1bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2009 The Guava Authors 3bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 4bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Licensed under the Apache License, Version 2.0 (the "License"); 5bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * you may not use this file except in compliance with the License. 6bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * You may obtain a copy of the License at 7bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 8bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * http://www.apache.org/licenses/LICENSE-2.0 9bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 10bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Unless required by applicable law or agreed to in writing, software 11bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * distributed under the License is distributed on an "AS IS" BASIS, 12bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * See the License for the specific language governing permissions and 14bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * limitations under the License. 15bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 16bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 17bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnorpackage com.google.common.primitives; 18bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport static com.google.common.base.Preconditions.checkArgument; 201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport static com.google.common.base.Preconditions.checkNotNull; 211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 22bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnorimport com.google.common.annotations.GwtCompatible; 23bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 24bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnorimport java.util.Comparator; 25bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 26bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor/** 27bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Static utility methods pertaining to {@code byte} primitives that 28bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * interpret values as signed. The corresponding methods that treat the values 29bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * as unsigned are found in {@link UnsignedBytes}, and the methods for which 30bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * signedness is not an issue are in {@link Bytes}. 31bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 32bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @author Kevin Bourrillion 331d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @since 1.0 34bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 351d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert// TODO(kevinb): how to prevent warning on UnsignedBytes when building GWT 361d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert// javadoc? 37bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor@GwtCompatible 38bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnorpublic final class SignedBytes { 39bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor private SignedBytes() {} 40bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 41bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 421d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * The largest power of two that can be represented as a signed {@code byte}. 431d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 441d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @since 10.0 451d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 461d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert public static final byte MAX_POWER_OF_TWO = 1 << 6; 471d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 481d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 49bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns the {@code byte} value that is equal to {@code value}, if possible. 50bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 51bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param value any value in the range of the {@code byte} type 52bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @return the {@code byte} value that equals {@code value} 53bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @throws IllegalArgumentException if {@code value} is greater than {@link 54bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Byte#MAX_VALUE} or less than {@link Byte#MIN_VALUE} 55bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 56bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static byte checkedCast(long value) { 57bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor byte result = (byte) value; 58bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor checkArgument(result == value, "Out of range: %s", value); 59bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return result; 60bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 61bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 62bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 63bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns the {@code byte} nearest in value to {@code value}. 64bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 65bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param value any {@code long} value 66bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @return the same value cast to {@code byte} if it is in the range of the 67bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * {@code byte} type, {@link Byte#MAX_VALUE} if it is too large, 68bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * or {@link Byte#MIN_VALUE} if it is too small 69bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 70bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static byte saturatedCast(long value) { 71bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (value > Byte.MAX_VALUE) { 72bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return Byte.MAX_VALUE; 73bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 74bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (value < Byte.MIN_VALUE) { 75bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return Byte.MIN_VALUE; 76bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 77bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return (byte) value; 78bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 79bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 80bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 81bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Compares the two specified {@code byte} values. The sign of the value 82bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * returned is the same as that of {@code ((Byte) a).compareTo(b)}. 83bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 84bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param a the first {@code byte} to compare 85bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param b the second {@code byte} to compare 86bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @return a negative value if {@code a} is less than {@code b}; a positive 87bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * value if {@code a} is greater than {@code b}; or zero if they are equal 88bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 89bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static int compare(byte a, byte b) { 90bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return a - b; // safe due to restricted range 91bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 92bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 93bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 94bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns the least value present in {@code array}. 95bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 96bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param array a <i>nonempty</i> array of {@code byte} values 97bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @return the value present in {@code array} that is less than or equal to 98bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * every other value in the array 99bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @throws IllegalArgumentException if {@code array} is empty 100bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 101bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static byte min(byte... array) { 102bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor checkArgument(array.length > 0); 103bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor byte min = array[0]; 104bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor for (int i = 1; i < array.length; i++) { 105bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (array[i] < min) { 106bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor min = array[i]; 107bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 108bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 109bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return min; 110bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 111bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 112bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 113bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns the greatest value present in {@code array}. 114bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 115bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param array a <i>nonempty</i> array of {@code byte} values 116bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @return the value present in {@code array} that is greater than or equal to 117bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * every other value in the array 118bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @throws IllegalArgumentException if {@code array} is empty 119bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 120bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static byte max(byte... array) { 121bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor checkArgument(array.length > 0); 122bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor byte max = array[0]; 123bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor for (int i = 1; i < array.length; i++) { 124bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (array[i] > max) { 125bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor max = array[i]; 126bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 127bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 128bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return max; 129bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 130bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 131bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 132bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns a string containing the supplied {@code byte} values separated 133bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * by {@code separator}. For example, {@code join(":", 0x01, 0x02, -0x01)} 134bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * returns the string {@code "1:2:-1"}. 135bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 136bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param separator the text that should appear between consecutive values in 137bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * the resulting string (but not at the start or end) 138bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @param array an array of {@code byte} values, possibly empty 139bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 140bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static String join(String separator, byte... array) { 141bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor checkNotNull(separator); 142bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (array.length == 0) { 143bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return ""; 144bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 145bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 146bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor // For pre-sizing a builder, just get the right order of magnitude 147bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor StringBuilder builder = new StringBuilder(array.length * 5); 148bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor builder.append(array[0]); 149bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor for (int i = 1; i < array.length; i++) { 150bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor builder.append(separator).append(array[i]); 151bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 152bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return builder.toString(); 153bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 154bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 155bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor /** 156bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Returns a comparator that compares two {@code byte} arrays 157bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * lexicographically. That is, it compares, using {@link 158bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * #compare(byte, byte)}), the first pair of values that follow any common 159bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * prefix, or when one array is a prefix of the other, treats the shorter 160bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * array as the lesser. For example, {@code [] < [0x01] < [0x01, 0x80] < 161bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * [0x01, 0x7F] < [0x02]}. Values are treated as signed. 162bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 163bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * <p>The returned comparator is inconsistent with {@link 164bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * Object#equals(Object)} (since arrays support only identity equality), but 165bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * it is consistent with {@link java.util.Arrays#equals(byte[], byte[])}. 166bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * 167bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor * @see <a href="http://en.wikipedia.org/wiki/Lexicographical_order"> 1681d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Lexicographical order article at Wikipedia</a> 1691d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @since 2.0 170bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor */ 171bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public static Comparator<byte[]> lexicographicalComparator() { 172bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return LexicographicalComparator.INSTANCE; 173bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 174bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 175bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor private enum LexicographicalComparator implements Comparator<byte[]> { 176bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor INSTANCE; 177bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor 1781d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override 179bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor public int compare(byte[] left, byte[] right) { 180bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor int minLength = Math.min(left.length, right.length); 181bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor for (int i = 0; i < minLength; i++) { 182bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor int result = SignedBytes.compare(left[i], right[i]); 183bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor if (result != 0) { 184bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return result; 185bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 186bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 187bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor return left.length - right.length; 188bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 189bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor } 190bfe2dd089341dcb4c1fb65a5b6b077ad0ebbf6dcDan Egnor} 191