Package com.pnfsoftware.jeb.util.encoding.zip.fsr

Class ZipFailSafeReader

java.lang.Object
com.pnfsoftware.jeb.util.encoding.zip.fsr.ZipFailSafeReader
All Implemented Interfaces:
AutoCloseable
public class ZipFailSafeReader extends Object implements AutoCloseable
PNF Software's Zip Fail Safe Reader (PZFSR). This parser attempts to handle corner-cases that fail Oracle's and Apache Commons parsers.

Limitations:

  • limited to 2Gb archives at most (and the size of an uncompressed entry may not exceed ENTRY_MAXSIZE bytes)
  • zip64 is not supported
  • uncommon flags are not supported
  • non-standard attributes are disregarded
  • the only compression scheme supported is DEFLATE

  • Field Details

    • STORED

      public static final int STORED
      Zip compression method identifier for stored entries.
      See Also:

    • DEFLATED

      public static final int DEFLATED
      Zip compression method identifier for deflated entries.
      See Also:

    • ENTRY_MAXSIZE

      public static final int ENTRY_MAXSIZE
      Maximum supported uncompressed size for a single entry.
      See Also:

  • Constructor Details

    • ZipFailSafeReader

      public ZipFailSafeReader(File file) throws IOException
      Construct with all optional settings set to false.
      Parameters:
      file - input file
      Throws:
      IOException - if the archive cannot be opened or parsed

    • ZipFailSafeReader

      public ZipFailSafeReader(SeekableByteChannel channel) throws IOException
      Construct with all optional settings set to false.
      Parameters:
      channel - input (closed when the client invokes close())
      Throws:
      IOException - if the archive cannot be parsed

    • ZipFailSafeReader

      public ZipFailSafeReader(File file, int treatUnsupportedCompressionAsMethod, boolean ignoreEncryption, boolean recoveryMode, boolean doNotParseEntries) throws IOException
      Construct a zip parser.
      Parameters:
      file - input file
      treatUnsupportedCompressionAsMethod - optional (use -1 to fail when an unsupported compression method is encountered); else, a compression method id
      ignoreEncryption - true to read encrypted entries as if they were not encrypted
      recoveryMode - optional; if true, the reader will attempt to recover zip entries of truncated files, including those with incomplete Central Directory
      doNotParseEntries - optional; if true, the zip entries will not be pre-emptively parsed, and it will be up to the user to trigger parsing through enumeration, via enumerateEntries() (this will result in faster opening of large archives)
      Throws:
      IOException - if the archive cannot be opened or parsed

    • ZipFailSafeReader

      public ZipFailSafeReader(SeekableByteChannel channel, int treatUnsupportedCompressionAsMethod, boolean ignoreEncryption, boolean recoveryMode, boolean doNotParseEntries) throws IOException
      Construct a zip parser.
      Parameters:
      channel - input (closed when the client invokes close())
      treatUnsupportedCompressionAsMethod - optional (use -1 to fail when an unsupported compression method is encountered); else, a compression method id
      ignoreEncryption - true to read encrypted entries as if they were not encrypted
      recoveryMode - optional; if true, the reader will attempt to recover zip entries of truncated files, including those with incomplete Central Directory
      doNotParseEntries - optional; if true, the zip entries will not be pre-emptively parsed, and it will be up to the user to trigger parsing through enumeration, via enumerateEntries() (this will result in faster opening of large archives)
      Throws:
      IOException - if the archive cannot be parsed

  • Method Details

    • enumerateEntries

      public Iterable<ZipEntry> enumerateEntries()
      Get the iterable to parse and enumerate over the zip entries. This method should be called once, and once only, if the object was constructed with doNotParseEntries=true. Any IOException raised will be wrapped in a RuntimeException.
      Returns:
      the iterable that will iterate and parse the zip entries

    • close

      public void close() throws IOException
      Specified by:
      close in interface AutoCloseable
      Throws:
      IOException

    • isClosed

      public boolean isClosed()

    • getOffsetFirstEntry

      public int getOffsetFirstEntry()

    • hasPrependedData

      public boolean hasPrependedData()

    • getOffsetAppendedData

      public int getOffsetAppendedData()

    • hasAppendedData

      public boolean hasAppendedData()

    • isTruncated

      public boolean isTruncated()

    • getNumberOfEntries

      public int getNumberOfEntries()

    • getEntries

      public List<ZipEntry> getEntries()
      Retrieve a read-only list of the current entries.

      This method may be called even if not all entries were enumerated (incomplete parsing). if so, it will return an incomplete list.

      Returns:
      read-only view of the parsed entries

    • getEntry

      public ZipEntry getEntry(String filename)
      Retrieve an entry by name.

      This method may be called even if not all entries were enumerated (incomplete parsing). It will fail if the entry has not been parsed yet.

      Parameters:
      filename - entry file name
      Returns:
      matching entry, or null

    • hasEntry

      public boolean hasEntry(String filename)
      Determine whether an entry exists.

      This method may be called even if not all entries were enumerated (incomplete parsing). It will fail if the entry has not been parsed yet.

      Parameters:
      filename - entry file name
      Returns:
      true if the entry has already been parsed

    • readData

      public ZipData readData(String filename) throws IOException
      Read an entry's data and provide the decompressed bytes.

      This method may be called even if not all entries were enumerated (incomplete parsing). It will fail if the entry has not been parsed yet.

      Parameters:
      filename - entry file name
      Returns:
      decompressed entry data and optional read exception
      Throws:
      IOException - if the entry does not exist or cannot be read

    • readData

      public ZipData readData(ZipEntry e) throws IOException
      Read an entry's data and provide the decompressed bytes.

      This method may be called even if not all entries were enumerated (incomplete parsing). It will fail if the entry has not been parsed yet.

      Parameters:
      e - entry descriptor
      Returns:
      decompressed entry data and optional read exception
      Throws:
      IOException - if the entry cannot be read

    • toString

      public String toString()
      Overrides:
      toString in class Object