[libcamera-devel] [PATCH] libcamera: utils: Add clamp()

[Laurent Pinchart]

Hi Niklas,

Thank you for the patch.

On Sat, Jul 13, 2019 at 08:39:46PM +0900, Niklas Söderlund wrote:
> C++11 does not support std::clamp(), add a custom implementation in
> utils.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
>  src/libcamera/include/utils.h | 7 +++++++
>  src/libcamera/utils.cpp       | 9 +++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/src/libcamera/include/utils.h b/src/libcamera/include/utils.h
> index 97bd470a45b050ef..beb2ce3ff7da9352 100644
> --- a/src/libcamera/include/utils.h
> +++ b/src/libcamera/include/utils.h
> @@ -7,6 +7,7 @@
>  #ifndef __LIBCAMERA_UTILS_H__
>  #define __LIBCAMERA_UTILS_H__
>  
> +#include <algorithm>
>  #include <memory>
>  
>  #define ARRAY_SIZE(a)	(sizeof(a) / sizeof(a[0]))
> @@ -45,6 +46,12 @@ unsigned int set_overlap(InputIt1 first1, InputIt1 last1,
>  	return count;
>  }
>  
> +/* C++11 doesn't provide std::clamp */
> +template <typename T>
> +T clamp(const T& v, const T& lo, const T& hi) {

The { should go to the next line.

The function should return a const T&. Ideally it should even be a
constexpr, but std::max and std::min are only constexpr starting in
C++14, so you would have to reimplement that, and it's likely not worth
it.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

with this fixed.

> +	return std::max(lo, std::min(v, hi));
> +}
> +
>  } /* namespace utils */
>  
>  } /* namespace libcamera */
> diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
> index ef365366f29b426e..b0ca3565ee5a0d83 100644
> --- a/src/libcamera/utils.cpp
> +++ b/src/libcamera/utils.cpp
> @@ -85,6 +85,15 @@ char *secure_getenv(const char *name)
>   * \return The number of elements in the intersection of the two ranges
>   */
>  
> +/**
> + * \fn libcamera::utils::clamp(const T& v, const T& lo, const T& hi)
> + * \param[in] v The value to clamp
> + * \param[in] lo The lower boundary to clamp v to
> + * \param[in] hi The higher boundary to clamp v to
> + *
> + * \return lo if v is less than lo, hi if v is greater than hi, otherwise v
> + */
> +
>  } /* namespace utils */
>  
>  } /* namespace libcamera */

-- 
Regards,

Laurent Pinchart