff --git a/doc/info/chap/introduction.texinfo b/doc/info/chap/introduction.texinfo
index 92f6273..ba08dbe 100644
--- a/doc/info/chap/introduction.texinfo
+++ b/doc/info/chap/introduction.texinfo
@@ -398,6 +398,12 @@ or @sc{SVID}@. To override this, define
 @code{_GNU_SOURCE} does not automatically
 define @code{_BSD_SOURCE} or @code{_SVID_SOURCE}@.
 
+@item _PLAN9_SOURCE
+@cpindex Plan 9 from Bell Labs
+@lvindex _PLAN9_SOURCE
+Enables extensions from Plan 9 from Bell Labs
+C standard library.
+
 @end table
 @c TODO: _LARGEFILE_SUPPORT
 @c TODO: _LARGEFILE64_SUPPORT
diff --git a/include/malloc.h b/include/malloc.h
index 66adcbd..f4a910a 100644
--- a/include/malloc.h
+++ b/include/malloc.h
@@ -73,6 +73,27 @@ void* malloc(size_t)
 void* calloc(size_t, size_t)
   __GCC_ONLY(__attribute__((__malloc__, __warn_unused_result__)));
 
+#if defined(__PLAN9_SOURCE)
+/**
+ * Variant of `malloc` that conditionally clears the allocation with zeroes.
+ * 
+ * This is a Plan 9 from Bell Labs extension.
+ * 
+ * @param   size   The size of the allocation.
+ * @param   clear  Clear the allocation unless this value is zero.
+ * @return         Pointer to the beginning of the new allocation.
+ *                 If `size` is zero, this function will either return
+ *                 `NULL` (that is what this implement does) or return
+ *                 a unique pointer that can later be freed with `free`.
+ *                 `NULL` is returned on error, and `errno` is set to
+ *                 indicate the error.
+ * 
+ * @throws  ENOMEM  The process cannot allocate more memory.
+ */
+void* mallocz(size_t, int)
+  __GCC_ONLY(__attribute__((__malloc__, __warn_unused_result__)));
+#endif
+
 #if !defined(__PORTABLE)
 /**
  * Variant of `malloc` that clears the allocation with zeroes.
diff --git a/include/slibc/portability.h b/include/slibc/portability.h
index 5eae353..5ccb9fb 100644
--- a/include/slibc/portability.h
+++ b/include/slibc/portability.h
@@ -56,6 +56,9 @@
 #ifdef __SUS_SOURCE
 # undef __SUS_SOURCE
 #endif
+#ifdef __PLAN9_SOURCE
+# undef __PLAN9_SOURCE
+#endif
 #ifdef __GNU_SOURCE
 # undef __GNU_SOURCE
 #endif
@@ -94,6 +97,9 @@
  * is not defined.
  */
 #if !defined(__PORTABLE)
+# if defined(_PLAN9_SOURCE)
+#  define __PLAN9_SOURCE  _PLAN9_SOURCE
+# endif
 # if defined(_GNU_SOURCE)
 #  define __GNU_SOURCE  _GNU_SOURCE
 # endif
diff --git a/src/malloc.c b/src/malloc.c
index cd22ccd..864a8f5 100644
--- a/src/malloc.c
+++ b/src/malloc.c
@@ -122,6 +122,31 @@ void* calloc(size_t elem_count, size_t elem_size)
 
 
 /**
+ * Variant of `malloc` that conditionally clears the allocation with zeroes.
+ * 
+ * This is a Plan 9 from Bell Labs extension.
+ * 
+ * @param   size   The size of the allocation.
+ * @param   clear  Clear the allocation unless this value is zero.
+ * @return         Pointer to the beginning of the new allocation.
+ *                 If `size` is zero, this function will either return
+ *                 `NULL` (that is what this implement does) or return
+ *                 a unique pointer that can later be freed with `free`.
+ *                 `NULL` is returned on error, and `errno` is set to
+ *                 indicate the error.
+ * 
+ * @throws  ENOMEM  The process cannot allocate more memory.
+ */
+void* mallocz(size_t size, int clear)
+{
+  void* ptr = memalign(sizeof(max_align_t), size);
+  if ((ptr != NULL) && clear)
+    explicit_bzero(ptr, size);
+  return ptr;
+}
+
+
+/**
  * Variant of `malloc` that clears the allocation with zeroes.
  * 
  * `zalloc(n)` is equivalent to `calloc(1, n)`, or equivalently,