/*
    * 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.EOFException;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.commons.compress.archivers.ArchiveInputStream;
  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.IOUtils;
  import org.apache.commons.compress.utils.ParsingUtils;
  
  /**
   * CpioArchiveInputStream is a stream for reading cpio streams. All formats of cpio are supported (old ascii, old binary, new portable format and the new
   * portable format with crc).
   * <p>
   * The stream can be read by extracting a cpio entry (containing all information about an entry) and afterwards reading from the stream the file specified by
   * the entry.
   * </p>
   * <pre>
   * CpioArchiveInputStream cpioIn = new CpioArchiveInputStream(Files.newInputStream(Paths.get(&quot;test.cpio&quot;)));
   * CpioArchiveEntry cpioEntry;
   *
   * while ((cpioEntry = cpioIn.getNextEntry()) != null) {
   *     System.out.println(cpioEntry.getName());
   *     int tmp;
   *     StringBuilder buf = new StringBuilder();
   *     while ((tmp = cpIn.read()) != -1) {
   *         buf.append((char) tmp);
   *     }
   *     System.out.println(buf.toString());
   * }
   * cpioIn.close();
   * </pre>
   * <p>
   * Note: This implementation should be compatible to cpio 2.5
   * </p>
   * <p>
   * This class uses mutable fields and is not considered to be threadsafe.
   * </p>
   * <p>
   * Based on code from the jRPM project (jrpm.sourceforge.net)
   * </p>
   */
  public class CpioArchiveInputStream extends ArchiveInputStream<CpioArchiveEntry> implements CpioConstants {
  
      /**
       * Checks if the signature matches one of the following magic values:
       *
       * Strings:
       *
       * "070701" - MAGIC_NEW "070702" - MAGIC_NEW_CRC "070707" - MAGIC_OLD_ASCII
       *
       * Octal Binary value:
       *
       * 070707 - MAGIC_OLD_BINARY (held as a short) = 0x71C7 or 0xC771
       *
       * @param signature data to match
       * @param length    length of data
       * @return whether the buffer seems to contain CPIO data
       */
      public static boolean matches(final byte[] signature, final int length) {
          if (length < 6) {
              return false;
          }
  
          // Check binary values
          if (signature[0] == 0x71 && (signature[1] & 0xFF) == 0xc7) {
              return true;
          }
          if (signature[1] == 0x71 && (signature[0] & 0xFF) == 0xc7) {
              return true;
          }
  
          // Check Ascii (String) values
          // 3037 3037 30nn
          if (signature[0] != 0x30) {
              return false;
          }
          if (signature[1] != 0x37) {
             return false;
         }
         if (signature[2] != 0x30) {
             return false;
         }
         if (signature[3] != 0x37) {
             return false;
         }
         if (signature[4] != 0x30) {
             return false;
         }
         // Check last byte
         if (signature[5] == 0x31) {
             return true;
         }
         if (signature[5] == 0x32) {
             return true;
         }
         if (signature[5] == 0x37) {
             return true;
         }
 
         return false;
     }
 
     private boolean closed;
 
     private CpioArchiveEntry entry;
 
     private long entryBytesRead;
 
     private boolean entryEOF;
 
     private final byte[] tmpbuf = new byte[4096];
 
     private long crc;
 
     /** Cached buffer - must only be used locally in the class (COMPRESS-172 - reduce garbage collection). */
     private final byte[] twoBytesBuf = new byte[2];
 
     /** Cached buffer - must only be used locally in the class (COMPRESS-172 - reduce garbage collection). */
     private final byte[] fourBytesBuf = new byte[4];
 
     private final byte[] sixBytesBuf = new byte[6];
 
     private final int blockSize;
 
     /**
      * The encoding to use for file names and labels.
      */
     private final ZipEncoding zipEncoding;
 
     /**
      * Constructs the cpio input stream with a blocksize of {@link CpioConstants#BLOCK_SIZE BLOCK_SIZE} and expecting ASCII file names.
      *
      * @param in The cpio stream
      */
     public CpioArchiveInputStream(final InputStream in) {
         this(in, BLOCK_SIZE, CpioUtil.DEFAULT_CHARSET_NAME);
     }
 
     /**
      * Constructs the cpio input stream with a blocksize of {@link CpioConstants#BLOCK_SIZE BLOCK_SIZE} expecting ASCII file names.
      *
      * @param in        The cpio stream
      * @param blockSize The block size of the archive.
      * @since 1.5
      */
     public CpioArchiveInputStream(final InputStream in, final int blockSize) {
         this(in, blockSize, CpioUtil.DEFAULT_CHARSET_NAME);
     }
 
     /**
      * Constructs the cpio input stream with a blocksize of {@link CpioConstants#BLOCK_SIZE BLOCK_SIZE}.
      *
      * @param in        The cpio stream
      * @param blockSize The block size of the archive.
      * @param encoding  The encoding of file names to expect - use null for the platform's default.
      * @throws IllegalArgumentException if {@code blockSize} is not bigger than 0
      * @since 1.6
      */
     public CpioArchiveInputStream(final InputStream in, final int blockSize, final String encoding) {
         super(in, encoding);
         this.in = in;
         if (blockSize <= 0) {
             throw new IllegalArgumentException("blockSize must be bigger than 0");
         }
         this.blockSize = blockSize;
         this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
     }
 
     /**
      * Constructs the cpio input stream with a blocksize of {@link CpioConstants#BLOCK_SIZE BLOCK_SIZE}.
      *
      * @param in       The cpio stream
      * @param encoding The encoding of file names to expect - use null for the platform's default.
      * @since 1.6
      */
     public CpioArchiveInputStream(final InputStream in, final String encoding) {
         this(in, BLOCK_SIZE, encoding);
     }
 
     /**
      * Returns 0 after EOF has reached for the current entry data, otherwise always return 1.
      * <p>
      * Programs should not count on this method to return the actual number of bytes that could be read without blocking.
      * </p>
      *
      * @return 1 before EOF and 0 after EOF has reached for current entry.
      * @throws IOException if an I/O error has occurred or if a CPIO file error has occurred
      */
     @Override
     public int available() throws IOException {
         ensureOpen();
         if (this.entryEOF) {
             return 0;
         }
         return 1;
     }
 
     /**
      * Closes the CPIO input stream.
      *
      * @throws IOException if an I/O error has occurred
      */
     @Override
     public void close() throws IOException {
         if (!this.closed) {
             in.close();
             this.closed = true;
         }
     }
 
     /**
      * Closes the current CPIO entry and positions the stream for reading the next entry.
      *
      * @throws IOException if an I/O error has occurred or if a CPIO file error has occurred
      */
     private void closeEntry() throws IOException {
         // the skip implementation of this class will not skip more
         // than Integer.MAX_VALUE bytes
         while (skip((long) Integer.MAX_VALUE) == Integer.MAX_VALUE) { // NOPMD NOSONAR
             // do nothing
         }
     }
 
     /**
      * 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");
         }
     }
 
     /**
      * Reads the next CPIO file entry and positions stream at the beginning of the entry data.
      *
      * @return the CpioArchiveEntry just read
      * @throws IOException if an I/O error has occurred or if a CPIO file error has occurred
      * @deprecated Use {@link #getNextEntry()}.
      */
     @Deprecated
     public CpioArchiveEntry getNextCPIOEntry() throws IOException {
         ensureOpen();
         if (this.entry != null) {
             closeEntry();
         }
         readFully(twoBytesBuf, 0, twoBytesBuf.length);
         if (CpioUtil.byteArray2long(twoBytesBuf, false) == MAGIC_OLD_BINARY) {
             this.entry = readOldBinaryEntry(false);
         } else if (CpioUtil.byteArray2long(twoBytesBuf, true) == MAGIC_OLD_BINARY) {
             this.entry = readOldBinaryEntry(true);
         } else {
             System.arraycopy(twoBytesBuf, 0, sixBytesBuf, 0, twoBytesBuf.length);
             readFully(sixBytesBuf, twoBytesBuf.length, fourBytesBuf.length);
             final String magicString = ArchiveUtils.toAsciiString(sixBytesBuf);
             switch (magicString) {
             case MAGIC_NEW:
                 this.entry = readNewEntry(false);
                 break;
             case MAGIC_NEW_CRC:
                 this.entry = readNewEntry(true);
                 break;
             case MAGIC_OLD_ASCII:
                 this.entry = readOldAsciiEntry();
                 break;
             default:
                 throw new IOException("Unknown magic [" + magicString + "]. Occurred at byte: " + getBytesRead());
             }
         }
 
         this.entryBytesRead = 0;
         this.entryEOF = false;
         this.crc = 0;
 
         if (this.entry.getName().equals(CPIO_TRAILER)) {
             this.entryEOF = true;
             skipRemainderOfLastBlock();
             return null;
         }
         return this.entry;
     }
 
     @Override
     public CpioArchiveEntry getNextEntry() throws IOException {
         return getNextCPIOEntry();
     }
 
     /**
      * Reads from the current CPIO 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
      * @throws IOException if an I/O error has occurred or if a CPIO file error has occurred
      */
     @Override
     public int read(final byte[] b, final int off, final int len) throws IOException {
         ensureOpen();
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new IndexOutOfBoundsException();
         }
         if (len == 0) {
             return 0;
         }
 
         if (this.entry == null || this.entryEOF) {
             return -1;
         }
         if (this.entryBytesRead == this.entry.getSize()) {
             skip(entry.getDataPadCount());
             this.entryEOF = true;
             if (this.entry.getFormat() == FORMAT_NEW_CRC && this.crc != this.entry.getChksum()) {
                 throw new IOException("CRC Error. Occurred at byte: " + getBytesRead());
             }
             return -1; // EOF for this entry
         }
         final int tmplength = (int) Math.min(len, this.entry.getSize() - this.entryBytesRead);
         if (tmplength < 0) {
             return -1;
         }
 
         final int tmpread = readFully(b, off, tmplength);
         if (this.entry.getFormat() == FORMAT_NEW_CRC) {
             for (int pos = 0; pos < tmpread; pos++) {
                 this.crc += b[pos] & 0xFF;
                 this.crc &= 0xFFFFFFFFL;
             }
         }
         if (tmpread > 0) {
             this.entryBytesRead += tmpread;
         }
 
         return tmpread;
     }
 
     private long readAsciiLong(final int length, final int radix) throws IOException {
         final byte[] tmpBuffer = readRange(length);
         return ParsingUtils.parseLongValue(ArchiveUtils.toAsciiString(tmpBuffer), radix);
     }
 
     private long readBinaryLong(final int length, final boolean swapHalfWord) throws IOException {
         final byte[] tmp = readRange(length);
         return CpioUtil.byteArray2long(tmp, swapHalfWord);
     }
 
     private String readCString(final int length) throws IOException {
         // don't include trailing NUL in file name to decode
         final byte[] tmpBuffer = readRange(length - 1);
         if (this.in.read() == -1) {
             throw new EOFException();
         }
         return zipEncoding.decode(tmpBuffer);
     }
 
     private int readFully(final byte[] b, final int off, final int len) throws IOException {
         final int count = IOUtils.readFully(in, b, off, len);
         count(count);
         if (count < len) {
             throw new EOFException();
         }
         return count;
     }
 
     private CpioArchiveEntry readNewEntry(final boolean hasCrc) throws IOException {
         final CpioArchiveEntry ret;
         if (hasCrc) {
             ret = new CpioArchiveEntry(FORMAT_NEW_CRC);
         } else {
             ret = new CpioArchiveEntry(FORMAT_NEW);
         }
 
         ret.setInode(readAsciiLong(8, 16));
         final long mode = readAsciiLong(8, 16);
         if (CpioUtil.fileType(mode) != 0) { // mode is initialized to 0
             ret.setMode(mode);
         }
         ret.setUID(readAsciiLong(8, 16));
         ret.setGID(readAsciiLong(8, 16));
         ret.setNumberOfLinks(readAsciiLong(8, 16));
         ret.setTime(readAsciiLong(8, 16));
         ret.setSize(readAsciiLong(8, 16));
         if (ret.getSize() < 0) {
             throw new IOException("Found illegal entry with negative length");
         }
         ret.setDeviceMaj(readAsciiLong(8, 16));
         ret.setDeviceMin(readAsciiLong(8, 16));
         ret.setRemoteDeviceMaj(readAsciiLong(8, 16));
         ret.setRemoteDeviceMin(readAsciiLong(8, 16));
         final long namesize = readAsciiLong(8, 16);
         if (namesize < 0) {
             throw new IOException("Found illegal entry with negative name length");
         }
         ret.setChksum(readAsciiLong(8, 16));
         final String name = readCString((int) namesize);
         ret.setName(name);
         if (CpioUtil.fileType(mode) == 0 && !name.equals(CPIO_TRAILER)) {
             throw new IOException(
                     "Mode 0 only allowed in the trailer. Found entry name: " + ArchiveUtils.sanitize(name) + " Occurred at byte: " + getBytesRead());
         }
         skip(ret.getHeaderPadCount(namesize - 1));
 
         return ret;
     }
 
     private CpioArchiveEntry readOldAsciiEntry() throws IOException {
         final CpioArchiveEntry ret = new CpioArchiveEntry(FORMAT_OLD_ASCII);
 
         ret.setDevice(readAsciiLong(6, 8));
         ret.setInode(readAsciiLong(6, 8));
         final long mode = readAsciiLong(6, 8);
         if (CpioUtil.fileType(mode) != 0) {
             ret.setMode(mode);
         }
         ret.setUID(readAsciiLong(6, 8));
         ret.setGID(readAsciiLong(6, 8));
         ret.setNumberOfLinks(readAsciiLong(6, 8));
         ret.setRemoteDevice(readAsciiLong(6, 8));
         ret.setTime(readAsciiLong(11, 8));
         final long namesize = readAsciiLong(6, 8);
         if (namesize < 0) {
             throw new IOException("Found illegal entry with negative name length");
         }
         ret.setSize(readAsciiLong(11, 8));
         if (ret.getSize() < 0) {
             throw new IOException("Found illegal entry with negative length");
         }
         final String name = readCString((int) namesize);
         ret.setName(name);
         if (CpioUtil.fileType(mode) == 0 && !name.equals(CPIO_TRAILER)) {
             throw new IOException("Mode 0 only allowed in the trailer. Found entry: " + ArchiveUtils.sanitize(name) + " Occurred at byte: " + getBytesRead());
         }
 
         return ret;
     }
 
     private CpioArchiveEntry readOldBinaryEntry(final boolean swapHalfWord) throws IOException {
         final CpioArchiveEntry ret = new CpioArchiveEntry(FORMAT_OLD_BINARY);
 
         ret.setDevice(readBinaryLong(2, swapHalfWord));
         ret.setInode(readBinaryLong(2, swapHalfWord));
         final long mode = readBinaryLong(2, swapHalfWord);
         if (CpioUtil.fileType(mode) != 0) {
             ret.setMode(mode);
         }
         ret.setUID(readBinaryLong(2, swapHalfWord));
         ret.setGID(readBinaryLong(2, swapHalfWord));
         ret.setNumberOfLinks(readBinaryLong(2, swapHalfWord));
         ret.setRemoteDevice(readBinaryLong(2, swapHalfWord));
         ret.setTime(readBinaryLong(4, swapHalfWord));
         final long namesize = readBinaryLong(2, swapHalfWord);
         if (namesize < 0) {
             throw new IOException("Found illegal entry with negative name length");
         }
         ret.setSize(readBinaryLong(4, swapHalfWord));
         if (ret.getSize() < 0) {
             throw new IOException("Found illegal entry with negative length");
         }
         final String name = readCString((int) namesize);
         ret.setName(name);
         if (CpioUtil.fileType(mode) == 0 && !name.equals(CPIO_TRAILER)) {
             throw new IOException("Mode 0 only allowed in the trailer. Found entry: " + ArchiveUtils.sanitize(name) + "Occurred at byte: " + getBytesRead());
         }
         skip(ret.getHeaderPadCount(namesize - 1));
 
         return ret;
     }
 
     private byte[] readRange(final int len) throws IOException {
         final byte[] b = IOUtils.readRange(in, len);
         count(b.length);
         if (b.length < len) {
             throw new EOFException();
         }
         return b;
     }
 
     private void skip(final int bytes) throws IOException {
         // bytes cannot be more than 3 bytes
         if (bytes > 0) {
             readFully(fourBytesBuf, 0, bytes);
         }
     }
 
     /**
      * Skips specified number of bytes in the current CPIO entry.
      *
      * @param n the number of bytes to skip
      * @return the actual number of bytes skipped
      * @throws IOException              if an I/O error has occurred
      * @throws IllegalArgumentException if n &lt; 0
      */
     @Override
     public long skip(final long n) throws IOException {
         if (n < 0) {
             throw new IllegalArgumentException("Negative skip length");
         }
         ensureOpen();
         final int max = (int) Math.min(n, Integer.MAX_VALUE);
         int total = 0;
 
         while (total < max) {
             int len = max - total;
             if (len > this.tmpbuf.length) {
                 len = this.tmpbuf.length;
             }
             len = read(this.tmpbuf, 0, len);
             if (len == -1) {
                 this.entryEOF = true;
                 break;
             }
             total += len;
         }
         return total;
     }
 
     /**
      * Skips the padding zeros written after the TRAILER!!! entry.
      */
     private void skipRemainderOfLastBlock() throws IOException {
         final long readFromLastBlock = getBytesRead() % blockSize;
         long remainingBytes = readFromLastBlock == 0 ? 0 : blockSize - readFromLastBlock;
         while (remainingBytes > 0) {
             final long skipped = skip(blockSize - readFromLastBlock);
             if (skipped <= 0) {
                 break;
             }
             remainingBytes -= skipped;
         }
     }
 }