org.apache.commons.compress.archivers.zip

Class ZipUtil

java.lang.Object

org.apache.commons.compress.archivers.zip.ZipUtil

public abstract class ZipUtil
extends java.lang.Object

Utility class for handling DOS and Java time conversions.

Constructor Summary

Constructors

Constructor and Description
ZipUtil()

Method Summary

Modifier and Type	Method and Description
static long	adjustToLong(int i) Assumes a negative integer really is a positive integer that has wrapped around and re-creates the original value.
static long	dosToJavaTime(long dosTime) Converts DOS time to Java time (number of milliseconds since epoch).
static java.util.Date	fromDosTime(ZipLong zipDosTime) Converts a DOS date/time field to a Date object.
static boolean	isDosTime(long time) Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time
static byte[]	reverse(byte[] array) Reverses a byte[] array.
static int	signedByteToUnsignedInt(byte b) Converts a signed byte into an unsigned integer representation (e.g., -1 becomes 255).
static ZipLong	toDosTime(java.util.Date time) Converts a Date object to a DOS date/time field.
static byte[]	toDosTime(long t) Converts a Date object to a DOS date/time field.
static void	toDosTime(long t, byte[] buf, int offset) Converts a Date object to a DOS date/time field.
static byte	unsignedIntToSignedByte(int i) Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).

Methods inherited from class java.lang.Object

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

Constructor Detail

ZipUtil

public ZipUtil()

Method Detail

adjustToLong

public static long adjustToLong(int i)

Assumes a negative integer really is a positive integer that has wrapped around and re-creates the original value.

Parameters:

i - the value to treat as unsigned int.

Returns:

the unsigned int as a long.

dosToJavaTime

public static long dosToJavaTime(long dosTime)

Converts DOS time to Java time (number of milliseconds since epoch).

Parameters:

dosTime - time to convert

Returns:

converted time

fromDosTime

public static java.util.Date fromDosTime(ZipLong zipDosTime)

Converts a DOS date/time field to a Date object.

Parameters:

zipDosTime - contains the stored DOS time.

Returns:

a Date instance corresponding to the given time.

isDosTime

public static boolean isDosTime(long time)

Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time

Parameters:

time - time in milliseconds since epoch

Returns:

true if the time can be safely represented as DOS time, false otherwise

Since:

1.23

reverse

public static byte[] reverse(byte[] array)

Reverses a byte[] array. Reverses in-place (thus provided array is mutated), but also returns same for convenience.

Parameters:

array - to reverse (mutated in-place, but also returned for convenience).

Returns:

the reversed array (mutated in-place, but also returned for convenience).

Since:

1.5

signedByteToUnsignedInt

public static int signedByteToUnsignedInt(byte b)

Converts a signed byte into an unsigned integer representation (e.g., -1 becomes 255).

Parameters:

b - byte to convert to int

Returns:

int representation of the provided byte

Since:

1.5

toDosTime

public static ZipLong toDosTime(java.util.Date time)

Converts a Date object to a DOS date/time field.

Parameters:

time - the Date to convert

Returns:

the date as a ZipLong

toDosTime

public static byte[] toDosTime(long t)

Converts a Date object to a DOS date/time field.

Stolen from InfoZip's fileio.c

Parameters:

t - number of milliseconds since the epoch

Returns:

the date as a byte array

toDosTime

public static void toDosTime(long t,
                             byte[] buf,
                             int offset)

Converts a Date object to a DOS date/time field.

Stolen from InfoZip's fileio.c

Parameters:

t - number of milliseconds since the epoch

buf - the output buffer

offset - The offset within the output buffer of the first byte to be written. must be non-negative and no larger than buf.length-4

unsignedIntToSignedByte

public static byte unsignedIntToSignedByte(int i)

Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).

Parameters:

i - integer to convert to byte

Returns:

byte representation of the provided int

Throws:

java.lang.IllegalArgumentException - if the provided integer is not inside the range [0,255].

Since:

1.5