Triple Shift Operator in Java
The triple shift operator in java is denoted by ">>>" and is a bit manipulation operator that fills the leftmost bits of a given value with zeros by shifting the bits of the value to the right by a certain number of places. The unsigned right shift operator (>>>) is a fundamental bitwise operator used in programming languages such as Java, JavaScript, and others.
It is used to shift a bitwise right on its operand without keeping the sign bit unaltered. By shifting all of the operand's bits to the right and treating it as an unsigned value, this operator fills the leftmost locations with zeros. In contrast, the signed right shift operator (>>) leaves the leftmost bits empty and inserts the sign bit (0 for positive numbers and 1 for negative numbers) into the empty bits.
Characteristics of Unsigned Right Shift Operator
- Shifts all bits to the right
The >>> operator shifts all bits of the operand to the right by a specified number of positions, including the sign bit.
- Does not preserve the sign bit
Unlike the regular right shift operator (>>), which preserves the sign bit and extends it when shifting, the >>> operator fills the leftmost positions with zeros, regardless of the original sign bit. This behavior makes it particularly useful for treating operands as unsigned values.
- Operates on integer types
The unsigned right shift operator typically operates on integer types such as int, long, short, and byte in programming languages like Java. It may not be applicable to floating-point types or other non-integer types.
- Useful for logical shifts
The >>> operator is commonly used in scenarios where logical right shifts are required, such as manipulating binary data, implementing hashing algorithms, or performing bitwise operations on unsigned values.
- No effect on negative numbers
Since the >>> operator treats the operand as an unsigned value, it does not have any effect on the sign of the operand. Negative numbers are treated as positive values during the shift operation, and the resulting bits are filled with zeros.
Examples of Unsigned Right Shift Operations
- Bitmap Processing
Filename: BitmapProcessing.java
import java.util.Arrays;
public class BitmapProcessing {
// Function to perform unsigned right shift operation on each pixel of a bitmap
public static int[] shiftBitmapPixels(int[] bitmap, int shiftAmount) {
int[] shiftedBitmap = new int[bitmap.length];
for (int i = 0; i < bitmap.length; i++) {
shiftedBitmap[i] = bitmap[i] >>> shiftAmount;
}
return shiftedBitmap;
}
public static void main(String[] args) {
// Sample bitmap data (array of pixel values)
int[] bitmap = {255, 127, 63, 31, 15}; // Binary: 11111111, 01111111, 00111111, 00011111, 00001111
// Display original bitmap
System.out.println("Original Bitmap: " + Arrays.toString(bitmap));
// Perform unsigned right shift by 2 on bitmap pixels
int[] shiftedBitmap = shiftBitmapPixels(bitmap, 2);
// Display shifted bitmap
System.out.println("Shifted Bitmap: " + Arrays.toString(shiftedBitmap));
}
}
Output:
Original Bitmap: [255, 127, 63, 31, 15]
Shifted Bitmap: [63, 31, 15, 7, 3]
Inside the shiftBitmapPixels method, a new array shiftedBitmap is created to store the shifted pixel values. Then, a loop iterates over each pixel of the input bitmap. For each pixel, the unsigned right shift operator (>>>) is applied to shift its bits to the right by the specified shiftAmount, and the result is stored in the corresponding position of the shiftedBitmap array.
The main method initializes a sample bitmap array with pixel values {255, 127, 63, 31, 15}. It then displays the original bitmap using Arrays.toString(bitmap). Next, it calls the shiftBitmapPixels method to perform an unsigned right shift by 2 on each pixel of the bitmap. Finally, it displays the shifted bitmap using Arrays.toString(shiftedBitmap).
- Hash Function Implementation
Filename: HashFunction.java
import java.util.Arrays;
public class HashFunction {
// Custom hash function using bitwise operations
public static int customHash(int value) {
// Apply bitwise XOR and unsigned right shift operations
value ^= (value << 13);
value ^= (value >>> 17);
value ^= (value << 5);
return value;
}
public static void main(String[] args) {
// Sample input values for hashing
int[] inputValues = {123, 456, 789, 321, 654};
// Display original input values
System.out.println("Original Input Values: " + Arrays.toString(inputValues));
// Apply custom hash function to each input value
for (int i = 0; i < inputValues.length; i++) {
inputValues[i] = customHash(inputValues[i]);
}
// Display hashed values
System.out.println("Hashed Values: " + Arrays.toString(inputValues));
}
}
Output:
Original Input Values: [123, 456, 789, 321, 654]
Hashed Values: [31682556, 119094100, 204916644, 86772725, 174691942]
The HashFunction class contains a static method customHash, which takes an integer value as input and applies bitwise XOR and unsigned right shift operations to generate a hashed value. These operations are performed in a sequence to produce a unique hash for the input value.
In the main method, an array inputValues is initialized with sample input values {123, 456, 789, 321, 654}. The original input values are displayed using Arrays.toString(inputValues). A loop iterates over each input value in the array. For each value, the customHash method is called to compute its hash, and the result is stored back into the array.