bindings: cxx: provide a method for reading multiple line events

Add a new method to gpiod::line class allowing to read up to 16 line
events at once.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/bindings/cxx/gpiod.hpp b/bindings/cxx/gpiod.hpp
index 078201bd047cd727a889dcc8f7019a0546159cdb..f5df18e566e4fe5094ff96236d8107fb256525e1 100644 (file)
--- a/bindings/cxx/gpiod.hpp
+++ b/bindings/cxx/gpiod.hpp
@@ -421,6 +421,12 @@ public:
         */
        GPIOD_API line_event event_read(void) const;
 
+       /**
+        * @brief Read multiple line events.
+        * @return Vector of line event objects.
+        */
+       GPIOD_API ::std::vector<line_event> event_read_multiple(void) const;
+
        /**
         * @brief Get the event file descriptor associated with this line.
         * @return File descriptor number.
@@ -513,6 +519,7 @@ private:
        line(::gpiod_line* line, const chip& owner);
 
        void throw_if_null(void) const;
+       line_event make_line_event(const ::gpiod_line_event& event) const noexcept;
 
        ::gpiod_line* _m_line;
        chip _m_chip;

diff --git a/bindings/cxx/line.cpp b/bindings/cxx/line.cpp
index ed6ef55c6efe2bc71d94bf4ae9f73d7e0e46874d..11deae6f3720bf99300a16877323efde8a58f0db 100644 (file)
--- a/bindings/cxx/line.cpp
+++ b/bindings/cxx/line.cpp
@@ -206,6 +206,23 @@ bool line::event_wait(const ::std::chrono::nanoseconds& timeout) const
        return !!event_bulk;
 }
 
+line_event line::make_line_event(const ::gpiod_line_event& event) const noexcept
+{
+       line_event ret;
+
+       if (event.event_type == GPIOD_LINE_EVENT_RISING_EDGE)
+               ret.event_type = line_event::RISING_EDGE;
+       else if (event.event_type == GPIOD_LINE_EVENT_FALLING_EDGE)
+               ret.event_type = line_event::FALLING_EDGE;
+
+       ret.timestamp = ::std::chrono::nanoseconds(
+                               event.ts.tv_nsec + (event.ts.tv_sec * 1000000000));
+
+       ret.source = *this;
+
+       return ret;
+}
+
 line_event line::event_read(void) const
 {
        this->throw_if_null();
@@ -219,17 +236,29 @@ line_event line::event_read(void) const
                throw ::std::system_error(errno, ::std::system_category(),
                                          "error reading line event");
 
-       if (event_buf.event_type == GPIOD_LINE_EVENT_RISING_EDGE)
-               event.event_type = line_event::RISING_EDGE;
-       else if (event_buf.event_type == GPIOD_LINE_EVENT_FALLING_EDGE)
-               event.event_type = line_event::FALLING_EDGE;
+       return this->make_line_event(event_buf);
+}
+
+::std::vector<line_event> line::event_read_multiple(void) const
+{
+       this->throw_if_null();
 
-       event.timestamp = ::std::chrono::nanoseconds(
-                               event_buf.ts.tv_nsec + (event_buf.ts.tv_sec * 1000000000));
+       /* 16 is the maximum number of events stored in the kernel FIFO. */
+       ::std::array<::gpiod_line_event, 16> event_buf;
+       ::std::vector<line_event> events;
+       int rv;
+
+       rv = ::gpiod_line_event_read_multiple(this->_m_line,
+                                             event_buf.data(), event_buf.size());
+       if (rv < 0)
+               throw ::std::system_error(errno, ::std::system_category(),
+                                         "error reading multiple line events");
 
-       event.source = *this;
+       events.reserve(rv);
+       for (int i = 0; i < rv; i++)
+               events.push_back(this->make_line_event(event_buf[i]));
 
-       return event;
+       return events;
 }
 
 int line::event_get_fd(void) const