1 /*
2 * Copyright (c) 1996, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util.zip;
27
28 import java.io.InputStream;
29 import java.io.IOException;
30 import java.io.EOFException;
31 import java.io.PushbackInputStream;
32 import java.nio.charset.Charset;
33 import java.nio.charset.StandardCharsets;
34 import static java.util.zip.ZipConstants64.*;
35 import static java.util.zip.ZipUtils.*;
36
37 /**
38 * This class implements an input stream filter for reading files in the
39 * ZIP file format. Includes support for both compressed and uncompressed
40 * entries.
41 *
42 * @author David Connelly
43 * @since 1.1
44 */
45 public
46 class ZipInputStream extends InflaterInputStream implements ZipConstants {
47 private ZipEntry entry;
48 private int flag;
49 private CRC32 crc = new CRC32();
50 private long remaining;
51 private byte[] tmpbuf = new byte[512];
52
53 private static final int STORED = ZipEntry.STORED;
54 private static final int DEFLATED = ZipEntry.DEFLATED;
55
56 private boolean closed = false;
57 // this flag is set to true after EOF has reached for
58 // one entry
59 private boolean entryEOF = false;
60
61 private ZipCoder zc;
62
63 /**
64 * Check to make sure that this stream has not been closed
65 */
66 private void ensureOpen() throws IOException {
67 if (closed) {
68 throw new IOException("Stream closed");
69 }
70 }
71
72 /**
73 * Creates a new ZIP input stream.
74 *
75 * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
76 * decode the entry names.
77 *
78 * @param in the actual input stream
79 */
80 public ZipInputStream(InputStream in) {
81 this(in, StandardCharsets.UTF_8);
82 }
83
84 /**
85 * Creates a new ZIP input stream.
86 *
87 * @param in the actual input stream
88 *
89 * @param charset
90 * The {@linkplain java.nio.charset.Charset charset} to be
91 * used to decode the ZIP entry name (ignored if the
92 * <a href="package-summary.html#lang_encoding"> language
93 * encoding bit</a> of the ZIP entry's general purpose bit
94 * flag is set).
95 *
96 * @since 1.7
97 */
98 public ZipInputStream(InputStream in, Charset charset) {
99 super(new PushbackInputStream(in, 512), new Inflater(true), 512);
100 usesDefaultInflater = true;
101 if(in == null) {
102 throw new NullPointerException("in is null");
103 }
104 if (charset == null)
105 throw new NullPointerException("charset is null");
106 this.zc = ZipCoder.get(charset);
107 }
108
109 /**
110 * Reads the next ZIP file entry and positions the stream at the
111 * beginning of the entry data.
112 * @return the next ZIP file entry, or null if there are no more entries
113 * @exception ZipException if a ZIP file error has occurred
114 * @exception IOException if an I/O error has occurred
115 */
116 public ZipEntry getNextEntry() throws IOException {
117 ensureOpen();
118 if (entry != null) {
119 closeEntry();
120 }
121 crc.reset();
122 inf.reset();
123 if ((entry = readLOC()) == null) {
124 return null;
125 }
126 if (entry.method == STORED) {
127 remaining = entry.size;
128 }
129 entryEOF = false;
130 return entry;
131 }
132
133 /**
134 * Closes the current ZIP entry and positions the stream for reading the
135 * next entry.
136 * @exception ZipException if a ZIP file error has occurred
137 * @exception IOException if an I/O error has occurred
138 */
139 public void closeEntry() throws IOException {
140 ensureOpen();
141 while (read(tmpbuf, 0, tmpbuf.length) != -1) ;
142 entryEOF = true;
143 }
144
145 /**
146 * Returns 0 after EOF has reached for the current entry data,
147 * otherwise always return 1.
148 * <p>
149 * Programs should not count on this method to return the actual number
150 * of bytes that could be read without blocking.
151 *
152 * @return 1 before EOF and 0 after EOF has reached for current entry.
153 * @exception IOException if an I/O error occurs.
154 *
155 */
156 public int available() throws IOException {
157 ensureOpen();
158 if (entryEOF) {
159 return 0;
160 } else {
161 return 1;
162 }
163 }
164
165 /**
166 * Reads from the current ZIP entry into an array of bytes.
167 * If <code>len</code> is not zero, the method
168 * blocks until some input is available; otherwise, no
169 * bytes are read and <code>0</code> is returned.
170 * @param b the buffer into which the data is read
171 * @param off the start offset in the destination array <code>b</code>
172 * @param len the maximum number of bytes read
173 * @return the actual number of bytes read, or -1 if the end of the
174 * entry is reached
175 * @exception NullPointerException if <code>b</code> is <code>null</code>.
176 * @exception IndexOutOfBoundsException if <code>off</code> is negative,
177 * <code>len</code> is negative, or <code>len</code> is greater than
178 * <code>b.length - off</code>
179 * @exception ZipException if a ZIP file error has occurred
180 * @exception IOException if an I/O error has occurred
181 */
182 public int read(byte[] b, int off, int len) throws IOException {
183 ensureOpen();
184 if (off < 0 || len < 0 || off > b.length - len) {
185 throw new IndexOutOfBoundsException();
186 } else if (len == 0) {
187 return 0;
188 }
189
190 if (entry == null) {
191 return -1;
192 }
193 switch (entry.method) {
194 case DEFLATED:
195 len = super.read(b, off, len);
196 if (len == -1) {
197 readEnd(entry);
198 entryEOF = true;
199 entry = null;
200 } else {
201 crc.update(b, off, len);
202 }
203 return len;
204 case STORED:
205 if (remaining <= 0) {
206 entryEOF = true;
207 entry = null;
208 return -1;
209 }
210 if (len > remaining) {
211 len = (int)remaining;
212 }
213 len = in.read(b, off, len);
214 if (len == -1) {
215 throw new ZipException("unexpected EOF");
216 }
217 crc.update(b, off, len);
218 remaining -= len;
219 if (remaining == 0 && entry.crc != crc.getValue()) {
220 throw new ZipException(
221 "invalid entry CRC (expected 0x" + Long.toHexString(entry.crc) +
222 " but got 0x" + Long.toHexString(crc.getValue()) + ")");
223 }
224 return len;
225 default:
226 throw new ZipException("invalid compression method");
227 }
228 }
229
230 /**
231 * Skips specified number of bytes in the current ZIP entry.
232 * @param n the number of bytes to skip
233 * @return the actual number of bytes skipped
234 * @exception ZipException if a ZIP file error has occurred
235 * @exception IOException if an I/O error has occurred
236 * @exception IllegalArgumentException if {@code n < 0}
237 */
238 public long skip(long n) throws IOException {
239 if (n < 0) {
240 throw new IllegalArgumentException("negative skip length");
241 }
242 ensureOpen();
243 int max = (int)Math.min(n, Integer.MAX_VALUE);
244 int total = 0;
245 while (total < max) {
246 int len = max - total;
247 if (len > tmpbuf.length) {
248 len = tmpbuf.length;
249 }
250 len = read(tmpbuf, 0, len);
251 if (len == -1) {
252 entryEOF = true;
253 break;
254 }
255 total += len;
256 }
257 return total;
258 }
259
260 /**
261 * Closes this input stream and releases any system resources associated
262 * with the stream.
263 * @exception IOException if an I/O error has occurred
264 */
265 public void close() throws IOException {
266 if (!closed) {
267 super.close();
268 closed = true;
269 }
270 }
271
272 private byte[] b = new byte[256];
273
274 /*
275 * Reads local file (LOC) header for next entry.
276 */
277 private ZipEntry readLOC() throws IOException {
278 try {
279 readFully(tmpbuf, 0, LOCHDR);
280 } catch (EOFException e) {
281 return null;
282 }
283 if (get32(tmpbuf, 0) != LOCSIG) {
284 return null;
285 }
286 // get flag first, we need check EFS.
287 flag = get16(tmpbuf, LOCFLG);
288 // get the entry name and create the ZipEntry first
289 int len = get16(tmpbuf, LOCNAM);
290 int blen = b.length;
291 if (len > blen) {
292 do {
293 blen = blen * 2;
294 } while (len > blen);
295 b = new byte[blen];
296 }
297 readFully(b, 0, len);
298 // Force to use UTF-8 if the EFS bit is ON, even the cs is NOT UTF-8
299 ZipEntry e = createZipEntry(((flag & EFS) != 0)
300 ? ZipCoder.toStringUTF8(b, len)
301 : zc.toString(b, len));
302 // now get the remaining fields for the entry
303 if ((flag & 1) == 1) {
304 throw new ZipException("encrypted ZIP entry not supported");
305 }
306 e.method = get16(tmpbuf, LOCHOW);
307 e.xdostime = get32(tmpbuf, LOCTIM);
308 if ((flag & 8) == 8) {
309 /* "Data Descriptor" present */
310 if (e.method != DEFLATED) {
311 throw new ZipException(
312 "only DEFLATED entries can have EXT descriptor");
313 }
314 } else {
315 e.crc = get32(tmpbuf, LOCCRC);
316 e.csize = get32(tmpbuf, LOCSIZ);
317 e.size = get32(tmpbuf, LOCLEN);
318 }
319 len = get16(tmpbuf, LOCEXT);
320 if (len > 0) {
321 byte[] extra = new byte[len];
322 readFully(extra, 0, len);
323 e.setExtra0(extra,
324 e.csize == ZIP64_MAGICVAL || e.size == ZIP64_MAGICVAL);
325 }
326 return e;
327 }
328
329 /**
330 * Creates a new <code>ZipEntry</code> object for the specified
331 * entry name.
332 *
333 * @param name the ZIP file entry name
334 * @return the ZipEntry just created
335 */
336 protected ZipEntry createZipEntry(String name) {
337 return new ZipEntry(name);
338 }
339
340 /**
341 * Reads end of deflated entry as well as EXT descriptor if present.
342 *
343 * Local headers for DEFLATED entries may optionally be followed by a
344 * data descriptor, and that data descriptor may optionally contain a
345 * leading signature (EXTSIG).
346 *
347 * From the zip spec http://www.pkware.com/documents/casestudies/APPNOTE.TXT
348 *
349 * """Although not originally assigned a signature, the value 0x08074b50
350 * has commonly been adopted as a signature value for the data descriptor
351 * record. Implementers should be aware that ZIP files may be
352 * encountered with or without this signature marking data descriptors
353 * and should account for either case when reading ZIP files to ensure
354 * compatibility."""
355 */
356 private void readEnd(ZipEntry e) throws IOException {
357 int n = inf.getRemaining();
358 if (n > 0) {
359 ((PushbackInputStream)in).unread(buf, len - n, n);
360 }
361 if ((flag & 8) == 8) {
362 /* "Data Descriptor" present */
363 if (inf.getBytesWritten() > ZIP64_MAGICVAL ||
364 inf.getBytesRead() > ZIP64_MAGICVAL) {
365 // ZIP64 format
366 readFully(tmpbuf, 0, ZIP64_EXTHDR);
367 long sig = get32(tmpbuf, 0);
368 if (sig != EXTSIG) { // no EXTSIG present
369 e.crc = sig;
370 e.csize = get64(tmpbuf, ZIP64_EXTSIZ - ZIP64_EXTCRC);
371 e.size = get64(tmpbuf, ZIP64_EXTLEN - ZIP64_EXTCRC);
372 ((PushbackInputStream)in).unread(
373 tmpbuf, ZIP64_EXTHDR - ZIP64_EXTCRC, ZIP64_EXTCRC);
374 } else {
375 e.crc = get32(tmpbuf, ZIP64_EXTCRC);
376 e.csize = get64(tmpbuf, ZIP64_EXTSIZ);
377 e.size = get64(tmpbuf, ZIP64_EXTLEN);
378 }
379 } else {
380 readFully(tmpbuf, 0, EXTHDR);
381 long sig = get32(tmpbuf, 0);
382 if (sig != EXTSIG) { // no EXTSIG present
383 e.crc = sig;
384 e.csize = get32(tmpbuf, EXTSIZ - EXTCRC);
385 e.size = get32(tmpbuf, EXTLEN - EXTCRC);
386 ((PushbackInputStream)in).unread(
387 tmpbuf, EXTHDR - EXTCRC, EXTCRC);
388 } else {
389 e.crc = get32(tmpbuf, EXTCRC);
390 e.csize = get32(tmpbuf, EXTSIZ);
391 e.size = get32(tmpbuf, EXTLEN);
392 }
393 }
394 }
395 if (e.size != inf.getBytesWritten()) {
396 throw new ZipException(
397 "invalid entry size (expected " + e.size +
398 " but got " + inf.getBytesWritten() + " bytes)");
399 }
400 if (e.csize != inf.getBytesRead()) {
401 throw new ZipException(
402 "invalid entry compressed size (expected " + e.csize +
403 " but got " + inf.getBytesRead() + " bytes)");
404 }
405 if (e.crc != crc.getValue()) {
406 throw new ZipException(
407 "invalid entry CRC (expected 0x" + Long.toHexString(e.crc) +
408 " but got 0x" + Long.toHexString(crc.getValue()) + ")");
409 }
410 }
411
412 /*
413 * Reads bytes, blocking until all bytes are read.
414 */
415 private void readFully(byte[] b, int off, int len) throws IOException {
416 while (len > 0) {
417 int n = in.read(b, off, len);
418 if (n == -1) {
419 throw new EOFException();
420 }
421 off += n;
422 len -= n;
423 }
424 }
425
426 }