Start some BT6000 data decoding.

[ultimatescore] / client / bodet.cpp

diff --git a/client/bodet.cpp b/client/bodet.cpp
new file mode 100644 (file)
index 0000000..840094a
--- /dev/null
+++ b/client/bodet.cpp
@@ -0,0 +1,82 @@
+// Bodet BT-6000 decoder.
+
+#include <stdio.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+using namespace std;
+
+void process(const string &buf)
+{
+       unsigned char checksum = 0;
+       for (size_t i = 1; i <= buf.size() - 2; ++i) {
+               checksum ^= buf[i];
+       }
+       checksum &= 0x7f;
+       if (checksum < 0x20) {
+               checksum += 0x20;
+       }
+       if (checksum != buf.back()) {
+       //      fprintf(stderr, "discarding message with broken checksum: [%s] [%x vs. %x]\n", buf.c_str(), checksum, buf.back());
+       } else {
+               string realmsg = buf.substr(3, buf.size() - 5);
+               fprintf(stderr, "msg: [%s]\n", realmsg.c_str());
+       }
+}
+
+int main(int argc, char **argv)
+{
+       // TODO: open serial port
+
+       string buf;
+
+       for ( ;; ) {
+               char ch;
+               int ret = read(0, &ch, 1);
+               if (ret == -1) {
+                       perror("read");
+                       exit(1);
+               }
+               if (ret == 0) {
+                       fprintf(stderr, "short read\n");
+                       exit(1);
+               }
+
+               if (ch == 1) {  // SOH
+                       buf = ch;
+                       continue;
+               } 
+               if (buf.size() == 1) {
+                       // Address
+                       buf.push_back(ch);
+                       continue;
+               }
+               if (ch == 2) {  // STX
+                       if (buf.size() == 2) {
+                               buf.push_back(ch);
+                       } else {
+                               buf.clear();  // STX out-of-order
+                       }
+                       continue;
+               }
+
+               if (!buf.empty() && buf.back() == 3) {  // Last was ETX, so this is LTC.
+                       buf.push_back(ch);
+                       process(buf);
+                       buf.clear();
+                       continue;
+               }
+
+               if (ch == 3) {  // ETX
+                       if (buf.size() >= 4) {
+                               buf.push_back(ch);
+                       } else {
+                               buf.clear();  // ETX out-of-order
+                       }
+                       continue;
+               }
+               buf.push_back(ch);
+       }
+}