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some refactoring and bugfixes

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This commit is contained in:
Ziver Koc 2016-02-02 17:06:06 +01:00
parent 4d31e66ebd
commit 63f191db4c
4 changed files with 56 additions and 17 deletions
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41
src/zutil/ByteUtil.java
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@ -6,7 +6,7 @@ package zutil;
* Created by Ziver on 2016-01-30.
*/
public class ByteUtil {
/** Bitmask array used by utility functions **/
private static final int[][] BYTE_MASK = new int[][]{
{0b0000_0001},
{0b0000_0010, 0b0000_0011},
@ -18,16 +18,37 @@ public class ByteUtil {
{0b1000_0000, 0b1100_0000, 0b1110_0000, 0b1111_0000, 0b1111_1000, 0b1111_1100, 0b1111_1110, 0b1111_1111}
};
public static byte getBits(byte data, int index, int length){
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");
int ret = data & BYTE_MASK[index][length];
ret = ret >>> index-length;
/**
* Creates a new subbyte from offset 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 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
*/
public static byte getShiftedBits(byte data, int offset, int length){
int ret = 0xFF & getBits(data, offset, length);
ret = ret >>> offset+1-length;
return (byte) ret;
}
/**
* Creates a new subbyte from offset and with a length
*
* @param data is the byte data
* @param offset 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
*/
public static byte getBits(byte data, int offset, 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]);
return ret;
}
}

2
src/zutil/parser/binary/BinaryStructParser.java
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@ -57,7 +57,7 @@ public class BinaryStructParser {
int readLength = 0;
byte[] valueData = new byte[(int) Math.ceil(length / 8.0)];
for (int index = 0; index < valueData.length; ++index) {
valueData[index] = ByteUtil.getBits(data[byteIndex], bitIndex, bitLength);
valueData[index] = ByteUtil.getShiftedBits(data[byteIndex], bitIndex, bitLength);
readLength += bitLength;
byteIndex++;
bitIndex = 7;