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  /*
   * Copyright (C) 2008 The Guava Authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 package com.google.common.primitives;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkElementIndex;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkPositionIndexes;
 
 
 import java.util.List;
Static utility methods pertaining to byte primitives, that are not already found in either java.lang.Byte or java.util.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.

Author(s):
Kevin Bourrillion
Since:
1.0
 
 // TODO(kevinb): how to prevent warning on UnsignedBytes when building GWT
 // javadoc?
 public final class Bytes {
   private Bytes() {}

  
Returns a hash code for value; equal to the result of invoking ((Byte) value).hashCode().

Parameters:
value a primitive byte value
Returns:
a hash code for the value
 
   public static int hashCode(byte value) {
     return value;
   }

  
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
 
   public static boolean contains(byte[] arraybyte target) {
     for (byte value : array) {
       if (value == target) {
         return true;
       }
     }
     return false;
   }

  
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.
 
   public static int indexOf(byte[] arraybyte target) {
     return indexOf(arraytarget, 0, array.length);
   }
 
   // TODO(kevinb): consider making this public
   private static int indexOf(
       byte[] arraybyte targetint startint end) {
     for (int i = starti < endi++) {
      if (array[i] == target) {
        return i;
      }
    }
    return -1;
  }

  
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 java.util.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
  public static int indexOf(byte[] arraybyte[] target) {
    checkNotNull(array"array");
    checkNotNull(target"target");
    if (target.length == 0) {
      return 0;
    }
    outer:
    for (int i = 0; i < array.length - target.length + 1; i++) {
      for (int j = 0; j < target.lengthj++) {
        if (array[i + j] != target[j]) {
          continue outer;
        }
      }
      return i;
    }
    return -1;
  }

  
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.
  public static int lastIndexOf(byte[] arraybyte target) {
    return lastIndexOf(arraytarget, 0, array.length);
  }
  // TODO(kevinb): consider making this public
  private static int lastIndexOf(
      byte[] arraybyte targetint startint end) {
    for (int i = end - 1; i >= starti--) {
      if (array[i] == target) {
        return i;
      }
    }
    return -1;
  }

  
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
  public static byte[] concat(byte[]... arrays) {
    int length = 0;
    for (byte[] array : arrays) {
      length += array.length;
    }
    byte[] result = new byte[length];
    int pos = 0;
    for (byte[] array : arrays) {
      System.arraycopy(array, 0, resultposarray.length);
      pos += array.length;
    }
    return result;
  }

  
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:
java.lang.IllegalArgumentException if minLength or padding is negative
  public static byte[] ensureCapacity(
      byte[] arrayint minLengthint padding) {
    checkArgument(minLength >= 0, "Invalid minLength: %s"minLength);
    checkArgument(padding >= 0, "Invalid padding: %s"padding);
    return (array.length < minLength)
        ? copyOf(arrayminLength + padding)
        : array;
  }
  // Arrays.copyOf() requires Java 6
  private static byte[] copyOf(byte[] originalint length) {
    byte[] copy = new byte[length];
    System.arraycopy(original, 0, copy, 0, Math.min(original.lengthlength));
    return copy;
  }

  
Returns an array containing each value of collection, converted to a byte value in the manner of java.lang.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:
java.lang.NullPointerException if collection or any of its elements is null
Since:
1.0 (parameter was Collection<Byte> before 12.0)
  public static byte[] toArray(Collection<? extends Numbercollection) {
    if (collection instanceof ByteArrayAsList) {
      return ((ByteArrayAsListcollection).toByteArray();
    }
    Object[] boxedArray = collection.toArray();
    int len = boxedArray.length;
    byte[] array = new byte[len];
    for (int i = 0; i < leni++) {
      // checkNotNull for GWT (do not optimize)
      array[i] = ((NumbercheckNotNull(boxedArray[i])).byteValue();
    }
    return array;
  }

  
Returns a fixed-size list backed by the specified array, similar to java.util.Arrays.asList(java.lang.Object[]). The list supports java.util.List.set(int,java.lang.Object), but any attempt to set a value to null will result in a java.lang.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.

Parameters:
backingArray the array to back the list
Returns:
a list view of the array
  public static List<ByteasList(byte... backingArray) {
    if (backingArray.length == 0) {
      return Collections.emptyList();
    }
    return new ByteArrayAsList(backingArray);
  }
  private static class ByteArrayAsList extends AbstractList<Byte>
      implements RandomAccessSerializable {
    final byte[] array;
    final int start;
    final int end;
    ByteArrayAsList(byte[] array) {
      this(array, 0, array.length);
    }
    ByteArrayAsList(byte[] arrayint startint end) {
      this. = array;
      this. = start;
      this. = end;
    }
    @Override public int size() {
      return  - ;
    }
    @Override public boolean isEmpty() {
      return false;
    }
    @Override public Byte get(int index) {
      checkElementIndex(indexsize());
      return [ + index];
    }
    @Override public boolean contains(Object target) {
      // Overridden to prevent a ton of boxing
      return (target instanceof Byte)
          && Bytes.indexOf(, (Bytetarget) != -1;
    }
    @Override public int indexOf(Object target) {
      // Overridden to prevent a ton of boxing
      if (target instanceof Byte) {
        int i = Bytes.indexOf(, (Bytetarget);
        if (i >= 0) {
          return i - ;
        }
      }
      return -1;
    }
    @Override public int lastIndexOf(Object target) {
      // Overridden to prevent a ton of boxing
      if (target instanceof Byte) {
        int i = Bytes.lastIndexOf(, (Bytetarget);
        if (i >= 0) {
          return i - ;
        }
      }
      return -1;
    }
    @Override public Byte set(int indexByte element) {
      checkElementIndex(indexsize());
      byte oldValue = [ + index];
      [ + index] = checkNotNull(element);  // checkNotNull for GWT (do not optimize)
      return oldValue;
    }
    @Override public List<BytesubList(int fromIndexint toIndex) {
      int size = size();
      checkPositionIndexes(fromIndextoIndexsize);
      if (fromIndex == toIndex) {
        return Collections.emptyList();
      }
      return new ByteArrayAsList( + fromIndex + toIndex);
    }
    @Override public boolean equals(Object object) {
      if (object == this) {
        return true;
      }
      if (object instanceof ByteArrayAsList) {
        ByteArrayAsList that = (ByteArrayAsListobject;
        int size = size();
        if (that.size() != size) {
          return false;
        }
        for (int i = 0; i < sizei++) {
          if ([ + i] != that.array[that.start + i]) {
            return false;
          }
        }
        return true;
      }
      return super.equals(object);
    }
    @Override public int hashCode() {
      int result = 1;
      for (int i = i < i++) {
        result = 31 * result + Bytes.hashCode([i]);
      }
      return result;
    }
    @Override public String toString() {
      StringBuilder builder = new StringBuilder(size() * 5);
      builder.append('[').append([]);
      for (int i =  + 1; i < i++) {
        builder.append(", ").append([i]);
      }
      return builder.append(']').toString();
    }
    byte[] toByteArray() {
      // Arrays.copyOfRange() requires Java 6
      int size = size();
      byte[] result = new byte[size];
      System.arraycopy(result, 0, size);
      return result;
    }
    private static final long serialVersionUID = 0;
  }
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