Apache Commons Compress 1.26.0 · org.apache.commons.compress.archivers.zip.ZipUtil

Modifier and Type	Field and Description
private static final long	DOSTIME_BEFORE_1980 DOS time constant for representing timestamps before 1980.
private static final long	DOSTIME_BEFORE_1980_AS_JAVA_TIME Java time representation of the smallest date/time ZIP can handle
private static final long	UPPER_DOSTIME_BOUND Approximately 128 years, in milliseconds (ignoring leap years, etc.).

Access	Constructor and Description
public	ZipUtil()

Method Summary

Modifier and Type	Method and Description
public static long	Returns: the unsigned int as a long. adjustToLong(final int the value to treat as unsigned int. i) Assumes a negative integer really is a positive integer that has wrapped around and re-creates the original value.
pack-priv static long	Returns: long representation of the BigInteger. bigToLong(final BigInteger BigInteger to convert. big) Converts a BigInteger into a long, and blows up (NumberFormatException) if the BigInteger is too big.
pack-priv static boolean	canHandleEntryData(final ZipArchiveEntry entry) Tests if this library is able to read or write the given entry.
pack-priv static void	checkRequestedFeatures(final ZipArchiveEntry ze) Checks whether the entry requires features not (yet) supported by the library and throws an exception if it does.
pack-priv static byte[]	copy(final byte[] from) Creates a copy of the given array - or return null if the argument is null.
pack-priv static void	copy(final byte[] from, final byte[] to, final int offset)
private static Date	dosToJavaDate(final long dosTime)
public static long	Returns: converted time dosToJavaTime(final long time to convert dosTime) Converts DOS time to Java time (number of milliseconds since epoch).
public static Date	Returns: a Date instance corresponding to the given time. fromDosTime(final ZipLong contains the stored DOS time. zipDosTime) Converts a DOS date/time field to a Date object.
private static String	getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f, final byte[] orig) If the stored CRC matches the one of the given name, return the Unicode name of the given field.
public static boolean	Returns: true if the time can be safely represented as DOS time, false otherwise isDosTime(final long time in milliseconds since epoch time) Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time
private static LocalDateTime	javaEpochToLocalDateTime(final long time)
private static long	javaToDosTime(final long t)
pack-priv static BigInteger	Returns: BigInteger representation of the provided long. longToBig(long long to convert to BigInteger. l) Converts a long into a BigInteger.
public static byte[]	Returns: the reversed array (mutated in-place, but also returned for convenience). reverse(final byte[] to reverse (mutated in-place, but also returned for convenience). array) Reverses a byte[] array.
pack-priv static void	setNameAndCommentFromExtraFields(final ZipArchiveEntry ze, final byte[] originalNameBytes, final byte[] commentBytes) If the entry has Unicode*ExtraFields and the CRCs of the names/comments match those of the extra fields, transfer the known Unicode values from the extra field.
public static int	Returns: int representation of the provided byte signedByteToUnsignedInt(final byte byte to convert to int b) Converts a signed byte into an unsigned integer representation (e.g., -1 becomes 255).
private static boolean	Returns: true if the entry isn't encrypted at all supportsEncryptionOf(final ZipArchiveEntry entry) Tests if this library supports the encryption used by the given entry.
private static boolean	Returns: true if the compression method is supported supportsMethodOf(final ZipArchiveEntry entry) Tests if this library supports the compression method used by the given entry.
public static ZipLong	Returns: the date as a `ZipLong` toDosTime(final Date the `Date` to convert time) Converts a Date object to a DOS date/time field.
public static byte[]	Returns: the date as a byte array toDosTime(final long number of milliseconds since the epoch t) Converts a Date object to a DOS date/time field.
public static void	toDosTime(final long number of milliseconds since the epoch t, final byte[] the output buffer buf, final int The offset within the output buffer of the first byte to be written. must be non-negative and no larger than `buf.length-4` offset) Converts a Date object to a DOS date/time field.
public static byte	Returns: byte representation of the provided int unsignedIntToSignedByte(final int integer to convert to byte i) Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

DOSTIME_BEFORE_1980 back to summary

DOSTIME_BEFORE_1980	back to summary
private static final long DOSTIME_BEFORE_1980 DOS time constant for representing timestamps before 1980. Smallest date/time ZIP can handle. MS-DOS records file dates and times as packed 16-bit values. An MS-DOS date has the following format. Bits Contents 0-4: Day of the month (1-31). 5-8: Month (1 = January, 2 = February, and so on). 9-15: Year offset from 1980 (add 1980 to get the actual year). An MS-DOS time has the following format. Bits Contents 0-4: Second divided by 2. 5-10: Minute (0-59). 11-15: Hour (0-23 on a 24-hour clock). This constant expresses the minimum DOS date of January 1st 1980 at 00:00:00 or, bit-by-bit: Year: 0000000 Month: 0001 Day: 00001 Hour: 00000 Minute: 000000 Seconds: 00000 This was copied from `ZipEntry`. Since 1.23

private static final long DOSTIME_BEFORE_1980

DOS time constant for representing timestamps before 1980. Smallest date/time ZIP can handle.

MS-DOS records file dates and times as packed 16-bit values. An MS-DOS date has the following format.

Bits Contents

0-4: Day of the month (1-31).
5-8: Month (1 = January, 2 = February, and so on).
9-15: Year offset from 1980 (add 1980 to get the actual year).

An MS-DOS time has the following format.

Bits Contents

0-4: Second divided by 2.
5-10: Minute (0-59).
11-15: Hour (0-23 on a 24-hour clock).

This constant expresses the minimum DOS date of January 1st 1980 at 00:00:00 or, bit-by-bit:

Year: 0000000
Month: 0001
Day: 00001
Hour: 00000
Minute: 000000
Seconds: 00000

This was copied from ZipEntry.

Since: 1.23

DOSTIME_BEFORE_1980_AS_JAVA_TIME	back to summary
private static final long DOSTIME_BEFORE_1980_AS_JAVA_TIME Java time representation of the smallest date/time ZIP can handle

UPPER_DOSTIME_BOUND back to summary

UPPER_DOSTIME_BOUND	back to summary
private static final long UPPER_DOSTIME_BOUND Approximately 128 years, in milliseconds (ignoring leap years, etc.). This establish an approximate high-bound value for DOS times in milliseconds since epoch, used to enable an efficient but sufficient bounds check to avoid generating extended last modified time entries. Calculating the exact number is locale dependent, would require loading TimeZone data eagerly, and would make little practical sense. Since DOS times theoretically go to 2107 - with compatibility not guaranteed after 2099 - setting this to a time that is before but near 2099 should be sufficient. This was copied from `ZipEntry`. Since 1.23

private static final long UPPER_DOSTIME_BOUND

Approximately 128 years, in milliseconds (ignoring leap years, etc.).

This establish an approximate high-bound value for DOS times in milliseconds since epoch, used to enable an efficient but sufficient bounds check to avoid generating extended last modified time entries.

Calculating the exact number is locale dependent, would require loading TimeZone data eagerly, and would make little practical sense. Since DOS times theoretically go to 2107 - with compatibility not guaranteed after 2099 - setting this to a time that is before but near 2099 should be sufficient.

This was copied from ZipEntry.

Since: 1.23

Constructor Detail

ZipUtil	back to summary
public ZipUtil()

Method Detail

adjustToLong	back to summary
public static long adjustToLong(final int i) Assumes a negative integer really is a positive integer that has wrapped around and re-creates the original value. Parameters i:int the value to treat as unsigned int. Returns:long the unsigned int as a long.

adjustToLong

back to summary

public static long adjustToLong(final int i)

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

Parameters

i:int: the value to treat as unsigned int.

Returns:long

the unsigned int as a long.

bigToLong	back to summary
pack-priv static long bigToLong(final BigInteger big) Converts a BigInteger into a long, and blows up (NumberFormatException) if the BigInteger is too big. Parameters big:BigInteger BigInteger to convert. Returns:long long representation of the BigInteger.

bigToLong

back to summary

pack-priv static long bigToLong(final BigInteger big)

Converts a BigInteger into a long, and blows up (NumberFormatException) if the BigInteger is too big.

Parameters

big:BigInteger: BigInteger to convert.

Returns:long

long representation of the BigInteger.

canHandleEntryData	back to summary
pack-priv static boolean canHandleEntryData(final ZipArchiveEntry entry) Tests if this library is able to read or write the given entry.

checkRequestedFeatures	back to summary
pack-priv static void checkRequestedFeatures(final ZipArchiveEntry ze) throws UnsupportedZipFeatureException Checks whether the entry requires features not (yet) supported by the library and throws an exception if it does.

copy	back to summary
pack-priv static byte[] copy(final byte[] from) Creates a copy of the given array - or return null if the argument is null.

copy	back to summary
pack-priv static void copy(final byte[] from, final byte[] to, final int offset)

dosToJavaDate	back to summary
private static Date dosToJavaDate(final long dosTime)

dosToJavaTime	back to summary
public static long dosToJavaTime(final long dosTime) Converts DOS time to Java time (number of milliseconds since epoch). Parameters dosTime:long time to convert Returns:long converted time

dosToJavaTime

back to summary

public static long dosToJavaTime(final long dosTime)

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

Parameters

dosTime:long: time to convert

Returns:long

converted time

fromDosTime	back to summary
public static Date fromDosTime(final ZipLong zipDosTime) Converts a DOS date/time field to a Date object. Parameters zipDosTime:ZipLong contains the stored DOS time. Returns:Date a Date instance corresponding to the given time.

fromDosTime

back to summary

public static Date fromDosTime(final ZipLong zipDosTime)

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

Parameters

zipDosTime:ZipLong: contains the stored DOS time.

Returns:Date

a Date instance corresponding to the given time.

getUnicodeStringIfOriginalMatches	back to summary
private static String getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f, final byte[] orig) If the stored CRC matches the one of the given name, return the Unicode name of the given field. If the field is null or the CRCs don't match, return null instead.

getUnicodeStringIfOriginalMatches

back to summary

private static String getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f, final byte[] orig)

If the stored CRC matches the one of the given name, return the Unicode name of the given field.

If the field is null or the CRCs don't match, return null instead.

isDosTime	back to summary
public static boolean isDosTime(final long time) Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time Parameters time:long time in milliseconds since epoch Returns:boolean true if the time can be safely represented as DOS time, false otherwise Since 1.23

isDosTime

back to summary

public static boolean isDosTime(final long time)

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

Parameters

time:long: time in milliseconds since epoch

Returns:boolean

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

Since

1.23

javaEpochToLocalDateTime	back to summary
private static LocalDateTime javaEpochToLocalDateTime(final long time)

javaToDosTime	back to summary
private static long javaToDosTime(final long t)

longToBig	back to summary
pack-priv static BigInteger longToBig(long l) Converts a long into a BigInteger. Negative numbers between -1 and -2^31 are treated as unsigned 32 bit (e.g., positive) integers. Negative numbers below -2^31 cause an IllegalArgumentException to be thrown. Parameters l:long long to convert to BigInteger. Returns:BigInteger BigInteger representation of the provided long.

longToBig

back to summary

pack-priv static BigInteger longToBig(long l)

Converts a long into a BigInteger. Negative numbers between -1 and -2^31 are treated as unsigned 32 bit (e.g., positive) integers. Negative numbers below -2^31 cause an IllegalArgumentException to be thrown.

Parameters

l:long: long to convert to BigInteger.

Returns:BigInteger

BigInteger representation of the provided long.

reverse	back to summary
public static byte[] reverse(final byte[] array) Reverses a byte[] array. Reverses in-place (thus provided array is mutated), but also returns same for convenience. Parameters array:byte[] to reverse (mutated in-place, but also returned for convenience). Returns:byte[] the reversed array (mutated in-place, but also returned for convenience). Since 1.5

reverse

back to summary

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

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

Parameters

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

Returns:byte[]

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

Since

1.5

setNameAndCommentFromExtraFields	back to summary
pack-priv static void setNameAndCommentFromExtraFields(final ZipArchiveEntry ze, final byte[] originalNameBytes, final byte[] commentBytes) If the entry has Unicode*ExtraFields and the CRCs of the names/comments match those of the extra fields, transfer the known Unicode values from the extra field.

signedByteToUnsignedInt	back to summary
public static int signedByteToUnsignedInt(final byte b) Converts a signed byte into an unsigned integer representation (e.g., -1 becomes 255). Parameters b:byte byte to convert to int Returns:int int representation of the provided byte Since 1.5

signedByteToUnsignedInt

back to summary

public static int signedByteToUnsignedInt(final byte b)

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

Parameters

b:byte: byte to convert to int

Returns:int

int representation of the provided byte

Since

1.5

supportsEncryptionOf	back to summary
private static boolean supportsEncryptionOf(final ZipArchiveEntry entry) Tests if this library supports the encryption used by the given entry. Returns:boolean true if the entry isn't encrypted at all

supportsEncryptionOf

back to summary

private static boolean supportsEncryptionOf(final ZipArchiveEntry entry)

Tests if this library supports the encryption used by the given entry.

Returns:boolean: true if the entry isn't encrypted at all

supportsMethodOf	back to summary
private static boolean supportsMethodOf(final ZipArchiveEntry entry) Tests if this library supports the compression method used by the given entry. Returns:boolean true if the compression method is supported

supportsMethodOf

back to summary

private static boolean supportsMethodOf(final ZipArchiveEntry entry)

Tests if this library supports the compression method used by the given entry.

Returns:boolean: true if the compression method is supported

toDosTime back to summary

toDosTime	back to summary
public static ZipLong toDosTime(final Date time) Converts a Date object to a DOS date/time field. Parameters time:Date the `Date` to convert Returns:ZipLong the date as a `ZipLong`

public static ZipLong toDosTime(final Date time)

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

Parameters

time:Date: the Date to convert

Returns:ZipLong

the date as a ZipLong

toDosTime back to summary

toDosTime	back to summary
public static byte[] toDosTime(final long t) Converts a Date object to a DOS date/time field. Stolen from InfoZip's `fileio.c` Parameters t:long number of milliseconds since the epoch Returns:byte[] the date as a byte array

public static byte[] toDosTime(final long t)

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

Stolen from InfoZip's fileio.c

Parameters

t:long: number of milliseconds since the epoch

Returns:byte[]

the date as a byte array

toDosTime back to summary

toDosTime	back to summary
public static void toDosTime(final long t, final byte[] buf, final int offset) Converts a Date object to a DOS date/time field. Stolen from InfoZip's `fileio.c` Parameters t:long number of milliseconds since the epoch buf:byte[] the output buffer offset:int The offset within the output buffer of the first byte to be written. must be non-negative and no larger than `buf.length-4`

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

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

Stolen from InfoZip's fileio.c

Parameters

t:long: number of milliseconds since the epoch
buf:byte[]: the output buffer
offset:int: 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	back to summary
public static byte unsignedIntToSignedByte(final int i) Converts an unsigned integer to a signed byte (e.g., 255 becomes -1). Parameters i:int integer to convert to byte Returns:byte byte representation of the provided int Exceptions IllegalArgumentException: if the provided integer is not inside the range [0,255]. Since 1.5

unsignedIntToSignedByte

back to summary

public static byte unsignedIntToSignedByte(final int i)

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

Parameters

i:int: integer to convert to byte

Returns:byte

byte representation of the provided int

Exceptions

IllegalArgumentException:: if the provided integer is not inside the range [0,255].

Since

1.5

public abstract Class ZipUtil

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