[Bf-blender-cvs] [490a385c812] master: Cleanup: comments, assert align is a power of two

[Campbell Barton]

Commit: 490a385c8124dea09c3d06cc0dd546189bc6ec11
Author: Campbell Barton
Date:   Sat Mar 2 11:57:39 2019 +1100
Branches: master
https://developer.blender.org/rB490a385c8124dea09c3d06cc0dd546189bc6ec11

Cleanup: comments, assert align is a power of two

===================================================================

M	source/blender/blenlib/intern/BLI_memarena.c

===================================================================

diff --git a/source/blender/blenlib/intern/BLI_memarena.c b/source/blender/blenlib/intern/BLI_memarena.c
index 2521320da97..8be64a44d2c 100644
--- a/source/blender/blenlib/intern/BLI_memarena.c
+++ b/source/blender/blenlib/intern/BLI_memarena.c
@@ -15,12 +15,11 @@
  *
  * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
  * All rights reserved.
- * Efficient memory allocation for lots of similar small chunks.
  */
 
 /** \file
  * \ingroup bli
- * \brief Memory arena ADT.
+ * \brief Efficient memory allocation for many small chunks.
  * \section aboutmemarena Memory Arena
  *
  * Memory arena's are commonly used when the program
@@ -54,8 +53,8 @@
 #if defined(__SANITIZE_ADDRESS__) || __has_feature(address_sanitizer)
 #  include "sanitizer/asan_interface.h"
 #else
-#  define ASAN_POISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
-#  define ASAN_UNPOISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
+#  define ASAN_POISON_MEMORY_REGION(addr, size) UNUSED_VARS(addr, size)
+#  define ASAN_UNPOISON_MEMORY_REGION(addr, size) UNUSED_VARS(addr, size)
 #endif
 
 struct MemBuf {
@@ -107,7 +106,9 @@ void BLI_memarena_use_malloc(MemArena *ma)
 
 void BLI_memarena_use_align(struct MemArena *ma, const size_t align)
 {
-	/* align should be a power of two */
+	/* Align must be a power of two. */
+	BLI_assert((align & (align - 1)) == 0);
+
 	ma->align = align;
 }
 
@@ -120,10 +121,10 @@ void BLI_memarena_free(MemArena *ma)
 	MEM_freeN(ma);
 }
 
-/* amt must be power of two */
+/** Pad num up by \a amt (must be power of two). */
 #define PADUP(num, amt) (((num) + ((amt) - 1)) & ~((amt) - 1))
 
-/* align alloc'ed memory (needed if align > 8) */
+/** Align alloc'ed memory (needed if `align > 8`). */
 static void memarena_curbuf_align(MemArena *ma)
 {
 	unsigned char *tmp;
@@ -137,8 +138,7 @@ void *BLI_memarena_alloc(MemArena *ma, size_t size)
 {
 	void *ptr;
 
-	/* ensure proper alignment by rounding
-	 * size up to multiple of 8 */
+	/* Ensure proper alignment by rounding size up to multiple of 8. */
 	size = PADUP(size, ma->align);
 
 	if (UNLIKELY(size > ma->cursize)) {
@@ -174,7 +174,7 @@ void *BLI_memarena_calloc(MemArena *ma, size_t size)
 {
 	void *ptr;
 
-	/* no need to use this function call if we're calloc'ing by default */
+	/* No need to use this function call if we're calloc'ing by default. */
 	BLI_assert(ma->use_calloc == false);
 
 	ptr = BLI_memarena_alloc(ma, size);