first re-commit.

pigpio-master/EXAMPLES/CPP/WIEGAND_CODE/README

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+Class to decode a Wiegand code.
+
+Follow the instructions in the test file to build and run.

pigpio-master/EXAMPLES/CPP/WIEGAND_CODE/test_wiegand.cpp

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+#include <iostream>
+
+#include <pigpio.h>
+
+#include "wiegand.hpp"
+
+/*
+
+REQUIRES
+
+Wiegand contacts 0 and 1 connected to separate gpios.
+
+TO BUILD
+
+g++ -o wiegand_cpp test_wiegand.cpp wiegand.cpp -lpigpio -lrt
+
+TO RUN
+
+sudo ./wiegand_cpp
+
+*/
+
+void callback(int bits, uint32_t value)
+{
+   std::cout << "bits=" << bits << " value=" << value << std::endl;
+}
+
+int main(int argc, char *argv[])
+{
+   if (gpioInitialise() < 0) return 1;
+
+   Wiegand dec(14, 15, callback);
+
+   sleep(300);
+
+   dec.cancel();
+
+   gpioTerminate();
+}
+

pigpio-master/EXAMPLES/CPP/WIEGAND_CODE/wiegand.cpp

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+#include <pigpio.h>
+
+#include "wiegand.hpp"
+
+Wiegand::Wiegand(int gpio_0, int gpio_1, WiegandCB_t callback, int timeout)
+{
+   /*
+      Instantiate with the gpio for 0 (green wire), the gpio for 1
+      (white wire), the callback function, and the bit timeout in
+      milliseconds which indicates the end of a code.
+
+      The callback is passed the code length in bits and the value.
+   */
+
+   mygpio_0 = gpio_0;
+   mygpio_1 = gpio_1;
+
+   mycallback = callback;
+
+   mytimeout = timeout;
+
+   in_code = 0;
+
+   gpioSetMode(gpio_0, PI_INPUT);
+   gpioSetMode(gpio_1, PI_INPUT);
+
+   gpioSetPullUpDown(gpio_0, PI_PUD_UP);
+   gpioSetPullUpDown(gpio_1, PI_PUD_UP);
+
+   gpioSetAlertFuncEx(gpio_0, _cbEx, this);
+   gpioSetAlertFuncEx(gpio_1, _cbEx, this);
+}
+
+void Wiegand::_cb(int gpio, int level, uint32_t tick)
+{
+   /*
+      Accumulate bits until both gpios 0 and 1 timeout.
+   */
+
+   if (level == 0) /* a falling edge indicates a new bit */
+   {
+      if (!in_code)
+      {
+         bits = 1;
+         num = 0;
+
+         in_code = 1;
+         code_timeout = 0;
+
+         gpioSetWatchdog(mygpio_0, mytimeout);
+         gpioSetWatchdog(mygpio_1, mytimeout);
+      }
+      else
+      {
+         bits++;
+         num <<= 1;
+      }
+
+      if (gpio == mygpio_0)
+      {
+         code_timeout &= 2; /* clear gpio 0 timeout */
+      }
+      else
+      {
+         code_timeout &= 1; /* clear gpio 1 timeout */
+         num |= 1;
+      }
+   }
+   else if (level == PI_TIMEOUT)
+   {
+      if (in_code)
+      {
+         if (gpio == mygpio_0)
+         {
+            code_timeout |= 1; /* timeout gpio 0 */
+         }
+         else
+         {
+            code_timeout |= 2; /* timeout gpio 1 */
+         }
+
+         if (code_timeout == 3) /* both gpios timed out */
+         {
+            gpioSetWatchdog(mygpio_0, 0);
+            gpioSetWatchdog(mygpio_1, 0);
+
+            in_code = 0;
+
+            (mycallback)(bits, num);
+         }
+      }
+   }
+}
+
+void Wiegand::_cbEx(int gpio, int level, uint32_t tick, void *user)
+{
+   /*
+      Need a static callback to link with C.
+   */
+
+   Wiegand *mySelf = (Wiegand *) user;
+
+   mySelf->_cb(gpio, level, tick); /* Call the instance callback. */
+}
+
+
+void Wiegand::cancel(void)
+{
+   /*
+      Cancel the Wiegand decoder.
+   */
+
+   gpioSetAlertFuncEx(mygpio_0, 0, this);
+   gpioSetAlertFuncEx(mygpio_1, 0, this);
+}
+

pigpio-master/EXAMPLES/CPP/WIEGAND_CODE/wiegand.hpp

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+#ifndef WIEGAND_HPP
+#define WIEGAND_HPP
+
+#include <stdint.h>
+
+typedef void (*WiegandCB_t)(int, uint32_t);
+
+class Wiegand
+{
+   int mygpio_0, mygpio_1, mytimeout, in_code, bits;
+
+   WiegandCB_t mycallback;
+
+   uint32_t num;
+
+   uint32_t code_timeout;
+
+   void _cb(int gpio, int level, uint32_t tick);
+
+   /* Need a static callback to link with C. */
+   static void _cbEx(int gpio, int level, uint32_t tick, void *user);
+
+   public:
+
+   Wiegand(int gpio_0, int gpio_1, WiegandCB_t callback, int timeout=5);
+   /*
+      This function establishes a Wiegand decoder on gpio_0 and gpio_1.
+
+      A gap of timeout milliseconds without a new bit indicates
+      the end of a code.
+
+      When the code is ended the callback function is called with the code
+      bit length and value.
+   */
+
+   void cancel(void);
+   /*
+      This function releases the resources used by the decoder.
+   */
+};
+
+#endif
+