| /* |
| * Copyright (C) 2008 Google Inc. |
| * |
| * 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 com.google.common.annotations.GwtCompatible; |
| import com.google.common.annotations.GwtIncompatible; |
| |
| import java.io.Serializable; |
| import java.util.AbstractList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.List; |
| import java.util.RandomAccess; |
| |
| 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; |
| |
| /** |
| * Static utility methods pertaining to {@code int} primitives, that are not |
| * already found in either {@link Integer} or {@link Arrays}. |
| * |
| * @author Kevin Bourrillion |
| * @since 2009.09.15 <b>tentative</b> |
| */ |
| @GwtCompatible |
| public final class Ints { |
| private Ints() {} |
| |
| /** |
| * The number of bytes required to represent a primitive {@code int} |
| * value. |
| */ |
| public static final int BYTES = Integer.SIZE / Byte.SIZE; |
| |
| /** |
| * Returns a hash code for {@code value}; equal to the result of invoking |
| * {@code ((Integer) value).hashCode()}. |
| * |
| * @param value a primitive {@code int} value |
| * @return a hash code for the value |
| */ |
| public static int hashCode(int value) { |
| return value; |
| } |
| |
| /** |
| * Returns the {@code int} value that is equal to {@code value}, if possible. |
| * |
| * @param value any value in the range of the {@code int} type |
| * @return the {@code int} value that equals {@code value} |
| * @throws IllegalArgumentException if {@code value} is greater than {@link |
| * Integer#MAX_VALUE} or less than {@link Integer#MIN_VALUE} |
| */ |
| public static int checkedCast(long value) { |
| int result = (int) value; |
| checkArgument(result == value, "Out of range: %s", value); |
| return result; |
| } |
| |
| /** |
| * Returns the {@code int} nearest in value to {@code value}. |
| * |
| * @param value any {@code long} value |
| * @return the same value cast to {@code int} if it is in the range of the |
| * {@code int} type, {@link Integer#MAX_VALUE} if it is too large, |
| * or {@link Integer#MIN_VALUE} if it is too small |
| */ |
| public static int saturatedCast(long value) { |
| if (value > Integer.MAX_VALUE) { |
| return Integer.MAX_VALUE; |
| } |
| if (value < Integer.MIN_VALUE) { |
| return Integer.MIN_VALUE; |
| } |
| return (int) value; |
| } |
| |
| /** |
| * Compares the two specified {@code int} values. The sign of the value |
| * returned is the same as that of {@code ((Integer) a).compareTo(b)}. |
| * |
| * @param a the first {@code int} to compare |
| * @param b the second {@code int} to compare |
| * @return a negative value if {@code a} is less than {@code b}; a positive |
| * value if {@code a} is greater than {@code b}; or zero if they are equal |
| */ |
| public static int compare(int a, int b) { |
| return (a < b) ? -1 : ((a > b) ? 1 : 0); |
| } |
| |
| /** |
| * Returns {@code true} if {@code target} is present as an element anywhere in |
| * {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return {@code true} if {@code array[i] == target} for some value of {@code |
| * i} |
| */ |
| public static boolean contains(int[] array, int target) { |
| for (int value : array) { |
| if (value == target) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Returns the index of the first appearance of the value {@code target} in |
| * {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return the least index {@code i} for which {@code array[i] == target}, or |
| * {@code -1} if no such index exists. |
| */ |
| public static int indexOf(int[] array, int target) { |
| return indexOf(array, target, 0, array.length); |
| } |
| |
| // TODO: consider making this public |
| private static int indexOf( |
| int[] array, int target, int start, int end) { |
| for (int i = start; i < end; i++) { |
| if (array[i] == target) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the start position of the first occurrence of the specified {@code |
| * target} within {@code array}, or {@code -1} if there is no such occurrence. |
| * |
| * <p>More formally, returns the lowest index {@code i} such that {@code |
| * java.util.Arrays.copyOfRange(array, i, i + target.length)} contains exactly |
| * the same elements as {@code target}. |
| * |
| * @param array the array to search for the sequence {@code target} |
| * @param target the array to search for as a sub-sequence of {@code array} |
| */ |
| public static int indexOf(int[] array, int[] 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.length; j++) { |
| if (array[i + j] != target[j]) { |
| continue outer; |
| } |
| } |
| return i; |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the index of the last appearance of the value {@code target} in |
| * {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return the greatest index {@code i} for which {@code array[i] == target}, |
| * or {@code -1} if no such index exists. |
| */ |
| public static int lastIndexOf(int[] array, int target) { |
| return lastIndexOf(array, target, 0, array.length); |
| } |
| |
| // TODO: consider making this public |
| private static int lastIndexOf( |
| int[] array, int target, int start, int end) { |
| for (int i = end - 1; i >= start; i--) { |
| if (array[i] == target) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the least value present in {@code array}. |
| * |
| * @param array a <i>nonempty</i> array of {@code int} values |
| * @return the value present in {@code array} that is less than or equal to |
| * every other value in the array |
| * @throws IllegalArgumentException if {@code array} is empty |
| */ |
| public static int min(int... array) { |
| checkArgument(array.length > 0); |
| int min = array[0]; |
| for (int i = 1; i < array.length; i++) { |
| if (array[i] < min) { |
| min = array[i]; |
| } |
| } |
| return min; |
| } |
| |
| /** |
| * Returns the greatest value present in {@code array}. |
| * |
| * @param array a <i>nonempty</i> array of {@code int} values |
| * @return the value present in {@code array} that is greater than or equal to |
| * every other value in the array |
| * @throws IllegalArgumentException if {@code array} is empty |
| */ |
| public static int max(int... array) { |
| checkArgument(array.length > 0); |
| int max = array[0]; |
| for (int i = 1; i < array.length; i++) { |
| if (array[i] > max) { |
| max = array[i]; |
| } |
| } |
| return max; |
| } |
| |
| /** |
| * Returns the values from each provided array combined into a single array. |
| * For example, {@code concat(new int[] {a, b}, new int[] {}, new |
| * int[] {c}} returns the array {@code {a, b, c}}. |
| * |
| * @param arrays zero or more {@code int} arrays |
| * @return a single array containing all the values from the source arrays, in |
| * order |
| */ |
| public static int[] concat(int[]... arrays) { |
| int length = 0; |
| for (int[] array : arrays) { |
| length += array.length; |
| } |
| int[] result = new int[length]; |
| int pos = 0; |
| for (int[] array : arrays) { |
| System.arraycopy(array, 0, result, pos, array.length); |
| pos += array.length; |
| } |
| return result; |
| } |
| |
| /** |
| * Returns a big-endian representation of {@code value} in a 4-element byte |
| * array; equivalent to {@code ByteBuffer.allocate(4).putInt(value).array()}. |
| * For example, the input value {@code 0x12131415} would yield the byte array |
| * {@code {0x12, 0x13, 0x14, 0x15}}. |
| * |
| * <p>If you need to convert and concatenate several values (possibly even of |
| * different types), use a shared {@link java.nio.ByteBuffer} instance, or use |
| * {@link com.google.common.io.ByteStreams#newDataOutput()} to get a growable |
| * buffer. |
| * |
| * <p><b>Warning:</b> do not use this method in GWT. It returns wrong answers. |
| */ |
| @GwtIncompatible("doesn't work") |
| public static byte[] toByteArray(int value) { |
| return new byte[] { |
| (byte) (value >> 24), |
| (byte) (value >> 16), |
| (byte) (value >> 8), |
| (byte) value}; |
| } |
| |
| /** |
| * Returns the {@code int} value whose big-endian representation is stored in |
| * the first 4 bytes of {@code bytes}; equivalent to {@code |
| * ByteBuffer.wrap(bytes).getInt()}. For example, the input byte array {@code |
| * {0x12, 0x13, 0x14, 0x15, 0x33}} would yield the {@code int} value {@code |
| * 0x12131415}. |
| * |
| * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that |
| * library exposes much more flexibility at little cost in readability. |
| * |
| * <p><b>Warning:</b> do not use this method in GWT. It returns wrong answers. |
| * |
| * @throws IllegalArgumentException if {@code bytes} has fewer than 4 elements |
| */ |
| @GwtIncompatible("doesn't work") |
| public static int fromByteArray(byte[] bytes) { |
| checkArgument(bytes.length >= BYTES, |
| "array too small: %s < %s", bytes.length, BYTES); |
| return bytes[0] << 24 |
| | (bytes[1] & 0xFF) << 16 |
| | (bytes[2] & 0xFF) << 8 |
| | (bytes[3] & 0xFF); |
| } |
| |
| /** |
| * Returns an array containing the same values as {@code array}, but |
| * guaranteed to be of a specified minimum length. If {@code array} already |
| * has a length of at least {@code minLength}, it is returned directly. |
| * Otherwise, a new array of size {@code minLength + padding} is returned, |
| * containing the values of {@code array}, and zeroes in the remaining places. |
| * |
| * @param array the source array |
| * @param minLength the minimum length the returned array must guarantee |
| * @param padding an extra amount to "grow" the array by if growth is |
| * necessary |
| * @throws IllegalArgumentException if {@code minLength} or {@code padding} is |
| * negative |
| * @return an array containing the values of {@code array}, with guaranteed |
| * minimum length {@code minLength} |
| */ |
| public static int[] ensureCapacity( |
| int[] array, int minLength, int padding) { |
| checkArgument(minLength >= 0, "Invalid minLength: %s", minLength); |
| checkArgument(padding >= 0, "Invalid padding: %s", padding); |
| return (array.length < minLength) |
| ? copyOf(array, minLength + padding) |
| : array; |
| } |
| |
| // Arrays.copyOf() requires Java 6 |
| private static int[] copyOf(int[] original, int length) { |
| int[] copy = new int[length]; |
| System.arraycopy(original, 0, copy, 0, Math.min(original.length, length)); |
| return copy; |
| } |
| |
| /** |
| * Returns a string containing the supplied {@code int} values separated |
| * by {@code separator}. For example, {@code join("-", 1, 2, 3)} returns |
| * the string {@code "1-2-3"}. |
| * |
| * @param separator the text that should appear between consecutive values in |
| * the resulting string (but not at the start or end) |
| * @param array an array of {@code int} values, possibly empty |
| */ |
| public static String join(String separator, int... array) { |
| checkNotNull(separator); |
| if (array.length == 0) { |
| return ""; |
| } |
| |
| // For pre-sizing a builder, just get the right order of magnitude |
| StringBuilder builder = new StringBuilder(array.length * 5); |
| builder.append(array[0]); |
| for (int i = 1; i < array.length; i++) { |
| builder.append(separator).append(array[i]); |
| } |
| return builder.toString(); |
| } |
| |
| /** |
| * Returns a comparator that compares two {@code int} arrays |
| * lexicographically. That is, it compares, using {@link |
| * #compare(int, int)}), the first pair of values that follow any |
| * common prefix, or when one array is a prefix of the other, treats the |
| * shorter array as the lesser. For example, {@code [] < [1] < [1, 2] < [2]}. |
| * |
| * <p>The returned comparator is inconsistent with {@link |
| * Object#equals(Object)} (since arrays support only identity equality), but |
| * it is consistent with {@link Arrays#equals(int[], int[])}. |
| * |
| * @see <a href="http://en.wikipedia.org/wiki/Lexicographical_order"> |
| * Lexicographical order</a> article at Wikipedia |
| * @since 2010.01.04 <b>tentative</b> |
| */ |
| public static Comparator<int[]> lexicographicalComparator() { |
| return LexicographicalComparator.INSTANCE; |
| } |
| |
| private enum LexicographicalComparator implements Comparator<int[]> { |
| INSTANCE; |
| |
| public int compare(int[] left, int[] right) { |
| int minLength = Math.min(left.length, right.length); |
| for (int i = 0; i < minLength; i++) { |
| int result = Ints.compare(left[i], right[i]); |
| if (result != 0) { |
| return result; |
| } |
| } |
| return left.length - right.length; |
| } |
| } |
| |
| /** |
| * Copies a collection of {@code Integer} instances into a new array of |
| * primitive {@code int} values. |
| * |
| * <p>Elements are copied from the argument collection as if by {@code |
| * collection.toArray()}. Calling this method is as thread-safe as calling |
| * that method. |
| * |
| * @param collection a collection of {@code Integer} objects |
| * @return an array containing the same values as {@code collection}, in the |
| * same order, converted to primitives |
| * @throws NullPointerException if {@code collection} or any of its elements |
| * is null |
| */ |
| public static int[] toArray(Collection<Integer> collection) { |
| if (collection instanceof IntArrayAsList) { |
| return ((IntArrayAsList) collection).toIntArray(); |
| } |
| |
| Object[] boxedArray = collection.toArray(); |
| int len = boxedArray.length; |
| int[] array = new int[len]; |
| for (int i = 0; i < len; i++) { |
| array[i] = (Integer) boxedArray[i]; |
| } |
| return array; |
| } |
| |
| /** |
| * Returns a fixed-size list backed by the specified array, similar to {@link |
| * Arrays#asList(Object[])}. The list supports {@link List#set(int, Object)}, |
| * but any attempt to set a value to {@code null} will result in a {@link |
| * NullPointerException}. |
| * |
| * <p>The returned list maintains the values, but not the identities, of |
| * {@code Integer} objects written to or read from it. For example, whether |
| * {@code list.get(0) == list.get(0)} is true for the returned list is |
| * unspecified. |
| * |
| * @param backingArray the array to back the list |
| * @return a list view of the array |
| */ |
| public static List<Integer> asList(int... backingArray) { |
| if (backingArray.length == 0) { |
| return Collections.emptyList(); |
| } |
| return new IntArrayAsList(backingArray); |
| } |
| |
| @GwtCompatible |
| private static class IntArrayAsList extends AbstractList<Integer> |
| implements RandomAccess, Serializable { |
| final int[] array; |
| final int start; |
| final int end; |
| |
| IntArrayAsList(int[] array) { |
| this(array, 0, array.length); |
| } |
| |
| IntArrayAsList(int[] array, int start, int end) { |
| this.array = array; |
| this.start = start; |
| this.end = end; |
| } |
| |
| @Override public int size() { |
| return end - start; |
| } |
| |
| @Override public boolean isEmpty() { |
| return false; |
| } |
| |
| @Override public Integer get(int index) { |
| checkElementIndex(index, size()); |
| return array[start + index]; |
| } |
| |
| @Override public boolean contains(Object target) { |
| // Overridden to prevent a ton of boxing |
| return (target instanceof Integer) |
| && Ints.indexOf(array, (Integer) target, start, end) != -1; |
| } |
| |
| @Override public int indexOf(Object target) { |
| // Overridden to prevent a ton of boxing |
| if (target instanceof Integer) { |
| int i = Ints.indexOf(array, (Integer) target, start, end); |
| if (i >= 0) { |
| return i - start; |
| } |
| } |
| return -1; |
| } |
| |
| @Override public int lastIndexOf(Object target) { |
| // Overridden to prevent a ton of boxing |
| if (target instanceof Integer) { |
| int i = Ints.lastIndexOf(array, (Integer) target, start, end); |
| if (i >= 0) { |
| return i - start; |
| } |
| } |
| return -1; |
| } |
| |
| @Override public Integer set(int index, Integer element) { |
| checkElementIndex(index, size()); |
| int oldValue = array[start + index]; |
| array[start + index] = element; |
| return oldValue; |
| } |
| |
| /** In GWT, List and AbstractList do not have the subList method. */ |
| /*@Override*/ public List<Integer> subList(int fromIndex, int toIndex) { |
| int size = size(); |
| checkPositionIndexes(fromIndex, toIndex, size); |
| if (fromIndex == toIndex) { |
| return Collections.emptyList(); |
| } |
| return new IntArrayAsList(array, start + fromIndex, start + toIndex); |
| } |
| |
| @Override public boolean equals(Object object) { |
| if (object == this) { |
| return true; |
| } |
| if (object instanceof IntArrayAsList) { |
| IntArrayAsList that = (IntArrayAsList) object; |
| int size = size(); |
| if (that.size() != size) { |
| return false; |
| } |
| for (int i = 0; i < size; i++) { |
| if (array[start + i] != that.array[that.start + i]) { |
| return false; |
| } |
| } |
| return true; |
| } |
| return super.equals(object); |
| } |
| |
| @Override public int hashCode() { |
| int result = 1; |
| for (int i = start; i < end; i++) { |
| result = 31 * result + Ints.hashCode(array[i]); |
| } |
| return result; |
| } |
| |
| @Override public String toString() { |
| StringBuilder builder = new StringBuilder(size() * 5); |
| builder.append('[').append(array[start]); |
| for (int i = start + 1; i < end; i++) { |
| builder.append(", ").append(array[i]); |
| } |
| return builder.append(']').toString(); |
| } |
| |
| int[] toIntArray() { |
| // Arrays.copyOfRange() requires Java 6 |
| int size = size(); |
| int[] result = new int[size]; |
| System.arraycopy(array, start, result, 0, size); |
| return result; |
| } |
| |
| private static final long serialVersionUID = 0; |
| } |
| } |