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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.fusesource.hawtbuf;

import java.io.*;


/**
 * Optimized ByteArrayInputStream that can be used more than once
 * 
 * @author Hiram Chirino
 */
public final class DataByteArrayInputStream extends InputStream implements DataInput {
    private byte[] buf;
    private int pos;
    private int offset;
    private int length;

    protected AbstractVarIntSupport helper = new AbstractVarIntSupport() {

        @Override
        protected byte readByte() throws IOException {
            return DataByteArrayInputStream.this.readByte();
        }

        @Override
        protected void writeByte(int value) throws IOException {
            throw new UnsupportedOperationException();
        }
    };

    /**
     * Creates a StoreByteArrayInputStream.
     * 
     * @param buf the input buffer.
     */
    public DataByteArrayInputStream(byte buf[]) {
        restart(buf);
    }

    /**
     * Creates a StoreByteArrayInputStream.
     * 
     * @param buffer the input buffer.
     */
    public DataByteArrayInputStream(Buffer buffer) {
        restart(buffer);
    }

    /**
     * reset the StoreByteArrayInputStream to use an new
     * Buffer
     *
     * @param buffer
     */
    public void restart(Buffer buffer) {
        this.buf = buffer.getData();
        this.offset = buffer.getOffset();
        this.pos = this.offset;
        this.length = buffer.getLength();
    }

    /**
     * re-start the input stream - reusing the current buffer
     *
     * @param size
     */
    public void restart(int size) {
        if (buf == null || buf.length < size) {
            buf = new byte[size];
        }
        restart(buf);
        this.length = size;
    }

    /**
     * Creates WireByteArrayInputStream with a minmalist byte
     * array
     */
    public DataByteArrayInputStream() {
        this(new byte[0]);
    }

    /**
     * @return the size
     */
    public int size() {
        return pos - offset;
    }

    /**
     * @return the underlying data array
     */
    public byte[] getRawData() {
        return buf;
    }

    public Buffer readBuffer(int len) {
        int endpos = offset + length;
        if (pos > endpos) {
            return null;
        }
        if (pos + len > endpos) {
            len = length - pos;
        }
        Buffer rc = new Buffer(buf, pos, len);
        pos += len;
        return rc;
    }

    /**
     * reset the StoreByteArrayInputStream to use an new byte
     * array
     * 
     * @param newBuff
     */
    public void restart(byte[] newBuff) {
        buf = newBuff;
        pos = 0;
        length = newBuff.length;
    }

    public void restart() {
        pos = 0;
        length = buf.length;
    }

    /**
     * Reads the next byte of data from this input stream. The value byte is
     * returned as an int in the range 0 to
     * 255. If no byte is available because the end of the
     * stream has been reached, the value -1 is returned.
     * 

* This read method cannot block. * * @return the next byte of data, or -1 if the end of the * stream has been reached. */ public int read() { return (pos < offset+length) ? (buf[pos++] & 0xff) : -1; } /** * Reads up to len bytes of data into an array of bytes from * this input stream. * * @param b the buffer into which the data is read. * @param off the start offset of the data. * @param len the maximum number of bytes read. * @return the total number of bytes read into the buffer, or * -1 if there is no more data because the end of the * stream has been reached. */ public int read(byte b[], int off, int len) { if (b == null) { throw new NullPointerException(); } int endpos = offset + length; if (pos >= endpos) { return -1; } if (pos + len > endpos) { len = length - pos; } if (len <= 0) { return 0; } System.arraycopy(buf, pos, b, off, len); pos += len; return len; } /** * @return the number of bytes that can be read from the input stream * without blocking. */ public int available() { return offset + length - pos; } public void readFully(byte[] b) { read(b, 0, b.length); } public void readFully(byte[] b, int off, int len) { read(b, off, len); } public int skip(int n) { return skipBytes(n); } public int skipBytes(int n) { int endpos = offset + length; if (pos + n > endpos) { n = endpos - pos; } if (n < 0) { return 0; } pos += n; return n; } public boolean readBoolean() { return read() != 0; } public byte readByte() { return (byte)read(); } public int readUnsignedByte() { return read(); } public short readShort() { int ch1 = read(); int ch2 = read(); return (short)((ch1 << 8) + (ch2 << 0)); } public int readUnsignedShort() { int ch1 = read(); int ch2 = read(); return (ch1 << 8) + (ch2 << 0); } public char readChar() { int ch1 = read(); int ch2 = read(); return (char)((ch1 << 8) + (ch2 << 0)); } public int readInt() { int ch1 = read(); int ch2 = read(); int ch3 = read(); int ch4 = read(); return (ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0); } public long readLong() { long rc = ((long)buf[pos++] << 56) + ((long)(buf[pos++] & 255) << 48) + ((long)(buf[pos++] & 255) << 40) + ((long)(buf[pos++] & 255) << 32); return rc + ((long)(buf[pos++] & 255) << 24) + ((buf[pos++] & 255) << 16) + ((buf[pos++] & 255) << 8) + ((buf[pos++] & 255) << 0); } public float readFloat() throws IOException { return Float.intBitsToFloat(readInt()); } public double readDouble() throws IOException { return Double.longBitsToDouble(readLong()); } public String readLine() { int start = pos; while (pos < offset+length) { int c = read(); if (c == '\n') { break; } if (c == '\r') { c = read(); if (c != '\n' && c != -1) { pos--; } break; } } return new String(buf, start, pos); } public String readUTF() throws IOException { int length = readUnsignedShort(); char[] characters = new char[length]; int c; int c2; int c3; int count = 0; int total = pos + length; while (pos < total) { c = (int)buf[pos] & 0xff; if (c > 127) { break; } pos++; characters[count++] = (char)c; } while (pos < total) { c = (int)buf[pos] & 0xff; switch (c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: pos++; characters[count++] = (char)c; break; case 12: case 13: pos += 2; if (pos > total) { throw new UTFDataFormatException("bad string"); } c2 = (int)buf[pos - 1]; if ((c2 & 0xC0) != 0x80) { throw new UTFDataFormatException("bad string"); } characters[count++] = (char)(((c & 0x1F) << 6) | (c2 & 0x3F)); break; case 14: pos += 3; if (pos > total) { throw new UTFDataFormatException("bad string"); } c2 = (int)buf[pos - 2]; c3 = (int)buf[pos - 1]; if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80)) { throw new UTFDataFormatException("bad string"); } characters[count++] = (char)(((c & 0x0F) << 12) | ((c2 & 0x3F) << 6) | ((c3 & 0x3F) << 0)); break; default: throw new UTFDataFormatException("bad string"); } } return new String(characters, 0, count); } public int getPos() { return pos; } public void setPos(int pos) { this.pos = pos; } public int getLength() { return length; } public void setLength(int length) { this.length = length; } public int readVarInt() throws IOException { return helper.readVarInt(); } public long readVarLong() throws IOException { return helper.readVarLong(); } public int readVarSignedInt() throws IOException { return helper.readVarSignedInt(); } public long readVarSignedLong() throws IOException { return helper.readVarSignedLong(); } }





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