libcamera: yaml_parser: Use std::from_chars()

std::from_chars(), introduced in C++17, is a fast, locale-independent
string-to-arithmetic conversion function. The C++ standard library
provides overloads for all integer types, making it a prime candidate to
replace the manual handling of integer sizes in the YamlParser string to
integer conversion.

Compared to std::strtol(), std::from_chars() doesn't recognize the '0x'
prefix or '+' prefix, and doesn't ignore leading white space. As the
YamlParser doesn't require those features, std::from_chars() can be used
safely, reducing the amount of code.

C++17 also requires the standard C++ library to provide overloads for
floating-point types, but libc++ does not implement those. The float and
bool implementations of YamlParser::Getter::get() are therefore kept
as-is.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/libcamera/internal/yaml_parser.h b/include/libcamera/internal/yaml_parser.h
index de452844..8c791656 100644
--- a/include/libcamera/internal/yaml_parser.h
+++ b/include/libcamera/internal/yaml_parser.h
@@ -224,7 +224,7 @@ private:
 		Empty,
 	};
 
-	template<typename T>
+	template<typename T, typename Enable = void>
 	struct Getter {
 		std::optional<T> get(const YamlObject &obj) const;
 	};