[Libguestfs] [PATCH v3 3/4] common: Add isaligned helper module

[Richard W.M. Jones]

On Sun, Aug 19, 2018 at 01:13:07AM +0300, Nir Soffer wrote:
> is_aligned (size, align) returns true if size is aligned to align,
> assuming that align is power of 2.
> 
> Suggested by Eric Blake in
> https://www.redhat.com/archives/libguestfs/2018-August/msg00036.html
> ---
>  common/include/isaligned.h | 51 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
>  create mode 100644 common/include/isaligned.h
> 
> diff --git a/common/include/isaligned.h b/common/include/isaligned.h

You have to add this file to common/include/Makefile.am otherwise
it will never be distributed.

Rich.

> new file mode 100644
> index 0000000..e693820
> --- /dev/null
> +++ b/common/include/isaligned.h
> @@ -0,0 +1,51 @@
> +/* nbdkit
> + * Copyright (C) 2018 Red Hat Inc.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions are
> + * met:
> + *
> + * * Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + *
> + * * Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * * Neither the name of Red Hat nor the names of its contributors may be
> + * used to endorse or promote products derived from this software without
> + * specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
> + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
> + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
> + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
> + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
> + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#ifndef NBDKIT_ISALIGNED_H
> +#define NBDKIT_ISALIGNED_H
> +
> +#include <assert.h>
> +#include <stdbool.h>
> +
> +#include "ispowerof2.h"
> +
> +/* Return true if size is a multiple of align. align must be power of 2.
> + */
> +static inline bool
> +is_aligned (unsigned int size, unsigned int align)
> +{
> +  assert (is_power_of_2 (align));
> +  return !(size & (align - 1));
> +}
> +
> +#endif /* NBDKIT_ISALIGNED_H */
> -- 
> 2.17.1

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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