java endian_java的little-endian和big-endian
簡(jiǎn)而言之：Big endian machine: It thinks the first byte it reads is the biggest.Little endian machine: It thinks the first byte it reads is the littlest.舉個(gè)例子，從內(nèi)存地址0x0000開(kāi)始有以下數(shù)據(jù)0x0000???? 0x120x0001???? 0x340x0002???? 0xab0x0003???? 0xcd如果我們?nèi)プx取一個(gè)地址為0x0000的四個(gè)字節(jié)變量，若字節(jié)序?yàn)閎ig-endian，則讀出結(jié)果為0x1234abcd；若字節(jié)序位little-endian，則讀出結(jié)果為0xcdab3412.如果我們將0x1234abcd寫(xiě)入到以0x0000開(kāi)始的內(nèi)存中，則結(jié)果為??????????????? big-endian???? little-endian0x0000???? 0x12????????????? 0xcd0x0001???? 0x23????????????? 0xab0x0002???? 0xab????????????? 0x340x0003???? 0xcd????????????? 0x12x86系列CPU都是little-endian的字節(jié)序.
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java的little-endian和big-endian
邢紅瑞 發(fā)表于 2007-4-10 19:25:43?java是與CPU無(wú)關(guān)的編程語(yǔ)言，但是java究竟是little-endian還是big-endian呢，因?yàn)閖ava誕生于soalris平臺(tái)，最初的solaris運(yùn)行于SPARC cpu上，SUN的SPARC和IBM的POWER PC均是big-endian，所以java也是big-endian。判斷java是big endian的代碼public final static int swabInt(int v) {??? return? (v >>> 24) | (v << 24) |????? ((v << 8) & 0x00FF0000) | ((v >> 8) & 0x0000FF00);??? }
public static void main(String argv[]) {??? //? before 0x01020304??? //??? after? 0x04030201??? int v = 0x01020304;??? System.out.println("before : 0x" + Integer.toString(v,16));??? System.out.println("after? : 0x" + Integer.toString(swabInt(v),16));??? }
// take 16-bit short apart into two 8-bit bytes.short x = 0xabcd;byte high = (byte)(x >>> 8);byte low = (byte)x;/* cast implies & 0xff */System.out.println( "x=" + x + " high=" + high + " low=" + low );
big endian是指低地址存放最高有效字節(jié)(MSB)，而little endian則是低地址存放最低有效字節(jié)(LSB)。?Big Endian
低地址???????????????????????????????????????????? 高地址??? ----------------------------------------->??? +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+??? |????? 12????? |?????? 34???? |????? 56?????? |????? 78???? |??? +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Little Endian
低地址???????????????????????????????????????????? 高地址??? ----------------------------------------->??? +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+??? |????? 78????? |?????? 56???? |????? 34?????? |????? 12???? |??? +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+?如果你做單機(jī)程序，這個(gè)基本不用考慮，如何和java程序通訊也沒(méi)有問(wèn)題，java中在AIX下生成的對(duì)象被序列化后能夠在windows下正確的反序列化，如果不這樣，EJB也就不存在了。如果你和C++的程序通訊，問(wèn)題就有了，C/C++語(yǔ)言編寫(xiě)的程序里數(shù)據(jù)存儲(chǔ)順序是跟編譯平臺(tái)所在的CPU相關(guān)的，而JAVA編寫(xiě)的程序則唯一采用big endian方式來(lái)存儲(chǔ)數(shù)據(jù)。你在x86平臺(tái)上，使用c語(yǔ)言通過(guò)socket把0x12345678發(fā)給java的serversocket，得到的是0x78563412，C程序傳給JAVA程序之前有必要進(jìn)行字節(jié)序的轉(zhuǎn)換工作。所有網(wǎng)絡(luò)協(xié)議也都是采用big endian的方式來(lái)傳輸數(shù)據(jù)的。所以有時(shí)我們也會(huì)把big endian方式稱之為網(wǎng)絡(luò)字節(jié)序。當(dāng)兩臺(tái)采用不同字節(jié)序的主機(jī)通信時(shí)，在發(fā)送數(shù)據(jù)之前都必須經(jīng)過(guò)字節(jié)序的轉(zhuǎn)換成為網(wǎng)絡(luò)字節(jié)序后再進(jìn)行傳輸。c/c++中發(fā)送方htonl，接收方ntohl。fseek(f,0L,SEEK_END);??unsigned int tcount=total;tcount=htonl(tcount);memcpy( &buffer[1], &tcount, 4);Java中不用做轉(zhuǎn)換。DataOutputStream.writeInt();DataInputStream.readInt();c語(yǔ)言轉(zhuǎn)換的4個(gè)宏ntoh：network->hosthton：host->networkntohs和htons針對(duì)2字節(jié)的數(shù)ntohl和htonl針對(duì)4字節(jié)的數(shù)為了保證代碼的移植性，必須用這兩個(gè)函數(shù)。
htons(): reorder the bytes of a 16-bit unsigned value from processor order to network order. The macro name can be read "host to network short."?htonl(): reorder the bytes of a 32-bit unsigned value from processor order to network order. The macro name can be read "host to network long."?ntohs(): reorder the bytes of a 16-bit unsigned value from network order to processor order. The macro name can be read "network to host short."?ntohl(): reorder the bytes of a 32-bit unsigned value from network order to processor order. The macro name can be read "network to host long."?#if defined(BIG_ENDIAN) && !defined(LITTLE_ENDIAN)
#define htons(A)? (A)#define htonl(A)? (A)#define ntohs(A)? (A)#define ntohl(A)? (A)
#elif defined(LITTLE_ENDIAN) && !defined(BIG_ENDIAN)
#define htons(A)? ((((uint16)(A) & 0xff00) >> 8) |??????????????????? (((uint16)(A) & 0x00ff) << 8))#define htonl(A)? ((((uint32)(A) & 0xff000000) >> 24) |??????????????????? (((uint32)(A) & 0x00ff0000) >> 8)? |??????????????????? (((uint32)(A) & 0x0000ff00) << 8)? |??????????????????? (((uint32)(A) & 0x000000ff) << 24))#define ntohs???? htons#define ntohl???? htohl
#else
#error "Either BIG_ENDIAN or LITTLE_ENDIAN must be #defined, but not both."
#endif但是如果不是走網(wǎng)絡(luò)，c語(yǔ)言把結(jié)構(gòu)直接寫(xiě)入了文件，那末java讀Little Endian 就麻煩一些，這方面的代碼很多。使用jdk1.4以后的版本，float f = ByteBuffer.wrap( array ).order( ByteOrder.LITTLE_ENDIAN ).getFloat();否則就得自己寫(xiě)代碼了package com.mindprod.ledatastream;
import java.io.DataOutput;import java.io.DataOutputStream;import java.io.IOException;import java.io.OutputStream;
/***
*?????? LEDataOutputStream.java* */public class LEDataOutputStream implements DataOutput {// ------------------------------ FIELDS ------------------------------
/**???? * work array for composing output???? */??? byte w[];
/**???? * to get at big-Endian write methods of DataOutPutStream???? */??? protected DataOutputStream d;
// -------------------------- STATIC METHODS --------------------------
/**???? * Embeds copyright notice???? *???? * @return copyright notice???? */??? public static final String getCopyright()??????? {??????? return "LeDataStream 1.7 freeware copyright (c) 1998-2007 Roedy Green, Canadian Mind Products,?http://mindprod.com?roedyg@mindprod.com";??????? }
// --------------------------- CONSTRUCTORS ---------------------------
/**???? * constructor???? *???? * @param out the outputstream we ware to write little endian binary data onto???? */??? public LEDataOutputStream( OutputStream out )??????? {??????? this.d = new DataOutputStream( out );??????? w = new byte[8];// work array for composing output??????? }
// ------------------------ INTERFACE METHODS ------------------------
// --------------------- Interface DataOutput ---------------------
/**???? * This method writes only one byte, even though it says int (non-Javadoc)???? *???? * @inheritDoc???? * @see java.io.DataOutput#write(int)???? */??? public final synchronized void write( int b ) throws IOException??????? {??????? d.write( b );??????? }
/**???? * @inheritDoc???? * @see java.io.DataOutput#write(byte[])???? */??? public final void write( byte b[] ) throws IOException??????? {??????? d.write( b, 0, b.length );??????? }
/**???? * @inheritDoc???? * @see java.io.DataOutput#write(byte[],int,int)???? */??? public final synchronized void write( byte b[],????????????????????????????????????????? int off,????????????????????????????????????????? int len ) throws IOException??????? {??????? d.write( b, off, len );??????? }
/**???? * @inheritDoc???? * @see java.io.DataOutput#writeBoolean(boolean)???? */??? /* Only writes one byte */??? public final void writeBoolean( boolean v ) throws IOException??????? {??????? d.writeBoolean( v );??????? }
// p u r e l y w r a p p e r m e t h o d s??? // We cannot inherit since DataOutputStream is final.
/**???? * @inheritDoc???? * @see java.io.DataOutput#writeByte(int)???? */??? public final void writeByte( int v ) throws IOException??????? {??????? d.writeByte( v );??????? }
/**???? * like DataOutputStream.writeShort. also acts as a writeUnsignedShort???? *???? * @param v the short you want written in little endian binary format???? *???? * @throws IOException???? * @inheritDoc???? */??? public final void writeShort( int v ) throws IOException??????? {??????? w[ 0 ] = (byte) v;??????? w[ 1 ] = (byte) ( v >> 8 );??????? d.write( w, 0, 2 );??????? }
/**???? * like DataOutputStream.writeChar. Note the parm is an int even though this???? * as a writeChar???? *???? * @param v???? *???? * @inheritDoc???? */??? public final void writeChar( int v ) throws IOException??????? {??????? // same code as writeShort??????? w[ 0 ] = (byte) v;??????? w[ 1 ] = (byte) ( v >> 8 );??????? d.write( w, 0, 2 );??????? }
/**???? * like DataOutputStream.writeInt.???? *???? * @param v???? *???? * @throws IOException???? * @inheritDoc???? */??? public final void writeInt( int v ) throws IOException??????? {??????? w[ 0 ] = (byte) v;??????? w[ 1 ] = (byte) ( v >> 8 );??????? w[ 2 ] = (byte) ( v >> 16 );??????? w[ 3 ] = (byte) ( v >> 24 );??????? d.write( w, 0, 4 );??????? }
/**???? * like DataOutputStream.writeLong.???? *???? * @param v???? *???? * @throws IOException???? * @inheritDoc???? */??? public final void writeLong( long v ) throws IOException??????? {??????? w[ 0 ] = (byte) v;??????? w[ 1 ] = (byte) ( v >> 8 );??????? w[ 2 ] = (byte) ( v >> 16 );??????? w[ 3 ] = (byte) ( v >> 24 );??????? w[ 4 ] = (byte) ( v >> 32 );??????? w[ 5 ] = (byte) ( v >> 40 );??????? w[ 6 ] = (byte) ( v >> 48 );??????? w[ 7 ] = (byte) ( v >> 56 );??????? d.write( w, 0, 8 );??????? }
/**???? * like DataOutputStream.writeFloat.???? *???? * @inheritDoc???? */??? public final void writeFloat( float v ) throws IOException??????? {??????? writeInt( Float.floatToIntBits( v ) );??????? }
/**???? * like DataOutputStream.writeDouble.???? *???? * @inheritDoc???? */??? public final void writeDouble( double v ) throws IOException??????? {??????? writeLong( Double.doubleToLongBits( v ) );??????? }
/**???? * @inheritDoc???? * @see java.io.DataOutput#writeBytes(java.lang.String)???? */??? public final void writeBytes( String s ) throws IOException??????? {??????? d.writeBytes( s );??????? }
/**???? * like DataOutputStream.writeChars, flip each char.???? *???? * @inheritDoc???? */??? public final void writeChars( String s ) throws IOException??????? {??????? int len = s.length();??????? for ( int i = 0; i < len; i++ )??????????? {??????????? writeChar( s.charAt( i ) );??????????? }??????? }// end writeChars
/**???? * @inheritDoc???? * @see java.io.DataOutput#writeUTF(java.lang.String)???? */??? public final void writeUTF( String str ) throws IOException??????? {??????? d.writeUTF( str );??????? }
// -------------------------- OTHER METHODS --------------------------
// L I T T L E E N D I A N W R I T E R S??? // Little endian methods for multi-byte numeric types.??? // Big-endian do fine for single-byte types and strings.
/**???? * @throws IOException???? */??? public final void close() throws IOException??????? {??????? d.close();??????? }
// DataOutputStream
/**???? * @throws IOException???? */??? public void flush() throws IOException??????? {??????? d.flush();??????? }
/**???? * @return bytes written so far in the stream. Note this is a int, not a???? *???????? long as you would exect. This because the underlying???? *???????? DataInputStream has a design flaw.???? */??? public final int size()??????? {??????? return d.size();??????? }}// end LEDataOutputStreampackage com.mindprod.ledatastream;
import java.io.DataInput;import java.io.DataInputStream;import java.io.IOException;import java.io.InputStream;
/*** LEDataInputStream.java copyright (c) 1998-2007 Roedy Green, Canadian Mind* Products [withheld] Victoria, BC Canada [withdrawn] tel: (250)* 361-9093 mailto:roedyg@mindprod.com?http://mindprod.com?Version 1.0 1998* January 6 1.1 1998 January 7 - officially implements DataInput 1.2 1998* January 9 - add LERandomAccessFile 1.3 1998 August 27 - fix bug, readFully* instead of read. 1.4 1998 November 10 - add address and phone. 1.5 1999* October 8 - use com.mindprod.ledatastream package name. 1.6 2005-06-13 - made* readLine deprecated Very similar to DataInputStream except it reads* little-endian instead of big-endian binary data. We can't extend* DataInputStream directly since it has only final methods, though* DataInputStream itself is not final. This forces us implement* LEDataInputStream with a DataInputStream object, and use wrapper methods.*/public class LEDataInputStream implements DataInput {
// ------------------------------ FIELDS ------------------------------
/**???? * work array for buffering input???? */??? byte w[];
/**???? * to get at the big-Endian methods of a basic DataInputStream???? */??? protected DataInputStream d;
/**???? * to get at the a basic readBytes method???? */??? protected InputStream in;
// -------------------------- STATIC METHODS --------------------------
/**???? * Embeds copyright notice???? *???? * @return copyright notice???? */??? public static final String getCopyright()??????? {??????? return "LeDataStream 1.7 freeware copyright (c) 1998-2007 Roedy Green, Canadian Mind Products,?http://mindprod.com?roedyg@mindprod.com";??????? }
/**???? * Note. This is a STATIC method!???? *???? * @param in stream to read UTF chars from (endian irrelevant)???? *???? * @return string from stream???? *???? * @throws IOException???? */??? public final static String readUTF( DataInput in ) throws IOException??????? {??????? return DataInputStream.readUTF( in );??????? }
// --------------------------- CONSTRUCTORS ---------------------------
// i n s t a n c e v a r i a b l e s
/**???? * constructor???? *???? * @param in binary inputstream of little-endian data.???? */??? public LEDataInputStream( InputStream in )??????? {??????? this.in = in;??????? this.d = new DataInputStream( in );??????? w = new byte[8];??????? }
// ------------------------ INTERFACE METHODS ------------------------
// --------------------- Interface DataInput ---------------------
/**???? * @inheritDoc???? * @see java.io.DataInput#readFully(byte[])???? */??? public final void readFully( byte b[] ) throws IOException??????? {??????? d.readFully( b, 0, b.length );??????? }
/**???? * @inheritDoc???? * @see java.io.DataInput#readFully(byte[],int,int)???? */??? public final void readFully( byte b[], int off, int len ) throws IOException??????? {??????? d.readFully( b, off, len );??????? }
/**???? * See the general contract of the skipBytes method of???? * DataInput.???? *
/**???? * only reads on byte???? *???? * @see java.io.DataInput#readBoolean()???? */??? public final boolean readBoolean() throws IOException??????? {??????? return d.readBoolean();??????? }
/**???? * @inheritDoc???? * @see java.io.DataInput#readByte()???? */??? public final byte readByte() throws IOException??????? {??????? return d.readByte();??????? }
/**???? * note: returns an int, even though says Byte (non-Javadoc)???? *???? * @inheritDoc???? * @see java.io.DataInput#readUnsignedByte()???? */??? public final int readUnsignedByte() throws IOException??????? {??????? return d.readUnsignedByte();??????? }
// L I T T L E E N D I A N R E A D E R S??? // Little endian methods for multi-byte numeric types.??? // Big-endian do fine for single-byte types and strings.??? /**???? * like DataInputStream.readShort except little endian.???? *???? * @return little endian binary short from stream???? *???? * @throws IOException???? */??? public final short readShort() throws IOException??????? {??????? d.readFully( w, 0, 2 );??????? return (short) ( ( w[ 1 ] & 0xff ) << 8 | ( w[ 0 ] & 0xff ) );??????? }
/**???? * like DataInputStream.readUnsignedShort except little endian. Note,???? * returns int even though it reads a short.???? *???? * @return little-endian int from the stream???? *???? * @throws IOException???? */??? public final int readUnsignedShort() throws IOException??????? {??????? d.readFully( w, 0, 2 );??????? return ( ( w[ 1 ] & 0xff ) << 8 | ( w[ 0 ] & 0xff ) );??????? }
/**???? * like DataInputStream.readChar except little endian.???? *???? * @return little endian 16-bit unicode char from the stream???? *???? * @throws IOException???? */??? public final char readChar() throws IOException??????? {??????? d.readFully( w, 0, 2 );??????? return (char) ( ( w[ 1 ] & 0xff ) << 8 | ( w[ 0 ] & 0xff ) );??????? }
/**???? * like DataInputStream.readInt except little endian.???? *???? * @return little-endian binary int from the datastream???? *???? * @throws IOException???? */??? public final int readInt() throws IOException??????? {??????? d.readFully( w, 0, 4 );??????? return ( w[ 3 ] ) << 24?????????????? | ( w[ 2 ] & 0xff ) << 16?????????????? | ( w[ 1 ] & 0xff ) << 8?????????????? | ( w[ 0 ] & 0xff );??????? }
/**???? * like DataInputStream.readLong except little endian.???? *???? * @return little-endian binary long from the datastream???? *???? * @throws IOException???? */??? public final long readLong() throws IOException??????? {??????? d.readFully( w, 0, 8 );??????? return (long) ( w[ 7 ] ) << 56?????????????? |?????????????? /* long cast needed or shift done modulo 32 */?????????????? (long) ( w[ 6 ] & 0xff ) << 48?????????????? | (long) ( w[ 5 ] & 0xff ) << 40?????????????? | (long) ( w[ 4 ] & 0xff ) << 32?????????????? | (long) ( w[ 3 ] & 0xff ) << 24?????????????? | (long) ( w[ 2 ] & 0xff ) << 16?????????????? | (long) ( w[ 1 ] & 0xff ) << 8?????????????? | (long) ( w[ 0 ] & 0xff );??????? }
/**???? * like DataInputStream.readFloat except little endian.???? *???? * @return little endian IEEE float from the datastream???? *???? * @throws IOException???? */??? public final float readFloat() throws IOException??????? {??????? return Float.intBitsToFloat( readInt() );??????? }
/**???? * like DataInputStream.readDouble except little endian.???? *???? * @return little endian IEEE double from the datastream???? *???? * @throws IOException???? */??? public final double readDouble() throws IOException??????? {??????? return Double.longBitsToDouble( readLong() );??????? }
/**???? * @return a rough approximation of the 8-bit stream as a 16-bit unicode???? *???????? string???? *???? * @throws IOException???? * @deprecated This method does not properly convert bytes to characters.???? *???????????? Use a Reader instead with a little-endian encoding.???? */??? public final String readLine() throws IOException??????? {??????? return d.readLine();??????? }
/**???? * @inheritDoc???? */??? public final String readUTF() throws IOException??????? {??????? return d.readUTF();??????? }
// -------------------------- OTHER METHODS --------------------------
/**???? * @throws IOException???? */??? public final void close() throws IOException??????? {??????? d.close();??????? }
// InputStream
// p u r e l y w r a p p e r m e t h o d s??? // We can't simply inherit since dataInputStream is final.
/**???? * Watch out, read may return fewer bytes than requested.???? *???? * @param b?? where the bytes go???? * @param off offset in buffer, not offset in file.???? * @param len count of bytes ot ade???? *???? * @return how many bytes read???? *???? * @throws IOException???? */??? public final int read( byte b[], int off, int len ) throws IOException??????? {??????? // For efficiency, we avoid one layer of wrapper??????? return in.read( b, off, len );??????? }}// end class LEDataInputStreamjava io的代碼/** @(#)LittleEndianOutputStream.java? 1.0.1 99/05/19*?* Copyright 1998, 1999 Elliotte Rusty Harold*??*/
package com.macfaq.io;
import java.io.*;
/*** A little endian output stream writes primitive Java numbers?* and characters to an output stream in a little endian format.?* The standard java.io.DataOutputStream class which this class* imitates uses big-endian integers.** @author? Elliotte Rusty Harold* @version 1.0.1, 19 May 1999* @see???? com.macfaq.io.LittleEndianInputStream* @see???? java.io.DataOutputStream*/public class LittleEndianOutputStream extends FilterOutputStream {
/**?? * The number of bytes written so far to the little endian output stream.??? */? protected int written;
/**?? * Creates a new little endian output stream and chains it to the???? * output stream specified by the out argument.??? *?? * @param?? out?? the underlying output stream.?? * @see???? java.io.FilterOutputStream#out?? */? public LittleEndianOutputStream(OutputStream out) {??? super(out);? }
/**?? * Writes the specified byte value to the underlying output stream.??? *?? * @param????? b?? the byte value to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public synchronized void write(int b) throws IOException {??? out.write(b);??? written++;? }
/**?? * Writes length bytes from the specified byte array??? * starting at offset to the underlying output stream.?? *?? * @param????? data???? the data.?? * @param????? offset?? the start offset in the data.?? * @param????? length?? the number of bytes to write.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public synchronized void write(byte[] data, int offset, int length)??? throws IOException {??? out.write(data, offset, length);??? written += length;? }
/**?? * Writes a boolean to the underlying output stream as??? * a single byte. If the argument is true, the byte value 1 is written.?? * If the argument is false, the byte value 0 in written.?? *?? * @param????? b?? the boolean value to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeBoolean(boolean b) throws IOException {??? if (b) this.write(1);??? else this.write(0);
}
/**?? * Writes out a byte to the underlying output stream?? *?? * @param????? b?? the byte value to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeByte(int b) throws IOException {??? out.write(b);??? written++;? }
/**?? * Writes a two byte short to the underlying output stream in?? * little endian order, low byte first.??? *?? * @param????? s?? the short to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeShort(int s) throws IOException {
out.write(s & 0xFF);??? out.write((s >>> 8) & 0xFF);??? written += 2;? }
/**?? * Writes a two byte char to the underlying output stream??? * in little endian order, low byte first.??? *?? * @param????? c?? the char value to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeChar(int c) throws IOException {
out.write(c & 0xFF);??? out.write((c >>> 8) & 0xFF);??? written += 2;? }
/**?? * Writes a four-byte int to the underlying output stream??? * in little endian order, low byte first, high byte last?? *?? * @param????? i?? the int to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeInt(int i) throws IOException {
out.write(i & 0xFF);??? out.write((i >>> 8) & 0xFF);??? out.write((i >>> 16) & 0xFF);??? out.write((i >>> 24) & 0xFF);??? written += 4;? }
/**?? * Writes an eight-byte long to the underlying output stream??? * in little endian order, low byte first, high byte last?? *?? * @param????? l?? the long to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeLong(long l) throws IOException {
out.write((int) l & 0xFF);??? out.write((int) (l >>> 8) & 0xFF);??? out.write((int) (l >>> 16) & 0xFF);??? out.write((int) (l >>> 24) & 0xFF);??? out.write((int) (l >>> 32) & 0xFF);??? out.write((int) (l >>> 40) & 0xFF);??? out.write((int) (l >>> 48) & 0xFF);??? out.write((int) (l >>> 56) & 0xFF);??? written += 8;
}
/**? * Writes a 4 byte Java float to the underlying output stream in? * little endian order.? *? * @param????? f?? the float value to be written.? * @exception? IOException? if an I/O error occurs.? */? public final void writeFloat(float f) throws IOException {??? this.writeInt(Float.floatToIntBits(f));? }
/**? * Writes an 8 byte Java double to the underlying output stream in? * little endian order.? *? * @param????? d?? the double value to be written.? * @exception? IOException? if an I/O error occurs.? */? public final void writeDouble(double d) throws IOException {??? this.writeLong(Double.doubleToLongBits(d));? }
/**?? * Writes a string to the underlying output stream as a sequence of??? * bytes. Each character is written to the data output stream as??? * if by the writeByte() method.??? *?? * @param????? s?? the String value to be written.?? * @exception? IOException? if the underlying stream throws an IOException.?? * @see??????? java.io.LittleEndianOutputStream#writeByte(int)?? * @see??????? java.io.LittleEndianOutputStream#out?? */? public void writeBytes(String s) throws IOException {
int length = s.length();??? for (int i = 0; i < length; i++) {????? out.write((byte) s.charAt(i));??? }??? written += length;??? }
/**?? * 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 the underlying stream throws an IOException.?? * @see??????? java.io.LittleEndianOutputStream#writeChar(int)?? * @see??????? java.io.LittleEndianOutputStream#out?? */? public void writeChars(String s) throws IOException {
int length = s.length();??? for (int i = 0; i < length; i++) {????? int c = s.charAt(i);????? out.write(c & 0xFF);????? out.write((c >>> 8) & 0xFF);??? }??? written += length * 2;? }
/**?? * Writes a string of no more than 65,535 characters??? * to the underlying output stream using UTF-8??? * encoding. This method first writes a two byte short??? * in big endian order as required by the??? * UTF-8 specification. This gives the number of bytes in the??? * UTF-8 encoded version of the string, not the number of characters?? * in the string. Next each character of the string is written?? * using the UTF-8 encoding for the character.?? *?? * @param????? s?? the string to be written.?? * @exception? UTFDataFormatException if the string is longer than??? *???????????? 65,535 characters.?? * @exception? IOException? if the underlying stream throws an IOException.?? */? public void writeUTF(String s) throws IOException {
int numchars = s.length();??? int numbytes = 0;
for (int i = 0 ; i < numchars ; i++) {????? int c = s.charAt(i);????? if ((c >= 0x0001) && (c <= 0x007F)) numbytes++;????? else if (c > 0x07FF) numbytes += 3;????? else numbytes += 2;??? }
if (numbytes > 65535) throw new UTFDataFormatException();
out.write((numbytes >>> 8) & 0xFF);??? out.write(numbytes & 0xFF);??? for (int i = 0 ; i < numchars ; i++) {????? int c = s.charAt(i);????? if ((c >= 0x0001) && (c <= 0x007F)) {??????? out.write(c);????? }????? else if (c > 0x07FF) {??????? out.write(0xE0 | ((c >> 12) & 0x0F));??????? out.write(0x80 | ((c >>? 6) & 0x3F));??????? out.write(0x80 | (c & 0x3F));??????? written += 2;????? }?????? else {??????? out.write(0xC0 | ((c >>? 6) & 0x1F));??????? out.write(0x80 | (c & 0x3F));??????? written += 1;????? }??? }??? written += numchars + 2;? }
/**?? * Returns the number of bytes written to this little endian output stream.?? * (This class is not thread-safe with respect to this method. It is??? * possible that this number is temporarily less than the actual??? * number of bytes written.)
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