001/* 002 * Copyright 2008-2020 Ping Identity Corporation 003 * All Rights Reserved. 004 */ 005/* 006 * Copyright 2008-2020 Ping Identity Corporation 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020/* 021 * Copyright (C) 2008-2020 Ping Identity Corporation 022 * 023 * This program is free software; you can redistribute it and/or modify 024 * it under the terms of the GNU General Public License (GPLv2 only) 025 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only) 026 * as published by the Free Software Foundation. 027 * 028 * This program is distributed in the hope that it will be useful, 029 * but WITHOUT ANY WARRANTY; without even the implied warranty of 030 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 031 * GNU General Public License for more details. 032 * 033 * You should have received a copy of the GNU General Public License 034 * along with this program; if not, see <http://www.gnu.org/licenses>. 035 */ 036package com.unboundid.asn1; 037 038 039 040import java.io.IOException; 041import java.io.OutputStream; 042import java.nio.BufferOverflowException; 043import java.nio.ByteBuffer; 044 045import com.unboundid.util.ByteStringBuffer; 046import com.unboundid.util.Debug; 047import com.unboundid.util.ThreadSafety; 048import com.unboundid.util.ThreadSafetyLevel; 049 050 051 052/** 053 * This class provides an efficient mechanism for writing ASN.1 elements to 054 * output streams. 055 */ 056@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE) 057public final class ASN1Writer 058{ 059 /** 060 * The thread-local buffers that will be used for encoding the elements. 061 */ 062 private static final ThreadLocal<ByteStringBuffer> buffers = 063 new ThreadLocal<>(); 064 065 066 067 /** 068 * The maximum amount of memory that will be used for a thread-local buffer. 069 */ 070 private static final int MAX_BUFFER_LENGTH = 524_288; 071 072 073 074 /** 075 * Prevent this class from being instantiated. 076 */ 077 private ASN1Writer() 078 { 079 // No implementation is required. 080 } 081 082 083 084 /** 085 * Writes an encoded representation of the provided ASN.1 element to the 086 * given output stream. 087 * 088 * @param element The ASN.1 element to be written. 089 * @param outputStream The output stream to which the encoded representation 090 * of the element should be written. 091 * 092 * @throws IOException If a problem occurs while writing the element. 093 */ 094 public static void writeElement(final ASN1Element element, 095 final OutputStream outputStream) 096 throws IOException 097 { 098 Debug.debugASN1Write(element); 099 100 ByteStringBuffer buffer = buffers.get(); 101 if (buffer == null) 102 { 103 buffer = new ByteStringBuffer(); 104 buffers.set(buffer); 105 } 106 107 element.encodeTo(buffer); 108 109 try 110 { 111 buffer.write(outputStream); 112 } 113 finally 114 { 115 if (buffer.capacity() > MAX_BUFFER_LENGTH) 116 { 117 buffer.setCapacity(MAX_BUFFER_LENGTH); 118 } 119 buffer.clear(); 120 } 121 } 122 123 124 125 /** 126 * Appends an encoded representation of the provided ASN.1 element to the 127 * given byte buffer. When this method completes, the position will be at the 128 * beginning of the written element, and the limit will be at the end. 129 * 130 * @param element The ASN.1 element to be written. 131 * @param buffer The buffer to which the element should be added. 132 * 133 * @throws BufferOverflowException If the provided buffer does not have 134 * enough space between the position and 135 * the limit to hold the encoded element. 136 */ 137 public static void writeElement(final ASN1Element element, 138 final ByteBuffer buffer) 139 throws BufferOverflowException 140 { 141 Debug.debugASN1Write(element); 142 143 ByteStringBuffer b = buffers.get(); 144 if (b == null) 145 { 146 b = new ByteStringBuffer(); 147 buffers.set(b); 148 } 149 150 element.encodeTo(b); 151 152 try 153 { 154 if (buffer.remaining() < b.length()) 155 { 156 throw new BufferOverflowException(); 157 } 158 159 final int pos = buffer.position(); 160 buffer.put(b.getBackingArray(), 0, b.length()); 161 buffer.limit(buffer.position()); 162 buffer.position(pos); 163 } 164 finally 165 { 166 if (b.capacity() > MAX_BUFFER_LENGTH) 167 { 168 b.setCapacity(MAX_BUFFER_LENGTH); 169 } 170 b.clear(); 171 } 172 } 173}