File	Doc	Category	Size	Date	Package
ZipInputStream.java	API Doc	Java SE 6 API	11930	Tue Jun 10 00:26:02 BST 2008	java.util.zip

ZipInputStream

• java.lang.Object
  • java.io.InputStream
    • java.io.FilterInputStream
      • java.util.zip.InflaterInputStream

Fields Summary
private ZipEntry	entry
private int	flag
private CRC32	crc
private long	remaining
private byte[]	tmpbuf
private static final int	STORED
private static final int	DEFLATED
private boolean	closed
private boolean	entryEOF
private byte[]	b

Constructors Summary
public ZipInputStream(InputStream in) Creates a new ZIP input stream. param in the actual input stream super(new PushbackInputStream(in, 512), new Inflater(true), 512); usesDefaultInflater = true; if(in == null) { throw new NullPointerException("in is null"); }

Methods Summary
public int	available() Returns 0 after EOF has reached for the current entry data, otherwise always return 1. Programs should not count on this method to return the actual number of bytes that could be read without blocking. return 1 before EOF and 0 after EOF has reached for current entry. exception IOException if an I/O error occurs. ensureOpen(); if (entryEOF) { return 0; } else { return 1; }
public void	close() Closes this input stream and releases any system resources associated with the stream. exception IOException if an I/O error has occurred if (!closed) { super.close(); closed = true; }
public void	closeEntry() Closes the current ZIP entry and positions the stream for reading the next entry. exception ZipException if a ZIP file error has occurred exception IOException if an I/O error has occurred ensureOpen(); while (read(tmpbuf, 0, tmpbuf.length) != -1) ; entryEOF = true;
protected java.util.zip.ZipEntry	createZipEntry(java.lang.String name) Creates a new ZipEntry object for the specified entry name. param name the ZIP file entry name return the ZipEntry just created return new ZipEntry(name);
private void	ensureOpen() Check to make sure that this stream has not been closed if (closed) { throw new IOException("Stream closed"); }
private static final int	get16(byte[] b, int off) return (b[off] & 0xff) | ((b[off+1] & 0xff) << 8);
private static final long	get32(byte[] b, int off) return get16(b, off) | ((long)get16(b, off+2) << 16);
public java.util.zip.ZipEntry	getNextEntry() Reads the next ZIP file entry and positions the stream at the beginning of the entry data. return the next ZIP file entry, or null if there are no more entries exception ZipException if a ZIP file error has occurred exception IOException if an I/O error has occurred ensureOpen(); if (entry != null) { closeEntry(); } crc.reset(); inf.reset(); if ((entry = readLOC()) == null) { return null; } if (entry.method == STORED) { remaining = entry.size; } entryEOF = false; return entry;
private static java.lang.String	getUTF8String(byte[] b, int off, int len) // First, count the number of characters in the sequence int count = 0; int max = off + len; int i = off; while (i < max) { int c = b[i++] & 0xff; switch (c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // 0xxxxxxx count++; break; case 12: case 13: // 110xxxxx 10xxxxxx if ((int)(b[i++] & 0xc0) != 0x80) { throw new IllegalArgumentException(); } count++; break; case 14: // 1110xxxx 10xxxxxx 10xxxxxx if (((int)(b[i++] & 0xc0) != 0x80) || ((int)(b[i++] & 0xc0) != 0x80)) { throw new IllegalArgumentException(); } count++; break; default: // 10xxxxxx, 1111xxxx throw new IllegalArgumentException(); } } if (i != max) { throw new IllegalArgumentException(); } // Now decode the characters... char[] cs = new char[count]; i = 0; while (off < max) { int c = b[off++] & 0xff; switch (c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // 0xxxxxxx cs[i++] = (char)c; break; case 12: case 13: // 110xxxxx 10xxxxxx cs[i++] = (char)(((c & 0x1f) << 6) | (b[off++] & 0x3f)); break; case 14: // 1110xxxx 10xxxxxx 10xxxxxx int t = (b[off++] & 0x3f) << 6; cs[i++] = (char)(((c & 0x0f) << 12) | t | (b[off++] & 0x3f)); break; default: // 10xxxxxx, 1111xxxx throw new IllegalArgumentException(); } } return new String(cs, 0, count);
public int	read(byte[] b, int off, int len) Reads from the current ZIP entry into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned. param b the buffer into which the data is read param off the start offset in the destination array b param len the maximum number of bytes read return the actual number of bytes read, or -1 if the end of the entry is reached exception NullPointerException If b is null. exception IndexOutOfBoundsException If off is negative, len is negative, or len is greater than b.length - off exception ZipException if a ZIP file error has occurred exception IOException if an I/O error has occurred ensureOpen(); if (off < 0 || len < 0 || off > b.length - len) { throw new IndexOutOfBoundsException(); } else if (len == 0) { return 0; } if (entry == null) { return -1; } switch (entry.method) { case DEFLATED: len = super.read(b, off, len); if (len == -1) { readEnd(entry); entryEOF = true; entry = null; } else { crc.update(b, off, len); } return len; case STORED: if (remaining <= 0) { entryEOF = true; entry = null; return -1; } if (len > remaining) { len = (int)remaining; } len = in.read(b, off, len); if (len == -1) { throw new ZipException("unexpected EOF"); } crc.update(b, off, len); remaining -= len; if (remaining == 0 && entry.crc != crc.getValue()) { throw new ZipException( "invalid entry CRC (expected 0x" + Long.toHexString(entry.crc) + " but got 0x" + Long.toHexString(crc.getValue()) + ")"); } return len; default: throw new ZipException("invalid compression method"); }
private void	readEnd(java.util.zip.ZipEntry e) int n = inf.getRemaining(); if (n > 0) { ((PushbackInputStream)in).unread(buf, len - n, n); } if ((flag & 8) == 8) { /* "Data Descriptor" present */ readFully(tmpbuf, 0, EXTHDR); long sig = get32(tmpbuf, 0); if (sig != EXTSIG) { // no EXTSIG present e.crc = sig; e.csize = get32(tmpbuf, EXTSIZ - EXTCRC); e.size = get32(tmpbuf, EXTLEN - EXTCRC); ((PushbackInputStream)in).unread( tmpbuf, EXTHDR - EXTCRC - 1, EXTCRC); } else { e.crc = get32(tmpbuf, EXTCRC); e.csize = get32(tmpbuf, EXTSIZ); e.size = get32(tmpbuf, EXTLEN); } } if (e.size != inf.getBytesWritten()) { throw new ZipException( "invalid entry size (expected " + e.size + " but got " + inf.getBytesWritten() + " bytes)"); } if (e.csize != inf.getBytesRead()) { throw new ZipException( "invalid entry compressed size (expected " + e.csize + " but got " + inf.getBytesRead() + " bytes)"); } if (e.crc != crc.getValue()) { throw new ZipException( "invalid entry CRC (expected 0x" + Long.toHexString(e.crc) + " but got 0x" + Long.toHexString(crc.getValue()) + ")"); }
private void	readFully(byte[] b, int off, int len) while (len > 0) { int n = in.read(b, off, len); if (n == -1) { throw new EOFException(); } off += n; len -= n; }
private java.util.zip.ZipEntry	readLOC() /* * Reads local file (LOC) header for next entry. */ try { readFully(tmpbuf, 0, LOCHDR); } catch (EOFException e) { return null; } if (get32(tmpbuf, 0) != LOCSIG) { return null; } // get the entry name and create the ZipEntry first int len = get16(tmpbuf, LOCNAM); int blen = b.length; if (len > blen) { do blen = blen * 2; while (len > blen); b = new byte[blen]; } readFully(b, 0, len); ZipEntry e = createZipEntry(getUTF8String(b, 0, len)); // now get the remaining fields for the entry flag = get16(tmpbuf, LOCFLG); if ((flag & 1) == 1) { throw new ZipException("encrypted ZIP entry not supported"); } e.method = get16(tmpbuf, LOCHOW); e.time = get32(tmpbuf, LOCTIM); if ((flag & 8) == 8) { /* "Data Descriptor" present */ if (e.method != DEFLATED) { throw new ZipException( "only DEFLATED entries can have EXT descriptor"); } } else { e.crc = get32(tmpbuf, LOCCRC); e.csize = get32(tmpbuf, LOCSIZ); e.size = get32(tmpbuf, LOCLEN); } len = get16(tmpbuf, LOCEXT); if (len > 0) { byte[] bb = new byte[len]; readFully(bb, 0, len); e.setExtra(bb); } return e;
public long	skip(long n) Skips specified number of bytes in the current ZIP entry. param n the number of bytes to skip return the actual number of bytes skipped exception ZipException if a ZIP file error has occurred exception IOException if an I/O error has occurred exception IllegalArgumentException if n < 0 if (n < 0) { throw new IllegalArgumentException("negative skip length"); } ensureOpen(); int max = (int)Math.min(n, Integer.MAX_VALUE); int total = 0; while (total < max) { int len = max - total; if (len > tmpbuf.length) { len = tmpbuf.length; } len = read(tmpbuf, 0, len); if (len == -1) { entryEOF = true; break; } total += len; } return total;