com.tangosol.io.PackedDataInputStream Maven / Gradle / Ivy
Show all versions of coherence Show documentation
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.io;
import com.tangosol.util.Base;
import java.io.DataInput;
import java.io.EOFException;
import java.io.InputStream;
import java.io.IOException;
import java.io.UTFDataFormatException;
/**
* This is an imitation DataInputStream class that reads from streams that
* were produced by a corresponding {@link PackedDataOutputStream}.
*
* @author cp 2004.09.09
*/
public class PackedDataInputStream
extends WrapperInputStream
implements DataInput
{
// ----- constructors ---------------------------------------------------
/**
* Construct a WrapperDataInputStream that will read from the specified
* InputStream object.
*
* @param in an InputStream to read from
*/
public PackedDataInputStream(InputStream in)
{
super(in);
}
// ----- DataInput methods ----------------------------------------------
/**
* Read ab.length bytes and store them in ab.
*
* This method blocks until input data is available, the end of the stream
* is detected, or an exception is thrown.
*
* @param ab the array to store the bytes which are read from the stream
*
* @exception NullPointerException if the passed array is null
* @exception EOFException if the stream is exhausted before the number
* of bytes indicated by the array length could be read
* @exception IOException if an I/O error occurs
*/
public void readFully(byte ab[])
throws IOException
{
readFully(ab, 0, ab.length);
}
/**
* Read cb bytes and store them in ab starting
* at offset of.
*
* This method blocks until input data is available, the end of the stream
* is detected, or an exception is thrown.
*
* @param ab the array to store the bytes which are read from the stream
* @param of the offset into the array that the read bytes will be stored
* @param cb the maximum number of bytes to read
*
* @exception NullPointerException if the passed array is null
* @exception IndexOutOfBoundsException if of or
* cb is negative, or of+cb is
* greater than the length of the ab
* @exception EOFException if the stream is exhausted before the number
* of bytes indicated by the array length could be read
* @exception IOException if an I/O error occurs
*/
public void readFully(byte ab[], int of, int cb)
throws IOException
{
if (of < 0 || cb < 0 || of + cb > ab.length)
{
throw new IndexOutOfBoundsException("ab.length=" + ab.length
+ ", of=" + of + ", cb=" + cb);
}
while (cb > 0)
{
int cbRead = read(ab, of, cb);
if (cbRead < 0)
{
throw new EOFException(cb + " bytes remaining to be read");
}
of += cbRead;
cb -= cbRead;
}
}
/**
* Skips over up to the specified number of bytes of data. The number of
* bytes actually skipped over may be fewer than the number specified to
* skip, and may even be zero; this can be caused by an end-of-file
* condition, but can also occur even when there is data remaining to
* be read. As a result, the caller should check the return value from
* this method, which indicates the actual number of bytes skipped.
*
* @param cb the maximum number of bytes to skip over
*
* @return the actual number of bytes that were skipped over
*
* @exception IOException if an I/O error occurs
*/
public int skipBytes(int cb)
throws IOException
{
return (int) skip(cb);
}
/**
* Read a boolean value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeBoolean} method.
*
* @return either true or false
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public boolean readBoolean()
throws IOException
{
return readUnsignedByte() != 0;
}
/**
* Read a byte value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeByte} method.
*
* @return a byte value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public byte readByte()
throws IOException
{
int n = read();
if (n < 0)
{
throw new EOFException();
}
return (byte) n;
}
/**
* Read an unsigned byte value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeByte} method when it is used with
* unsigned 8-bit values.
*
* @return an int value in the range 0x00 to 0xFF
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public int readUnsignedByte()
throws IOException
{
int n = read();
if (n < 0)
{
throw new EOFException();
}
return n;
}
/**
* Read a short value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeShort} method.
*
* @return a short value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public short readShort()
throws IOException
{
return (short) readInt();
}
/**
* Read an unsigned short value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeShort} method when it is used with
* unsigned 16-bit values.
*
* @return an int value in the range of 0x0000 to 0xFFFF
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public int readUnsignedShort()
throws IOException
{
return readInt() & 0xFFFF;
}
/**
* Read a char value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeChar} method.
*
* @return a char value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public char readChar()
throws IOException
{
int ch = readUnsignedByte();
switch ((ch & 0xF0) >>> 4)
{
case 0x0: case 0x1: case 0x2: case 0x3:
case 0x4: case 0x5: case 0x6: case 0x7:
// 1-byte format: 0xxx xxxx
return (char) ch;
case 0xC: case 0xD:
{
// 2-byte format: 110x xxxx, 10xx xxxx
int ch2 = readUnsignedByte();
if ((ch2 & 0xC0) != 0x80)
{
throw new UTFDataFormatException();
}
return (char) (((ch & 0x1F) << 6) | ch2 & 0x3F);
}
case 0xE:
{
// 3-byte format: 1110 xxxx, 10xx xxxx, 10xx xxxx
int ch2 = readUnsignedByte();
int ch3 = readUnsignedByte();
if ((ch2 & 0xC0) != 0x80 || (ch3 & 0xC0) != 0x80)
{
throw new UTFDataFormatException();
}
return (char) (((ch & 0x0F) << 12) | ((ch2 & 0x3F) << 6) | ch3 & 0x3F);
}
default:
throw new UTFDataFormatException("illegal leading UTF byte: " + ch);
}
}
/**
* Read an int value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeInt} method.
*
* @return an int value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public int readInt()
throws IOException
{
int b = readUnsignedByte();
int n = b & 0x3F; // only 6 bits of data in first byte
int cBits = 6;
boolean fNeg = (b & 0x40) != 0; // seventh bit is a sign bit
while ((b & 0x80) != 0) // eighth bit is the continuation bit
{
b = readUnsignedByte();
n |= ((b & 0x7F) << cBits);
cBits += 7;
}
if (fNeg)
{
n = ~n;
}
return n;
}
/**
* Read a long value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeLong} method.
*
* @return a long value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public long readLong()
throws IOException
{
int b = readUnsignedByte();
long l = b & 0x3F; // only 6 bits of data in first byte
int cBits = 6;
boolean fNeg = (b & 0x40) != 0; // seventh bit is a sign bit
while ((b & 0x80) != 0) // eighth bit is the continuation bit
{
b = readUnsignedByte();
l |= (((long) (b & 0x7F)) << cBits);
cBits += 7;
}
if (fNeg)
{
l = ~l;
}
return l;
}
/**
* Read a float value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeFloat} method.
*
* @return a float value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public float readFloat()
throws IOException
{
byte[] ab = m_abBuf;
readFully(ab, 0, 4);
int n = ((ab[0] ) << 24)
| ((ab[1] & 0xFF) << 16)
| ((ab[2] & 0xFF) << 8)
| ((ab[3] & 0xFF));
return Float.intBitsToFloat(n);
}
/**
* Read a double value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeDouble} method.
*
* @return a double value
*
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public double readDouble()
throws IOException
{
byte[] ab = m_abBuf;
readFully(ab, 0, 8);
int nMSB = ((ab[0] ) << 24)
| ((ab[1] & 0xFF) << 16)
| ((ab[2] & 0xFF) << 8)
| ((ab[3] & 0xFF));
int nLSB = ((ab[4] ) << 24)
| ((ab[5] & 0xFF) << 16)
| ((ab[6] & 0xFF) << 8)
| ((ab[7] & 0xFF));
long l = (((long) nMSB) << 32) | (nLSB & 0xFFFFFFFFL);
return Double.longBitsToDouble(l);
}
/**
* Reads the next "line" of text.
*
* This method does not have a counterpart in the
* {@link java.io.DataOutput} interface. Furthermore, this method is
* defined as operating on bytes and not on characters, and thus it should
* be selected for use only after careful consideration, as if it were
* deprecated.
*
* @return a line of text as a String
* @exception IOException if an I/O error occurs.
*/
public String readLine()
throws IOException
{
throw new IOException("unsupported");
}
/**
* Reads a String value.
*
* This method is the counterpart for the
* {@link java.io.DataOutput#writeUTF} method.
*
* @return a String value
*
* @exception UTFDataFormatException if the bytes that were read were not
* a valid UTF-8 encoded string
* @exception EOFException if the value could not be read because no
* more data remains to be read
* @exception IOException if an I/O error occurs
*/
public String readUTF()
throws IOException
{
int cch = readInt();
if (cch == 0)
{
// this is a constant, and thus is NOT allocated dynamically
return "";
}
int cb = readInt();
byte[] ab = (cb <= MAX_BUF ? m_abBuf : new byte[cb]);
readFully(ab, 0, cb);
char[] ach = new char[cch];
for (int of = 0, ofb = 0; of < cch; ++of)
{
int ch = ab[ofb++];
switch ((ch & 0xF0) >>> 4)
{
case 0x0: case 0x1: case 0x2: case 0x3:
case 0x4: case 0x5: case 0x6: case 0x7:
// 1-byte format: 0xxx xxxx
ach[of] = (char) ch;
break;
case 0xC: case 0xD:
{
// 2-byte format: 110x xxxx, 10xx xxxx
int ch2 = ab[ofb++];
if ((ch2 & 0xC0) != 0x80)
{
throw new UTFDataFormatException();
}
ach[of] = (char) (((ch & 0x1F) << 6) | ch2 & 0x3F);
}
break;
case 0xE:
{
// 3-byte format: 1110 xxxx, 10xx xxxx, 10xx xxxx
int ch2 = ab[ofb++];
int ch3 = ab[ofb++];
if ((ch2 & 0xC0) != 0x80 || (ch3 & 0xC0) != 0x80)
{
throw new UTFDataFormatException();
}
ach[of] = (char) (((ch & 0x0F) << 12) | ((ch2 & 0x3F) << 6) | ch3 & 0x3F);
}
break;
default:
throw new UTFDataFormatException("illegal leading UTF byte: " + ch);
}
}
return new String(ach);
}
// ----- data members ---------------------------------------------------
/**
* The size of the internal buffer.
*/
static final int MAX_BUF = 32;
/**
* An internal buffer to use for reading data.
*/
private byte[] m_abBuf = new byte[MAX_BUF];
}