RorateBits 함수 추가

misc.go

@@ -147,3 +147,75 @@ func FindOneInSlice[T any](in []T, compare func(elem *T) bool) (int, bool) {
 	}
 	return -1, false
 }
+
+// RotateRight rotates the bits in the byte array to the right by n positions
+func rotateBitsRight(data []byte, n int) {
+	// Normalize n to avoid unnecessary rotations
+	n = n % (len(data) * 8)
+	if n == 0 {
+		return
+	}
+
+	// To hold the final rotated result
+	inlen := len(data)
+	for k := 0; k < n/8; k++ {
+		last := data[inlen-1]
+		for i := 0; i < inlen-1; i++ {
+			data[inlen-1-i] = data[inlen-2-i]
+		}
+		data[0] = last
+	}
+
+	n = n % 8
+	if n == 0 {
+		return
+	}
+
+	mask := byte(1<<n) - 1
+	carry := data[0] & mask
+	for i := 1; i < inlen; i++ {
+		nextcarry := data[i] & mask
+		data[i] = (data[i] >> n) | (carry << (8 - n))
+		carry = nextcarry
+	}
+	data[0] = (data[0] >> n) | (carry << (8 - n))
+}
+
+func rotateBitsLeft(data []byte, n int) {
+	// Normalize n to avoid unnecessary rotations
+	n = n % (len(data) * 8)
+	if n == 0 {
+		return
+	}
+
+	// To hold the final rotated result
+	inlen := len(data)
+	for k := 0; k < n/8; k++ {
+		last := data[0]
+		for i := 0; i < inlen-1; i++ {
+			data[i] = data[i+1]
+		}
+		data[inlen-1] = last
+	}
+
+	n = n % 8
+	if n == 0 {
+		return
+	}
+
+	mask := (byte(1<<n) - 1) << (8 - n)
+	carry := data[0] & mask
+	for i := inlen - 1; i >= 0; i-- {
+		nextcarry := data[i] & mask
+		data[i] = (data[i] << n) | (carry >> (8 - n))
+		carry = nextcarry
+	}
+}
+
+func RotateBits(data []byte, n int) {
+	if n > 0 {
+		rotateBitsRight(data, n)
+	} else {
+		rotateBitsLeft(data, -n)
+	}
+}