first commit

src/control_pipe.c

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+/*
+ * mpxgen - FM multiplex encoder with Stereo and RDS
+ * Copyright (C) 2019 Anthony96922
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "common.h"
+#include "ascii_cmd.h"
+#include "control_pipe.h"
+
+static int fd;
+static struct pollfd poller;
+
+/*
+ * Opens a file (pipe) to be used to control the RDS coder.
+ */
+int open_control_pipe(char *filename) {
+	fd = open(filename, O_RDONLY | O_NONBLOCK);
+	if (fd == -1) return -1;
+
+	/* setup the poller */
+	poller.fd = fd;
+	poller.events = POLLIN;
+
+	return 0;
+}
+
+/*
+ * Polls the control file (pipe), and if a command is received,
+ * calls process_ascii_cmd.
+ */
+void poll_control_pipe() {
+	static unsigned char pipe_buf[CTL_BUFFER_SIZE];
+	static unsigned char cmd_buf[CMD_BUFFER_SIZE];
+	struct timeval timeout;
+	int ret;
+	fd_set set;
+	char *token;
+
+	FD_ZERO(&set);
+	FD_SET(fd, &set);
+	timeout.tv_sec = 0;
+	timeout.tv_usec = READ_TIMEOUT_MS * 1000;
+
+	/* check for new commands */
+	if (poll(&poller, 1, READ_TIMEOUT_MS) <= 0) return;
+
+	/* return early if there are no new commands */
+	if (poller.revents == 0) return;
+
+	memset(pipe_buf, 0, CTL_BUFFER_SIZE);
+
+	ret = select(fd + 1, &set, NULL, NULL, &timeout);
+	if (ret == -1 || ret == 0) {
+		return;
+	} else {
+		read(fd, pipe_buf, CTL_BUFFER_SIZE - 1);
+	}
+
+	/* handle commands per line this is really good because if were sending text commands very quick after eachother then we can get a rt of for example 'Now its 12:00RT Now its 12:01' */
+	token = strtok((char *)pipe_buf, "\n");
+	while (token != NULL) {
+		memset(cmd_buf, 0, CMD_BUFFER_SIZE);
+		memcpy(cmd_buf, token, CMD_BUFFER_SIZE - 1);
+		token = strtok(NULL, "\n");
+
+		process_ascii_cmd(cmd_buf);
+	}
+}
+void close_control_pipe() {
+	if (fd > 0) close(fd);
+}