initial commit.

1 files changed, 194 insertions, 0 deletions

diff --git a/src/server/main.c b/src/server/main.c
new file mode 100644
index 0000000..902898e
--- /dev/null
+++ b/src/server/main.c
@@ -0,0 +1,194 @@
+/*
+ * An unnamed project – client module
+ *
+ * Copyright (C) 2017 Gediminas Jakutis
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1
+ * of the License.
+ *
+ * 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/udp.h>
+#include <poll.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <ncurses.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <time.h>
+
+static void init(const unsigned int port, int *sock);
+static int getpacket(char *data, size_t buffsize, int *sock, struct sockaddr_in *sender);
+static void draw_idle(void);
+static void draw_busy(const char * const data);
+static float digest_mpu_temp(const short int rawdata);
+static float digest_thermistor_voltage(const short int rawdata);
+
+int main(void)
+{
+	static const char servermagic[] = "I love coffee!";
+	static const char clientmagic[] = "I love tea!";
+	struct sockaddr_in srvaddr = {0};
+	char buff[9001] = {0};
+	int sock;
+	int pstatus;
+	struct timespec lastreply;
+	struct timespec now;
+
+	init(2191, &sock);
+
+	clock_gettime(CLOCK_MONOTONIC_RAW, &now);
+	lastreply = now;
+	lastreply.tv_sec -= 5;
+
+	do {
+		clock_gettime(CLOCK_MONOTONIC_RAW, &now);
+		pstatus = getpacket(buff, sizeof(buff), &sock, &srvaddr);
+
+		switch (pstatus) {
+		case 0:
+			if ((now.tv_sec - lastreply.tv_sec) >= 5) {
+				draw_idle();
+			}
+			break;
+		case 1:
+			lastreply = now;
+			if (buff[0] == 'I') {
+				if (!(strcmp(buff, servermagic))) {
+					sendto(sock, clientmagic, sizeof(clientmagic),
+							MSG_DONTWAIT, (struct sockaddr *) &srvaddr, sizeof(srvaddr));
+				}
+				draw_idle();
+				continue;
+			}
+			draw_busy(buff);
+			break;
+		default:
+			; /* noop */
+		}
+	} while (getch() != 'q' && pstatus >= 0);
+
+	close(sock);
+	endwin();
+
+	return 0;
+}
+
+static void init(const unsigned int port, int *sock)
+{
+	struct sockaddr_in bindaddress = {0};
+
+	bindaddress.sin_family = AF_INET;
+	bindaddress.sin_port = htons(port);
+	*sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	bind(*sock, (struct sockaddr*) &bindaddress, sizeof(bindaddress));
+
+	initscr();
+	nodelay(stdscr, 1);
+	noecho();
+}
+
+static int getpacket(char *data, size_t buffsize, int *sock, struct sockaddr_in *sender)
+{
+	static struct pollfd pfd = {0};
+	int ret;
+	socklen_t sender_len = sizeof(*sender);
+
+	if (!pfd.fd) {
+		pfd.fd = *sock;
+		pfd.events = POLLIN;
+		pfd.revents = 0;
+	}
+
+	ret = poll(&pfd, 1, 25);
+	if (ret <= 0) {
+		return ret;
+	}
+	if (pfd.revents & POLLIN) {
+		recvfrom(*sock, data, buffsize, MSG_DONTWAIT, (struct sockaddr *) sender, &sender_len);
+		ret = 1;
+	} else {
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static void draw_idle(void)
+{
+	move(0, 0);
+	clrtoeol();
+	printw("sequence: [waiting for ESP8266...]");
+	move(1, 0);
+	clrtoeol();
+	mvprintw(1, 0, "mpu temp: [waiting for ESP8266...]");
+	move(2, 0);
+	clrtoeol();
+	mvprintw(2, 0, "thermistor voltage: [waiting for ESP8266...]");
+	move(3, 0);
+	clrtoeol();
+	mvprintw(3, 0, "press 'q' to exit");
+	refresh();
+}
+
+static void draw_busy(const char * const data)
+{
+	unsigned int sequence;
+	short int mpu_data;
+	short int thermistor_data;
+	float mpu_temp;
+	float thermistor_voltage;
+
+	memcpy(&sequence, data + 2, sizeof(sequence));
+	memcpy(&mpu_data, data + 6, sizeof(mpu_data));
+	memcpy(&thermistor_data, data + 8, sizeof(mpu_data));
+	mpu_temp = digest_mpu_temp(mpu_data);
+	thermistor_voltage = digest_thermistor_voltage(thermistor_data);
+
+	move(0, 0);
+	clrtoeol();
+	printw("sequence: %u", sequence);
+	move(1, 0);
+	clrtoeol();
+	mvprintw(1, 0, "mpu temp: %.3fC", mpu_temp);
+	move(2, 0);
+	clrtoeol();
+	mvprintw(2, 0, "thermistor voltage: %.3fV", thermistor_voltage);
+	move(3, 0);
+	clrtoeol();
+	mvprintw(3, 0, "press 'q' to exit");
+	refresh();
+}
+
+static float digest_mpu_temp(const short int rawdata)
+{
+	float ret;
+
+	ret = rawdata / 340.0f + 36.53f;
+
+	return ret;
+}
+
+static float digest_thermistor_voltage(const short int rawdata)
+{
+	float ret;
+
+	ret = rawdata * 0.003222656f;
+
+	return ret;
+}