helliker.id3
Class BinaryParser

java.lang.Object
  |
  +--helliker.id3.BinaryParser

public final class BinaryParser

extends java.lang.Object

Constructor Summary

BinaryParser()

Method Summary

static boolean	bitSet(byte b, int pos) Tests to see if the bit at postion pos is set in byte b
static byte[]	convertToBytes(int num) Convert the integer passed to a array of 4 bytes (32-bits).
static int	convertToDecimal(byte b, int start, int end) Convert a portion of a byte to an integer.
static int	convertToInt(byte[] b) Convert an array of bytes into an integer.
static boolean	matchPattern(byte b, java.lang.String pattern) This function takes an 8 character string representation of a byte in binary mode.
static byte	setBit(byte b, int location) Sets the bit at the specified location in the byte given.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BinaryParser

public BinaryParser()

Method Detail

bitSet

public static boolean bitSet(byte b,
                             int pos)

Tests to see if the bit at postion pos is set in byte b

Parameters:

b - the byte to test

pos - a value between 0 (least significant bit) and 7 (most significant bit) indicating the position to test

Returns:

true if the bit at the location is set

matchPattern

public static boolean matchPattern(byte b,
                                   java.lang.String pattern)

This function takes an 8 character string representation of a byte in binary mode. It will match 0's and 1's at the locations specified and skip other characters (x is the standard wildcard). If the values of the bits at the locations where a 0 is set is 0 and values of the bits at the locations where 1 is set is 1, then the function will return true.

Parameters:

b - the byte to test

pattern - the 8 character long pattern to test the byte

Returns:

true if the bits at the locations specified are set

convertToDecimal

public static int convertToDecimal(byte b,
                                   int start,
                                   int end)

Convert a portion of a byte to an integer. This assumes that the length of the byte is end - start bits long with end being the most significant bit. The start and end values must be between 0 and 7. If the start and end values are incorrect, it will set start to 0 and end to 7.

Parameters:

b - the byte to convert from

start - the starting bit

end - the ending bit

Returns:

the converted value (unsigned)

convertToInt

public static int convertToInt(byte[] b)

Convert an array of bytes into an integer. The array must not contain more than 4 bytes (32 bits). This assumes that the most significant byte is in the first index of the array. If an array is not 4 bytes long, then it will assume that the bytes are preceded by leading 0's.

Parameters:

b - the array of bytes

Returns:

the converted integer in decimal

convertToBytes

public static byte[] convertToBytes(int num)

Convert the integer passed to a array of 4 bytes (32-bits). Does the opposite of the convertToInt method.

Parameters:

num - the integer to convert

Returns:

the integer converted to a byte array

setBit

public static byte setBit(byte b,
                          int location)

Sets the bit at the specified location in the byte given. Location should be between 0 and 7. If an invalid location is specified, 0 will be returned.

Parameters:

b - the byte to set the index in

location - the index to set in b

Returns:

b with the bit at location set to 1