Package com.google.common.primitives

Class Bytes

  • @GwtCompatible
public final class Bytes
extends Object
    Static utility methods pertaining to byte primitives, that are not already found in either Byte or Arrays, and interpret bytes as neither signed nor unsigned. The methods which specifically treat bytes as signed or unsigned are found in SignedBytes and UnsignedBytes.

    See the Guava User Guide article on primitive utilities.

    Since:
    1.0
    Author:
    Kevin Bourrillion

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static List<Byte> asList​(byte... backingArray)
      Returns a fixed-size list backed by the specified array, similar to Arrays.asList(Object[]).
      static byte[] concat​(byte[]... arrays)
      Returns the values from each provided array combined into a single array.
      static boolean contains​(byte[] array, byte target)
      Returns true if target is present as an element anywhere in array.
      static byte[] ensureCapacity​(byte[] array, int minLength, int padding)
      Returns an array containing the same values as array, but guaranteed to be of a specified minimum length.
      static int hashCode​(byte value)
      Returns a hash code for value; equal to the result of invoking ((Byte) value).hashCode().
      static int indexOf​(byte[] array, byte target)
      Returns the index of the first appearance of the value target in array.
      static int indexOf​(byte[] array, byte[] target)
      Returns the start position of the first occurrence of the specified target within array, or -1 if there is no such occurrence.
      static int lastIndexOf​(byte[] array, byte target)
      Returns the index of the last appearance of the value target in array.
      static void reverse​(byte[] array)
      Reverses the elements of array.
      static void reverse​(byte[] array, int fromIndex, int toIndex)
      Reverses the elements of array between fromIndex inclusive and toIndex exclusive.
      static void rotate​(byte[] array, int distance)
      Performs a right rotation of array of "distance" places, so that the first element is moved to index "distance", and the element at index i ends up at index (distance + i) mod array.length.
      static void rotate​(byte[] array, int distance, int fromIndex, int toIndex)
      Performs a right rotation of array between fromIndex inclusive and toIndex exclusive.
      static byte[] toArray​(Collection<? extends Number> collection)
      Returns an array containing each value of collection, converted to a byte value in the manner of Number.byteValue().

    • Method Detail

      • hashCode

        public static int hashCode​(byte value)
        Returns a hash code for value; equal to the result of invoking ((Byte) value).hashCode().

        Java 8+ users: use Byte.hashCode(byte) instead.

        Parameters:
        value - a primitive byte value
        Returns:
        a hash code for the value

      • contains

        public static boolean contains​(byte[] array,
                               byte target)
        Returns true if target is present as an element anywhere in array.
        Parameters:
        array - an array of byte values, possibly empty
        target - a primitive byte value
        Returns:
        true if array[i] == target for some value of i

      • indexOf

        public static int indexOf​(byte[] array,
                          byte target)
        Returns the index of the first appearance of the value target in array.
        Parameters:
        array - an array of byte values, possibly empty
        target - a primitive byte value
        Returns:
        the least index i for which array[i] == target, or -1 if no such index exists.

      • indexOf

        public static int indexOf​(byte[] array,
                          byte[] target)
        Returns the start position of the first occurrence of the specified target within array, or -1 if there is no such occurrence.

        More formally, returns the lowest index i such that Arrays.copyOfRange(array, i, i + target.length) contains exactly the same elements as target.

        Parameters:
        array - the array to search for the sequence target
        target - the array to search for as a sub-sequence of array

      • lastIndexOf

        public static int lastIndexOf​(byte[] array,
                              byte target)
        Returns the index of the last appearance of the value target in array.
        Parameters:
        array - an array of byte values, possibly empty
        target - a primitive byte value
        Returns:
        the greatest index i for which array[i] == target, or -1 if no such index exists.

      • concat

        public static byte[] concat​(byte[]... arrays)
        Returns the values from each provided array combined into a single array. For example, concat(new byte[] {a, b}, new byte[] {}, new byte[] {c} returns the array {a, b, c}.
        Parameters:
        arrays - zero or more byte arrays
        Returns:
        a single array containing all the values from the source arrays, in order
        Throws:
        IllegalArgumentException - if the total number of elements in arrays does not fit in an int

      • ensureCapacity

        public static byte[] ensureCapacity​(byte[] array,
                                    int minLength,
                                    int padding)
        Returns an array containing the same values as array, but guaranteed to be of a specified minimum length. If array already has a length of at least minLength, it is returned directly. Otherwise, a new array of size minLength + padding is returned, containing the values of array, and zeroes in the remaining places.
        Parameters:
        array - the source array
        minLength - the minimum length the returned array must guarantee
        padding - an extra amount to "grow" the array by if growth is necessary
        Returns:
        an array containing the values of array, with guaranteed minimum length minLength
        Throws:
        IllegalArgumentException - if minLength or padding is negative

      • toArray

        public static byte[] toArray​(Collection<? extends Number> collection)
        Returns an array containing each value of collection, converted to a byte value in the manner of Number.byteValue().

        Elements are copied from the argument collection as if by collection.toArray(). Calling this method is as thread-safe as calling that method.

        Parameters:
        collection - a collection of Number instances
        Returns:
        an array containing the same values as collection, in the same order, converted to primitives
        Throws:
        NullPointerException - if collection or any of its elements is null
        Since:
        1.0 (parameter was Collection<Byte> before 12.0)

      • asList

        public static List<Byte> asList​(byte... backingArray)
        Returns a fixed-size list backed by the specified array, similar to Arrays.asList(Object[]). The list supports List.set(int, Object), but any attempt to set a value to null will result in a NullPointerException.

        The returned list maintains the values, but not the identities, of Byte objects written to or read from it. For example, whether list.get(0) == list.get(0) is true for the returned list is unspecified.

        The returned list is serializable.

        Parameters:
        backingArray - the array to back the list
        Returns:
        a list view of the array

      • reverse

        public static void reverse​(byte[] array)
        Reverses the elements of array. This is equivalent to Collections.reverse(Bytes.asList(array)), but is likely to be more efficient.
        Since:
        23.1

      • reverse

        public static void reverse​(byte[] array,
                           int fromIndex,
                           int toIndex)
        Reverses the elements of array between fromIndex inclusive and toIndex exclusive. This is equivalent to Collections.reverse(Bytes.asList(array).subList(fromIndex, toIndex)), but is likely to be more efficient.
        Throws:
        IndexOutOfBoundsException - if fromIndex < 0, toIndex > array.length, or toIndex > fromIndex
        Since:
        23.1

      • rotate

        public static void rotate​(byte[] array,
                          int distance)
        Performs a right rotation of array of "distance" places, so that the first element is moved to index "distance", and the element at index i ends up at index (distance + i) mod array.length. This is equivalent to Collections.rotate(Bytes.asList(array), distance), but is somewhat faster.

        The provided "distance" may be negative, which will rotate left.

        Since:
        32.0.0

      • rotate

        public static void rotate​(byte[] array,
                          int distance,
                          int fromIndex,
                          int toIndex)
        Performs a right rotation of array between fromIndex inclusive and toIndex exclusive. This is equivalent to Collections.rotate(Bytes.asList(array).subList(fromIndex, toIndex), distance), but is somewhat faster.

        The provided "distance" may be negative, which will rotate left.

        Throws:
        IndexOutOfBoundsException - if fromIndex < 0, toIndex > array.length, or toIndex > fromIndex
        Since:
        32.0.0