001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.kahadb.util;
018    
019    import java.io.IOException;
020    import java.io.InputStream;
021    
022    /**
023     * Very similar to the java.io.ByteArrayInputStream but this version is not
024     * thread safe.
025     */
026    public class ByteArrayInputStream extends InputStream {
027    
028        byte buffer[];
029        int limit;
030        int pos;
031        int mark;
032    
033        public ByteArrayInputStream(byte data[]) {
034            this(data, 0, data.length);
035        }
036    
037        public ByteArrayInputStream(ByteSequence sequence) {
038            this(sequence.getData(), sequence.getOffset(), sequence.getLength());
039        }
040    
041        public ByteArrayInputStream(byte data[], int offset, int size) {
042            this.buffer = data;
043            this.mark = offset;
044            this.pos = offset;
045            this.limit = offset + size;
046        }
047    
048        public int read() throws IOException {
049            if (pos < limit) {
050                return buffer[pos++] & 0xff;
051            } else {
052                return -1;
053            }
054        }
055    
056        public int read(byte[] b) throws IOException {
057            return read(b, 0, b.length);
058        }
059    
060        public int read(byte b[], int off, int len) {
061            if (pos < limit) {
062                len = Math.min(len, limit - pos);
063                if (len > 0) {
064                    System.arraycopy(buffer, pos, b, off, len);
065                    pos += len;
066                }
067                return len;
068            } else {
069                return -1;
070            }
071        }
072    
073        public long skip(long len) throws IOException {
074            if (pos < limit) {
075                len = Math.min(len, limit - pos);
076                if (len > 0) {
077                    pos += len;
078                }
079                return len;
080            } else {
081                return -1;
082            }
083        }
084    
085        public int available() {
086            return limit - pos;
087        }
088    
089        public boolean markSupported() {
090            return true;
091        }
092    
093        public void mark(int markpos) {
094            mark = pos;
095        }
096    
097        public void reset() {
098            pos = mark;
099        }
100    }