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#include <stdint.h>
const uint8_t deBruijn64tab[64] = {
0, 1, 56, 2, 57, 49, 28, 3, 61, 58, 42, 50, 38, 29, 17, 4,
62, 47, 59, 36, 45, 43, 51, 22, 53, 39, 33, 30, 24, 18, 12, 5,
63, 55, 48, 27, 60, 41, 37, 16, 46, 35, 44, 21, 52, 32, 23, 11,
54, 26, 40, 15, 34, 20, 31, 10, 25, 14, 19, 9, 13, 8, 7, 6,
};
int TrailingZeros64(uint64_t x) {
static const uint64_t deBruijn64 = 0x03f79d71b4ca8b09ULL;
if (x == 0) {
return 64;
}
return (int)deBruijn64tab[(x&-x)*deBruijn64>>(64-6)];
}
const uint8_t lead0tab[16] = {
//0b0000 0b0001 0b0010 0b0011 0b0100 0b0101 0b0110 0b0111 0b1000...
0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3
};
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