Source for java.util.zip.ZipInputStream

   1: /* ZipInputStream.java --
   2:    Copyright (C) 2001, 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.util.zip;
  40: 
  41: import java.io.EOFException;
  42: import java.io.IOException;
  43: import java.io.InputStream;
  44: import java.io.UnsupportedEncodingException;
  45: 
  46: /**
  47:  * This is a FilterInputStream that reads the files in an zip archive
  48:  * one after another.  It has a special method to get the zip entry of
  49:  * the next file.  The zip entry contains information about the file name
  50:  * size, compressed size, CRC, etc.
  51:  *
  52:  * It includes support for STORED and DEFLATED entries.
  53:  *
  54:  * @author Jochen Hoenicke
  55:  */
  56: public class ZipInputStream extends InflaterInputStream implements ZipConstants
  57: {
  58:   private CRC32 crc = new CRC32();
  59:   private ZipEntry entry = null;
  60: 
  61:   private int csize;
  62:   private int size;
  63:   private int method;
  64:   private int flags;
  65:   private int avail;
  66:   private boolean entryAtEOF;
  67: 
  68:   /**
  69:    * Creates a new Zip input stream, reading a zip archive.
  70:    */
  71:   public ZipInputStream(InputStream in)
  72:   {
  73:     super(in, new Inflater(true));
  74:   }
  75: 
  76:   private void fillBuf() throws IOException
  77:   {
  78:     avail = len = in.read(buf, 0, buf.length);
  79:   }
  80: 
  81:   private int readBuf(byte[] out, int offset, int length) throws IOException
  82:   {
  83:     if (avail <= 0)
  84:       {
  85:     fillBuf();
  86:     if (avail <= 0)
  87:       return -1;
  88:       }
  89:     if (length > avail)
  90:       length = avail;
  91:     System.arraycopy(buf, len - avail, out, offset, length);
  92:     avail -= length;
  93:     return length;
  94:   }
  95:   
  96:   private void readFully(byte[] out) throws IOException
  97:   {
  98:     int off = 0;
  99:     int len = out.length;
 100:     while (len > 0)
 101:       {
 102:     int count = readBuf(out, off, len);
 103:     if (count == -1)
 104:       throw new EOFException();
 105:     off += count;
 106:     len -= count;
 107:       }
 108:   }
 109:   
 110:   private int readLeByte() throws IOException
 111:   {
 112:     if (avail <= 0)
 113:       {
 114:     fillBuf();
 115:     if (avail <= 0)
 116:       throw new ZipException("EOF in header");
 117:       }
 118:     return buf[len - avail--] & 0xff;
 119:   }
 120: 
 121:   /**
 122:    * Read an unsigned short in little endian byte order.
 123:    */
 124:   private int readLeShort() throws IOException 
 125:   {
 126:     return readLeByte() | (readLeByte() << 8);
 127:   }
 128: 
 129:   /**
 130:    * Read an int in little endian byte order.
 131:    */
 132:   private int readLeInt() throws IOException 
 133:   {
 134:     return readLeShort() | (readLeShort() << 16);
 135:   }
 136: 
 137:   /**
 138:    * Open the next entry from the zip archive, and return its description.
 139:    * If the previous entry wasn't closed, this method will close it.
 140:    */
 141:   public ZipEntry getNextEntry() throws IOException
 142:   {
 143:     if (crc == null)
 144:       throw new IOException("Stream closed.");
 145:     if (entry != null)
 146:       closeEntry();
 147: 
 148:     int header = readLeInt();
 149:     if (header == CENSIG)
 150:       {
 151:     /* Central Header reached. */
 152:     close();
 153:     return null;
 154:       }
 155:     if (header != LOCSIG)
 156:       throw new ZipException("Wrong Local header signature: "
 157:                  + Integer.toHexString(header));
 158:     /* skip version */
 159:     readLeShort();
 160:     flags = readLeShort();
 161:     method = readLeShort();
 162:     int dostime = readLeInt();
 163:     int crc = readLeInt();
 164:     csize = readLeInt();
 165:     size = readLeInt();
 166:     int nameLen = readLeShort();
 167:     int extraLen = readLeShort();
 168: 
 169:     if (method == ZipOutputStream.STORED && csize != size)
 170:       throw new ZipException("Stored, but compressed != uncompressed");
 171: 
 172: 
 173:     byte[] buffer = new byte[nameLen];
 174:     readFully(buffer);
 175:     String name;
 176:     try
 177:       {
 178:     name = new String(buffer, "UTF-8");
 179:       }
 180:     catch (UnsupportedEncodingException uee)
 181:       {
 182:     throw new AssertionError(uee);
 183:       }
 184:     
 185:     entry = createZipEntry(name);
 186:     entryAtEOF = false;
 187:     entry.setMethod(method);
 188:     if ((flags & 8) == 0)
 189:       {
 190:     entry.setCrc(crc & 0xffffffffL);
 191:     entry.setSize(size & 0xffffffffL);
 192:     entry.setCompressedSize(csize & 0xffffffffL);
 193:       }
 194:     entry.setDOSTime(dostime);
 195:     if (extraLen > 0)
 196:       {
 197:     byte[] extra = new byte[extraLen];
 198:     readFully(extra);
 199:     entry.setExtra(extra);
 200:       }
 201: 
 202:     if (method == ZipOutputStream.DEFLATED && avail > 0)
 203:       {
 204:     System.arraycopy(buf, len - avail, buf, 0, avail);
 205:     len = avail;
 206:     avail = 0;
 207:     inf.setInput(buf, 0, len);
 208:       }
 209:     return entry;
 210:   }
 211: 
 212:   private void readDataDescr() throws IOException
 213:   {
 214:     if (readLeInt() != EXTSIG)
 215:       throw new ZipException("Data descriptor signature not found");
 216:     entry.setCrc(readLeInt() & 0xffffffffL);
 217:     csize = readLeInt();
 218:     size = readLeInt();
 219:     entry.setSize(size & 0xffffffffL);
 220:     entry.setCompressedSize(csize & 0xffffffffL);
 221:   }
 222: 
 223:   /**
 224:    * Closes the current zip entry and moves to the next one.
 225:    */
 226:   public void closeEntry() throws IOException
 227:   {
 228:     if (crc == null)
 229:       throw new IOException("Stream closed.");
 230:     if (entry == null)
 231:       return;
 232: 
 233:     if (method == ZipOutputStream.DEFLATED)
 234:       {
 235:     if ((flags & 8) != 0)
 236:       {
 237:         /* We don't know how much we must skip, read until end. */
 238:         byte[] tmp = new byte[2048];
 239:         while (read(tmp) > 0)
 240:           ;
 241:             
 242:         /* read will close this entry */
 243:         return;
 244:       }
 245:     csize -= inf.getTotalIn();
 246:     avail = inf.getRemaining();
 247:       }
 248: 
 249:     if (avail > csize && csize >= 0)
 250:       avail -= csize;
 251:     else
 252:       {
 253:     csize -= avail;
 254:     avail = 0;
 255:     while (csize != 0)
 256:       {
 257:         long skipped = in.skip(csize & 0xffffffffL);
 258:         if (skipped <= 0)
 259:           throw new ZipException("zip archive ends early.");
 260:         csize -= skipped;
 261:       }
 262:       }
 263: 
 264:     size = 0;
 265:     crc.reset();
 266:     if (method == ZipOutputStream.DEFLATED)
 267:       inf.reset();
 268:     entry = null;
 269:     entryAtEOF = true;
 270:   }
 271: 
 272:   public int available() throws IOException
 273:   {
 274:     return entryAtEOF ? 0 : 1;
 275:   }
 276: 
 277:   /**
 278:    * Reads a byte from the current zip entry.
 279:    * @return the byte or -1 on EOF.
 280:    * @exception IOException if a i/o error occured.
 281:    * @exception ZipException if the deflated stream is corrupted.
 282:    */
 283:   public int read() throws IOException
 284:   {
 285:     byte[] b = new byte[1];
 286:     if (read(b, 0, 1) <= 0)
 287:       return -1;
 288:     return b[0] & 0xff;
 289:   }
 290: 
 291:   /**
 292:    * Reads a block of bytes from the current zip entry.
 293:    * @return the number of bytes read (may be smaller, even before
 294:    * EOF), or -1 on EOF.
 295:    * @exception IOException if a i/o error occured.
 296:    * @exception ZipException if the deflated stream is corrupted.
 297:    */
 298:   public int read(byte[] b, int off, int len) throws IOException
 299:   {
 300:     if (len == 0)
 301:       return 0;
 302:     if (crc == null)
 303:       throw new IOException("Stream closed.");
 304:     if (entry == null)
 305:       return -1;
 306:     boolean finished = false;
 307:     switch (method)
 308:       {
 309:       case ZipOutputStream.DEFLATED:
 310:     len = super.read(b, off, len);
 311:     if (len < 0)
 312:       {
 313:         if (!inf.finished())
 314:           throw new ZipException("Inflater not finished!?");
 315:         avail = inf.getRemaining();
 316:         if ((flags & 8) != 0)
 317:           readDataDescr();
 318: 
 319:         if (inf.getTotalIn() != csize
 320:         || inf.getTotalOut() != size)
 321:           throw new ZipException("size mismatch: "+csize+";"+size+" <-> "+inf.getTotalIn()+";"+inf.getTotalOut());
 322:         inf.reset();
 323:         finished = true;
 324:       }
 325:     break;
 326:     
 327:       case ZipOutputStream.STORED:
 328: 
 329:     if (len > csize && csize >= 0)
 330:       len = csize;
 331:     
 332:     len = readBuf(b, off, len);
 333:     if (len > 0)
 334:       {
 335:         csize -= len;
 336:         size -= len;
 337:       }
 338: 
 339:     if (csize == 0)
 340:       finished = true;
 341:     else if (len < 0)
 342:       throw new ZipException("EOF in stored block");
 343:     break;
 344:       }
 345: 
 346:     if (len > 0)
 347:       crc.update(b, off, len);
 348: 
 349:     if (finished)
 350:       {
 351:     if ((crc.getValue() & 0xffffffffL) != entry.getCrc())
 352:       throw new ZipException("CRC mismatch");
 353:     crc.reset();
 354:     entry = null;
 355:     entryAtEOF = true;
 356:       }
 357:     return len;
 358:   }
 359: 
 360:   /**
 361:    * Closes the zip file.
 362:    * @exception IOException if a i/o error occured.
 363:    */
 364:   public void close() throws IOException
 365:   {
 366:     super.close();
 367:     crc = null;
 368:     entry = null;
 369:     entryAtEOF = true;
 370:   }
 371: 
 372:   /**
 373:    * Creates a new zip entry for the given name.  This is equivalent
 374:    * to new ZipEntry(name).
 375:    * @param name the name of the zip entry.
 376:    */
 377:   protected ZipEntry createZipEntry(String name) 
 378:   {
 379:     return new ZipEntry(name);
 380:   }
 381: }