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#include <pigpio.h>
#include "ir_hasher.hpp"
void Hasher::_hash(int old_val, int new_val)
{
int val;
if (new_val < (old_val * 0.60)) val = 13;
else if (old_val < (new_val * 0.60)) val = 23;
else val = 2;
hash_val ^= val;
hash_val *= 16777619; /* FNV_PRIME_32 */
}
void Hasher::_callback(int gpio, int level, uint32_t tick)
{
if (level != PI_TIMEOUT)
{
if (in_code == 0)
{
in_code = 1;
gpioSetWatchdog(mygpio, mytimeout);
hash_val = 2166136261U; /* FNV_BASIS_32 */
edges = 1;
t1 = 0;
t2 = 0;
t3 = 0;
t4 = tick;
}
else
{
edges++;
t1 = t2;
t2 = t3;
t3 = t4;
t4 = tick;
if (edges > 3) _hash(t2-t1, t4-t3);
}
}
else
{
if (in_code)
{
in_code = 0;
gpioSetWatchdog(mygpio, 0);
if (edges > 12) /* Anything less is probably noise. */
{
(mycallback)(hash_val);
}
}
}
}
void Hasher::_callbackExt(int gpio, int level, uint32_t tick, void *user)
{
/*
Need a static callback to link with C.
*/
Hasher *mySelf = (Hasher *) user;
mySelf->_callback(gpio, level, tick); /* Call the instance callback. */
}
Hasher::Hasher(int gpio, HasherCB_t callback, int timeout)
{
/*
Initialises an IR remote hasher on a gpio. A gap of timeout
milliseconds indicates the end of the remote key press.
*/
mygpio = gpio;
mycallback = callback;
mytimeout = timeout;
in_code = 0;
gpioSetMode(gpio, PI_INPUT);
gpioSetAlertFuncEx(gpio, _callbackExt, (void *)this);
}
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