Barcode code.

terminal/barcode.c

@@ -0,0 +1,105 @@
+#include <termios.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/time.h>
+
+int g_BarcodeFD;
+
+int barcode_initialize(char *Device)
+{
+    g_BarcodeFD = open(Device, O_RDWR | O_NONBLOCK);
+    if (g_BarcodeFD == -1)
+    {
+        printf("Failed to open barcode reader TTY.\n");
+        return 1;
+    }
+
+    struct termios Config;
+
+    if (!isatty(g_BarcodeFD))
+    {
+        printf("Barcode TTY is not a TTY!\n");
+        return 1;
+    }
+
+    if (tcgetattr(g_BarcodeFD, &Config))
+    {
+        printf("Could not get barcode TTY config.\n");
+        return 1;
+    }
+
+    memset(&Config, 0, sizeof(Config));
+    Config.c_iflag = 0;
+    Config.c_oflag = 0;
+    Config.c_lflag = 0;
+    Config.c_cflag = CS8|CREAD|CLOCAL;
+    Config.c_cc[VMIN] = 1;
+    Config.c_cc[VTIME] = 0;
+
+    if (cfsetispeed(&Config, B9600) < 0 || cfsetospeed(&Config, B9600) < 0)
+    {
+        printf("Could not set barcode TTY baudrate!\n");
+        return 1;
+    }
+
+    if (tcsetattr(g_BarcodeFD, TCSAFLUSH, &Config) < 0)
+    {
+        printf("Could not set barcode TTY attributes!\n");
+        return 1;
+    }
+
+    return 0;
+}
+
+int _async_read_timeout(int FD, char *DataOut, int NumBytes, int Timeout)
+{
+    fd_set Read, Write, Special;
+    FD_ZERO(&Read);
+    FD_ZERO(&Write);
+    FD_ZERO(&Special);
+
+    FD_SET(FD, &Read);
+
+    struct timeval TTimeout;
+    memset(&TTimeout, 0, sizeof(TTimeout));
+    TTimeout.tv_sec = Timeout;
+
+    int ResultFD = select(FD + 1, &Read, &Write, &Special, &TTimeout);
+    if (ResultFD == -1)
+    {
+        return -1;
+    }
+
+    return read(FD, DataOut, NumBytes);
+}
+
+int barcode_read(char *BarcodeOut)
+{
+    int BytesRead = 0;
+
+    // read the first byte with a long timeout
+    BytesRead += _async_read_timeout(g_BarcodeFD, BarcodeOut + BytesRead, 14, 20);
+    if (BytesRead == -1)
+    {
+        printf("Timeout on reading first barcode bytes.\n");
+        return 1;
+    }
+
+    while (BytesRead < 14)
+    {
+        int Result = _async_read_timeout(g_BarcodeFD, BarcodeOut + BytesRead, 14 - BytesRead, 1);
+        if (Result == -1)
+        {
+            printf("Timeout on reading following bytecode bytes.\n");
+            return 1;
+        }
+        BytesRead += Result;
+    }
+    BarcodeOut[13] = 0;
+
+    return 0;
+}
+

terminal/barcode.h

@@ -0,0 +1,7 @@
+#ifndef __BARCODE_H__
+#define __BARCODE_H__
+
+int barcode_initialize(char *Device);
+int barcode_read(char *BarcodeOut);
+
+#endif

terminal/test-barcode.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+
+#include "barcode.h"
+
+int main()
+{
+    if (barcode_initialize("/dev/ttyUSB0"))
+    {
+        printf("Could not initialize barcode.\n");
+        return 1;
+    }
+
+    char Barcode[14];
+    if (barcode_read(Barcode))
+    {
+        printf("Could not read barcode.\n");
+        return 1;
+    }
+    printf("barcode: %s\n", Barcode);
+    if (barcode_read(Barcode))
+    {
+        printf("Could not read barcode.\n");
+        return 1;
+    }
+    printf("barcode: %s\n", Barcode);
+
+    return 0;
+}