- * DataInputStream is not necessarily safe for multithreaded access.
- * Thread safety is optional and is the responsibility of users of
- * methods in this class.
- *
- * @author Arthur van Hoff
- * @see java.io.DataOutputStream
- * @since JDK1.0
- */
-public
-class DataInputStream extends FilterInputStream implements DataInput {
-
- /**
- * Creates a DataInputStream that uses the specified
- * underlying InputStream.
- *
- * @param in the specified input stream
- */
- public DataInputStream(InputStream in) {
- super(in);
- }
-
- /**
- * working arrays initialized on demand by readUTF
- */
- private byte bytearr[] = new byte[80];
- private char chararr[] = new char[80];
-
- /**
- * Reads some number of bytes from the contained input stream and
- * stores them into the buffer array b. The number of
- * bytes actually read is returned as an integer. This method blocks
- * until input data is available, end of file is detected, or an
- * exception is thrown.
- *
- *
If b is null, a NullPointerException is
- * thrown. If the length of b is zero, then no bytes are
- * read and 0 is returned; otherwise, there is an attempt
- * to read at least one byte. If no byte is available because the
- * stream is at end of file, the value -1 is returned;
- * otherwise, at least one byte is read and stored into b.
- *
- *
The first byte read is stored into element b[0], the
- * next one into b[1], and so on. The number of bytes read
- * is, at most, equal to the length of b. Let k
- * be the number of bytes actually read; these bytes will be stored in
- * elements b[0] through b[k-1], leaving
- * elements b[k] through b[b.length-1]
- * unaffected.
- *
- *
The read(b) method has the same effect as:
- *
- * - * @param b the buffer into which the data is read. - * @return the total number of bytes read into the buffer, or - *- * read(b, 0, b.length) - *
-1 if there is no more data because the end
- * of the stream has been reached.
- * @exception IOException if the first byte cannot be read for any reason
- * other than end of file, the stream has been closed and the underlying
- * input stream does not support reading after close, or another I/O
- * error occurs.
- * @see java.io.FilterInputStream#in
- * @see java.io.InputStream#read(byte[], int, int)
- */
- public final int read(byte b[]) throws IOException {
- return in.read(b, 0, b.length);
- }
-
- /**
- * Reads up to len bytes of data from the contained
- * input stream into an array of bytes. An attempt is made to read
- * as many as len bytes, but a smaller number may be read,
- * possibly zero. The number of bytes actually read is returned as an
- * integer.
- *
- * This method blocks until input data is available, end of file is - * detected, or an exception is thrown. - * - *
If len is zero, then no bytes are read and
- * 0 is returned; otherwise, there is an attempt to read at
- * least one byte. If no byte is available because the stream is at end of
- * file, the value -1 is returned; otherwise, at least one
- * byte is read and stored into b.
- *
- *
The first byte read is stored into element b[off], the
- * next one into b[off+1], and so on. The number of bytes read
- * is, at most, equal to len. Let k be the number of
- * bytes actually read; these bytes will be stored in elements
- * b[off] through b[off+k-1],
- * leaving elements b[off+k] through
- * b[off+len-1] unaffected.
- *
- *
In every case, elements b[0] through
- * b[off] and elements b[off+len] through
- * b[b.length-1] are unaffected.
- *
- * @param b the buffer into which the data is read.
- * @param off the start offset in the destination array b
- * @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.
- * @exception NullPointerException If b is null.
- * @exception IndexOutOfBoundsException If off is negative,
- * len is negative, or len is greater than
- * b.length - off
- * @exception IOException if the first byte cannot be read for any reason
- * other than end of file, the stream has been closed and the underlying
- * input stream does not support reading after close, or another I/O
- * error occurs.
- * @see java.io.FilterInputStream#in
- * @see java.io.InputStream#read(byte[], int, int)
- */
- public final int read(byte b[], int off, int len) throws IOException {
- return in.read(b, off, len);
- }
-
- /**
- * See the general contract of the readFully
- * method of DataInput.
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @param b the buffer into which the data is read.
- * @exception EOFException if this input stream reaches the end before
- * reading all the bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final void readFully(byte b[]) throws IOException {
- readFully(b, 0, b.length);
- }
-
- /**
- * See the general contract of the readFully
- * method of DataInput.
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @param b the buffer into which the data is read.
- * @param off the start offset of the data.
- * @param len the number of bytes to read.
- * @exception EOFException if this input stream reaches the end before
- * reading all the bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final void readFully(byte b[], int off, int len) throws IOException {
- if (len < 0)
- throw new IndexOutOfBoundsException();
- int n = 0;
- while (n < len) {
- int count = in.read(b, off + n, len - n);
- if (count < 0)
- throw new EOFException();
- n += count;
- }
- }
-
- /**
- * See the general contract of the skipBytes
- * method of DataInput.
- *
- * Bytes for this operation are read from the contained
- * input stream.
- *
- * @param n the number of bytes to be skipped.
- * @return the actual number of bytes skipped.
- * @exception IOException if the contained input stream does not support
- * seek, or the stream has been closed and
- * the contained input stream does not support
- * reading after close, or another I/O error occurs.
- */
- public final int skipBytes(int n) throws IOException {
- int total = 0;
- int cur = 0;
-
- while ((total
- * Bytes for this operation are read from the contained
- * input stream.
- *
- * @return the
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next byte of this input stream as a signed 8-bit
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next byte of this input stream, interpreted as an
- * unsigned 8-bit number.
- * @exception EOFException if this input stream has reached the end.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final int readUnsignedByte() throws IOException {
- int ch = in.read();
- if (ch < 0)
- throw new EOFException();
- return ch;
- }
-
- /**
- * See the general contract of the
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next two bytes of this input stream, interpreted as a
- * signed 16-bit number.
- * @exception EOFException if this input stream reaches the end before
- * reading two bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final short readShort() throws IOException {
- int ch1 = in.read();
- int ch2 = in.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (short)((ch1 << 8) + (ch2 << 0));
- }
-
- /**
- * See the general contract of the
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next two bytes of this input stream, interpreted as an
- * unsigned 16-bit integer.
- * @exception EOFException if this input stream reaches the end before
- * reading two bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final int readUnsignedShort() throws IOException {
- int ch1 = in.read();
- int ch2 = in.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (ch1 << 8) + (ch2 << 0);
- }
-
- /**
- * See the general contract of the
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next two bytes of this input stream, interpreted as a
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next four bytes of this input stream, interpreted as an
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next eight bytes of this input stream, interpreted as a
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next four bytes of this input stream, interpreted as a
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return the next eight bytes of this input stream, interpreted as a
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @deprecated This method does not properly convert bytes to characters.
- * As of JDK 1.1, the preferred way to read lines of text is via the
- *
- * Bytes
- * for this operation are read from the contained
- * input stream.
- *
- * @return a Unicode string.
- * @exception EOFException if this input stream reaches the end before
- * reading all the bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @exception UTFDataFormatException if the bytes do not represent a valid
- * modified UTF-8 encoding of a string.
- * @see java.io.DataInputStream#readUTF(java.io.DataInput)
- */
- public final String readUTF() throws IOException {
- return readUTF(this);
- }
-
- /**
- * Reads from the
- * stream readBoolean
- * method of DataInput.
- * boolean value read.
- * @exception EOFException if this input stream has reached the end.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final boolean readBoolean() throws IOException {
- int ch = in.read();
- if (ch < 0)
- throw new EOFException();
- return (ch != 0);
- }
-
- /**
- * See the general contract of the readByte
- * method of DataInput.
- * byte.
- * @exception EOFException if this input stream has reached the end.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final byte readByte() throws IOException {
- int ch = in.read();
- if (ch < 0)
- throw new EOFException();
- return (byte)(ch);
- }
-
- /**
- * See the general contract of the readUnsignedByte
- * method of DataInput.
- * readShort
- * method of DataInput.
- * readUnsignedShort
- * method of DataInput.
- * readChar
- * method of DataInput.
- * char.
- * @exception EOFException if this input stream reaches the end before
- * reading two bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final char readChar() throws IOException {
- int ch1 = in.read();
- int ch2 = in.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (char)((ch1 << 8) + (ch2 << 0));
- }
-
- /**
- * See the general contract of the readInt
- * method of DataInput.
- * int.
- * @exception EOFException if this input stream reaches the end before
- * reading four bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final int readInt() throws IOException {
- int ch1 = in.read();
- int ch2 = in.read();
- int ch3 = in.read();
- int ch4 = in.read();
- if ((ch1 | ch2 | ch3 | ch4) < 0)
- throw new EOFException();
- return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
- }
-
- private byte readBuffer[] = new byte[8];
-
- /**
- * See the general contract of the readLong
- * method of DataInput.
- * long.
- * @exception EOFException if this input stream reaches the end before
- * reading eight bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public final long readLong() throws IOException {
- readFully(readBuffer, 0, 8);
- return (((long)readBuffer[0] << 56) +
- ((long)(readBuffer[1] & 255) << 48) +
- ((long)(readBuffer[2] & 255) << 40) +
- ((long)(readBuffer[3] & 255) << 32) +
- ((long)(readBuffer[4] & 255) << 24) +
- ((readBuffer[5] & 255) << 16) +
- ((readBuffer[6] & 255) << 8) +
- ((readBuffer[7] & 255) << 0));
- }
-
- /**
- * See the general contract of the readFloat
- * method of DataInput.
- * float.
- * @exception EOFException if this input stream reaches the end before
- * reading four bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.DataInputStream#readInt()
- * @see java.lang.Float#intBitsToFloat(int)
- */
- public final float readFloat() throws IOException {
- return Float.intBitsToFloat(readInt());
- }
-
- /**
- * See the general contract of the readDouble
- * method of DataInput.
- * double.
- * @exception EOFException if this input stream reaches the end before
- * reading eight bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @see java.io.DataInputStream#readLong()
- * @see java.lang.Double#longBitsToDouble(long)
- */
- public final double readDouble() throws IOException {
- int hi = readInt();
- int low = readInt();
- return toDouble(hi, low);
- }
-
- @JavaScriptBody(args={ "hi", "low" },
- body=
- "if (low == 0) {\n"
- + " if (hi === 0x7ff00000) return Number.POSITIVE_INFINITY;\n"
- + " if (hi === 0xfff00000) return Number.NEGATIVE_INFINITY;\n"
- + "}\n"
- + "if (hi >= 0x7ff00000 && hi <= 0x7fffffff) return Number.NaN;\n"
- + "if (hi >= 0xfff00000 && hi <= 0xffffffff) return Number.NaN;\n"
- + "var s = (hi & 0x80000000) === 0 ? 1 : -1;\n"
- + "var e = (hi >> 20) & 0x7ff;\n"
- + "var to32 = low >> 0;\n"
- + "if (e === 0) {\n"
- + " if (to32 & 0x80000000) {\n"
- + " hi = hi << 1 + 1; low = low << 1;\n"
- + " } else {\n"
- + " hi = hi << 1; low = low << 1;\n"
- + " }\n"
- + "} else {\n"
- + " hi = (hi & 0xfffff) | 0x100000;\n"
- + "}\n"
- + "to32 = low >> 0;\n"
- + "var m = Math.pow(2.0, 32) * hi + to32;\n"
- + "var r = s * m * Math.pow(2.0, e - 1075);\n"
- + "//throw 'exp: ' + e + ' sign: ' + s + ' hi:' + hi + ' low: ' + low + ' m: ' + m + ' r: ' + r;\n"
- + "return r;\n"
- )
- private static double toDouble(int hi, int low) {
- long both = hi;
- both = (both << 32) & low;
- return Double.doubleToLongBits(both);
- }
-
- private char lineBuffer[];
-
- /**
- * See the general contract of the readLine
- * method of DataInput.
- * BufferedReader.readLine() method. Programs that use the
- * DataInputStream class to read lines can be converted to use
- * the BufferedReader class by replacing code of the form:
- *
- * with:
- *
- * DataInputStream d = new DataInputStream(in);
- *
- *
- * @return the next line of text from this input stream.
- * @exception IOException if an I/O error occurs.
- * @see java.io.BufferedReader#readLine()
- * @see java.io.FilterInputStream#in
- */
- @Deprecated
- public final String readLine() throws IOException {
- char buf[] = lineBuffer;
-
- if (buf == null) {
- buf = lineBuffer = new char[128];
- }
-
- int room = buf.length;
- int offset = 0;
- int c;
-
-loop: while (true) {
- switch (c = in.read()) {
- case -1:
- case '\n':
- break loop;
-
- case '\r':
- int c2 = in.read();
- if ((c2 != '\n') && (c2 != -1)) {
- if (!(in instanceof PushbackInputStream)) {
- this.in = new PushbackInputStream(in);
- }
- ((PushbackInputStream)in).unread(c2);
- }
- break loop;
-
- default:
- if (--room < 0) {
- buf = new char[offset + 128];
- room = buf.length - offset - 1;
- System.arraycopy(lineBuffer, 0, buf, 0, offset);
- lineBuffer = buf;
- }
- buf[offset++] = (char) c;
- break;
- }
- }
- if ((c == -1) && (offset == 0)) {
- return null;
- }
- return String.copyValueOf(buf, 0, offset);
- }
-
- /**
- * See the general contract of the
- * BufferedReader d
- * = new BufferedReader(new InputStreamReader(in));
- *
readUTF
- * method of DataInput.
- * in a representation
- * of a Unicode character string encoded in
- * modified UTF-8 format;
- * this string of characters is then returned as a String.
- * The details of the modified UTF-8 representation
- * are exactly the same as for the readUTF
- * method of DataInput.
- *
- * @param in a data input stream.
- * @return a Unicode string.
- * @exception EOFException if the input stream reaches the end
- * before all the bytes.
- * @exception IOException the stream has been closed and the contained
- * input stream does not support reading after close, or
- * another I/O error occurs.
- * @exception UTFDataFormatException if the bytes do not represent a
- * valid modified UTF-8 encoding of a Unicode string.
- * @see java.io.DataInputStream#readUnsignedShort()
- */
- public final static String readUTF(DataInput in) throws IOException {
- int utflen = in.readUnsignedShort();
- byte[] bytearr = null;
- char[] chararr = null;
- if (in instanceof DataInputStream) {
- DataInputStream dis = (DataInputStream)in;
- if (dis.bytearr.length < utflen){
- dis.bytearr = new byte[utflen*2];
- dis.chararr = new char[utflen*2];
- }
- chararr = dis.chararr;
- bytearr = dis.bytearr;
- } else {
- bytearr = new byte[utflen];
- chararr = new char[utflen];
- }
-
- int c, char2, char3;
- int count = 0;
- int chararr_count=0;
-
- in.readFully(bytearr, 0, utflen);
-
- while (count < utflen) {
- c = (int) bytearr[count] & 0xff;
- if (c > 127) break;
- count++;
- chararr[chararr_count++]=(char)c;
- }
-
- while (count < utflen) {
- c = (int) bytearr[count] & 0xff;
- switch (c >> 4) {
- case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
- /* 0xxxxxxx*/
- count++;
- chararr[chararr_count++]=(char)c;
- break;
- case 12: case 13:
- /* 110x xxxx 10xx xxxx*/
- count += 2;
- if (count > utflen)
- throw new UTFDataFormatException(
- "malformed input: partial character at end");
- char2 = (int) bytearr[count-1];
- if ((char2 & 0xC0) != 0x80)
- throw new UTFDataFormatException(
- "malformed input around byte " + count);
- chararr[chararr_count++]=(char)(((c & 0x1F) << 6) |
- (char2 & 0x3F));
- break;
- case 14:
- /* 1110 xxxx 10xx xxxx 10xx xxxx */
- count += 3;
- if (count > utflen)
- throw new UTFDataFormatException(
- "malformed input: partial character at end");
- char2 = (int) bytearr[count-2];
- char3 = (int) bytearr[count-1];
- if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80))
- throw new UTFDataFormatException(
- "malformed input around byte " + (count-1));
- chararr[chararr_count++]=(char)(((c & 0x0F) << 12) |
- ((char2 & 0x3F) << 6) |
- ((char3 & 0x3F) << 0));
- break;
- default:
- /* 10xx xxxx, 1111 xxxx */
- throw new UTFDataFormatException(
- "malformed input around byte " + count);
- }
- }
- // The number of chars produced may be less than utflen
- return new String(chararr, 0, chararr_count);
- }
-}