Blinker.cxx

Go to the documentation of this file.

 
#include "utils/blinker.h"
 
extern "C"
{
 
unsigned parseblink(uint32_t pattern)
{
    unsigned ret = 0;
    if (!pattern)
    {
        return ret;
    }
    // Finds the top bit.
    uint32_t tb = 1U << 31;
    while ((tb & pattern) == 0)
    {
        tb >>= 1;
    }
    unsigned nibble_shift = 1;
    unsigned last_len = 1;
    unsigned curr_len = 1;
    pattern &= ~tb;
    while (true)
    {
        if (curr_len)
        {
            if (pattern & 1)
            {
                curr_len++;
            }
            else
            {
                // end of lit period
                if (last_len != curr_len)
                {
                    // new blink length
                    nibble_shift <<= 4;
                    last_len = curr_len;
                }
                ret += nibble_shift;
                curr_len = 0;
            }
        }
        else
        {
            // we are in unlit
            if (pattern & 1)
            {
                // start of a new lit period.
                curr_len = 1;
            }
        }
        if (!pattern)
        {
            break;
        }
        pattern >>= 1;
    }
    return ret;
}
 
}