px4_cli: add px4_get_parameter_value CLI helper method

src/platforms/common/CMakeLists.txt

@@ -42,6 +42,7 @@ endif()
 px4_add_library(platforms__common
 	module.cpp
 	px4_getopt.c
+	px4_cli.cpp
 	shutdown.cpp
 	${SRCS}
 	)

src/platforms/common/px4_cli.cpp

@@ -0,0 +1,84 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2018 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <parameters/param.h>
+#include <px4_cli.h>
+#include <px4_log.h>
+
+#include <cstring>
+#include <errno.h>
+#include <cstdlib>
+
+int px4_get_parameter_value(const char *option, int &value)
+{
+	value = 0;
+
+	/* check if this is a param name */
+	if (strncmp("p:", option, 2) == 0) {
+
+		const char *param_name = option + 2;
+
+		/* user wants to use a param name */
+		param_t param_handle = param_find(param_name);
+
+		if (param_handle != PARAM_INVALID) {
+
+			if (param_type(param_handle) != PARAM_TYPE_INT32) {
+				return -EINVAL;
+			}
+
+			int32_t pwm_parm;
+			int ret = param_get(param_handle, &pwm_parm);
+
+			if (ret != 0) {
+				return ret;
+			}
+
+			value = pwm_parm;
+
+		} else {
+			PX4_ERR("param name '%s' not found", param_name);
+			return -ENXIO;
+		}
+
+	} else {
+		char *ep;
+		value = strtol(option, &ep, 0);
+
+		if (*ep != '\0') {
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}

src/platforms/px4_cli.h

@@ -0,0 +1,54 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2018 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file px4_cli.h
+ * Helper methods for command-line parameters
+ */
+
+#pragma once
+
+
+/**
+ * Parse a CLI argument to an integer. There are 2 valid formats:
+ * - 'p:<param_name>'
+ *   in this case the parameter is loaded from an integer parameter
+ * - <int>
+ *   an integer value, so just a string to integer conversion is done
+ * @param option CLI argument
+ * @param value returned value
+ * @return 0 on success, -errno otherwise
+ */
+int px4_get_parameter_value(const char *option, int &value);
+
+