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static const unsigned char g_pop_cnt[256] =

{

#   define B2(n) n,     n+1,     n+1,     n+2

#   define B4(n) B2(n), B2(n+1), B2(n+1), B2(n+2)

#   define B6(n) B4(n), B4(n+1), B4(n+1), B4(n+2)

    B6(0), B6(1), B6(1), B6(2)

};

static unsigned int POPCNT_Table(const unsigned char * buf, unsigned int len) {

    unsigned int cnt = 0;

    unsigned int ndwords = len / 4;

    for(; ndwords; ndwords--) {

        unsigned int v = *(unsigned int*)buf;

        cnt += g_pop_cnt[v & 0xff] +

               g_pop_cnt[(v >> 8) & 0xff] +

               g_pop_cnt[(v >> 16) & 0xff] +

               g_pop_cnt[v >> 24];

        buf += 4;

    }

    if (len & 2) {

        unsigned int v = *(short*)buf;

        cnt += g_pop_cnt[ v & 0xff ] +

               g_pop_cnt[ v >> 8 ];

        buf += 2;

    }

    if (len & 1)

        cnt += g_pop_cnt[ *buf ];

    return cnt;

}

int main(int argc, char const *argv[])

{

    unsigned int value = 1;

    for (unsigned int i = 0; i < 262151000; i++) {

        unsigned int res = POPCNT_Table((unsigned char*)&i, 4);

    }

    return 0;

}