bit manipulation tricks

bit-manipulation-tricks.md

• drop the first bit

x >> 1;

• drop LSB (the least Significant bit)

x & (x - 1);

• extracts the lowest set bit of x (all other bits are cleared)

x & !(x - 1);

• extracts i-th bit

(x >>> i) & 1;

• flip bit value

x ^= 1;

• extracts part of bits from x using bit mask

// e.g : extract the 2nd 2 bytes (16 bits) from long x
x = x >> 16; // step 1. get rid of unwanted part (the first 2 bytes)
x = x & 0xFFFF; // step 2. extract only the bit mask number of bits, in this case, the bit mask is 16 bits