[FFmpeg-devel] [PATCH 01/16] avutil/buffer: add helper to allocate aligned memory

[averne <averne381@gmail.com>]

This is useful eg. for memory-mapped buffers that need page-aligned memory, when dealing with hardware devices

Signed-off-by: averne <averne381@gmail.com>
---
 libavutil/buffer.c | 31 +++++++++++++++++++++++++++++++
 libavutil/buffer.h |  7 +++++++
 2 files changed, 38 insertions(+)

diff --git a/libavutil/buffer.c b/libavutil/buffer.c
index e4562a79b1..b8e357f540 100644
--- a/libavutil/buffer.c
+++ b/libavutil/buffer.c
@@ -16,9 +16,14 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "config.h"
+
 #include <stdatomic.h>
 #include <stdint.h>
 #include <string.h>
+#if HAVE_MALLOC_H
+#include <malloc.h>
+#endif
 
 #include "avassert.h"
 #include "buffer_internal.h"
@@ -100,6 +105,32 @@ AVBufferRef *av_buffer_allocz(size_t size)
     return ret;
 }
 
+AVBufferRef *av_buffer_aligned_alloc(size_t size, size_t align)
+{
+    AVBufferRef *ret = NULL;
+    uint8_t    *data = NULL;
+
+#if HAVE_POSIX_MEMALIGN
+    if (posix_memalign((void **)&data, align, size))
+        return NULL;
+#elif HAVE_ALIGNED_MALLOC
+    data = aligned_alloc(align, size);
+#elif HAVE_MEMALIGN
+    data = memalign(align, size);
+#else
+    return NULL;
+#endif
+
+    if (!data)
+        return NULL;
+
+    ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
+    if (!ret)
+        av_freep(&data);
+
+    return ret;
+}
+
 AVBufferRef *av_buffer_ref(const AVBufferRef *buf)
 {
     AVBufferRef *ret = av_mallocz(sizeof(*ret));
diff --git a/libavutil/buffer.h b/libavutil/buffer.h
index e1ef5b7f07..8422ec3453 100644
--- a/libavutil/buffer.h
+++ b/libavutil/buffer.h
@@ -107,6 +107,13 @@ AVBufferRef *av_buffer_alloc(size_t size);
  */
 AVBufferRef *av_buffer_allocz(size_t size);
 
+/**
+ * Allocate an AVBuffer of the given size and alignment.
+ *
+ * @return an AVBufferRef of given size or NULL when out of memory
+ */
+AVBufferRef *av_buffer_aligned_alloc(size_t size, size_t align);
+
 /**
  * Always treat the buffer as read-only, even when it has only one
  * reference.
-- 
2.45.1

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