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

Class GeneralPurposeBit

  • All Implemented Interfaces:
    java.lang.Cloneable
    public final class GeneralPurposeBit
extends java.lang.Object
implements java.lang.Cloneable
    Parser/encoder for the "general purpose bit" field in ZIP's local file and central directory headers.
    Since:
    1.1

    • Field Detail

      • ENCRYPTION_FLAG

        private static final int ENCRYPTION_FLAG
        Indicates that the file is encrypted.
        See Also:
        Constant Field Values

      • SLIDING_DICTIONARY_SIZE_FLAG

        private static final int SLIDING_DICTIONARY_SIZE_FLAG
        Indicates the size of the sliding dictionary used by the compression method 6 (imploding).
        • 0: 4096 bytes
        • 1: 8192 bytes
        See Also:
        Constant Field Values

      • NUMBER_OF_SHANNON_FANO_TREES_FLAG

        private static final int NUMBER_OF_SHANNON_FANO_TREES_FLAG
        Indicates the number of Shannon-Fano trees used by the compression method 6 (imploding).
        • 0: 2 trees (lengths, distances)
        • 1: 3 trees (literals, lengths, distances)
        See Also:
        Constant Field Values

      • DATA_DESCRIPTOR_FLAG

        private static final int DATA_DESCRIPTOR_FLAG
        Indicates that a data descriptor stored after the file contents will hold CRC and size information.
        See Also:
        Constant Field Values

      • STRONG_ENCRYPTION_FLAG

        private static final int STRONG_ENCRYPTION_FLAG
        Indicates strong encryption.
        See Also:
        Constant Field Values

      • UFT8_NAMES_FLAG

        public static final int UFT8_NAMES_FLAG
        Indicates that file names are written in UTF-8.

        The only reason this is public is that ZipArchiveOutputStream.EFS_FLAG was public in Apache Commons Compress 1.0 and we needed a substitute for it.

        See Also:
        Constant Field Values

      • languageEncodingFlag

        private boolean languageEncodingFlag

      • dataDescriptorFlag

        private boolean dataDescriptorFlag

      • encryptionFlag

        private boolean encryptionFlag

      • strongEncryptionFlag

        private boolean strongEncryptionFlag

      • slidingDictionarySize

        private int slidingDictionarySize

      • numberOfShannonFanoTrees

        private int numberOfShannonFanoTrees

    • Constructor Detail

      • GeneralPurposeBit

        public GeneralPurposeBit()

    • Method Detail

      • usesUTF8ForNames

        public boolean usesUTF8ForNames()
        whether the current entry uses UTF8 for file name and comment.
        Returns:
        whether the current entry uses UTF8 for file name and comment.

      • useUTF8ForNames

        public void useUTF8ForNames​(boolean b)
        whether the current entry will use UTF8 for file name and comment.
        Parameters:
        b - whether the current entry will use UTF8 for file name and comment.

      • usesDataDescriptor

        public boolean usesDataDescriptor()
        whether the current entry uses the data descriptor to store CRC and size information.
        Returns:
        whether the current entry uses the data descriptor to store CRC and size information

      • useDataDescriptor

        public void useDataDescriptor​(boolean b)
        whether the current entry will use the data descriptor to store CRC and size information.
        Parameters:
        b - whether the current entry will use the data descriptor to store CRC and size information

      • usesEncryption

        public boolean usesEncryption()
        whether the current entry is encrypted.
        Returns:
        whether the current entry is encrypted

      • useEncryption

        public void useEncryption​(boolean b)
        whether the current entry will be encrypted.
        Parameters:
        b - whether the current entry will be encrypted

      • usesStrongEncryption

        public boolean usesStrongEncryption()
        whether the current entry is encrypted using strong encryption.
        Returns:
        whether the current entry is encrypted using strong encryption

      • useStrongEncryption

        public void useStrongEncryption​(boolean b)
        whether the current entry will be encrypted using strong encryption.
        Parameters:
        b - whether the current entry will be encrypted using strong encryption

      • getSlidingDictionarySize

        int getSlidingDictionarySize()
        Returns the sliding dictionary size used by the compression method 6 (imploding).

      • getNumberOfShannonFanoTrees

        int getNumberOfShannonFanoTrees()
        Returns the number of trees used by the compression method 6 (imploding).

      • encode

        public byte[] encode()
        Encodes the set bits in a form suitable for ZIP archives.
        Returns:
        the encoded general purpose bits

      • encode

        public void encode​(byte[] buf,
                   int offset)
        Encodes the set bits in a form suitable for ZIP archives.
        Parameters:
        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-2

      • parse

        public static GeneralPurposeBit parse​(byte[] data,
                                      int offset)
        Parses the supported flags from the given archive data.
        Parameters:
        data - local file header or a central directory entry.
        offset - offset at which the general purpose bit starts
        Returns:
        parsed flags

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • clone

        public java.lang.Object clone()
        Overrides:
        clone in class java.lang.Object