/* Copyright (C) 1998, 1999 Cygnus Solutions
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
package java.io;
/**
* @author Warren Levy <warrenl@cygnus.com>
* @date October 20, 1998.
*/
/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
* "The Java Language Specification", ISBN 0-201-63451-1
* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
* Status: Believed complete and correct.
*/
public class DataInputStream extends FilterInputStream implements DataInput
{
// readLine() hack to ensure that an '\r' not followed by an '\n' is
// handled correctly. If set, readLine() will ignore the first char it sees
// if that char is a '\n'
boolean ignoreInitialNewline = false;
public DataInputStream(InputStream in)
{
super(in);
}
public final int read(byte[] b) throws IOException
{
return super.read(b, 0, b.length);
}
public final int read(byte[] b, int off, int len) throws IOException
{
if (off < 0 || len < 0 || off + len > b.length)
throw new ArrayIndexOutOfBoundsException();
return super.read(b, off, len);
}
public final boolean readBoolean() throws IOException
{
return (readByte() != 0);
}
public final byte readByte() throws IOException
{
int i = read();
if (i < 0)
throw new EOFException();
return (byte) i;
}
public final char readChar() throws IOException
{
return (char) ((readByte() << 8) | readUnsignedByte());
}
public final double readDouble() throws IOException
{
return Double.longBitsToDouble(readLong());
}
public final float readFloat() throws IOException
{
return Float.intBitsToFloat(readInt());
}
public final void readFully(byte[] b) throws IOException
{
readFully(b, 0, b.length);
}
public final void readFully(byte[] b, int off, int len) throws IOException
{
if (off < 0 || len < 0 || off + len > b.length)
throw new ArrayIndexOutOfBoundsException();
while (len > 0)
{
// super.read will block until some data is available.
int numread = super.read(b, off, len);
if (numread < 0)
throw new EOFException();
len -= numread;
off += numread;
}
}
public final int readInt() throws IOException
{
int retval = 0;
for (int i = 0; i < 4; i++)
retval |= readUnsignedByte() << (24 - i * 8);
return retval;
}
// Deprecated as of JDK 1.1
public final String readLine() throws IOException
{
StringBuffer strb = new StringBuffer();
readloop: while (true)
{
int c = 0;
char ch = ' ';
boolean getnext = true;
while (getnext)
{
getnext = false;
c = read();
if (c < 0) // got an EOF
return strb.length() > 0 ? strb.toString() : null;
ch = (char) c;
if ((ch &= 0xFF) == '\n')
// hack to correctly handle '\r\n' sequences
if (ignoreInitialNewline)
{
ignoreInitialNewline = false;
getnext = true;
}
else
break readloop;
}
if (ch == '\r')
{
// FIXME: The following code tries to adjust the stream back one
// character if the next char read is '\n'. As a last resort,
// it tries to mark the position before reading but the bottom
// line is that it is possible that this method will not properly
// deal with a '\r' '\n' combination thus not fulfilling the
// DataInput contract for readLine. It's not a particularly
// safe approach threadwise since it is unsynchronized and
// since it might mark an input stream behind the users back.
// Along the same vein it could try the same thing for
// ByteArrayInputStream and PushbackInputStream, but that is
// probably overkill since this is deprecated & BufferedInputStream
// is the most likely type of input stream.
//
// The alternative is to somehow push back the next byte if it
// isn't a '\n' or to have the reading methods of this class
// keep track of whether the last byte read was '\r' by readLine
// and then skip the very next byte if it is '\n'. Either way,
// this would increase the complexity of the non-deprecated methods
// and since it is undesirable to make non-deprecated methods
// less efficient, the following seems like the most reasonable
// approach.
int next_c = 0;
char next_ch = ' ';
if (in instanceof BufferedInputStream)
{
next_c = read();
next_ch = (char) (next_c & 0xFF);
if ((next_ch != '\n') && (next_c >= 0))
{
BufferedInputStream bin = (BufferedInputStream) in;
if (bin.pos > 0)
bin.pos--;
}
}
else if (markSupported())
{
next_c = read();
next_ch = (char) (next_c & 0xFF);
if ((next_ch != '\n') && (next_c >= 0))
{
mark(1);
if ((read() & 0xFF) != '\n')
reset();
}
}
// In order to catch cases where 'in' isn't a BufferedInputStream
// and doesn't support mark() (such as reading from a Socket), set
// a flag that instructs readLine() to ignore the first character
// it sees _if_ that character is a '\n'.
else ignoreInitialNewline = true;
break;
}
strb.append(ch);
}
return strb.length() > 0 ? strb.toString() : "";
}
public final long readLong() throws IOException
{
long retval = 0L;
for (int i = 0; i < 8; i++)
retval |= (long) readUnsignedByte() << (56 - i * 8);
return retval;
}
public final short readShort() throws IOException
{
return (short) ((readByte() << 8) | readUnsignedByte());
}
public final int readUnsignedByte() throws IOException
{
int i = read();
if (i < 0)
throw new EOFException();
return (i & 0xFF);
}
public final int readUnsignedShort() throws IOException
{
return (readUnsignedByte() << 8) | readUnsignedByte();
}
public final String readUTF() throws IOException
{
return readUTF(this);
}
public final static String readUTF(DataInput in) throws IOException
{
final int UTFlen = in.readUnsignedShort();
byte[] buf = new byte[UTFlen];
StringBuffer strbuf = new StringBuffer();
// This blocks until the entire string is available rather than
// doing partial processing on the bytes that are available and then
// blocking. An advantage of the latter is that Exceptions
// could be thrown earlier. The former is a bit cleaner.
in.readFully(buf, 0, UTFlen);
for (int i = 0; i < UTFlen; )
{
if ((buf[i] & 0x80) == 0) // bit pattern 0xxxxxxx
strbuf.append((char) (buf[i++] & 0xFF));
else if ((buf[i] & 0xE0) == 0xC0) // bit pattern 110xxxxx
{
if (i + 1 >= UTFlen || (buf[i+1] & 0xC0) != 0x80)
throw new UTFDataFormatException();
strbuf.append((char) (((buf[i++] & 0x1F) << 6) |
(buf[i++] & 0x3F)));
}
else if ((buf[i] & 0xF0) == 0xE0) // bit pattern 1110xxxx
{
if (i + 2 >= UTFlen ||
(buf[i+1] & 0xC0) != 0x80 || (buf[i+2] & 0xC0) != 0x80)
throw new UTFDataFormatException();
strbuf.append((char) (((buf[i++] & 0x0F) << 12) |
((buf[i++] & 0x3F) << 6) |
(buf[i++] & 0x3F)));
}
else // must be ((buf[i] & 0xF0) == 0xF0 || (buf[i] & 0xC0) == 0x80)
throw new UTFDataFormatException(); // bit patterns 1111xxxx or
// 10xxxxxx
}
return strbuf.toString();
}
public final int skipBytes(int n) throws IOException
{
// The contract in the Java Lang. Spec. says that this never
// throws an EOFException and infers that it doesn't block (since
// it may skip less than the requested number of bytes).
// BUT, the JCL book specifically says that this method blocks
// and can throw an EOFException. Finally, the Java 1.2 online
// doc simply refers to the general contract. As such, we will
// stick to the contract and assume for now that the JCL book
// is incorrect.
// Since we're only skipping at most an int number of bytes, the cast
// of return value to an int is fine.
if (n > 0)
{
n = Math.min(n, available());
return (int) super.skip((long) n);
}
return 0;
}
}