/* * @(#)ZipInputStream.java 1.37 04/06/11 * * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package java.util.zip; import java.io.InputStream; import java.io.IOException; import java.io.EOFException; import java.io.PushbackInputStream; /** * This class implements an input stream filter for reading files in the * ZIP file format. Includes support for both compressed and uncompressed * entries. * * @author David Connelly * @version 1.37, 06/11/04 */ public class ZipInputStream extends InflaterInputStream implements ZipConstants { private ZipEntry entry; private CRC32 crc = new CRC32(); private long remaining; private byte[] tmpbuf = new byte[512]; private static final int STORED = ZipEntry.STORED; private static final int DEFLATED = ZipEntry.DEFLATED; private boolean closed = false; // this flag is set to true after EOF has reached for // one entry private boolean entryEOF = false; /** * Check to make sure that this stream has not been closed */ private void ensureOpen() throws IOException { if (closed) { throw new IOException("Stream closed"); } } /** * Creates a new ZIP input stream. * @param in the actual input stream */ public ZipInputStream(InputStream in) { super(new PushbackInputStream(in, 512), new Inflater(true), 512); usesDefaultInflater = true; if(in == null) { throw new NullPointerException("in is null"); } } /** * 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 */ public ZipEntry getNextEntry() throws IOException { 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; } /** * 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 */ public void closeEntry() throws IOException { ensureOpen(); while (read(tmpbuf, 0, tmpbuf.length) != -1) ; entryEOF = true; } /** * 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.
*
*/
public int available() throws IOException {
ensureOpen();
if (entryEOF) {
return 0;
} else {
return 1;
}
}
/**
* Reads from the current ZIP entry into an array of bytes. Blocks until
* some input is available.
* @param b the buffer into which the data is read
* @param off the start offset of the data
* @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 ZipException if a ZIP file error has occurred
* @exception IOException if an I/O error has occurred
*/
public int read(byte[] b, int off, int len) throws IOException {
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;
return len;
default:
throw new InternalError("invalid compression method");
}
}
/**
* 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
*/
public long skip(long n) throws IOException {
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;
}
/**
* Closes this input stream and releases any system resources associated
* with the stream.
* @exception IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
super.close();
closed = true;
}
}
private byte[] b = new byte[256];
/*
* Reads local file (LOC) header for next entry.
*/
private ZipEntry readLOC() throws IOException {
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);
if (len == 0) {
throw new ZipException("missing entry name");
}
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
e.version = get16(tmpbuf, LOCVER);
e.flag = get16(tmpbuf, LOCFLG);
if ((e.flag & 1) == 1) {
throw new ZipException("encrypted ZIP entry not supported");
}
e.method = get16(tmpbuf, LOCHOW);
e.time = get32(tmpbuf, LOCTIM);
if ((e.flag & 8) == 8) {
/* EXT 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.extra = bb;
}
return e;
}
/*
* Fetches a UTF8-encoded String from the specified byte array.
*/
private static 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);
}
/**
* Creates a new ZipEntry
object for the specified
* entry name.
*
* @param name the ZIP file entry name
* @return the ZipEntry just created
*/
protected ZipEntry createZipEntry(String name) {
return new ZipEntry(name);
}
/*
* Reads end of deflated entry as well as EXT descriptor if present.
*/
private void readEnd(ZipEntry e) throws IOException {
int n = inf.getRemaining();
if (n > 0) {
((PushbackInputStream)in).unread(buf, len - n, n);
}
if ((e.flag & 8) == 8) {
/* EXT 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()) + ")");
}
}
/*
* Reads bytes, blocking until all bytes are read.
*/
private void readFully(byte[] b, int off, int len) throws IOException {
while (len > 0) {
int n = in.read(b, off, len);
if (n == -1) {
throw new EOFException();
}
off += n;
len -= n;
}
}
/*
* Fetches unsigned 16-bit value from byte array at specified offset.
* The bytes are assumed to be in Intel (little-endian) byte order.
*/
private static final int get16(byte b[], int off) {
return (b[off] & 0xff) | ((b[off+1] & 0xff) << 8);
}
/*
* Fetches unsigned 32-bit value from byte array at specified offset.
* The bytes are assumed to be in Intel (little-endian) byte order.
*/
private static final long get32(byte b[], int off) {
return get16(b, off) | ((long)get16(b, off+2) << 16);
}
}