1 /* 2 * Copyright 2017 LINE Corporation 3 * 4 * LINE Corporation licenses this file to you under the Apache License, 5 * version 2.0 (the "License"); you may not use this file except in compliance 6 * with the License. You may obtain a copy of the License at: 7 * 8 * https://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, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 17 package com.linecorp.centraldogma.server.internal.storage.repository.git; 18 19 final class TagUtil { 20 21 private static final String[] TABLE; 22 23 static { 24 TABLE = new String[256]; 25 for (int i = 0; i < TABLE.length; i++) { 26 TABLE[i] = String.format("%02x/", i); 27 } 28 } 29 30 /** 31 * Generates a string by joining hex representation for each byte in {@code majorRevision} with '/' in 32 * little endian order. 33 * <p> 34 * For example, 35 * <ul> 36 * <li>0x0d0c0b0a -> '0a/0b/0c/0d/'</li> 37 * <li>0x00000b0a -> '0a/0b/'</li> 38 * <li>0x00000001 -> '01/'</li> 39 * </ul> 40 * </p> 41 * 42 * @throws IllegalArgumentException if {@code majorRevision} is a zero or a negative value. 43 */ 44 static String byteHexDirName(int majorRevision) { 45 46 if (majorRevision <= 0) { 47 throw new IllegalArgumentException("invalid majorRevision " + majorRevision + " (expected: > 0)"); 48 } 49 50 final StringBuilder sb = new StringBuilder(16); 51 final int shift = 8; 52 53 do { 54 sb.append(TABLE[majorRevision & 0xFF]); 55 majorRevision >>>= shift; 56 } while (majorRevision != 0); 57 return sb.toString(); 58 } 59 60 private TagUtil() {} 61 }