Checkers游戏源码 |
| 作者：J2MEDEV 来源：J2MEDEV 发布时间：2006-7-25 9:04:09 |
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me, // then close up and delete everything. try { if(dos != null) { dos.write(END_GAME_FLAG); dos.close(); } if(dis != null) { dis.close(); } if(conn != null) { conn.close(); } dis = null; dos = null; conn = null; } catch(Exception e) { // if this throws, at least we made our best effort // to close everything up.... } } // one last paint job to display the "Game Over" myCanvas.repaint(); myCanvas.serviceRepaints(); } } /** * This class is a set of simple utility functions that * can be used to convert standard data types to bytes * and back again. It is used especially for data storage, * but also for sending and receiving data. * * @author Carol Hamer */ class DataConverter { //-------------------------------------------------------- // utilities to encode small, compactly-stored small ints. /** * Encodes a coordinate pair into a byte. * @param coordPair a pair of integers to be compacted into * a single byte for storage. * WARNING: each of the two values MUST BE * between 0 and 15 (inclusive). This method does not * verify the length of the array (which must be 2!) * nor does it verify that the ints are of the right size. */ public static byte encodeCoords(int[] coordPair) { // get the byte value of the first coordinate: byte retVal = (new Integer(coordPair[0])).byteValue(); // move the first coordinate's value up to the top // half of the storage byte: retVal = (new Integer(retVal << 4)).byteValue(); // store the second coordinate in the lower half // of the byte: retVal += (new Integer(coordPair[1])).byteValue(); return(retVal); } /** * Encodes eight ints into a byte. * This could be easily modified to encode eight booleans. * @param eight an array of at least eight ints. * WARNING: all values must be 0 or 1! This method does * not verify that the values are in the correct range * nor does it verify that the array is long enough. * @param offset the index in the array eight to start * reading data from. (should usually be 0) */ public static byte encode8(int[] eight, int offset) { // get the byte value of the first int: byte retVal = (new Integer(eight[offset])).byteValue(); // progressively move the data up one bit in the // storage byte and then record the next int in // the lowest spot in the storage byte: for(int i = offset + 1; i < 8 + offset; i++) { retVal = (new Integer(retVal << 1)).byteValue(); retVal += (new Integer(eight[i])).byteValue(); } return(retVal); } //-------------------------------------------------------- // utilities to decode small, compactly-stored small ints. /** * Turns a byte into a pair of coordinates. */ public static int[] decodeCoords(byte coordByte) { int[] retArray = new int[2]; // we perform a bitwise and with the value 15 // in order to just get the bits of the lower // half of the byte: retArray[1] = coordByte & 15; // To get the bits of the upper half of the // byte, we perform a shift to move them down: retArray[0] = coordByte >> 4; // bytes in Java are generally assumed to be // signed, but in this coding algorithm we // would like to treat them as unsigned: if(retArray[0] < 0) { retArray[0] += 16; } return(retArray); } /** * Turns a byte into eight ints. */ public static int[] decode8(byte data) { int[] retArray = new int[8]; // The flag allows us to look at each bit individually // to determine if it is 1 or 0. The number 128 // corresponds to the highest bit of a byte, so we // start with that one. int flag = 128; // We use a loop that checks // the data bit by bit by performing a bitwise // and (&) between the data byte and a flag: for(int i = 0; i < 8; i++) { if((flag & data) != 0) { retArray[i] = 1; } else { retArray[i] = 0; } // move the flag down one bit so that we can // check the next bit of data on the next pass // through the loop: flag = flag >> 1; } return(retArray); } //-------------------------------------------------------- // standard integer interpretation /** * Uses an input stream to convert an array of bytes to an int. */ public static int parseInt(byte[] data) throws IOException { DataInputStream stream = new DataInputStream(new ByteArrayInputStream(data)); int retVal = stream.readInt(); stream.close(); return(retVal); } /** * Uses an output stream to convert an int to four bytes. */ public static byte[] intToFourBytes(int i) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(4); DataOutputStream dos = new DataOutputStream(baos); dos.writeInt(i); baos.close(); dos.close(); byte[] retArray = baos.toByteArray(); return(retArray); } //-------------------------------------------------------- // integer interpretation illustrated /** * Java appears to treat a byte as being signed when * returning it as an int--this function converts from * the signed value to the corresponding unsigned value. * This method is used by nostreamParseInt. */ public static int unsign(int signed) { int retVal = signed; if(retVal < 0) { retVal += 256; } return(retVal); } /** * Takes an array of bytes and returns an int. * This version will return the same value as the * method parseInt above. This version is included * in order to illustrate how Java encodes int values * in terms of bytes. * @param data an array of 1, 2, or 4 bytes. */ public static int nostreamParseInt(byte[] data) { // byte 0 is the high byte which is assumed // to be signed. As we add the lower bytes // one by one, we unsign them because because // a single byte alone is interpreted as signed, // but in an int only the top byte should be signed. // (note that the high byte is the first one in the array) int retVal = data[0]; for(int i = 1; i < data.length; i++) { retVal = retVal << 8; retVal += unsign(data[i]); } return(retVal); } /** * Takes an arbitrary int and returns * an array of four bytes. * This version will return the same byte array * as the method intToFourByt |
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