package nlp.nlp;

/**

* 小端数据，Byte转换

*

*/

public class ByteConvert {

public static void main(String[] args) {

ByteConvert c = new ByteConvert();

c.Int2Bytes_LE(126);

}

public static final int UNICODE_LEN = 2;

/**

* int转换为小端byte[](高位放在高地址中)

* @param iValue

* @return

*/

public byte[] Int2Bytes_LE(int iValue){

byte[] rst = new byte[4];

// 先写int的最后一个字节

rst[0] = (byte)(iValue & 0xFF);

// int 倒数第二个字节

rst[1] = (byte)((iValue & 0xFF00) >> 8 );

// int 倒数第三个字节

rst[2] = (byte)((iValue & 0xFF0000) >> 16 );

// int 第一个字节

rst[3] = (byte)((iValue & 0xFF000000) >> 24 );

return rst;

}

/**

* 转换String为byte[]

* @param str

* @return

*/

public byte[] String2Bytes_LE(String str) {

if(str == null){

return null;

}

char[] chars = str.toCharArray();

byte[] rst = Chars2Bytes_LE(chars);

return rst;

}

/**

* 转换字符数组为定长byte[]

* @param chars 字符数组

* @return 若指定的定长不足返回null, 否则返回byte数组

*/

public byte[] Chars2Bytes_LE(char[] chars){

if(chars == null)

return null;

int iCharCount = chars.length;

byte[] rst = new byte[iCharCount*UNICODE_LEN];

int i = 0;

for( i = 0; i < iCharCount; i++){

rst[i*2] = (byte)(chars[i] & 0xFF);

rst[i*2 + 1] = (byte)(( chars[i] & 0xFF00 ) >> 8);

}

return rst;

}

/**

* 转换byte数组为int(小端)

* @return

* @note 数组长度至少为4，按小端方式转换,即传入的bytes是小端的，按这个规律组织成int

*/

public int Bytes2Int_LE(byte[] bytes){

if(bytes.length < 4)

return -1;

int iRst = (bytes[0] & 0xFF);

iRst |= (bytes[1] & 0xFF) << 8;

iRst |= (bytes[2] & 0xFF) << 16;

iRst |= (bytes[3] & 0xFF)<< 24;

return iRst;

}

/**

* 转换byte数组为int(大端)

* @return

* @note 数组长度至少为4，按小端方式转换，即传入的bytes是大端的，按这个规律组织成int

*/

public int Bytes2Int_BE(byte[] bytes){

if(bytes.length < 4)

return -1;

int iRst = (bytes[0] << 24) & 0xFF;

iRst |= (bytes[1] << 16) & 0xFF;

iRst |= (bytes[2] << 8) & 0xFF;

iRst |= bytes[3] & 0xFF;

return iRst;

}

/**

* 转换byte数组为Char(小端)

* @return

* @note 数组长度至少为2，按小端方式转换

*/

public char Bytes2Char_LE(byte[] bytes){

if(bytes.length < 2)

return (char)-1;

int iRst = (bytes[0] & 0xFF);

iRst |= (bytes[1] & 0xFF) << 8;

return (char)iRst;

}

/**

* 转换byte数组为char(大端)

* @return

* @note 数组长度至少为2，按小端方式转换

*/

public char Bytes2Char_BE(byte[] bytes){

if(bytes.length < 2)

return (char)-1;

int iRst = (bytes[0] << 8) & 0xFF;

iRst |= bytes[1] & 0xFF;

return (char)iRst;

}

}