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Bit-shift methods #2

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Bit-shift methods #2

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6ea5094
Added shiftLeft method
ica4c Mar 24, 2020
c137eda
Added shiftRight method
ica4c Mar 24, 2020
473a41b
Added tests for both new methods
ica4c Mar 24, 2020
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14 changes: 14 additions & 0 deletions lib/BigInteger.php
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Original file line number Diff line number Diff line change
Expand Up @@ -625,6 +625,20 @@ public function equals($x) {
public function sign() {
return $this->value[0] === "-" ? -1 : ($this->value === "0" ? 0 : 1);
}

public function shiftLeft($n) {
return $this->mul((new static(2))->pow($n));
}

public function shiftRight($n) {
$newInt = $this->div((new static(2))->pow($n));

if ($newInt->add($n)->cmp(0) < 0) {
return $newInt->sub(1);
}

return $newInt;
}
}

}
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2 changes: 2 additions & 0 deletions test/test.php
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Expand Up @@ -74,6 +74,8 @@ function testOp() {
testB((new BigInteger(20))->binaryAnd(18), "16", "binaryAnd");
testB((new BigInteger(20))->binaryOr(18), "22", "binaryOr");
testB((new BigInteger(20))->binaryXor(18), "6", "binaryXor");
testB((new BigInteger(3))->shiftLeft(4), "48", "shiftLeft");
testB((new BigInteger(3))->shiftRight(4), "0", "shiftRight");
testB((new BigInteger(20))->setbit(3), "28", "setbit");
test((new BigInteger(20))->testbit(4), true, "testbit true");
test((new BigInteger(20))->testbit(3), false, "testbit false");
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