www.pudn.com > j2me_cldc-1_1-fcs-src-winunix.rar > DataOutputStream.java
/*
* Copyright © 2003 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*/
package java.io;
/**
* A data output stream lets an application write primitive Java data
* types to an output stream in a portable way. An application can
* then use a data input stream to read the data back in.
*
* @author unascribed
* @version 12/17/01 (CLDC 1.1)
* @see java.io.DataInputStream
* @since JDK1.0, CLDC 1.0
*/
public
class DataOutputStream extends OutputStream implements DataOutput {
/**
* The output stream.
*/
protected OutputStream out;
/**
* Creates a new data output stream to write data to the specified
* underlying output stream.
*
* @param out the underlying output stream, to be saved for later
* use.
*/
public DataOutputStream(OutputStream out) {
this.out = out;
}
/**
* Writes the specified byte (the low eight bits of the argument
* b) to the underlying output stream.
*
* Implements the write method of OutputStream.
*
* @param b the byte to be written.
* @exception IOException if an I/O error occurs.
*/
public void write(int b) throws IOException {
out.write(b);
}
/**
* Writes len bytes from the specified byte array
* starting at offset off to the underlying output stream.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @exception IOException if an I/O error occurs.
*/
public void write(byte b[], int off, int len) throws IOException {
out.write(b, off, len);
}
/**
* Flushes this data output stream. This forces any buffered output
* bytes to be written out to the stream.
*
* The flush method of DataOutputStream
* calls the flush method of its underlying output stream.
*
* @exception IOException if an I/O error occurs.
*/
public void flush() throws IOException {
out.flush();
}
/**
* Closes this output stream and releases any system resources
* associated with the stream.
*
* The close method
* calls its flush method, and then calls the
* close method of its underlying output stream.
*
* @exception IOException if an I/O error occurs.
*/
public void close() throws IOException {
out.close();
}
/**
* Writes a boolean to the underlying output stream as
* a 1-byte value. The value true is written out as the
* value (byte)1; the value false is
* written out as the value (byte)0.
*
* @param v a boolean value to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeBoolean(boolean v) throws IOException {
write(v ? 1 : 0);
}
/**
* Writes out a byte to the underlying output stream as
* a 1-byte value.
*
* @param v a byte value to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeByte(int v) throws IOException {
write(v);
}
/**
* Writes a short to the underlying output stream as two
* bytes, high byte first.
*
* @param v a short to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeShort(int v) throws IOException {
write((v >>> 8) & 0xFF);
write((v >>> 0) & 0xFF);
}
/**
* Writes a char to the underlying output stream as a
* 2-byte value, high byte first.
*
* @param v a char value to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeChar(int v) throws IOException {
write((v >>> 8) & 0xFF);
write((v >>> 0) & 0xFF);
}
/**
* Writes an int to the underlying output stream as four
* bytes, high byte first.
*
* @param v an int to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeInt(int v) throws IOException {
write((v >>> 24) & 0xFF);
write((v >>> 16) & 0xFF);
write((v >>> 8) & 0xFF);
write((v >>> 0) & 0xFF);
}
/**
* Writes a long to the underlying output stream as eight
* bytes, high byte first.
*
* @param v a long to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeLong(long v) throws IOException {
write((int)(v >>> 56) & 0xFF);
write((int)(v >>> 48) & 0xFF);
write((int)(v >>> 40) & 0xFF);
write((int)(v >>> 32) & 0xFF);
write((int)(v >>> 24) & 0xFF);
write((int)(v >>> 16) & 0xFF);
write((int)(v >>> 8) & 0xFF);
write((int)(v >>> 0) & 0xFF);
}
/**
* Converts the float argument to an int using the
* floatToIntBits method in class Float,
* and then writes that int value to the underlying
* output stream as a 4-byte quantity, high byte first.
*
* @param v a float value to be written.
* @exception IOException if an I/O error occurs.
* @see java.lang.Float#floatToIntBits(float)
* @since CLDC 1.1
*/
public final void writeFloat(float v) throws IOException {
writeInt(Float.floatToIntBits(v));
}
/**
* Converts the double argument to a long using the
* doubleToLongBits method in class Double,
* and then writes that long value to the underlying
* output stream as an 8-byte quantity, high byte first.
*
* @param v a double value to be written.
* @exception IOException if an I/O error occurs.
* @see java.lang.Double#doubleToLongBits(double)
* @since CLDC 1.1
*/
public final void writeDouble(double v) throws IOException {
writeLong(Double.doubleToLongBits(v));
}
/**
* Writes a string to the underlying output stream as a sequence of
* characters. Each character is written to the data output stream as
* if by the writeChar method.
*
* @param s a String value to be written.
* @exception IOException if an I/O error occurs.
* @see java.io.DataOutputStream#writeChar(int)
*/
public final void writeChars(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
int v = s.charAt(i);
write((v >>> 8) & 0xFF);
write((v >>> 0) & 0xFF);
}
}
/**
* Writes a string to the underlying output stream using UTF-8
* encoding in a machine-independent manner.
*
* First, two bytes are written to the output stream as if by the
* writeShort method giving the number of bytes to
* follow. This value is the number of bytes actually written out,
* not the length of the string. Following the length, each character
* of the string is output, in sequence, using the UTF-8 encoding
* for the character.
*
* @param str a string to be written.
* @exception IOException if an I/O error occurs.
*/
public final void writeUTF(String str) throws IOException {
writeUTF(str, this);
}
/**
* Writes a string to the specified DataOutput using UTF-8 encoding in a
* machine-independent manner.
*
* First, two bytes are written to out as if by the writeShort
* method giving the number of bytes to follow. This value is the number of
* bytes actually written out, not the length of the string. Following the
* length, each character of the string is output, in sequence, using the
* UTF-8 encoding for the character.
*
* @param str a string to be written.
* @param out destination to write to
* @return The number of bytes written out.
* @exception IOException if an I/O error occurs.
*/
static final int writeUTF(String str, DataOutput out) throws IOException {
int strlen = str.length();
int utflen = 0;
char[] charr = new char[strlen];
int c, count = 0;
str.getChars(0, strlen, charr, 0);
for (int i = 0; i < strlen; i++) {
c = charr[i];
if ((c >= 0x0001) && (c <= 0x007F)) {
utflen++;
} else if (c > 0x07FF) {
utflen += 3;
} else {
utflen += 2;
}
}
if (utflen > 65535)
throw new UTFDataFormatException();
byte[] bytearr = new byte[utflen+2];
bytearr[count++] = (byte) ((utflen >>> 8) & 0xFF);
bytearr[count++] = (byte) ((utflen >>> 0) & 0xFF);
for (int i = 0; i < strlen; i++) {
c = charr[i];
if ((c >= 0x0001) && (c <= 0x007F)) {
bytearr[count++] = (byte) c;
} else if (c > 0x07FF) {
bytearr[count++] = (byte) (0xE0 | ((c >> 12) & 0x0F));
bytearr[count++] = (byte) (0x80 | ((c >> 6) & 0x3F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
} else {
bytearr[count++] = (byte) (0xC0 | ((c >> 6) & 0x1F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
}
}
out.write(bytearr);
return utflen + 2;
}
}