001 /*
002 GRANITE DATA SERVICES
003 Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005 This file is part of Granite Data Services.
006
007 Granite Data Services is free software; you can redistribute it and/or modify
008 it under the terms of the GNU Library General Public License as published by
009 the Free Software Foundation; either version 2 of the License, or (at your
010 option) any later version.
011
012 Granite Data Services is distributed in the hope that it will be useful, but
013 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015 for more details.
016
017 You should have received a copy of the GNU Library General Public License
018 along with this library; if not, see <http://www.gnu.org/licenses/>.
019 */
020
021 package org.granite.gravity.tomcat;
022
023 import java.io.IOException;
024 import java.io.InputStream;
025
026 /**
027 * An unsynchronized input/output byte buffer that avoids useless byte array copies.
028 *
029 * @author Franck
030 */
031 public class ByteArrayCometIO extends InputStream implements CometIO {
032
033 private static final byte[] BYTES_0 = new byte[0];
034
035 protected final int initialCapacity;
036 protected byte buf[] = BYTES_0;
037 protected int pos = 0;
038 protected int mark = 0;
039 protected int count = 0;
040
041 public ByteArrayCometIO() {
042 this(2048);
043 }
044
045 public ByteArrayCometIO(int initialCapacity) {
046 if (initialCapacity < 1)
047 throw new IllegalArgumentException("initialCapacity must be > 1: " + initialCapacity);
048 this.initialCapacity = initialCapacity;
049 }
050
051 public int readFully(InputStream is) throws IOException {
052 try {
053 int b = -1;
054
055 while ((b = is.read()) != -1) {
056 if (count + 1 >= buf.length) {
057 if (buf.length > 0) {
058 byte[] tmp = new byte[buf.length << 1];
059 System.arraycopy(buf, 0, tmp, 0, buf.length);
060 buf = tmp;
061 }
062 else
063 buf = new byte[initialCapacity];
064 }
065 buf[count++] = (byte)b;
066 }
067
068 return count;
069 }
070 finally {
071 is.close();
072 }
073 }
074
075 public boolean readAvailable(InputStream is) throws IOException {
076 boolean eof = false;
077
078 try {
079 int available = -1;
080 while ((available = is.available()) > 0) {
081
082 if (count > 0) {
083 byte[] newBytes = new byte[available + count + 1];
084 System.arraycopy(buf, 0, newBytes, 0, count);
085 buf = newBytes;
086 }
087 else
088 buf = new byte[available + 1];
089
090 if (is.read(buf, count, available) != available)
091 throw new IOException("Could not read available bytes: " + available);
092
093 count += available;
094 }
095
096 int b = is.read();
097 if (b == -1) {
098 eof = true;
099 return false;
100 }
101
102 buf[buf.length - 1] = (byte)b;
103 count++;
104
105 return true;
106 }
107 finally {
108 if (eof)
109 is.close();
110 }
111 }
112
113 public InputStream getInputStream() throws IOException {
114 return this;
115 }
116
117 @Override
118 public int read() throws IOException {
119 return (pos < count) ? (buf[pos++] & 0xff) : -1;
120 }
121
122 @Override
123 public int read(byte b[], int off, int len) {
124 if (b == null)
125 throw new NullPointerException();
126
127 if (off < 0 || len < 0 || len > b.length - off)
128 throw new IndexOutOfBoundsException();
129
130 if (pos >= count)
131 return -1;
132
133 if (pos + len > count)
134 len = count - pos;
135
136 if (len <= 0)
137 return 0;
138
139 System.arraycopy(buf, pos, b, off, len);
140 pos += len;
141 return len;
142 }
143
144 @Override
145 public long skip(long n) {
146 if (pos + n > count)
147 n = count - pos;
148
149 if (n < 0)
150 return 0;
151
152 pos += n;
153 return n;
154 }
155
156 @Override
157 public int available() {
158 return count - pos;
159 }
160
161 @Override
162 public boolean markSupported() {
163 return true;
164 }
165
166 @Override
167 public void mark(int readAheadLimit) {
168 mark = pos;
169 }
170
171 @Override
172 public void reset() {
173 pos = mark;
174 }
175
176 @Override
177 public void close() throws IOException {
178 }
179 }