Package org.apache.commons.compress.archivers.zip

Class ZipUtil

  • public abstract class ZipUtil
extends java.lang.Object
    Utility class for handling DOS and Java time conversions.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static byte[] DOS_TIME_MIN
      Smallest date/time ZIP can handle.

    • Constructor Summary

      Constructors 
      Constructor Description
      ZipUtil()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method 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.
      (package private) static long bigToLong​(java.math.BigInteger big)
      Converts a BigInteger into a long, and blows up (NumberFormatException) if the BigInteger is too big.
      (package private) static boolean canHandleEntryData​(ZipArchiveEntry entry)
      Whether this library is able to read or write the given entry.
      (package private) static void checkRequestedFeatures​(ZipArchiveEntry ze)
      Checks whether the entry requires features not (yet) supported by the library and throws an exception if it does.
      (package private) static byte[] copy​(byte[] from)
      Create a copy of the given array - or return null if the argument is null.
      (package private) static void copy​(byte[] from, byte[] to, int offset)  
      static long dosToJavaTime​(long dosTime)
      Converts DOS time to Java time (number of milliseconds since epoch).
      static java.util.Date fromDosTime​(ZipLong zipDosTime)
      Convert a DOS date/time field to a Date object.
      private static java.lang.String getUnicodeStringIfOriginalMatches​(AbstractUnicodeExtraField f, byte[] orig)
      If the stored CRC matches the one of the given name, return the Unicode name of the given field.
      (package private) static java.math.BigInteger longToBig​(long l)
      Converts a long into a BigInteger.
      static byte[] reverse​(byte[] array)
      Reverses a byte[] array.
      (package private) static void setNameAndCommentFromExtraFields​(ZipArchiveEntry ze, byte[] originalNameBytes, 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.
      static int signedByteToUnsignedInt​(byte b)
      Converts a signed byte into an unsigned integer representation (e.g., -1 becomes 255).
      private static boolean supportsEncryptionOf​(ZipArchiveEntry entry)
      Whether this library supports the encryption used by the given entry.
      private static boolean supportsMethodOf​(ZipArchiveEntry entry)
      Whether this library supports the compression method used by the given entry.
      static byte[] toDosTime​(long t)
      Convert a Date object to a DOS date/time field.
      static void toDosTime​(long t, byte[] buf, int offset)
      Convert a Date object to a DOS date/time field.
      (package private) static void toDosTime​(java.util.Calendar c, long t, byte[] buf, int offset)  
      static ZipLong toDosTime​(java.util.Date time)
      Convert 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

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

    • Field Detail

      • DOS_TIME_MIN

        private static final byte[] DOS_TIME_MIN
        Smallest date/time ZIP can handle.

    • Constructor Detail

      • ZipUtil

        public ZipUtil()

    • Method Detail

      • toDosTime

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

      • toDosTime

        static void toDosTime​(java.util.Calendar c,
                      long t,
                      byte[] buf,
                      int offset)

      • 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.

      • 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

      • bigToLong

        static long bigToLong​(java.math.BigInteger big)
        Converts a BigInteger into a long, and blows up (NumberFormatException) if the BigInteger is too big.
        Parameters:
        big - BigInteger to convert.
        Returns:
        long representation of the BigInteger.

      • longToBig

        static java.math.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 to convert to BigInteger.
        Returns:
        BigInteger representation of the provided long.

      • 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

      • 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

      • fromDosTime

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

      • 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

      • setNameAndCommentFromExtraFields

        static void setNameAndCommentFromExtraFields​(ZipArchiveEntry ze,
                                             byte[] originalNameBytes,
                                             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.

      • getUnicodeStringIfOriginalMatches

        private static java.lang.String getUnicodeStringIfOriginalMatches​(AbstractUnicodeExtraField f,
                                                                  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.

      • copy

        static byte[] copy​(byte[] from)
        Create a copy of the given array - or return null if the argument is null.

      • copy

        static void copy​(byte[] from,
                 byte[] to,
                 int offset)

      • canHandleEntryData

        static boolean canHandleEntryData​(ZipArchiveEntry entry)
        Whether this library is able to read or write the given entry.

      • supportsEncryptionOf

        private static boolean supportsEncryptionOf​(ZipArchiveEntry entry)
        Whether this library supports the encryption used by the given entry.
        Returns:
        true if the entry isn't encrypted at all

      • supportsMethodOf

        private static boolean supportsMethodOf​(ZipArchiveEntry entry)
        Whether this library supports the compression method used by the given entry.
        Returns:
        true if the compression method is supported