linux-kernel - Re: [PATCH 2/7] tools lib: Add bitmap

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Date:	Tue, 2 Aug 2016 12:25:57 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Jiri Olsa <jolsa@...nel.org>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH 2/7] tools lib: Add bitmap_snprintf function

Em Mon, Aug 01, 2016 at 08:02:30PM +0200, Jiri Olsa escreveu:
> Add support to print bitmap list. Code mostly
> taken from kernel's bitmap_list_string.

Renaming it to bitmap_scnprintf() as it is a wrapper on top of
scnprintf() that has a different semanting for the return value than
snprintf().

- Arnaldo
 
> Link: http://lkml.kernel.org/n/tip-ictn3ke5ewrzwyn8webfeai9@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/include/linux/bitmap.h | 10 ++++++++++
>  tools/lib/bitmap.c           | 29 +++++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
> index 66ddd992e690..43a0d06beabb 100644
> --- a/tools/include/linux/bitmap.h
> +++ b/tools/include/linux/bitmap.h
> @@ -75,4 +75,14 @@ static inline unsigned long *bitmap_alloc(int nbits)
>  	return malloc(BITS_TO_LONGS(nbits) * sizeof(unsigned long));
>  }
>  
> +/**
> + * bitmap_snprintf - print bitmap list into buffer
> + * @bitmap: bitmap
> + * @nbits: size of bitmap
> + * @buf: buffer to store output
> + * @size: size of @buf
> + */
> +size_t bitmap_snprintf(unsigned long *bitmap, int nbits,
> +		       char *buf, size_t size);
> +
>  #endif /* _PERF_BITOPS_H */
> diff --git a/tools/lib/bitmap.c b/tools/lib/bitmap.c
> index 0a1adc1111fd..184d97b276a1 100644
> --- a/tools/lib/bitmap.c
> +++ b/tools/lib/bitmap.c
> @@ -29,3 +29,32 @@ void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
>  	for (k = 0; k < nr; k++)
>  		dst[k] = bitmap1[k] | bitmap2[k];
>  }
> +
> +size_t bitmap_snprintf(unsigned long *bitmap, int nbits,
> +		      char *buf, size_t size)
> +{
> +	/* current bit is 'cur', most recently seen range is [rbot, rtop] */
> +	int cur, rbot, rtop;
> +	bool first = true;
> +	size_t ret = 0;
> +
> +	rbot = cur = find_first_bit(bitmap, nbits);
> +	while (cur < nbits) {
> +		rtop = cur;
> +		cur = find_next_bit(bitmap, nbits, cur + 1);
> +		if (cur < nbits && cur <= rtop + 1)
> +			continue;
> +
> +		if (!first)
> +			ret += scnprintf(buf + ret, size - ret, ",");
> +
> +		first = false;
> +
> +		ret += scnprintf(buf + ret, size - ret, "%d", rbot);
> +		if (rbot < rtop)
> +			ret += scnprintf(buf + ret, size - ret, "-%d", rtop);
> +
> +		rbot = cur;
> +	}
> +	return ret;
> +}
> -- 
> 2.4.11