1 /* 2 * Copyright (C) 2017 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 android.location.cts.asn1.base; 18 19 /** 20 */ 21 public class PacketBuilder { 22 private BitStream bitStream = new BitStream(); 23 24 public void append(BitStream appendix) { 25 if (appendix.beginsByteAligned()) { 26 bitStream.spoolToByteBoundary(); 27 } 28 int bitsToAppend = appendix.getBitCount(); 29 byte[] bytes = appendix.getPaddedBytes(); 30 for (int i = 0; bitsToAppend >= 8; i++, bitsToAppend -= 8) { 31 bitStream.appendByte(bytes[i]); 32 } 33 if (bitsToAppend != 0) { 34 byte highBits = bytes[bytes.length - 1]; 35 byte lowBits = (byte) ((highBits & 0xFF) 36 >> (8 - bitsToAppend)); 37 bitStream.appendLowBits(bitsToAppend, lowBits); 38 } 39 } 40 41 public byte[] getPaddedBytes() { 42 return bitStream.getPaddedBytes(); 43 } 44 45 public int getBitCount() { 46 return bitStream.getBitCount(); 47 } 48 49 public void appendAll(Iterable<BitStream> bitStreams) { 50 for (BitStream bitStream : bitStreams) { 51 append(bitStream); 52 } 53 } 54 } 55
