/*
 * 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 org.apache.commons.compress.archivers.cpio;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.HashMap;

import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.ArchiveOutputStream;
import org.apache.commons.compress.archivers.zip.ZipEncoding;
import org.apache.commons.compress.archivers.zip.ZipEncodingHelper;
import org.apache.commons.compress.utils.ArchiveUtils;
import org.apache.commons.compress.utils.CharsetNames;

CpioArchiveOutputStream is a stream for writing CPIO streams. All formats of
CPIO are supported (old ASCII, old binary, new portable format and the new
portable format with CRC).
An entry can be written by creating an instance of CpioArchiveEntry and fill
it with the necessary values and put it into the CPIO stream. Afterwards
write the contents of the file into the CPIO stream. Either close the stream
by calling finish() or put a next entry into the cpio stream.
CpioArchiveOutputStream out = new CpioArchiveOutputStream(
        new FileOutputStream(new File("test.cpio")));
CpioArchiveEntry entry = new CpioArchiveEntry();
entry.setName("testfile");
String contents = "12345";
entry.setFileSize(contents.length());
entry.setMode(CpioConstants.C_ISREG); // regular file
... set other attributes, e.g. time, number of links
out.putArchiveEntry(entry);
out.write(testContents.getBytes());
out.close();

Note: This implementation should be compatible to cpio 2.5
This class uses mutable fields and is not considered threadsafe.
based on code from the jRPM project (jrpm.sourceforge.net)
/**
 * CpioArchiveOutputStream is a stream for writing CPIO streams. All formats of
 * CPIO are supported (old ASCII, old binary, new portable format and the new
 * portable format with CRC).
 *
 * <p>An entry can be written by creating an instance of CpioArchiveEntry and fill
 * it with the necessary values and put it into the CPIO stream. Afterwards
 * write the contents of the file into the CPIO stream. Either close the stream
 * by calling finish() or put a next entry into the cpio stream.</p>
 *
 * <pre>
 * CpioArchiveOutputStream out = new CpioArchiveOutputStream(
 *         new FileOutputStream(new File("test.cpio")));
 * CpioArchiveEntry entry = new CpioArchiveEntry();
 * entry.setName("testfile");
 * String contents = &quot;12345&quot;;
 * entry.setFileSize(contents.length());
 * entry.setMode(CpioConstants.C_ISREG); // regular file
 * ... set other attributes, e.g. time, number of links
 * out.putArchiveEntry(entry);
 * out.write(testContents.getBytes());
 * out.close();
 * </pre>
 *
 * <p>Note: This implementation should be compatible to cpio 2.5</p>
 *
 * <p>This class uses mutable fields and is not considered threadsafe.</p>
 *
 * <p>based on code from the jRPM project (jrpm.sourceforge.net)</p>
 */
public class CpioArchiveOutputStream extends ArchiveOutputStream implements
        CpioConstants {

    private CpioArchiveEntry entry;

    private boolean closed = false;

    
indicates if this archive is finished /** indicates if this archive is finished */
    private boolean finished;

    
See CpioArchiveEntry.setFormat(short) for possible values. /**
     * See {@link CpioArchiveEntry#setFormat(short)} for possible values.
     */
    private final short entryFormat;

    private final HashMap<String, CpioArchiveEntry> names =
        new HashMap<>();

    private long crc = 0;

    private long written;

    private final OutputStream out;

    private final int blockSize;

    private long nextArtificalDeviceAndInode = 1;

    
The encoding to use for file names and labels.
/**
     * The encoding to use for file names and labels.
     */
    private final ZipEncoding zipEncoding;

    // the provided encoding (for unit tests)
    final String encoding;

    
Construct the cpio output stream with a specified format, a blocksize of BLOCK_SIZE and using ASCII as the file name encoding. 
Params:
out – 
           The cpio stream
format – 
           The format of the stream/**
     * Construct the cpio output stream with a specified format, a
     * blocksize of {@link CpioConstants#BLOCK_SIZE BLOCK_SIZE} and
     * using ASCII as the file name encoding.
     *
     * @param out
     *            The cpio stream
     * @param format
     *            The format of the stream
     */
    public CpioArchiveOutputStream(final OutputStream out, final short format) {
        this(out, format, BLOCK_SIZE, CharsetNames.US_ASCII);
    }

    
Construct the cpio output stream with a specified format using
ASCII as the file name encoding.
Params:
out – 
           The cpio stream
format – 
           The format of the stream
blockSize – 
           The block size of the archive.
Since:
1.1/**
     * Construct the cpio output stream with a specified format using
     * ASCII as the file name encoding.
     *
     * @param out
     *            The cpio stream
     * @param format
     *            The format of the stream
     * @param blockSize
     *            The block size of the archive.
     *
     * @since 1.1
     */
    public CpioArchiveOutputStream(final OutputStream out, final short format,
                                   final int blockSize) {
        this(out, format, blockSize, CharsetNames.US_ASCII);
    }

    
Construct the cpio output stream with a specified format using
ASCII as the file name encoding.
Params:
out – 
           The cpio stream
format – 
           The format of the stream
blockSize – 
           The block size of the archive.
encoding – 
           The encoding of file names to write - use null for
           the platform's default.
Since:
1.6/**
     * Construct the cpio output stream with a specified format using
     * ASCII as the file name encoding.
     *
     * @param out
     *            The cpio stream
     * @param format
     *            The format of the stream
     * @param blockSize
     *            The block size of the archive.
     * @param encoding
     *            The encoding of file names to write - use null for
     *            the platform's default.
     *
     * @since 1.6
     */
    public CpioArchiveOutputStream(final OutputStream out, final short format,
                                   final int blockSize, final String encoding) {
        this.out = out;
        switch (format) {
        case FORMAT_NEW:
        case FORMAT_NEW_CRC:
        case FORMAT_OLD_ASCII:
        case FORMAT_OLD_BINARY:
            break;
        default:
            throw new IllegalArgumentException("Unknown format: "+format);

        }
        this.entryFormat = format;
        this.blockSize = blockSize;
        this.encoding = encoding;
        this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
    }

    
Construct the cpio output stream. The format for this CPIO stream is the
"new" format using ASCII encoding for file names
Params:
out – 
           The cpio stream/**
     * Construct the cpio output stream. The format for this CPIO stream is the
     * "new" format using ASCII encoding for file names
     *
     * @param out
     *            The cpio stream
     */
    public CpioArchiveOutputStream(final OutputStream out) {
        this(out, FORMAT_NEW);
    }

    
Construct the cpio output stream. The format for this CPIO stream is the
"new" format.
Params:
out – 
           The cpio stream
encoding – 
           The encoding of file names to write - use null for
           the platform's default.
Since:
1.6/**
     * Construct the cpio output stream. The format for this CPIO stream is the
     * "new" format.
     *
     * @param out
     *            The cpio stream
     * @param encoding
     *            The encoding of file names to write - use null for
     *            the platform's default.
     * @since 1.6
     */
    public CpioArchiveOutputStream(final OutputStream out, final String encoding) {
        this(out, FORMAT_NEW, BLOCK_SIZE, encoding);
    }

    
Check to make sure that this stream has not been closed
Throws:
IOException – 
            if the stream is already closed/**
     * Check to make sure that this stream has not been closed
     *
     * @throws IOException
     *             if the stream is already closed
     */
    private void ensureOpen() throws IOException {
        if (this.closed) {
            throw new IOException("Stream closed");
        }
    }

    
Begins writing a new CPIO file entry and positions the stream to the
start of the entry data. Closes the current entry if still active. The
current time will be used if the entry has no set modification time and
the default header format will be used if no other format is specified in
the entry.
Params:
entry – 
           the CPIO cpioEntry to be written
Throws:
IOException – 
            if an I/O error has occurred or if a CPIO file error has
            occurred
ClassCastException – if entry is not an instance of CpioArchiveEntry/**
     * Begins writing a new CPIO file entry and positions the stream to the
     * start of the entry data. Closes the current entry if still active. The
     * current time will be used if the entry has no set modification time and
     * the default header format will be used if no other format is specified in
     * the entry.
     *
     * @param entry
     *            the CPIO cpioEntry to be written
     * @throws IOException
     *             if an I/O error has occurred or if a CPIO file error has
     *             occurred
     * @throws ClassCastException if entry is not an instance of CpioArchiveEntry
     */
    @Override
    public void putArchiveEntry(final ArchiveEntry entry) throws IOException {
        if(finished) {
            throw new IOException("Stream has already been finished");
        }

        final CpioArchiveEntry e = (CpioArchiveEntry) entry;
        ensureOpen();
        if (this.entry != null) {
            closeArchiveEntry(); // close previous entry
        }
        if (e.getTime() == -1) {
            e.setTime(System.currentTimeMillis() / 1000);
        }

        final short format = e.getFormat();
        if (format != this.entryFormat){
            throw new IOException("Header format: "+format+" does not match existing format: "+this.entryFormat);
        }

        if (this.names.put(e.getName(), e) != null) {
            throw new IOException("Duplicate entry: " + e.getName());
        }

        writeHeader(e);
        this.entry = e;
        this.written = 0;
    }

    private void writeHeader(final CpioArchiveEntry e) throws IOException {
        switch (e.getFormat()) {
        case FORMAT_NEW:
            out.write(ArchiveUtils.toAsciiBytes(MAGIC_NEW));
            count(6);
            writeNewEntry(e);
            break;
        case FORMAT_NEW_CRC:
            out.write(ArchiveUtils.toAsciiBytes(MAGIC_NEW_CRC));
            count(6);
            writeNewEntry(e);
            break;
        case FORMAT_OLD_ASCII:
            out.write(ArchiveUtils.toAsciiBytes(MAGIC_OLD_ASCII));
            count(6);
            writeOldAsciiEntry(e);
            break;
        case FORMAT_OLD_BINARY:
            final boolean swapHalfWord = true;
            writeBinaryLong(MAGIC_OLD_BINARY, 2, swapHalfWord);
            writeOldBinaryEntry(e, swapHalfWord);
            break;
        default:
            throw new IOException("Unknown format " + e.getFormat());
        }
    }

    private void writeNewEntry(final CpioArchiveEntry entry) throws IOException {
        long inode = entry.getInode();
        long devMin = entry.getDeviceMin();
        if (CPIO_TRAILER.equals(entry.getName())) {
            inode = devMin = 0;
        } else {
            if (inode == 0 && devMin == 0) {
                inode = nextArtificalDeviceAndInode & 0xFFFFFFFF;
                devMin = (nextArtificalDeviceAndInode++ >> 32) & 0xFFFFFFFF;
            } else {
                nextArtificalDeviceAndInode =
                    Math.max(nextArtificalDeviceAndInode,
                             inode + 0x100000000L * devMin) + 1;
            }
        }

        writeAsciiLong(inode, 8, 16);
        writeAsciiLong(entry.getMode(), 8, 16);
        writeAsciiLong(entry.getUID(), 8, 16);
        writeAsciiLong(entry.getGID(), 8, 16);
        writeAsciiLong(entry.getNumberOfLinks(), 8, 16);
        writeAsciiLong(entry.getTime(), 8, 16);
        writeAsciiLong(entry.getSize(), 8, 16);
        writeAsciiLong(entry.getDeviceMaj(), 8, 16);
        writeAsciiLong(devMin, 8, 16);
        writeAsciiLong(entry.getRemoteDeviceMaj(), 8, 16);
        writeAsciiLong(entry.getRemoteDeviceMin(), 8, 16);
        byte[] name = encode(entry.getName());
        writeAsciiLong(name.length + 1L, 8, 16);
        writeAsciiLong(entry.getChksum(), 8, 16);
        writeCString(name);
        pad(entry.getHeaderPadCount(name.length));
    }

    private void writeOldAsciiEntry(final CpioArchiveEntry entry)
            throws IOException {
        long inode = entry.getInode();
        long device = entry.getDevice();
        if (CPIO_TRAILER.equals(entry.getName())) {
            inode = device = 0;
        } else {
            if (inode == 0 && device == 0) {
                inode = nextArtificalDeviceAndInode & 0777777;
                device = (nextArtificalDeviceAndInode++ >> 18) & 0777777;
            } else {
                nextArtificalDeviceAndInode =
                    Math.max(nextArtificalDeviceAndInode,
                             inode + 01000000 * device) + 1;
            }
        }

        writeAsciiLong(device, 6, 8);
        writeAsciiLong(inode, 6, 8);
        writeAsciiLong(entry.getMode(), 6, 8);
        writeAsciiLong(entry.getUID(), 6, 8);
        writeAsciiLong(entry.getGID(), 6, 8);
        writeAsciiLong(entry.getNumberOfLinks(), 6, 8);
        writeAsciiLong(entry.getRemoteDevice(), 6, 8);
        writeAsciiLong(entry.getTime(), 11, 8);
        byte[] name = encode(entry.getName());
        writeAsciiLong(name.length + 1L, 6, 8);
        writeAsciiLong(entry.getSize(), 11, 8);
        writeCString(name);
    }

    private void writeOldBinaryEntry(final CpioArchiveEntry entry,
            final boolean swapHalfWord) throws IOException {
        long inode = entry.getInode();
        long device = entry.getDevice();
        if (CPIO_TRAILER.equals(entry.getName())) {
            inode = device = 0;
        } else {
            if (inode == 0 && device == 0) {
                inode = nextArtificalDeviceAndInode & 0xFFFF;
                device = (nextArtificalDeviceAndInode++ >> 16) & 0xFFFF;
            } else {
                nextArtificalDeviceAndInode =
                    Math.max(nextArtificalDeviceAndInode,
                             inode + 0x10000 * device) + 1;
            }
        }

        writeBinaryLong(device, 2, swapHalfWord);
        writeBinaryLong(inode, 2, swapHalfWord);
        writeBinaryLong(entry.getMode(), 2, swapHalfWord);
        writeBinaryLong(entry.getUID(), 2, swapHalfWord);
        writeBinaryLong(entry.getGID(), 2, swapHalfWord);
        writeBinaryLong(entry.getNumberOfLinks(), 2, swapHalfWord);
        writeBinaryLong(entry.getRemoteDevice(), 2, swapHalfWord);
        writeBinaryLong(entry.getTime(), 4, swapHalfWord);
        byte[] name = encode(entry.getName());
        writeBinaryLong(name.length + 1L, 2, swapHalfWord);
        writeBinaryLong(entry.getSize(), 4, swapHalfWord);
        writeCString(name);
        pad(entry.getHeaderPadCount(name.length));
    }

    /*(non-Javadoc)
     *
     * @see
     * org.apache.commons.compress.archivers.ArchiveOutputStream#closeArchiveEntry
     * ()
     */
    @Override
    public void closeArchiveEntry() throws IOException {
        if(finished) {
            throw new IOException("Stream has already been finished");
        }

        ensureOpen();

        if (entry == null) {
            throw new IOException("Trying to close non-existent entry");
        }

        if (this.entry.getSize() != this.written) {
            throw new IOException("Invalid entry size (expected "
                    + this.entry.getSize() + " but got " + this.written
                    + " bytes)");
        }
        pad(this.entry.getDataPadCount());
        if (this.entry.getFormat() == FORMAT_NEW_CRC
            && this.crc != this.entry.getChksum()) {
            throw new IOException("CRC Error");
        }
        this.entry = null;
        this.crc = 0;
        this.written = 0;
    }

    
Writes an array of bytes to the current CPIO entry data. This method will
block until all the bytes are written.
Params:
b – 
           the data to be written
off – 
           the start offset in the data
len – 
           the number of bytes that are written
Throws:
IOException – 
            if an I/O error has occurred or if a CPIO file error has
            occurred/**
     * Writes an array of bytes to the current CPIO entry data. This method will
     * block until all the bytes are written.
     *
     * @param b
     *            the data to be written
     * @param off
     *            the start offset in the data
     * @param len
     *            the number of bytes that are written
     * @throws IOException
     *             if an I/O error has occurred or if a CPIO file error has
     *             occurred
     */
    @Override
    public void write(final byte[] b, final int off, final int len)
            throws IOException {
        ensureOpen();
        if (off < 0 || len < 0 || off > b.length - len) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return;
        }

        if (this.entry == null) {
            throw new IOException("No current CPIO entry");
        }
        if (this.written + len > this.entry.getSize()) {
            throw new IOException("Attempt to write past end of STORED entry");
        }
        out.write(b, off, len);
        this.written += len;
        if (this.entry.getFormat() == FORMAT_NEW_CRC) {
            for (int pos = 0; pos < len; pos++) {
                this.crc += b[pos] & 0xFF;
                this.crc &= 0xFFFFFFFFL;
            }
        }
        count(len);
    }

    
Finishes writing the contents of the CPIO output stream without closing
the underlying stream. Use this method when applying multiple filters in
succession to the same output stream.
Throws:
IOException – 
            if an I/O exception has occurred or if a CPIO file error has
            occurred/**
     * Finishes writing the contents of the CPIO output stream without closing
     * the underlying stream. Use this method when applying multiple filters in
     * succession to the same output stream.
     *
     * @throws IOException
     *             if an I/O exception has occurred or if a CPIO file error has
     *             occurred
     */
    @Override
    public void finish() throws IOException {
        ensureOpen();
        if (finished) {
            throw new IOException("This archive has already been finished");
        }

        if (this.entry != null) {
            throw new IOException("This archive contains unclosed entries.");
        }
        this.entry = new CpioArchiveEntry(this.entryFormat);
        this.entry.setName(CPIO_TRAILER);
        this.entry.setNumberOfLinks(1);
        writeHeader(this.entry);
        closeArchiveEntry();

        final int lengthOfLastBlock = (int) (getBytesWritten() % blockSize);
        if (lengthOfLastBlock != 0) {
            pad(blockSize - lengthOfLastBlock);
        }

        finished = true;
    }

    
Closes the CPIO output stream as well as the stream being filtered.
Throws:
IOException – 
            if an I/O error has occurred or if a CPIO file error has
            occurred/**
     * Closes the CPIO output stream as well as the stream being filtered.
     *
     * @throws IOException
     *             if an I/O error has occurred or if a CPIO file error has
     *             occurred
     */
    @Override
    public void close() throws IOException {
        try {
            if (!finished) {
                finish();
            }
        } finally {
            if (!this.closed) {
                out.close();
                this.closed = true;
            }
        }
    }

    private void pad(final int count) throws IOException{
        if (count > 0){
            final byte buff[] = new byte[count];
            out.write(buff);
            count(count);
        }
    }

    private void writeBinaryLong(final long number, final int length,
            final boolean swapHalfWord) throws IOException {
        final byte tmp[] = CpioUtil.long2byteArray(number, length, swapHalfWord);
        out.write(tmp);
        count(tmp.length);
    }

    private void writeAsciiLong(final long number, final int length,
            final int radix) throws IOException {
        final StringBuilder tmp = new StringBuilder();
        String tmpStr;
        if (radix == 16) {
            tmp.append(Long.toHexString(number));
        } else if (radix == 8) {
            tmp.append(Long.toOctalString(number));
        } else {
            tmp.append(Long.toString(number));
        }

        if (tmp.length() <= length) {
            final int insertLength = length - tmp.length();
            for (int pos = 0; pos < insertLength; pos++) {
                tmp.insert(0, "0");
            }
            tmpStr = tmp.toString();
        } else {
            tmpStr = tmp.substring(tmp.length() - length);
        }
        final byte[] b = ArchiveUtils.toAsciiBytes(tmpStr);
        out.write(b);
        count(b.length);
    }

    
Encodes the given string using the configured encoding.
Params:
str – the String to write
Throws:
IOException – if the string couldn't be written
Returns:
result of encoding the string/**
     * Encodes the given string using the configured encoding.
     *
     * @param str the String to write
     * @throws IOException if the string couldn't be written
     * @return result of encoding the string
     */
    private byte[] encode(final String str) throws IOException {
        final ByteBuffer buf = zipEncoding.encode(str);
        final int len = buf.limit() - buf.position();
        return Arrays.copyOfRange(buf.array(), buf.arrayOffset(), buf.arrayOffset() + len);
    }

    
Writes an encoded string to the stream followed by \0
Params:
str – the String to write
Throws:
IOException – if the string couldn't be written/**
     * Writes an encoded string to the stream followed by \0
     * @param str the String to write
     * @throws IOException if the string couldn't be written
     */
    private void writeCString(byte[] str) throws IOException {
        out.write(str);
        out.write('\0');
        count(str.length + 1);
    }

    
Creates a new ArchiveEntry. The entryName must be an ASCII encoded string.
See Also:
createArchiveEntry.createArchiveEntry(File, String)/**
     * Creates a new ArchiveEntry. The entryName must be an ASCII encoded string.
     *
     * @see org.apache.commons.compress.archivers.ArchiveOutputStream#createArchiveEntry(java.io.File, java.lang.String)
     */
    @Override
    public ArchiveEntry createArchiveEntry(final File inputFile, final String entryName)
            throws IOException {
        if(finished) {
            throw new IOException("Stream has already been finished");
        }
        return new CpioArchiveEntry(inputFile, entryName);
    }

}