[libcamera-devel] [PATCH 15/31] libcamera: controls: Expose raw data in ControlValue

[Kieran Bingham]

Hi Laurent,

On 29/02/2020 16:42, Laurent Pinchart wrote:
> Add a data() function to the ControlValue class to expose the raw data
> stored by the class as a Span<const uint8_t>. This will be useful to
> simplify the serialization of ControlValue instances.
> 
> The size computation for the raw data is moved from the
> ControlSerializer, which is updated accordingly to use the data()
> function in order to access the size. Simplification of the
> ControlSerializer will happen in a subsequent change.
> 

Nice, I think I see where this is going...


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>


> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  include/libcamera/controls.h         |  3 +++
>  src/libcamera/control_serializer.cpp | 13 +------------
>  src/libcamera/controls.cpp           | 23 +++++++++++++++++++++++
>  3 files changed, 27 insertions(+), 12 deletions(-)
> 
> diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
> index 6f0ebf4f3ca5..4538be06af93 100644
> --- a/include/libcamera/controls.h
> +++ b/include/libcamera/controls.h
> @@ -12,6 +12,8 @@
>  #include <string>
>  #include <unordered_map>
>  
> +#include <libcamera/span.h>
> +
>  namespace libcamera {
>  
>  class ControlValidator;
> @@ -65,6 +67,7 @@ public:
>  
>  	ControlType type() const { return type_; }
>  	bool isNone() const { return type_ == ControlTypeNone; }
> +	Span<const uint8_t> data() const;
>  
>  	std::string toString() const;
>  
> diff --git a/src/libcamera/control_serializer.cpp b/src/libcamera/control_serializer.cpp
> index 803ac16c2456..2b66ab978f81 100644
> --- a/src/libcamera/control_serializer.cpp
> +++ b/src/libcamera/control_serializer.cpp
> @@ -27,17 +27,6 @@ namespace libcamera {
>  
>  LOG_DEFINE_CATEGORY(Serializer)
>  
> -namespace {
> -
> -static constexpr size_t ControlValueSize[] = {
> -	[ControlTypeNone]	= 1,
> -	[ControlTypeBool]	= sizeof(bool),
> -	[ControlTypeInteger32]	= sizeof(int32_t),
> -	[ControlTypeInteger64]	= sizeof(int64_t),
> -};
> -
> -} /* namespace */
> -
>  /**
>   * \class ControlSerializer
>   * \brief Serializer and deserializer for control-related classes
> @@ -106,7 +95,7 @@ void ControlSerializer::reset()
>  
>  size_t ControlSerializer::binarySize(const ControlValue &value)
>  {
> -	return ControlValueSize[value.type()];
> +	return value.data().size_bytes();
>  }
>  
>  size_t ControlSerializer::binarySize(const ControlRange &range)
> diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> index 76230a052de1..b2331ab7540d 100644
> --- a/src/libcamera/controls.cpp
> +++ b/src/libcamera/controls.cpp
> @@ -47,6 +47,17 @@ namespace libcamera {
>  
>  LOG_DEFINE_CATEGORY(Controls)
>  
> +namespace {
> +
> +static constexpr size_t ControlValueSize[] = {
> +	[ControlTypeNone]		= 1,
> +	[ControlTypeBool]		= sizeof(bool),
> +	[ControlTypeInteger32]		= sizeof(int32_t),
> +	[ControlTypeInteger64]		= sizeof(int64_t),
> +};
> +
> +} /* namespace */
> +
>  /**
>   * \enum ControlType
>   * \brief Define the data type of a Control
> @@ -91,6 +102,18 @@ ControlValue::ControlValue()
>   * \return True if the value type is ControlTypeNone, false otherwise
>   */
>  
> +/**
> + * \brief Retrieve the raw of a control value

Retrieve the raw '{data, bytes}' of a control value?

> + * \return The raw data of the control value as a span of uint8_t
> + */
> +Span<const uint8_t> ControlValue::data() const
> +{
> +	return {
> +		reinterpret_cast<const uint8_t *>(&bool_),
> +		ControlValueSize[type_]
> +	};

Eeep, that starts looking like some sort of lambda/function/scope syntax
due to the { }; positions ...


> +}
> +
>  /**
>   * \brief Assemble and return a string describing the value
>   * \return A string describing the ControlValue
> 

-- 
Regards
--
Kieran