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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 com.google.common.annotations.Beta; import com.google.common.annotations.GwtCompatible; import com.google.common.annotations.GwtIncompatible; import com.google.common.base.Converter; 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 javax.annotation.CheckReturnValue; /** * Static utility methods pertaining to {@code short} primitives, that are not * already found in either {@link Short} or {@link Arrays}. * * <p>See the Guava User Guide article on <a href= * "https://github.com/google/guava/wiki/PrimitivesExplained"> * primitive utilities</a>. * * @author Kevin Bourrillion * @since 1.0 */ @CheckReturnValue @GwtCompatible(emulated = true) public final class Shorts { private Shorts() { } /** * The number of bytes required to represent a primitive {@code short} * value. */ public static final int BYTES = Short.SIZE / Byte.SIZE; /** * The largest power of two that can be represented as a {@code short}. * * @since 10.0 */ public static final short MAX_POWER_OF_TWO = 1 << (Short.SIZE - 2); /** * Returns a hash code for {@code value}; equal to the result of invoking * {@code ((Short) value).hashCode()}. * * @param value a primitive {@code short} value * @return a hash code for the value */ public static int hashCode(short value) { return value; } /** * Returns the {@code short} value that is equal to {@code value}, if * possible. * * @param value any value in the range of the {@code short} type * @return the {@code short} value that equals {@code value} * @throws IllegalArgumentException if {@code value} is greater than {@link * Short#MAX_VALUE} or less than {@link Short#MIN_VALUE} */ public static short checkedCast(long value) { short result = (short) value; if (result != value) { // don't use checkArgument here, to avoid boxing throw new IllegalArgumentException("Out of range: " + value); } return result; } /** * Returns the {@code short} nearest in value to {@code value}. * * @param value any {@code long} value * @return the same value cast to {@code short} if it is in the range of the * {@code short} type, {@link Short#MAX_VALUE} if it is too large, * or {@link Short#MIN_VALUE} if it is too small */ public static short saturatedCast(long value) { if (value > Short.MAX_VALUE) { return Short.MAX_VALUE; } if (value < Short.MIN_VALUE) { return Short.MIN_VALUE; } return (short) value; } /** * Compares the two specified {@code short} values. The sign of the value * returned is the same as that of {@code ((Short) a).compareTo(b)}. * * <p><b>Note for Java 7 and later:</b> this method should be treated as * deprecated; use the equivalent {@link Short#compare} method instead. * * @param a the first {@code short} to compare * @param b the second {@code short} 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(short a, short b) { return a - b; // safe due to restricted range } /** * Returns {@code true} if {@code target} is present as an element anywhere in * {@code array}. * * @param array an array of {@code short} values, possibly empty * @param target a primitive {@code short} value * @return {@code true} if {@code array[i] == target} for some value of {@code * i} */ public static boolean contains(short[] array, short target) { for (short 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 short} values, possibly empty * @param target a primitive {@code short} 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(short[] array, short target) { return indexOf(array, target, 0, array.length); } // TODO(kevinb): consider making this public private static int indexOf(short[] array, short 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(short[] array, short[] 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 short} values, possibly empty * @param target a primitive {@code short} 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(short[] array, short target) { return lastIndexOf(array, target, 0, array.length); } // TODO(kevinb): consider making this public private static int lastIndexOf(short[] array, short 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 short} 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 short min(short... array) { checkArgument(array.length > 0); short 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 short} 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 short max(short... array) { checkArgument(array.length > 0); short 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 short[] {a, b}, new short[] {}, new * short[] {c}} returns the array {@code {a, b, c}}. * * @param arrays zero or more {@code short} arrays * @return a single array containing all the values from the source arrays, in * order */ public static short[] concat(short[]... arrays) { int length = 0; for (short[] array : arrays) { length += array.length; } short[] result = new short[length]; int pos = 0; for (short[] 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 2-element byte * array; equivalent to {@code * ByteBuffer.allocate(2).putShort(value).array()}. For example, the input * value {@code (short) 0x1234} would yield the byte array {@code {0x12, * 0x34}}. * * <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. */ @GwtIncompatible("doesn't work") public static byte[] toByteArray(short value) { return new byte[] { (byte) (value >> 8), (byte) value }; } /** * Returns the {@code short} value whose big-endian representation is * stored in the first 2 bytes of {@code bytes}; equivalent to {@code * ByteBuffer.wrap(bytes).getShort()}. For example, the input byte array * {@code {0x54, 0x32}} would yield the {@code short} value {@code 0x5432}. * * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that * library exposes much more flexibility at little cost in readability. * * @throws IllegalArgumentException if {@code bytes} has fewer than 2 * elements */ @GwtIncompatible("doesn't work") public static short fromByteArray(byte[] bytes) { checkArgument(bytes.length >= BYTES, "array too small: %s < %s", bytes.length, BYTES); return fromBytes(bytes[0], bytes[1]); } /** * Returns the {@code short} value whose byte representation is the given 2 * bytes, in big-endian order; equivalent to {@code Shorts.fromByteArray(new * byte[] {b1, b2})}. * * @since 7.0 */ @GwtIncompatible("doesn't work") public static short fromBytes(byte b1, byte b2) { return (short) ((b1 << 8) | (b2 & 0xFF)); } private static final class ShortConverter extends Converter<String, Short> implements Serializable { static final ShortConverter INSTANCE = new ShortConverter(); @Override protected Short doForward(String value) { return Short.decode(value); } @Override protected String doBackward(Short value) { return value.toString(); } @Override public String toString() { return "Shorts.stringConverter()"; } private Object readResolve() { return INSTANCE; } private static final long serialVersionUID = 1; } /** * Returns a serializable converter object that converts between strings and * shorts using {@link Short#decode} and {@link Short#toString()}. * * @since 16.0 */ @Beta public static Converter<String, Short> stringConverter() { return ShortConverter.INSTANCE; } /** * 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 short[] ensureCapacity(short[] 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 short[] copyOf(short[] original, int length) { short[] copy = new short[length]; System.arraycopy(original, 0, copy, 0, Math.min(original.length, length)); return copy; } /** * Returns a string containing the supplied {@code short} values separated * by {@code separator}. For example, {@code join("-", (short) 1, (short) 2, * (short) 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 short} values, possibly empty */ public static String join(String separator, short... 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 * 6); 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 short} arrays * lexicographically. That is, it compares, using {@link * #compare(short, short)}), 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 [] < [(short) 1] < * [(short) 1, (short) 2] < [(short) 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(short[], short[])}. * * @see <a href="http://en.wikipedia.org/wiki/Lexicographical_order"> * Lexicographical order article at Wikipedia</a> * @since 2.0 */ public static Comparator<short[]> lexicographicalComparator() { return LexicographicalComparator.INSTANCE; } private enum LexicographicalComparator implements Comparator<short[]> { INSTANCE; @Override public int compare(short[] left, short[] right) { int minLength = Math.min(left.length, right.length); for (int i = 0; i < minLength; i++) { int result = Shorts.compare(left[i], right[i]); if (result != 0) { return result; } } return left.length - right.length; } } /** * Returns an array containing each value of {@code collection}, converted to * a {@code short} value in the manner of {@link Number#shortValue}. * * <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 Number} instances * @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 * @since 1.0 (parameter was {@code Collection<Short>} before 12.0) */ public static short[] toArray(Collection<? extends Number> collection) { if (collection instanceof ShortArrayAsList) { return ((ShortArrayAsList) collection).toShortArray(); } Object[] boxedArray = collection.toArray(); int len = boxedArray.length; short[] array = new short[len]; for (int i = 0; i < len; i++) { // checkNotNull for GWT (do not optimize) array[i] = ((Number) checkNotNull(boxedArray[i])).shortValue(); } 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 Short} 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<Short> asList(short... backingArray) { if (backingArray.length == 0) { return Collections.emptyList(); } return new ShortArrayAsList(backingArray); } @GwtCompatible private static class ShortArrayAsList extends AbstractList<Short> implements RandomAccess, Serializable { final short[] array; final int start; final int end; ShortArrayAsList(short[] array) { this(array, 0, array.length); } ShortArrayAsList(short[] 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 Short 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 Short) && Shorts.indexOf(array, (Short) target, start, end) != -1; } @Override public int indexOf(Object target) { // Overridden to prevent a ton of boxing if (target instanceof Short) { int i = Shorts.indexOf(array, (Short) 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 Short) { int i = Shorts.lastIndexOf(array, (Short) target, start, end); if (i >= 0) { return i - start; } } return -1; } @Override public Short set(int index, Short element) { checkElementIndex(index, size()); short oldValue = array[start + index]; // checkNotNull for GWT (do not optimize) array[start + index] = checkNotNull(element); return oldValue; } @Override public List<Short> subList(int fromIndex, int toIndex) { int size = size(); checkPositionIndexes(fromIndex, toIndex, size); if (fromIndex == toIndex) { return Collections.emptyList(); } return new ShortArrayAsList(array, start + fromIndex, start + toIndex); } @Override public boolean equals(Object object) { if (object == this) { return true; } if (object instanceof ShortArrayAsList) { ShortArrayAsList that = (ShortArrayAsList) 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 + Shorts.hashCode(array[i]); } return result; } @Override public String toString() { StringBuilder builder = new StringBuilder(size() * 6); builder.append('[').append(array[start]); for (int i = start + 1; i < end; i++) { builder.append(", ").append(array[i]); } return builder.append(']').toString(); } short[] toShortArray() { // Arrays.copyOfRange() is not available under GWT int size = size(); short[] result = new short[size]; System.arraycopy(array, start, result, 0, size); return result; } private static final long serialVersionUID = 0; } }