[libcamera-devel] [PATCH v3 02/11] libcamera: utils: Add string join function

[Kieran Bingham]

Hi Laurent,

On 20/03/2020 01:48, Laurent Pinchart wrote:
> Add a utils::join() function to join elements of a container into a
> string, with a separator and an optional conversion function if the
> elements are not implicitly convertible to std::string.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/libcamera/include/utils.h | 44 +++++++++++++++++++++++++++++++++++
>  src/libcamera/utils.cpp       | 16 +++++++++++++
>  test/utils.cpp                |  7 +++++-
>  3 files changed, 66 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libcamera/include/utils.h b/src/libcamera/include/utils.h
> index cfa620f24581..242eeded9d50 100644
> --- a/src/libcamera/include/utils.h
> +++ b/src/libcamera/include/utils.h
> @@ -11,6 +11,7 @@
>  #include <chrono>
>  #include <memory>
>  #include <ostream>
> +#include <sstream>
>  #include <string>
>  #include <string.h>
>  #include <sys/time.h>
> @@ -109,6 +110,49 @@ inline _hex hex<uint64_t>(uint64_t value, unsigned int width)
>  
>  size_t strlcpy(char *dst, const char *src, size_t size);
>  
> +#ifndef __DOXYGEN__
> +template<typename Container, typename UnaryOp>
> +std::string join(const Container &items, const std::string &sep, UnaryOp op)
> +{
> +	std::ostringstream ss;
> +	bool first = true;
> +
> +	for (typename Container::const_iterator it = std::begin(items);
> +	     it != std::end(items); ++it) {
> +		if (!first)
> +			ss << sep;
> +		else
> +			first = false;
> +
> +		ss << op(*it);
> +	}
> +
> +	return ss.str();
> +}
> +
> +template<typename Container>
> +std::string join(const Container &items, const std::string &sep)
> +{
> +	std::ostringstream ss;
> +	bool first = true;
> +
> +	for (typename Container::const_iterator it = std::begin(items);
> +	     it != std::end(items); ++it) {
> +		if (!first)
> +			ss << sep;
> +		else
> +			first = false;
> +
> +		ss << *it;
> +	}
> +
> +	return ss.str();
> +}
> +#else
> +template<typename Container, typename UnaryOp>
> +std::string join(const Container &items, const std::string &sep, UnaryOp op = nullptr);
> +#endif
> +
>  namespace details {
>  
>  class StringSplitter
> diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
> index 58ee7cc19c8c..97f9b632e45b 100644
> --- a/src/libcamera/utils.cpp
> +++ b/src/libcamera/utils.cpp
> @@ -297,6 +297,22 @@ details::StringSplitter::iterator details::StringSplitter::end() const
>  	return iterator(this, std::string::npos);
>  }
>  
> +/**
> + * \fn template<typename Container, typename UnaryOp> \
> + * std::string utils::join(const Container &items, const std::string &sep, UnaryOp op)
> + * \brief Join elements of a container in a string with a separator
> + * \param[in] items The container
> + * \param[in] sep The separator to add between elements
> + * \param[in] op A function that converts individual elements to strings
> + *
> + * This function joins all elements in the \a items container into a string and
> + * returns it. The \a sep separator is added between elements. If the container
> + * elements are not implicitly convertible to std::string, the \a op function
> + * shall be provided to perform conversion of elements to std::string.
> + *
> + * \return A string that concatenates all elements in the container
> + */
> +
>  /**
>   * \fn split(const std::string &str, const std::string &delim)
>   * \brief Split a string based on a delimiter
> diff --git a/test/utils.cpp b/test/utils.cpp
> index 58816f153066..2fca89ef3278 100644
> --- a/test/utils.cpp
> +++ b/test/utils.cpp
> @@ -99,7 +99,7 @@ protected:
>  			return TestFail;
>  		}
>  
> -		/* utils::split() test. */
> +		/* utils::join() and utils::split() test. */
>  		std::vector<std::string> elements = {
>  			"/bin",
>  			"/usr/bin",
> @@ -111,6 +111,11 @@ protected:
>  		for (const auto &element : elements)
>  			path += (path.empty() ? "" : ":") + element;
>  
> +		if (path != utils::join(elements, ":")) {
> +			cerr << "utils::join() test failed" << endl;
> +			return TestFail;
> +		}
> +


This is lacking a test for the optional conversion function ?


>  		std::vector<std::string> dirs;
>  
>  		for (const auto &dir : utils::split(path, ":"))
> 

-- 
Regards
--
Kieran