Re: [Qemu-devel] [PATCH v6 04/10] hbitmap: Add hbitmap_copy

[Max Reitz <mreitz@redhat.com>]

On 2014-10-30 at 04:22, Fam Zheng wrote:
> This makes a deep copy of an HBitmap.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   include/qemu/hbitmap.h |  8 ++++++++
>   util/hbitmap.c         | 16 ++++++++++++++++
>   2 files changed, 24 insertions(+)
>
> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
> index 550d7ce..b645cfc 100644
> --- a/include/qemu/hbitmap.h
> +++ b/include/qemu/hbitmap.h
> @@ -65,6 +65,14 @@ struct HBitmapIter {
>   HBitmap *hbitmap_alloc(uint64_t size, int granularity);
>   
>   /**
> + * hbitmap_copy:
> + * @bitmap: The original bitmap to copy.
> + *
> + * Copy a HBitmap.
> + */
> +HBitmap *hbitmap_copy(const HBitmap *bitmap);
> +
> +/**
>    * hbitmap_empty:
>    * @hb: HBitmap to operate on.
>    *
> diff --git a/util/hbitmap.c b/util/hbitmap.c
> index b3060e6..78d449e 100644
> --- a/util/hbitmap.c
> +++ b/util/hbitmap.c
> @@ -395,3 +395,19 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
>       hb->levels[0][0] |= 1UL << (BITS_PER_LONG - 1);
>       return hb;
>   }
> +
> +HBitmap *hbitmap_copy(const HBitmap *bitmap)
> +{
> +    int i;
> +    int64_t size;

Why not uint64_t, like HBitmap::size? Not that it matters in practice, I 
hope.

> +    HBitmap *hb = g_memdup(bitmap, sizeof(struct HBitmap));

"struct" can be omitted.

> +
> +    size = bitmap->size;
> +    for (i = HBITMAP_LEVELS; i-- > 0; ) {

Urgh... I'd prefer "for (i = HBITMAP_LEVELS - 1; i >= 0; i--)" though 
yours is correct and shorter.

> +        size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
> +        hb->levels[i] = g_memdup(bitmap->levels[i],
> +                                 size * sizeof(unsigned long));
> +    }
> +
> +    return hb;
> +}

With or without any of the changes:

Reviewed-by: Max Reitz <mreitz@redhat.com>