Package java.util.zip

Source Code of java.util.zip.ZipInputStream

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package java.util.zip;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;

import org.apache.harmony.archive.internal.nls.Messages;
import org.apache.harmony.luni.util.Util;

/**
* ZipInputStream is an input stream for reading zip files.
*
* @see ZipEntry
* @see ZipFile
*/
public class ZipInputStream extends InflaterInputStream implements ZipConstants {
    static final int DEFLATED = 8;

    static final int STORED = 0;

    static final int ZIPDataDescriptorFlag = 8;

    static final int ZIPLocalHeaderVersionNeeded = 20;

    private boolean zipClosed = false;

    private boolean entriesEnd = false;

    private boolean hasDD = false;

    private int entryIn = 0;

    private int inRead, lastRead = 0;

    ZipEntry currentEntry;

    private final byte[] hdrBuf = new byte[LOCHDR - LOCVER];

    private final CRC32 crc = new CRC32();

    private byte[] nameBuf = new byte[256];

    private char[] charBuf = new char[256];

    /**
     * Constructs a new ZipInputStream on the specified input stream.
     *
     * @param stream
     *            the input stream
     */
    public ZipInputStream(InputStream stream) {
        super(new PushbackInputStream(stream, BUF_SIZE), new Inflater(true));
        if (stream == null) {
            throw new NullPointerException();
        }
    }

    /**
     * Closes this ZipInputStream.
     */
    @Override
    public void close() throws IOException {
        if (zipClosed != true) {
            closeEntry(); // Close the current entry
            zipClosed = true;
            super.close();
        }
    }

    /**
     * Closes the current zip entry and positions to read the next entry.
     */
    public void closeEntry() throws IOException {
        if (zipClosed) {
            throw new IOException(Messages.getString("archive.1E")); //$NON-NLS-1$
        }
        if (currentEntry == null) {
            return;
        }
        if (currentEntry instanceof java.util.jar.JarEntry) {
            Attributes temp = ((JarEntry) currentEntry).getAttributes();
            if (temp != null && temp.containsKey("hidden")) { //$NON-NLS-1$
                return;
            }
        }
        // Ensure all entry bytes are read
        skip(Long.MAX_VALUE);
        int inB, out;
        if (currentEntry.compressionMethod == DEFLATED) {
            inB = inf.getTotalIn();
            out = inf.getTotalOut();
        } else {
            inB = inRead;
            out = inRead;
        }
        int diff = 0;
        // Pushback any required bytes
        if ((diff = entryIn - inB) != 0) {
            ((PushbackInputStream) in).unread(buf, len - diff, diff);
        }

        if (hasDD) {
            in.read(hdrBuf, 0, EXTHDR);
            if (getLong(hdrBuf, 0) != EXTSIG) {
                throw new ZipException(Messages.getString("archive.1F")); //$NON-NLS-1$
            }
            currentEntry.crc = getLong(hdrBuf, EXTCRC);
            currentEntry.compressedSize = getLong(hdrBuf, EXTSIZ);
            currentEntry.size = getLong(hdrBuf, EXTLEN);
        }
        if (currentEntry.crc != crc.getValue()) {
            throw new ZipException(Messages.getString("archive.20")); //$NON-NLS-1$
        }
        if (currentEntry.compressedSize != inB || currentEntry.size != out) {
            throw new ZipException(Messages.getString("archive.21")); //$NON-NLS-1$
        }

        inf.reset();
        lastRead = inRead = entryIn = len = 0;
        crc.reset();
        currentEntry = null;
    }

    /**
     * Reads the next zip entry from this ZipInputStream.
     */
    public ZipEntry getNextEntry() throws IOException {
        if (currentEntry != null) {
            closeEntry();
        }
        if (entriesEnd) {
            return null;
        }

        int x = 0, count = 0;
        while (count != 4) {
            count += x = in.read(hdrBuf, count, 4 - count);
            if (x == -1) {
                return null;
            }
        }
        long hdr = getLong(hdrBuf, 0);
        if (hdr == CENSIG) {
            entriesEnd = true;
            return null;
        }
        if (hdr != LOCSIG) {
            return null;
        }

        // Read the local header
        count = 0;
        while (count != (LOCHDR - LOCVER)) {
            count += x = in.read(hdrBuf, count, (LOCHDR - LOCVER) - count);
            if (x == -1) {
                throw new EOFException();
            }
        }
        int version = getShort(hdrBuf, 0) & 0xff;
        if (version > ZIPLocalHeaderVersionNeeded) {
            throw new ZipException(Messages.getString("archive.22")); //$NON-NLS-1$
        }
        int flags = getShort(hdrBuf, LOCFLG - LOCVER);
        hasDD = ((flags & ZIPDataDescriptorFlag) == ZIPDataDescriptorFlag);
        int cetime = getShort(hdrBuf, LOCTIM - LOCVER);
        int cemodDate = getShort(hdrBuf, LOCTIM - LOCVER + 2);
        int cecompressionMethod = getShort(hdrBuf, LOCHOW - LOCVER);
        long cecrc = 0, cecompressedSize = 0, cesize = -1;
        if (!hasDD) {
            cecrc = getLong(hdrBuf, LOCCRC - LOCVER);
            cecompressedSize = getLong(hdrBuf, LOCSIZ - LOCVER);
            cesize = getLong(hdrBuf, LOCLEN - LOCVER);
        }
        int flen = getShort(hdrBuf, LOCNAM - LOCVER);
        if (flen == 0) {
            throw new ZipException(Messages.getString("archive.23")); //$NON-NLS-1$
        }
        int elen = getShort(hdrBuf, LOCEXT - LOCVER);

        count = 0;
        if (flen > nameBuf.length) {
            nameBuf = new byte[flen];
            charBuf = new char[flen];
        }
        while (count != flen) {
            count += x = in.read(nameBuf, count, flen - count);
            if (x == -1) {
                throw new EOFException();
            }
        }
        currentEntry = createZipEntry(Util.convertUTF8WithBuf(nameBuf, charBuf,
                0, flen));
        currentEntry.time = cetime;
        currentEntry.modDate = cemodDate;
        currentEntry.setMethod(cecompressionMethod);
        if (cesize != -1) {
            currentEntry.setCrc(cecrc);
            currentEntry.setSize(cesize);
            currentEntry.setCompressedSize(cecompressedSize);
        }
        if (elen > 0) {
            count = 0;
            byte[] e = new byte[elen];
            while (count != elen) {
                count += x = in.read(e, count, elen - count);
                if (x == -1) {
                    throw new EOFException();
                }
            }
            currentEntry.setExtra(e);
        }
        return currentEntry;
    }

    /* Read 4 bytes from the buffer and store it as an int */

    /**
     * Reads up to the specified number of uncompressed bytes into the buffer
     * starting at the offset.
     *
     * @param buffer
     *            a byte array
     * @param start
     *            the starting offset into the buffer
     * @param length
     *            the number of bytes to read
     * @return the number of bytes read
     */
    @Override
    public int read(byte[] buffer, int start, int length) throws IOException {
        if (zipClosed) {
            throw new IOException(Messages.getString("archive.1E")); //$NON-NLS-1$
        }
        if (inf.finished() || currentEntry == null) {
            return -1;
        }
        // avoid int overflow, check null buffer
        if (start <= buffer.length && length >= 0 && start >= 0
                && buffer.length - start >= length) {
            if (currentEntry.compressionMethod == STORED) {
                int csize = (int) currentEntry.size;
                if (inRead >= csize) {
                    return -1;
                }
                if (lastRead >= len) {
                    lastRead = 0;
                    if ((len = in.read(buf)) == -1) {
                        return -1;
                    }
                    entryIn += len;
                }
                int toRead = length > len ? len - lastRead : length;
                if ((csize - inRead) < toRead) {
                    toRead = csize - inRead;
                }
                System.arraycopy(buf, lastRead, buffer, start, toRead);
                lastRead += toRead;
                inRead += toRead;
                crc.update(buffer, start, toRead);
                return toRead;
            }
            if (inf.needsInput()) {
                fill();
                if (len > 0) {
                    entryIn += len;
                }
            }
            int read = 0;
            try {
                read = inf.inflate(buffer, start, length);
            } catch (DataFormatException e) {
                throw new ZipException(e.getMessage());
            }
            if (read == 0 && inf.finished()) {
                return -1;
            }
            crc.update(buffer, start, read);
            return read;
        }
        throw new ArrayIndexOutOfBoundsException();
    }

    /**
     * Skips up to the specified number of bytes in the current zip entry.
     *
     * @param value
     *            the number of bytes to skip
     * @return the number of bytes skipped
     */
    @Override
    public long skip(long value) throws IOException {
        if (value >= 0) {
            long skipped = 0;
            byte[] b = new byte[1024];
            while (skipped != value) {
                long rem = value - skipped;
                int x = read(b, 0, (int) (b.length > rem ? rem : b.length));
                if (x == -1) {
                    return skipped;
                }
                skipped += x;
            }
            return skipped;
        }
        throw new IllegalArgumentException();
    }

    /**
     * Answers 1 if the EOF has been reached, otherwise returns 0.
     *
     * @return 0 after EOF of current entry, 1 otherwise
     */
    @Override
    public int available() throws IOException {
        if (zipClosed) {
            throw new IOException(Messages.getString("archive.1E")); //$NON-NLS-1$
        }
        if (currentEntry == null) {
            return 1;
        }
        if (currentEntry.compressionMethod == STORED) {
            if (inRead >= currentEntry.size) {
                return 0;
            }
        } else {
            if (inf.finished()) {
                return 0;
            }
        }
        return 1;
    }

    protected ZipEntry createZipEntry(String name) {
        return new ZipEntry(name);
    }

    private int getShort(byte[] buffer, int off) {
        return (buffer[off] & 0xFF) | ((buffer[off + 1] & 0xFF) << 8);
    }

    private long getLong(byte[] buffer, int off) {
        long l = 0;
        l |= (buffer[off] & 0xFF);
        l |= (buffer[off + 1] & 0xFF) << 8;
        l |= (buffer[off + 2] & 0xFF) << 16;
        l |= ((long) (buffer[off + 3] & 0xFF)) << 24;
        return l;
    }
}
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