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authorPeter Lieven <pl@kamp.de>2015-10-30 12:09:56 +0100
committerGerd Hoffmann <kraxel@redhat.com>2015-11-05 09:08:29 +0100
commit5c10dbb7b577370e86ff459973b06d530c3777cf (patch)
treeb357398dd2197ba03f51cd82b07380e1faf221c1 /util
parent79cf9fad341e6e7bd6b55395b71d5c5727d7f5b0 (diff)
buffer: make the Buffer capacity increase in powers of two
This makes sure the number of reallocs is in O(log N). Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Message-id: 1446203414-4013-2-git-send-email-kraxel@redhat.com [ rebased to util/buffer.c ] Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'util')
-rw-r--r--util/buffer.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/util/buffer.c b/util/buffer.c
index cedd055680..7ddd693fa8 100644
--- a/util/buffer.c
+++ b/util/buffer.c
@@ -20,10 +20,13 @@
#include "qemu/buffer.h"
+#define BUFFER_MIN_INIT_SIZE 4096
+
void buffer_reserve(Buffer *buffer, size_t len)
{
if ((buffer->capacity - buffer->offset) < len) {
- buffer->capacity += (len + 1024);
+ buffer->capacity = pow2ceil(buffer->offset + len);
+ buffer->capacity = MAX(buffer->capacity, BUFFER_MIN_INIT_SIZE);
buffer->buffer = g_realloc(buffer->buffer, buffer->capacity);
}
}