Runtime: add PMT fmt-formatting capabilities

This was long overdue; PMTs have to be logged routinely.

Signed-off-by: Marcus Müller <[email protected]>

Author: marcusmueller

gnuradio-runtime/include/gnuradio/CMakeLists.txt

@@ -45,6 +45,7 @@ install(
           msg_handler.h
           msg_queue.h
           nco.h
+          pmt_fmt.h
           pdu.h
           prefs.h
           pycallback_object.h

gnuradio-runtime/include/gnuradio/pmt_fmt.h

@@ -0,0 +1,23 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2023 Marcus Müller
+ *
+ * This file is part of GNU Radio
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+#ifndef INCLUDED_GNURADIO_PMT_FMT_H
+#define INCLUDED_GNURADIO_PMT_FMT_H
+#include <gnuradio/api.h>
+#include <pmt/pmt.h>
+#include <spdlog/fmt/fmt.h>
+#include <string_view>
+
+//!\brief enables PMTs to be formatted with fmt
+template <>
+struct GR_RUNTIME_API fmt::formatter<pmt::pmt_t> : formatter<std::string_view> {
+    fmt::format_context::iterator format(const pmt::pmt_t& obj,
+                                         format_context& ctx) const;
+};
+#endif

gnuradio-runtime/lib/CMakeLists.txt

@@ -71,6 +71,7 @@ add_library(
     msg_queue.cc
     pagesize.cc
     pdu.cc
+    pmt_fmt.cc
     prefs.cc
     realtime.cc
     realtime_impl.cc

gnuradio-runtime/lib/pmt_fmt.cc

@@ -0,0 +1,19 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2023 Marcus Müller
+ *
+ * This file is part of GNU Radio
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+#include <gnuradio/pmt_fmt.h>
+#include <pmt/pmt.h>
+#include <spdlog/fmt/fmt.h>
+#include <string_view>
+
+fmt::format_context::iterator
+fmt::formatter<pmt::pmt_t>::format(const pmt::pmt_t& obj, fmt::format_context& ctx) const
+{
+    return fmt::format_to(ctx.out(), "{}", pmt::write_string(obj));
+}