1 /* 2 * Copyright 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.conscrypt; 18 19 /** 20 * 21 * Helper class for dealing with hexadecimal strings. 22 * 23 * @hide 24 */ 25 @Internal 26 // public for testing by TrustedCertificateStoreTest 27 // TODO(nathanmittler): Move to InternalUtil? 28 public final class Hex { 29 private Hex() {} 30 31 private final static char[] DIGITS = { 32 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; 33 34 public static String bytesToHexString(byte[] bytes) { 35 char[] buf = new char[bytes.length * 2]; 36 int c = 0; 37 for (byte b : bytes) { 38 buf[c++] = DIGITS[(b >> 4) & 0xf]; 39 buf[c++] = DIGITS[b & 0xf]; 40 } 41 return new String(buf); 42 } 43 44 public static String intToHexString(int i, int minWidth) { 45 int bufLen = 8; // Max number of hex digits in an int 46 char[] buf = new char[bufLen]; 47 int cursor = bufLen; 48 49 do { 50 buf[--cursor] = DIGITS[i & 0xf]; 51 } while ((i >>>= 4) != 0 || (bufLen - cursor < minWidth)); 52 53 return new String(buf, cursor, bufLen - cursor); 54 } 55 } 56
