Add linux/raspberry_pi client.

network_clients/linux_or_raspberry/Makefile

@@ -0,0 +1,10 @@
+SOURCES=sys-con-client.c
+OUT=sys-con-client
+
+$(OUT): $(SOURCES)
+	gcc -o $@ $<
+
+.PHONY: clean
+
+clean:
+	rm $(OUT)

network_clients/linux_or_raspberry/sys-con-client.c

@@ -0,0 +1,210 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <linux/joystick.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/tcp.h>
+
+#define BUFFER_SIZE 7
+
+static unsigned char buffer[BUFFER_SIZE] = {0};
+
+struct button_map
+{
+    unsigned char index;
+    unsigned char position;
+};
+
+enum hat_state
+{
+    HAT_UP,
+    HAT_UPRIGHT,
+    HAT_RIGHT,
+    HAT_DOWNRIGHT,
+    HAT_DOWN,
+    HAT_DOWNLEFT,
+    HAT_LEFT,
+    HAT_UPLEFT,
+    HAT_UNPRESSED,
+};
+
+static struct button_map buttonMaps[] =
+{
+    {4, 5},
+    {4, 6},
+    {4, 7},
+    {4, 4},
+    {5, 0},
+    {5, 1},
+    {5, 2},
+    {5, 3},
+    {5, 4},
+    {5, 5},
+    {6, 0},
+    {5, 6},
+    {5, 7},
+    {4, 1},
+    {4, 3},
+    {4, 0},
+    {4, 2},
+};
+
+int axisToIndexMap[] =
+{
+    0,
+    1,
+    -1,
+    2,
+    3,
+};
+
+int read_event(int fd, struct js_event *event)
+{
+    ssize_t bytes;
+
+    bytes = read(fd, event, sizeof(*event));
+
+    if (bytes == sizeof(*event))
+        return 0;
+
+    /* Error, could not read full event. */
+    return -1;
+}
+
+int main(int argc, char *argv[])
+{
+    char device[] = "/dev/input/js0";
+    int js, gd, yes = 1;
+    struct js_event event;
+    struct sockaddr_in saddr;
+
+    if(argc != 3)
+    {
+        printf("\n Usage: %s <ip of server> <js number>\n",argv[0]);
+        return 1;
+    } 
+
+    device[13] = argv[2][0];
+
+    js = open(device, O_RDONLY);
+
+    if (js == -1)
+        perror("Could not open joystick");
+
+    gd = socket(AF_INET, SOCK_STREAM, 0);
+    if (gd == -1)
+        perror("Could not open socket");
+
+    memset(&saddr, 0, sizeof(saddr));
+
+    saddr.sin_family = AF_INET;
+    saddr.sin_port = htons(8080);
+
+    if (inet_pton(AF_INET, argv[1], &saddr.sin_addr) <= 0)
+    {
+        printf("\n inet_pton error occured\n");
+        return 1;
+    }
+
+    if (connect(gd, (struct sockaddr *)&saddr, sizeof(saddr)) < 0)
+    {
+        printf("\n Error : Connect Failed \n");
+        return 1;
+    }
+
+    if (setsockopt(gd, IPPROTO_TCP, TCP_NODELAY, (void *)&yes, sizeof(yes)) < 0)
+    {
+        printf("\n Error : TCP NODELAY Failed \n");
+        return 1;
+    }
+
+    memset(buffer, 0, sizeof(buffer));
+
+    // Init axis at rest
+    buffer[0] = 127;
+    buffer[1] = 127;
+    buffer[2] = 127;
+    buffer[3] = 127;
+     
+    /* This loop will exit if the controller is unplugged. */
+    while (read_event(js, &event) == 0)
+    {
+        switch (event.type)
+        {
+            case JS_EVENT_BUTTON:
+                printf("Button %u %s\n", event.number, event.value ?
+                                                       "pressed" : "released");
+
+                struct button_map map = buttonMaps[event.number];
+                if (event.value)
+                {
+                    buffer[map.index] |= 1 << map.position; 
+                }
+                else
+                {
+                    buffer[map.index] &= ~(1 << map.position); 
+                }
+
+                write(gd, buffer, BUFFER_SIZE);
+                break;
+            case JS_EVENT_AXIS:
+                printf("Axis %zu value %6d\n", event.number, event.value);
+
+                switch (event.number)
+                {
+                    case 6:
+                    case 7:
+                    {
+                        int buttonNumber, buttonValue = 1;
+                        buttonNumber = (event.number == 6 && event.value < 0) ? 15 :
+                                       (event.number == 6 && event.value > 0) ? 16 :
+                                       (event.number == 7 && event.value < 0) ? 13 :
+                                       (event.number == 7 && event.value > 0) ? 14 : -1;
+
+                        if (buttonNumber == -1) 
+                        {
+                            int i;
+                            for (i = 0; i < 2; i++)
+                            {
+                                struct button_map map = buttonMaps[(event.number == 7 ? 13 : 15) + i];
+                                buffer[map.index] &= ~(1 << map.position);
+                            }
+                        }
+                        else
+                        {
+                            struct button_map map = buttonMaps[buttonNumber];
+                            buffer[map.index] |= 1 << map.position; 
+                        }
+                    }
+                    break;
+
+                    case 0:
+                    case 1:
+                    case 3:
+                    case 4:
+                    {
+                        int index = axisToIndexMap[event.number];
+                        buffer[index] = (unsigned char)
+                                            (((int)event.value + 32767) >> 8);
+                        printf("Normalized value %3d\n",
+                                                (unsigned char)buffer[index]);
+                    }
+                    break;
+                }
+                write(gd, buffer, BUFFER_SIZE);
+                break;
+
+            default:
+                /* Ignore init events. */
+                printf("Weird event: %d\n", event.type);
+                break;
+        }
+
+        fflush(stdout);
+    }
+
+    close(js);
+    return 0;
+}