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implemented variable length field

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Ziver Koc 2016-03-08 23:27:15 +01:00
parent 6e49a343f9
commit 227f294ae0
3 changed files with 62 additions and 40 deletions
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40
src/zutil/ByteUtil.java
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@ -43,36 +43,44 @@ public class ByteUtil {
};
/**
* Creates a new subbyte from offset and with a length and shifts the data to the left
* Creates a new sub byte from index and with a length and shifts the data to the left
*
* @param data is the byte data
* @param offset is the bit index, valid values 0-7
* @param index is the bit index, valid values 0-7
* @param length is the length of bits to return, valid values 1-8
* @return a new byte containing a subbyte defined by the offset and length
* @return a new byte containing a sub byte defined by the index and length
*/
public static byte getShiftedBits(byte data, int offset, int length){
int ret = 0xFF & getBits(data, offset, length);
ret = ret >>> offset+1-length;
public static byte getShiftedBits(byte data, int index, int length){
int ret = 0xFF & getBits(data, index, length);
ret = ret >>> index+1-length;
return (byte) ret;
}
/**
* Creates a new subbyte from offset and with a length
* Creates a new sub byte from index and with a length
*
* @param data is the byte data
* @param offset is the bit index, valid values 0-7
* @param index is the bit index, valid values 0-7
* @param length is the length of bits to return, valid values 1-8
* @return a new byte containing a subbyte defined by the offset and length
* @return a new byte containing a sub byte defined by the index and length
*/
public static byte getBits(byte data, int offset, int length){
public static byte getBits(byte data, int index, int length){
length--;
if(0 > offset || offset > 7)
throw new IllegalArgumentException("Invalid index argument, allowed value is 0-7");
if(length < 0 && offset-length < 0)
throw new IllegalArgumentException("Invalid length argument: "+length+", allowed values 1-8 depending on index");
byte ret = (byte) (data & BYTE_MASK[offset][length]);
byte ret = (byte) (data & getBitMask(index, length));
return ret;
}
/**
* Returns a byte bitmask
*
* @param index start index of the mask, valid values 0-7
* @param length length of mask from index, valid values 1-8
*/
public static byte getBitMask(int index, int length) {
if(0 > index || index > 7)
throw new IllegalArgumentException("Invalid index argument, allowed value is 0-7");
if(length < 0 && index-length < 0)
throw new IllegalArgumentException("Invalid length argument: "+length+", allowed values 1-8 depending on index");
return (byte) BYTE_MASK[index][length];
}
}